# Commonway System, full text

Every page of the Commonway System guidebook as markdown, concatenated. Index and per-page files: https://commonwaysystem.org/llms.txt

---

Source: https://commonwaysystem.org/

# Commonway System

One system, grounded in what's proven.

A pattern language for roads and streets, built on Vision Zero and Dutch Sustainable Safety evidence, layered on NACTO's foundation.

[Start with the Guide](https://commonwaysystem.org/guide.md) [Browse Patterns](https://commonwaysystem.org/patterns.md)

Why this guide is different

Every prescriptive claim in this guidebook traces to a cited source, and every source carries an evidence tier, so you can see how strong the backing is before you decide whether to trust it. [Learn how evidence tiers work](https://commonwaysystem.org/about/governance.md#how-disputes-over-evidence-are-resolved).

-   Legal / regulatory Legal / regulatory
-   Evidence-based Evidence-based
-   Precedent-based Precedent-based

-   ## [Guide](https://commonwaysystem.org/guide.md)
    
    Start here. How the system is put together, how patterns are classified, and how to read one.
    
-   ## [Patterns](https://commonwaysystem.org/patterns.md)
    
    Every Street Typology in the system, organized from Local to Freeway.
    
-   ## [Reference](https://commonwaysystem.org/references.md)
    
    The technical layer beneath each pattern: dimensions, criteria, specifications.
    
-   ## [Blog](https://commonwaysystem.org/blog.md)
    
    Process notes and research as the guidebook grows.
    
-   ## [About](https://commonwaysystem.org/about.md)
    
    What this is, who maintains it, how decisions get made.
    
-   ## [What's New](https://commonwaysystem.org/about/release-history.md)
    
    See what's changed recently, and what's coming next.

---

Source: https://commonwaysystem.org/about/

# About

The Commonway System (CS) is a pattern language for roads and streets. This section covers the project itself: what it is, how it is branded and written, how to get involved, and how it is governed.

## In this section

**[Site Map](https://commonwaysystem.org/about/sitemap.md)** Every page of the publication in one list, grouped like the navigation, plus other ways to browse.

**[The Commonway System](https://commonwaysystem.org/about/commonway-system.md)** What CS is, who compiled it, and how it relates to NACTO, Complete Streets, Strong Towns, and the primary research it cites.

**[Brand Guide](https://commonwaysystem.org/about/brand-guide.md)** The full visual and editorial system: colors, typography, voice, illustration rules, citation format, and the Commonway logo.

**[Release History & Roadmap](https://commonwaysystem.org/about/release-history.md)** How CalVer versioning works, the current version, the changelog, and what's planned but not yet built.

**[Submit a Change](https://commonwaysystem.org/about/contributing.md)** How to propose a pattern, suggest a correction, or otherwise help build out the guidebook.

**[Project Governance](https://commonwaysystem.org/about/governance.md)** How decisions about the system get made and who makes them.

**[Report a Problem](https://commonwaysystem.org/about/reporting.md)** How to flag an error, an unsourced claim, or a dead citation link.

**[Acknowledgments](https://commonwaysystem.org/about/acknowledgments.md)** Everyone who has helped correct, source, or build the Commonway System.

**[Terms and Conditions](https://commonwaysystem.org/about/terms-and-conditions.md)** The terms governing use of the Commonway System publication and guidebook.

**[Privacy Policy](https://commonwaysystem.org/about/privacy-policy.md)** What data Commonway System collects, why, and how it's used.

**[AI Policy](https://commonwaysystem.org/about/ai-policy.md)** How AI was used in building Commonway System, and how human oversight stays in the loop.

**[Accessibility Policy](https://commonwaysystem.org/about/accessibility-policy.md)** Where accessibility stands today, the standard we're working toward, known limitations, and how to report a barrier.

---

Source: https://commonwaysystem.org/about/accessibility-policy/

# Accessibility Policy

**Effective date:** September 26, 2026

Commonway System wants everyone, including people with disabilities, to be able to read and use this publication. This page describes where accessibility efforts stand today, honestly, rather than claiming a finished result.

## Standard we're working toward

We aim to conform to the Web Content Accessibility Guidelines (WCAG) 2.2 at Level AA, the current internationally recognized standard for web accessibility. This publication has not undergone an independent accessibility audit, and we don't claim full conformance. Where we know of a specific gap, it's documented below.

## Known limitations

Accessibility has not been comprehensively tested against every WCAG 2.2 success criterion, and gaps likely exist beyond those listed here. What follows is what an automated audit found, plus a few things that audit can't check.

### How this was audited

On September 26, 2026, every page of the publication (165 pages) was scanned with axe-core 4.10.2, an automated accessibility checker, against the WCAG 2.0, 2.1, and 2.2 Level A and AA rules plus axe's own best-practice rules. Each page was scanned three ways: desktop width in dark mode, desktop width in light mode, and a 375px phone width in light mode. Automated scanning typically catches only a portion of real accessibility problems, so a clean result on any item below does not mean it is fully accessible. Every issue the audit found was fixed the same day: a missing main landmark, two unlabeled side landmarks, a skipped heading level before the Pattern ID and Retrofit Strategy cards, two light-mode text colors below the contrast minimum, small tap targets on citation badges, empty table header cells, and stray images without alt text in the Release History.

### Result of the automated audit

No open items from the automated audit remain. Each of the issues it found was fixed, which does not mean the publication is fully accessible. The audit also prompted two additions: a "Skip to main content" link on every page, and a pause button on the homepage's animated background (the choice is remembered, and the button is hidden for anyone whose device is set to reduce motion). See the sections below for what has been checked by hand and what has not.

### Flagged by the audit for manual review, then checked by hand

Axe couldn't compute a verdict for a few contrast checks and asked for a human decision. Each was checked directly, and none is a failure:

-   **Numbered citation badges** (129 pages): axe said the text was too short to evaluate. Measured directly, the badge text (`#002d27`) on its fill (`#00a896`) is 5.01:1,, above the 4.5:1 minimum, and it is the same in light and dark mode because both colors are fixed.
-   **Sidebar links** (about 100 pages): axe said an element partly covered the link, so it couldn't find the background. In the rendered page nothing sits over the links. The link text measures 8.5:1 in light mode and 10.6:1 in dark mode, and the current-page link measures 6.7:1 in light and 8.2:1 in dark. Axe raised the flag because the sidebar is a sticky panel that is partly out of view during the scan.
-   **Speed-limit sign graphics** (`SpeedLimitSign.svelte`): axe couldn't read the background behind text drawn inside an SVG. The sign's text is fixed black (`#000`) on a fixed white face (`#fff`), 21:1,, in both themes, since a real regulatory sign is black on white regardless of the site's theme.

Axe will keep listing these as "needs review" on future scans, because it can't evaluate them on its own.

### Not covered by the automated audit

-   **Not yet tested:** full keyboard-only walkthroughs, screen reader testing (NVDA, VoiceOver, JAWS), 200% and 400% zoom, Windows forced-colors mode, and touch-screen use beyond the phone-width scan above.

## Display settings

The "Aa" button in the header (and "Display settings" in the mobile menu) opens a panel with these options. Choices are saved in your browser only. With no saved choice, the site follows your device's own "more contrast" setting.

-   **Reading font:** replaces the publication's fonts with Lexend, Atkinson Hyperlegible Next, or OpenDyslexic. All three are served from this publication's own files, never from an outside font service. Research has not shown that any dyslexia-specific font makes reading faster for everyone; some readers simply find one easier, so the choice is yours.
-   **Color symbols:** a small symbol tab on colored cards, using the free ColorSym system, for readers who cannot tell the colors apart. Text labels already carry the same information; the symbols are an extra. The key is on the [Brand Guide](https://commonwaysystem.org/about/brand-guide.md#color-symbols).
-   **Text size:** four steps up to 150%, scaled from your browser's own text size. Your browser's zoom and your operating system's text settings still work on top of it.
-   **High contrast:** pure black and white, solid borders, underlined links, and a text label for every classification color (Local street, Arterial street, and so on) so color is never the only signal.
-   **Reading ruler:** shades the page except for a clear window of one to three lines that follows your mouse, a finger, or keyboard focus (Alt plus the up or down arrow key also moves it). You choose the window height and how dark the shading is. Text in the shaded area is deliberately dimmer, so choose Light if you need more contrast there. It turns off the pointer highlight, does nothing in forced-colors mode or in print, and is not available on the text-only pages.
-   **Simplified view:** one column in a plain system font, with hero art, card illustrations, and animation removed, and every collapsed section expanded.
-   **Enhanced focus outline:** a thicker two-color outline around whatever has keyboard focus, visible on light and dark backgrounds.
-   **Large pointer:** a larger mouse arrow over the page. Your operating system's pointer-size setting works everywhere, including outside the page, and is the better option if you can use it.
-   **Pointer highlight:** a translucent yellow circle that follows the mouse pointer.

## Text-only pages

Every page has a text-only version, linked as "Text-only version" beneath the page and from the Display settings panel. These are plain, unstyled pages with no images, scripts, or animation, built from the same content as the full page and linked to each other. An index of all of them is at [All text pages](https://commonwaysystem.org/text/all-pages/). Text-only pages ask search engines not to index them and point back to the full page as the canonical version.

## Search

The Search button in the header (in the mobile menu at phone width) opens a search dialog, and Ctrl+K (Cmd+K on a Mac) opens it from anywhere. The dialog is a native modal: focus moves into it, the page behind it is inert, Escape closes it, and focus returns to where you were. Results are ordinary links, and the arrow keys move between them (Tab works too). The number of results is announced as you type. The same search is available as a full page at [Search](https://commonwaysystem.org/search/), which is also where "See all results" leads. If you would rather browse than search, the [Site Map](https://commonwaysystem.org/about/sitemap.md) lists every page, grouped like the navigation, without needing JavaScript. There is deliberately no single-key shortcut such as "/", because single-key shortcuts need a way to be turned off or remapped. Search needs JavaScript; without it, the [text-only page index](https://commonwaysystem.org/text/all-pages/) and the Pattern Index are the way to browse. It has been checked with automated tools only, not yet with a screen reader.

## What we're planning

Further accessibility work will be added here as testing turns up issues. This page will be updated to reflect the current state rather than the intended one.

## External and third-party content

The guidebook links extensively to external sources: government manuals, published studies, agency sites. We don't control the accessibility of those external pages. Some embedded media (video, for example) may not have captions or transcripts if the source platform doesn't provide them.

## Feedback

If you run into an accessibility barrier anywhere on this publication, we want to know. Contact us at [info@commonwaysystem.org](mailto:info@commonwaysystem.org), and describe the page and the problem you ran into. We'll do our best to respond and address it, though as a small, independently maintained project, response times will vary.

## Changes to this policy

This page is updated as accessibility work on the publication progresses. Updates are reflected in the publication's version history; see [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md).

## Contact

Questions about this policy can be directed to [info@commonwaysystem.org](mailto:info@commonwaysystem.org).

---

Source: https://commonwaysystem.org/about/acknowledgments/

# Acknowledgments

Commonway System is compiled and maintained by [Kevin Young](https://commonwaysystem.org/about/commonway-system.md#about-the-author). Everyone listed below has helped make it more accurate, more complete, or better built, through a correction, a citation, a new pattern proposal, or a contribution to the publication itself. See [Submit a Change](https://commonwaysystem.org/about/contributing.md) for how to be added to this list.

_No contributions yet. [Be the first.](https://commonwaysystem.org/about/contributing.md)_

---

Source: https://commonwaysystem.org/about/ai-policy/

# AI Policy

**Effective date:** August 29, 2026

Commonway System uses AI tools throughout its research, drafting, and development, and this page says so plainly rather than leaving it unstated. AI does not have final say over anything published here. Every classification, citation, and design decision is reviewed and decided by a human before it goes live.

## What AI was used for

Claude, built by Anthropic, has been closely involved throughout this project: researching source material, drafting pattern content, structuring the classification system, building the brand guide, and assisting with the publication's own code through Claude Code. Commonway System would look very different, and would have taken far longer to build, without it. We think that's worth crediting openly rather than treating as incidental.

## Human oversight

AI drafts, researches, and suggests. It doesn't decide. Every pattern's classification, every citation, every structural decision in the guidebook is reviewed against the same evidence-tier system described on the [Project Governance](https://commonwaysystem.org/about/governance.md) page, legal or regulatory sources first, then evidence-based research, then documented precedent, before it's published. An AI-drafted paragraph doesn't get special trust for being AI-drafted; it gets checked the same as anything else.

## Why this matters for a citation-based project

AI systems can misstate a source, misread a number, or state something with more confidence than the underlying evidence actually supports. That's exactly the failure mode the guidebook's citation and evidence-tier system already exists to catch, whether the original error came from an AI, a contributor, or the maintainer's own mistake. The unsourced-claim flag⚠ applies the same way regardless of who or what drafted the claim it's attached to.

## What AI does not do here

There's no AI chatbot, voice agent, or automated assistant on this publication talking to visitors. AI isn't used to auto-generate a pattern's classification or citation without a human checking it against a real source first. Nothing on this publication is AI-generated content published without review.

## Limitations

AI-assisted drafting can contain errors, outdated information, or misattributed sources, the same as human drafting can. This is exactly why nothing on this publication is treated as authoritative on the strength of who or what wrote it; see the [Terms and Conditions](https://commonwaysystem.org/about/terms-and-conditions.md) page for the publication's broader disclaimer on accuracy and reliance.

## Changes to this policy

This page may be updated as the tools and processes behind Commonway System change. Updates are reflected in the publication's version history; see [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md).

## Contact

Questions about this policy can be directed to [info@commonwaysystem.org](mailto:info@commonwaysystem.org).

---

Source: https://commonwaysystem.org/about/brand-guide/

# Brand Guide

The visual and editorial system behind the Commonway System (CS): how it looks, how it's written, and how its evidence is presented. This page transcribes the working brand reference; treat the color values and rules below as the source of truth over anything in the publication's theme.

## Voice attributes

| CS voice is... | CS voice is not... |
| --- | --- |
| Encyclopedic | Conversational or chatty |
| Evidence-led (claims trace to citations) | Opinion-led or persuasive |
| Layered (plain language first, technical depth beneath) | Dumbed-down, or gatekept behind jargon |
| Precise (specific numbers, named sources) | Vague or hand-wavy |
| Confident through sourcing | Confident through authority or credential-claiming |
| Neutral and descriptive | Salesy, urgent, or marketing-toned |
| Inclusive of total beginners | Exclusionary of experts who already know the material |

### The disagreement-phrasing pattern

Every place CS takes a position against, or beyond, conventional practice uses the same underlying shape: name the origin (an intentional baseline practice, or an emergent structural pattern), then close with a classification backed by specific evidence. A baseline source is never called "wrong," "outdated," or "flawed."

-   **Opening A** (intentional practice): "\[Baseline source\] recommends/practices \[X\]."
-   **Opening B** (emergent/structural): "\[Pattern\] emerges when \[structural cause\]."
-   **Closer, always:** "CS classifies this as \[Default / Situational-Discouraged / Avoid\], informed by \[specific evidence source and finding\]."

Correct

NACTO's guidance allows Local street design speeds up to 25 mph in many contexts. CS sets a 20 mph hard maximum with no exceptions, informed by Dutch Sustainable Safety research linking pedestrian survival rates to impact speed.

## Editorial standards

Sentence-level production rules, distinct from the voice attributes above.

-   **Word-lite principle.** Say as little as possible while conveying as much meaning and nuance as possible. Every sentence gets tested for whether it can be shorter without losing precision.
-   **Layered sentence complexity.** Plain-language passages use short, direct sentences with common words. Technical-layer passages, sitting just beneath, can carry longer sentences with precise technical terms and multiple citation badges. The two layers never mix mid-paragraph.

Caution

No em-dashes, ever, anywhere in CS content. This is a standing, non-negotiable rule. Use a comma for a brief interruption, a period to split into two sentences, a semicolon to connect related independent clauses, parentheses for a true aside, or a colon to introduce an explanation or list.

-   **Plain-language-first terminology.** The first time a technical term appears in a plain-language passage, it's introduced in accessible language before the formal term is used, not the reverse.

## Color system

### Base tokens

Ink #141414

Paper #FDFAF3

Commonway teal #00A896

Deep indigo #3D3AAB

Amber (reserved) #FF9F1C

Caution

Amber is reserved exclusively for the unsourced-claim flag and pattern-illustration highlighting. It never appears anywhere else in the system.

### Evidence tiers (one hue, three depths)

Represents a strength gradient, not unrelated categories. Legal requirement is the strongest backing, precedent the weakest, so tiers separate by lightness and remain readable to red-green color blindness.

Legal / regulatory #005F52

Evidence-based #00A896

Precedent-based #7FDCCF

**As rendered chips:**

Legal / regulatory Evidence-based Precedent-based

### Density tiers

The Commonway System design encodes density _within_ each Scale Hierarchy and Functional Classification's own 6-step ramp, not as a separate overlay. `DensityChip` deviates from that on purpose: pattern pages need to show "typical at" density tiers independent of any one classification (a card in the Pattern Index has no classification color context of its own until the page around it supplies one), so it uses its own independent neutral-tan ramp instead, lightest at Undeveloped and darkest at Core, deliberately distinct from both the amber accent and every classification color so it never gets confused with either system.

Undeveloped #EFE9DD

Rural #DCCDAF

Suburban #C3A97E

Compact #A3844F

Urban #7C6238

Core #4A3A20

**As rendered chips:**

Undeveloped Rural Suburban Compact Urban Core

### Scale ramps

Every Scale prefix in the Pattern ID scheme gets its own 6-step tint/shade ramp across density tiers, lightest at Undeveloped, darkest at Core: nine ramps in total, one per prefix (Network, Corridor, Local, Collector, Arterial, Freeway, Intersections & Crossings, Facility, Element). The hues are placed in spectrum order matching Scale sequence (Network=red through Element=violet), chosen by simulating protanopia, deuteranopia, and tritanopia across candidate layouts and maximizing worst-case separation, then hand-adjusted for wider Local/Collector/Arterial separation specifically. The ramp color itself is aesthetic and for fast wayfinding, not the mechanism that makes classification colorblind-safe — a text label next to every colored element is what does that. Never color alone.

**Network**

Undeveloped #F7D5D4

Rural #EDA4A2

Suburban #E4726F

Compact #DA413C

Urban #B62723

Core #841C19

**Corridor**

Undeveloped #F7EFD4

Rural #EDDDA2

Suburban #E4CA6F

Compact #DAB73C

Urban #B69623

Core #846C19

**Local**

Undeveloped #EDF4D7

Rural #D8E8A7

Suburban #C3DB77

Compact #AFCE48

Urban #8EAB2E

Core #677C21

**Collector**

Undeveloped #DAF2D9

Rural #AFE3AC

Suburban #84D47E

Compact #58C551

Urban #3DA336

Core #2C7627

**Arterial**

Undeveloped #D7F4E6

Rural #A9E6C9

Suburban #7AD8AC

Compact #4BCB8F

Urban #31A870

Core #237A51

**Freeway**

Undeveloped #D8EBF3

Rural #ABD4E4

Suburban #7CBCD6

Compact #4FA4C7

Urban #3484A5

Core #266077

**Intersections & Crossings**

Undeveloped #D7DDF4

Rural #A7B5E8

Suburban #778DDB

Compact #4865CE

Urban #2E49AB

Core #21357C

**Facility**

Undeveloped #E1D8F3

Rural #BDABE4

Suburban #997CD6

Compact #754FC7

Urban #5834A5

Core #3F2677

**Element**

Undeveloped #F3D6F5

Rural #E5A5EA

Suburban #D774DE

Compact #C943D3

Urban #A629B0

Core #791E7F

### Color symbols

An optional reading aid, switched on from the Display settings panel (Color symbols). A small cream tab with near-black symbols appears in the bottom-left corner of the colored image area on Pattern and Retrofit index cards, and on the bottom-left of the Pattern ID and Retrofit ID cards, so a reader who cannot tell two hues apart can still tell them apart. The symbols come from [ColorSym](https://colorsym.com), a free color-identification system by Chris Eastridge and Luis Francisco (symbols under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/), used here unmodified). ColorSym has three primary symbols (red is a dot, yellow is a line, blue is a chevron), and its combined colors join their parents.

ColorSym has no symbol for yellow-green, teal, or magenta, and four of this publication's hues fall between its colors. Those are drawn as two symbols joined by a slash, dominant hue first. This is an extra affordance for people who can use it, not the way classification is communicated: every colored element already carries a text label. The tab is decorative (hidden from screen readers), fixed cream and near-black in both themes so it clears contrast over any card color, and scales with text size.

| Scale or classification | Color | Symbol | Reads as |
| --- | --- | --- | --- |
| Network | Red |  | Dot |
| Corridor | Yellow |  | Line |
| Local street | Yellow leaning green |  | Line, then green (line and chevron together) |
| Collector street | Green |  | Green (line and chevron together) |
| Arterial street | Green leaning blue |  | Green, then chevron |
| Freeway | Blue leaning green |  | Chevron, then green |
| Intersections and crossings | Blue |  | Chevron |
| Facility | Violet |  | Violet (dot and chevron together) |
| Element | Violet leaning red |  | Violet, then dot |

## Typography

Fraunces (variable serif) for headings, Inter (variable sans) for body text. Both free, open-source, true variable fonts that hold up in print and web. Fraunces carries warmth and distinctiveness at display size; Inter stays clean and legible through dense technical passages.

\--type-display  
40px Commonway

\--type-h1  
28px Urban main street

\--type-h2  
20px Section header

\--type-h3  
16px Technical subhead

\--type-body-lg  
17px Pattern definition sentence

\--type-body  
14px Standard paragraph text

\--type-meta  
12px Pattern ID, classification labels

\--type-micro  
10px Citation badges, chips, flags

## Illustration & photography

Clean flat vector illustration, NACTO-inspired, warmed by human figures at true scale. Spot-color amber technique: context stays grayscale, the specific pattern being illustrated floods amber.

**The amber trigger rule.** Only the specific pattern a page is about floods amber. Adjacent patterns appearing in the same illustration for context stay grayscale, even if they're themselves named CS Typologies with their own pages elsewhere. One page, one amber subject, no exceptions. The amber-flooded pattern occupies roughly 60 to 70 percent of the frame, with just enough grayscale context to make the relationship legible.

**Human figures.** Render in a fixed, neutral ink-based treatment regardless of what's flooding amber around them, since their job is scale and presence, not representing the pattern. Cap at 2 to 3 figures per illustration. Across the publication as a whole, figures should reflect a real range of ages and mobility.

**Sizing and aspect ratio by scale**

| Scale level | Format |
| --- | --- |
| Network / Corridor | Wide format (16:9 or wider) |
| Segment | Cross-section format (about 2.8:1)) |
| Intersection | Near-square or 4:3,, plan-view |
| Facility / Element | Smaller square detail insets |

**Photography** is reserved for case-study and precedent documentation only (before/after material for a real corridor), never for core pattern definitions, which stay flat vector illustration.

## Components

### Pattern ID card

`ART-UMS-09`

Arterial

Urban main street

An Urban main street is an Arterial typology combining retail frontage access with continuous pedestrian priority along both edges.

The colored left edge always matches the pattern's Scale/classification, using that ramp's own representative color from `tokens.css`: whichever tier is lightest while still clearing (or getting closest to) the 3:1 UI-component contrast minimum, which differs by hue (Core for Corridor, Local, Collector, Arterial, and Freeway; Compact for Intersections & Crossings and Facility; Urban for Network and Element). The ID text itself is always ink, per the guide: "a constant identity mark distinct from classification color."

### Pattern Index card

1

### [Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md)

`LOC-DEF-01`

5

### [Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md)

`ART-STD-05` Avoid

6

### [One-Way Street](https://commonwaysystem.org/patterns/arterials/one-way-street.md)

`ART-OWS-06` Situational / Discouraged

1

### [Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md)

`INT-RAB-01`

Used on the Pattern Index (`/patterns/`) in place of a plain bulleted list, one card per Street Typology. The image area recolors per classification with a `mix-blend-mode: color` overlay (Suburban tier at rest, Core tier as the hover border, for every one of the nine Scale ramps). Most patterns still use a single shared placeholder graphic; a handful have a real illustration in already, and swapping the rest in over time only means setting `image:` in that pattern page's own frontmatter (the card looks it up itself), and the recolor mechanism keeps working unchanged either way. The number circle restarts at 1 for each Functional Classification group and is always ink-fixed/paper-fixed regardless of theme, the same "constant identity mark" reasoning as the Pattern ID text. The status badge only appears for Situational and Avoid; Recommended (the unremarkable default) gets no badge here at all, unlike its quiet pill on the full pattern page.

### Retrofit Strategy card

`RFT-CDR-01` Corridor

Four-to-three lane road diet

Converts an existing four-lane undivided roadway into three lanes: one through lane each direction plus a center two-way left-turn lane, reclaiming the freed width for other uses.

`RFT-INT-02` Intersection

Median U-Turn (MUT) retrofit

Reroutes left-turn and through movements from a minor approach away from the main intersection, requiring drivers to turn right first, then complete a U-turn at a median opening downstream.

Same visual language as the Pattern ID card above, minus the status badge: a Retrofit Strategy is never Recommended, Situational, or Avoid, it's either applicable to a given street or it isn't, and that judgment lives in each entry's own Applicability and thresholds section rather than a badge. In place of a Functional Classification, the right-aligned label shows the strategy's Scale (Corridor, Intersection, or Network, matching the `RFT-SCALE-##` ID's own middle segment), and the left edge color follows whichever Pattern classification is that scale's functional peer rather than an invented Retrofit-only palette: Intersection strategies use the real Intersections & Crossings ramp, Corridor and Network strategies use Patterns' own real corridor/network ramps, now that all nine Scale prefixes have one (see the Scale ramps above). The ID text is always ink, same "constant identity mark" reasoning as the Pattern ID card.

### Retrofit Strategy Index card

1

### [Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md)

`RFT-CDR-01`

2

### [Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md)

`RFT-INT-02`

2

### [Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md)

`RFT-NET-02`

Used on the Retrofit Strategy Index (`/retrofits/`), the same card-grid treatment the Pattern Index card gets above, right down to reusing the same `.pattern-index-grid` layout utility and the same shared placeholder graphic (no Retrofit Strategy has a real illustration yet). No status badge appears here either, for the same reason as the card above. The number circle restarts at 1 within each scale group, following the `RFT-SCALE-##` numbering directly, the same "no separate counter prop needed" mechanism the Pattern Index card uses.

### Citation badge

Corner radii should not exceed 15 ft (4.6 m) at the crossing edge.[14]

### Unsourced-claim flag

This sentence is a placeholder for a claim that has not been sourced yet.⚠

### Speed & Modal Hierarchy card

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local Character Type's rule: 20 mph hard maximum, no exceptions.

Modal hierarchy

Pedestrian > Bicycle > Transit > Vehicle > Freight

No override: this Typology follows the Local base order.

Design speed & speed limit

\[SPEED LIMIT 30\] \[SPEED LIMIT 35\] \[SPEED LIMIT 40\]

Follows the Arterial density-tiered baseline for its typical Compact, Urban, and Core contexts.

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

Follows the Arterial base order without an override.

Every Local, Collector, and Arterial pattern that allows automobiles carries this card, split into Section A (Design Speed & Speed Limit) and Section B (Modal Hierarchy). Section A shows one MUTCD-style speed-limit sign per applicable speed, paired with a line stating whether the pattern inherits its Character Type's rule as written or carries a documented override, and a link to [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md). Section B shows a row of [Modal Hierarchy pills](#modal-hierarchy-pills), described in its own entry below.

Five named layout variations:

-   **Local / Collector.** Signs and description run side by side, as in the first example above.
-   **Arterial.** Signs stack above the description instead, as in the second example above, needed once a pattern can carry more than two signs at once (up to five, one per density tier).
-   **Speed-only** ([Stroad](https://commonwaysystem.org/patterns/arterials/stroad.md)). Section A's signs with no Section B pill row at all, since Stroad is an explicit Avoid pattern with no ranked hierarchy to show.
-   **Modal-Hierarchy-only** (patterns that exclude automobiles entirely, [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md) and [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) among them). Section B with no Section A at all, since Design Speed & Speed Limits has nothing to say about a street with no cars on it.
-   **Time-conditional** ([Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md), [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md)). Two labeled pill rows inside one Section B, since each pattern's modal hierarchy changes by time of day.

### Modal hierarchy pills

Pedestrian > Bicycle > Transit > Vehicle > Freight

Pedestrian = Bicycle

A reusable component in its own right, not just a piece of the card above. Each pill pairs a small icon with the mode's name, one pill per mode across five modes: Pedestrian, Bicycle, Transit, Vehicle, and Freight.

Background color is the pattern's own Functional Classification color, the same token the Pattern ID card's left edge uses above, not a fixed "Core tier" value: it's whichever tier of that classification's ramp the publication's `--cw-local`/`--cw-collector`/`--cw-arterial` tokens already point to (see the Pattern ID card entry above and `tokens.css`'s own comments), which differs by classification and shifts again between light and dark mode. Text and icon color is whichever of `#FFFFFF` or `#000000` clears contrast against that background by the larger margin, computed per classification and per theme rather than fixed to one value across all three, with one documented exception for Arterial; see Accessibility notes below.

Two pills separated by a ">" means the left one strictly outranks the right, the first example row above. Two pills separated by an "=" means they're explicitly tied at the same rank, the second example row above, a real case on [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md) and [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md), where Pedestrian and Bicycle share top priority with no ranking between them.

### Guide diagram

\[Image: Commonway System density tiers diagram showing six levels of development from Undeveloped to Core.\]

Illustration inspired by FDOT, generated by Gemini.

Used for the full-width topic diagrams on Foundations guide pages (currently Density Tiers, Design Speed & Speed Limits, Scale Hierarchy, and Street Types & Classifications), one per page, placed as the first element right after the page's own `<script>` block. Same rounded-corner/hairline-border/shadow treatment as any other standalone content image on the publication, reproduced in this component's own styles for the captioned case above, since the image is no longer a direct child of the page's content column once it's wrapped for a caption.

Four props beyond the required `src`/`alt`, all optional and independent of each other. `width`/`height` set the image's real pixel dimensions as HTML attributes, not just CSS, so the browser can reserve the correct layout space before a lazy-loaded image actually finishes downloading, instead of leaving a gap or reflowing the page once it lands. `aspectRatio` is a fallback for when only the ratio is known, not the exact pixel size. `caption` adds a line of visible text under the image, shown above, inside a real `<figure>`/`<figcaption>` pair, semantics an assistive technology already understands with no extra ARIA needed. Caption is deliberately kept distinct from alt text: alt describes what the image shows, for someone who can't see it; caption is visible context or attribution for everyone, the generation credit in the example above rather than a restatement of the image's content. Every diagram lazy-loads (`loading="lazy"`) regardless of which of these props are set, so a diagram below the fold costs nothing until a reader actually scrolls to it. Omit all four optional props for a bare, unsized `<img>`, the same shape these diagrams originally shipped with before width/height/caption support existed.

## Buttons, links & forms

The interactive-site build needs these regardless of how sparingly the publication itself uses them, since search, filtering, and the eventual interactive Guide diagnostic tool all depend on real form controls. The publication does not have production `<button>`/`<select>` styling wired up as reusable components yet, but these previews use the same `tokens.css` values everything else on the publication does.

### Buttons

Primary uses the signature teal fill with ink text, not paper text. Paper-on-teal only reaches 2.86:1 contrast and fails; ink-on-teal reaches 6.18:1.. At most one primary button per view; everything else is secondary or dark.

### Hyperlinks

Read more about the [FHWA self-enforcing roadway framework](https://www.fhwa.dot.gov/), or see the [full citation format](https://commonwaysystem.org/about/brand-guide.md#citation-format) for this pattern. Toggle dark mode to see the link color switch, and note the small "opens in new tab" icon this publication adds to every outbound link automatically.

Links use indigo, not teal, since teal is already committed to citations and evidence tiers. Underlined always, not just on hover, since this is a reference work first and a marketing publication second. This example uses the publication's real `--cw-link` token, which reflects both modes correctly.

Link, light mode #3D3AAB

Link, dark mode #A79EFF

The working draft's original indigo (`#3D3AAB`) reaches 8.28:1 contrast on light paper, but only 2.1:1 on a dark background, well below the 4.5:1 WCAG AA minimum. The dark-mode value is the same indigo/violet hue lightened, not a different color, and reaches 7.89:1 on dark paper. Dark mode isn't part of the original working draft; this pairing is a publication-only addition, documented here since it's now the real token every hyperlink in the guidebook uses.

### Form controls

Search patterns

Functional Classification

Local Collector Arterial Freeway

Sort by

Focus state on text inputs and selects uses a teal outline ring, not a color change on the border alone, so keyboard navigation stays visible against every classification color context.

## Citation format

The house citation format is modeled on agency-reference conventions: source name, year, title, publisher (when distinct from the source), and URL. Entries are numbered to match their inline badges, sorted by publication date, and, within a single source cited multiple times, ordered by where the content appears in that source, not by citation number or alphabetically.

**Link maintenance**

| Link state | Handling |
| --- | --- |
| Live | URL shown as-is, with a last-checked date in the metadata line |
| Redirected | Updated to the new URL, original URL noted, with the date the redirect was found |
| Dead | Original URL retained, paired with an archive.org snapshot link, dated to when the page was last known live |

One citation, one purpose.

## SEO / AEO / GEO strategy

Google's own guidance treats generative AI search optimization as fundamentally the same discipline as SEO, rooted in the same core ranking and quality systems, and explicitly debunks several tactics marketed as "GEO best practices" (llms.txt for Google specifically, content "chunking," and structured data as a requirement rather than a nice-to-have). What actually drives visibility, per Google's guidance, is unique point-of-view content and non-commodity material with genuine expert insight, organized into clear sections with real navigational headings, which is exactly what CS already is by design.

**What CS does:**

-   Lets the plain-language layer at the top of each pattern entry function as a natural, self-contained answer block.
-   URL structure mirrors the Pattern ID system (e.g. `/patterns/art-ums-07`).
-   Uses structured data (`DefinedTerm` or `Article` schema, `dateModified` tied to CalVer) for genuine rich-result eligibility, not because AI visibility requires it.
-   Keeps entity clarity through the Functional Classification / Street Typology terminology discipline: consistent, unambiguous naming.
-   Treats the citation system as a genuine GEO asset, not a performance of one. It exists for credibility reasons first.
-   Surfaces CalVer versioning visibly on every page as a real freshness signal.

**What CS skips:** llms.txt treated as load-bearing for Google specifically, content chunking as an optimization tactic, and structured data treated as a hard requirement rather than a nice-to-have.

## Accessibility notes

A contrast issue was caught and fixed during design: the citation badge and Evidence-based chip originally used `#003D35` text on `#00A896`, a 4.10:1 contrast ratio, below the 4.5:1 WCAG AA requirement for text at that size. Corrected to `#002D27`, reaching 5.01:1 (the value used by the evidence chips above).

| Pairing | Ratio | Status |
| --- | --- | --- |
| Citation badge (corrected) | 5.01:1 | Pass |
| Precedent-based chip | 7.59:1 | Pass |
| Legal/regulatory chip | 6.41:1 | Pass |
| Pattern ID / metadata label | 5.04:1 | Pass |
| Unsourced-claim flag | 8.97:1 | Pass |
| Body text on paper | 17.67:1 | Pass |
| Modal hierarchy pill, Local (light mode) | 4.69:1 | Pass |
| Modal hierarchy pill, Local (dark mode) | 8.01:1 | Pass |
| Modal hierarchy pill, Collector (light mode) | 5.63:1 | Pass |
| Modal hierarchy pill, Collector (dark mode) | 6.49:1 | Pass |
| Modal hierarchy pill, Arterial (light mode) | 5.28:1 | Pass |
| Modal hierarchy pill, Arterial (dark mode) | 6.97:1 | Pass |

The nine Scale ramps (see above) are simulated against protanopia, deuteranopia, and tritanopia as part of choosing each hue, maximizing worst-case separation across the palette rather than checking colors one at a time after the fact. Per the site owner: this separation is a wayfinding/aesthetic concern for this palette, not the mechanism that makes classification colorblind-safe, since a text label always accompanies every colored element on the publication.

**The Modal hierarchy pill's old Arterial exception no longer applies.** Before the 2026.09.23 recolor, Arterial's previous yellow-green hue failed 4.5:1 with both black and white text, and white was kept anyway (3.57:1 light, 2.32:1 dark) with a dark text-shadow glow standing in for the missing margin, a real, flagged exception at the time. The new Arterial hue clears 4.5:1 cleanly both ways in both themes (table above), so the glow hack was removed along with it — nothing to flag here now.

A separate legibility issue surfaced after the contrast fix above: the citation badge and unsourced-claim flag pass their contrast ratios at the working draft's `--type-micro` size (10px), but a numeral at 10px in a tight colored pill was hard to actually read, a real-world legibility problem the contrast ratio alone doesn't catch. Both now render at 12px, semibold, independent of the type scale documented above. Contrast is unaffected, this is a size correction, not a color one.

## Logo & wordmark

The Commonway System mark is a set of flowing ribbon shapes rendered in a warm red-to-amber gradient, paired with the wordmark "Commonway System." This is the finalized, production logo system, delivered as clean vector art with a complete set of variants for light and dark contexts.

Two explicit exceptions to the rest of this guide, scoped to the logo only:

-   **Gradient.** The red-to-amber gradient exists nowhere else in the Commonway System. Every other use of color in this guide, illustrations, UI components, classification ramps, stays flat, no gradients. The logo is the sole exception.
-   **Typography.** "Commonway" is set in Fraunces Bold (700), heavier than the SemiBold (600) used for headings throughout the rest of the system. "SYSTEM" is set in Inter Light (300) with extended letter-spacing. Neither weight should be replicated in body headings, card titles, or any other heading context.

### Full lockup, standard use

\[Image: Dark variation, on light\]

Dark variation, on light

\[Image: Light variation, on dark\]

Light variation, on dark

This is what the publication itself uses in its navbar, switching automatically with the reader's light/dark mode.

### Full lockup, muted / watermark use only

\[Image: Light variation, on light\]

Light variation, on light

\[Image: Dark variation, on dark\]

Dark variation, on dark

### Square lockup

\[Image: Dark variation, on light\]

Dark variation, on light

\[Image: Light variation, on dark\]

Light variation, on dark

\[Image: Light variation, on light (muted)\]

Light variation, on light (muted)

\[Image: Dark variation, on dark (muted)\]

Dark variation, on dark (muted)

### Icon only, no wordmark

\[Image: For light backgrounds\]

For light backgrounds

\[Image: For dark backgrounds\]

For dark backgrounds

All logo variants ship in `static/logos/`, including the muted/watermark pairs, even where only the standard pair is used live on the publication today.

---

Source: https://commonwaysystem.org/about/commonway-system/

# The Commonway System

The Commonway System (CS) is a pattern language for roads and streets. It organizes established transportation design knowledge, from NACTO's guides to Dutch Sustainable Safety and Vision Zero research, into a single, cross-referenced reference usable by a total beginner or a practicing engineer alike.

**Subtitle:** "A Pattern Language for Roads and Streets" **Tagline:** "One system, grounded in what's proven."

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why Aren't Dangerous Drivers Punished?](https://www.youtube.com/watch?v=dHRfClVJg70)

Global Cycling Network

Traces why traffic law rarely punishes road violence proportionally, then makes the case CS already builds on: infrastructure should be designed so mistakes aren't fatal, rather than relying on punishment after the fact.

## How CS relates to other frameworks

CS does not replace or compete with NACTO, Complete Streets, or Strong Towns. It cites and builds on their work, adding evidence layers where the research supports going further. Every pattern in the system traces back to a source, so the authority behind CS is the citation trail, not a credential.

Where CS takes a position beyond conventional practice, it says so directly and names the evidence: naming the baseline practice or the structural cause of a pattern, then closing with a classification (Default, Situational-Discouraged, or Avoid) backed by a specific source. A baseline source is never called wrong, outdated, or flawed, since the disagreement is about evidence, not authority.

## Who, how, and why

Google's own helpful-content guidance asks three questions of any piece of content: who created it and what's their real experience with it, how was it made, and why does it exist. CS answers these directly, since the answers are the actual foundation of its credibility, not an afterthought.

| Question | Answer |
| --- | --- |
| **Who** | Kevin, an enthusiast and researcher/compiler, explicitly not a credentialed engineer or planner. The citation system substitutes for personal authority. See [About the author](#about-the-author) below. |
| **How** | Primary sources read directly and cross-referenced, not secondhand summaries. Every design claim traces to a named source, dated and linked. |
| **Why** | To make the accumulated evidence behind good street design legible to a beginner and useful to a practitioner, in one place, without requiring a credential to access it. |

## How the guidebook is organized

Every pattern sits inside one of four Functional Classifications: Local, Collector, Arterial, or Freeway, plus a fifth cross-cutting set for Intersections and Crossings. Within a classification, patterns are grouped by purpose-based Street Typology, and each pattern exists at one of five scales: Network, Corridor, Segment or Intersection, Facility, and Element. A pattern's ID encodes its scale and context, for example `LOC-BBG-12`.

See the [guide introduction](https://commonwaysystem.org/guide.md) for the full mechanics of reading a pattern, and the [Brand Guide](https://commonwaysystem.org/about/brand-guide.md) for how the system is written and designed.

## About the author

Kevin Young is the author of the Commonway System, an evidence-based pattern language for roads and streets, with a catalog of retrofit strategies for streets that already exist. He started it in 2026 as an enthusiast and compiler, not a transportation professional, so the work rests on its citations and not on his credentials. Claims are cited to sources, and any not yet sourced carry a visible flag. Plain-language explanations come first, with technical detail beneath. The guide is published online and dated by version, so readers can see how current it is.

More about him at [kevinyoung.net](https://kevinyoung.net) and on [LinkedIn](https://www.linkedin.com/in/youngkev/).

\[Image: Kevin Young\]

Kevin Young, Author, Commonway System

---

Source: https://commonwaysystem.org/about/contributing/

# Submit a Change

Commonway System is public and built in the open on GitHub. If you've noticed something that could be stronger, more accurate, or missing entirely, you can help fix it directly.

This page covers submitting an actual change yourself, a correction, a new citation, or a new pattern proposal. If you've spotted a problem but aren't able to fix it yourself, see [Report a Problem](https://commonwaysystem.org/about/reporting.md) instead: that's the faster, no-writing-required path for flagging an error, a dead link, or an unsourced claim.

## New to Git and GitHub? Start here

Git and GitHub are the tools this project uses to track changes and let people propose edits. If you've never used them, here's the shape of it: you make a personal copy of this repository (a "fork"), edit the file you want to change, and submit your edit back as a "pull request", a formal request asking the maintainers to review and merge it. Everything below assumes you've read this repo's own README for the mechanics of forking and getting a copy running.

Which path makes sense depends on what you're fixing:

**A small text-only fix** (a typo, a broken link, a wording tweak): you can edit the file directly on GitHub's website, no downloads required. [How to create a pull request with no coding required](https://www.youtube.com/watch?v=j1MUcVQn40g) walks through the whole process, start to finish, editing a single markdown file with no coding experience.

**Anything larger, or any change to a pattern page:** pattern pages use custom layout components (Pattern ID cards, citation badges, and so on), so you'll want to preview your change locally before submitting rather than editing blind on GitHub's website. Follow this repository's own README to get a full local copy running, then use GitHub Desktop instead of the command line if you're not comfortable with a terminal. [Learn GitHub without needing the terminal](https://www.youtube.com/watch?v=2SgI1kAczfk) walks through the GitHub Desktop app specifically, no terminal required.

Once you've made your change, whichever path you took, the checklist below is what every contribution gets held to.

## What you can contribute

-   **A correction** to an existing pattern page: a wrong figure, an outdated citation, a broken link, an unclear description
-   **A missing citation** for a claim currently marked with the unsourced-claim flag⚠
-   **A new pattern proposal**, when you believe a Street Typology, an intersection treatment, or a related pattern is missing from the guidebook
-   **General improvements**: clearer wording, a better example, a fix to the publication itself

One thing worth knowing before you start on something large: foundational structure, the Functional Classification system, the pattern ID format, core safety rules like the Local speed cap, isn't open to change through a routine pull request. See [Project Governance](https://commonwaysystem.org/about/governance.md) for how that's decided. If you're proposing something that touches the guidebook's underlying structure rather than its content, open an issue to discuss it first, before putting in the work on a full pull request.

## How a contribution moves through review

Commonway System uses the standard GitHub workflow: fork the [repository](https://github.com/Commonway-System/commonwaysystem.org), make your change, and open a pull request. The [pull request template](https://github.com/Commonway-System/commonwaysystem.org/blob/main/.github/PULL_REQUEST_TEMPLATE.md) bakes in the checklist below, so you can self-check before submitting.

Every contribution is checked against the same standard every existing page is held to:

-   **Does it cite a source?** New or changed factual claims need a citation, ranked by evidence tier (legal/regulatory, evidence-based, or precedent-based). Every citation's entry in that page's `## References` list needs its evidence-tier chip alongside it, added at the same time as the citation itself, not as a follow-up. A claim without a source gets the unsourced-claim flag rather than getting rejected outright, but citing it yourself gets it merged faster.
-   **Does it match the house style?** Third-person voice for pattern entries, no first-person framing, no words implying certification or guaranteed compliance ("code-approved," "certified"), and no reproduced excerpts from source manuals like MUTCD or CROW, paraphrase and cite instead.
-   **Does it fit the existing structure?** A correction or new pattern within an existing Functional Classification moves through normal review. A change to the structure itself needs the discussion described above before a pull request is the right next step.

Once a pull request is approved and merged, it goes live on the next publish, and shows up in the changelog on the [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md) page.

## Terms of contributing

Everything submitted through a pull request becomes part of a public repository, visible to anyone. By submitting a contribution, you're confirming it's your own work, or something you have the right to share, and you're granting Commonway System a license to use, edit, and publish it as part of the guidebook. You're not asked to give up authorship of your own words, and you're not asked for payment or ownership in return, but you also aren't granting yourself any ownership claim over the guidebook itself: Commonway System retains the rights to the compiled work, the same way a publisher retains rights to a book that many people contributed research to.

The publication's underlying code, Svelte components, configuration, and build tooling, is licensed separately and far more permissively, under [MIT](https://github.com/Commonway-System/commonwaysystem.org/blob/main/LICENSE). Only the guidebook content itself, the pattern pages and prose, follows the terms described above.

## Credit

Contributors are credited by name (or GitHub handle, if you'd rather not use your name) on the [Acknowledgments](https://commonwaysystem.org/about/acknowledgments.md) page. Credit reflects that you helped build this, it isn't authorship of the guidebook itself, and it isn't a claim on any part of it.

## Code of conduct

Transportation design attracts strong opinions, and not all of them are evidence-based. Contributors are expected to engage in good faith and keep disagreements focused on evidence, not volume or persistence. See the project's [code of conduct](https://github.com/Commonway-System/commonwaysystem.org/blob/main/CODE_OF_CONDUCT.md) for the full expectations.

---

Source: https://commonwaysystem.org/about/governance/

# Project Governance

The Commonway System is maintained by a single person. [Kevin Young](https://commonwaysystem.org/about/commonway-system.md#about-the-author) compiles, edits, and has final say over everything published here. This isn't a committee project or a consensus process, and this page says so plainly rather than dressing it up as something more collaborative than it is.

That said, final say doesn't mean personal preference decides things. It means the maintainer applies a fixed set of rules consistently, the same rules described below, and is accountable to those rules in every decision.

## Who has final say on a pattern's classification

The maintainer does. But classification decisions aren't made by feel: they follow directly from the evidence and citation system already built into every pattern page. A Street Typology's status (Recommended, Situational/Discouraged, or Avoid), its density-tier fit, and its modal hierarchy all trace back to a cited source. Where the evidence is clear, the classification follows the evidence. Where it isn't yet, the page carries the unsourced-claim flag⚠ until it is.

## How disputes over evidence are resolved

When two sources point in different directions, the disagreement is resolved by evidence tier, not by who argued it more persuasively or how long a claim has been in the publication. Sources rank in this order:

1.  **Legal or regulatory** (a statute, an adopted code, a government manual)
2.  **Evidence-based** (a peer-reviewed study, published crash data, a formal research report)
3.  **Precedent-based** (a real place doing it successfully, without a formal study behind it)

A higher-tier source overrides a lower-tier one by default. The maintainer only makes a judgment call when two sources sit at the same tier and genuinely conflict, and when that happens, the reasoning behind the call is documented alongside the citation, not left implicit.

An opinion without a citation behind it doesn't move a classification, no matter how many people share it. This system exists specifically so the guidebook's credibility rests on its sources, not on anyone's personal authority, including the maintainer's own.

## How the project's direction is set

The maintainer sets priorities and decides what gets built next. The [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md) page is the running record of both what's shipped and what's planned, and it's the place to look for where the project is headed.

Two different kinds of changes are held to two different bars:

**Foundational structure** (the Functional Classification system, the pattern ID format, the scale hierarchy, core safety rules like the Local speed cap) requires the maintainer's direct sign-off, regardless of how well a proposed change is cited. These decisions shape everything built on top of them, so they don't move on the strength of a single well-argued case.

**Content within the existing structure** (a new citation, a correction to a stated range, a new pattern proposal that fits into an existing Functional Classification) moves faster and follows the ordinary review process described on the [Submit a Change](https://commonwaysystem.org/about/contributing.md) page.

## Participation isn't a vote

Anyone can propose a change, and every contribution is genuinely reviewed on its merits. But Commonway System isn't run by majority opinion, and won't be swayed by volume of comments or repetition of a claim. If a proposed change doesn't carry evidence at least as strong as what it would replace, it doesn't get made, no matter how many people ask for it.

This project also covers a topic, how streets should prioritize different modes of travel, that reliably attracts strong, non-evidence-based opinions in both directions. Participants are expected to engage in good faith and to keep discussion evidence-focused; see the project's [code of conduct](https://github.com/Commonway-System/commonwaysystem.org/blob/main/CODE_OF_CONDUCT.md) for specifics.

---

Source: https://commonwaysystem.org/about/privacy-policy/

# Privacy Policy

**Effective date:** August 29, 2026

Commonway System doesn't run accounts, doesn't sell anything, and doesn't collect information directly from visitors beyond what's described below. This page covers the third-party services the publication relies on, and the ordinary logging that comes from being hosted on the web at all.

## What we use

**Google Analytics.** We use Google Analytics to understand how the publication is used: which pages get visited, how people arrive at the publication, and general device and browser information. This is aggregate usage data, not information tied to your name or identity. See [Google's own privacy policy](https://policies.google.com/privacy) for how Google processes this data.

**GitHub.** The publication's content and code are maintained in a public GitHub repository. If you open an issue, submit a pull request, or otherwise interact with the repository, GitHub collects and publicly displays your GitHub username and activity, the way it does for any public repository. We don't control that data ourselves; see [GitHub's Privacy Statement](https://docs.github.com/site-policy/privacy-policies/github-general-privacy-statement) for how GitHub handles it.

**Netlify (hosting).** This publication is hosted as a static site through Netlify, which automatically logs basic request information (like IP address and request timestamp) as a normal part of serving any website. We don't use this data ourselves beyond what Netlify's own infrastructure requires to operate. See [Netlify's Privacy Policy](https://www.netlify.com/privacy/) for details.

**Site search.** The search feature runs entirely in your browser, against an index that is part of the publication itself. What you type is never sent to us or to anyone else, and search adds no cookies.

We don't run ads, don't sell or share data with advertisers, and don't have any other analytics, tracking, or data collection on the publication beyond what's listed above.

## Cookies

Google Analytics may set cookies in your browser to distinguish visitors and sessions. You can block or delete these through your browser's settings, or use [Google's Analytics Opt-out Browser Add-on](https://tools.google.com/dlpage/gaoptout) to opt out entirely. Blocking cookies won't affect your ability to read the publication; it only affects the usage data we can see.

## Children's privacy

Commonway System isn't directed at children, and we don't knowingly collect personal information from anyone under 13.

## Links to other sites

Nearly every pattern page in the guidebook cites external sources: government manuals, published studies, agency documents. Clicking through to those sources takes you to a site we don't control and aren't responsible for. Check the privacy practices of any external site you visit from a citation link.

## Your choices

You can use the Google Analytics opt-out tool linked above, adjust your browser's cookie and tracking settings, or use browser extensions that block analytics scripts. None of this affects your ability to use the publication.

## Changes to this policy

This page may be updated as the publication's tools or practices change. Updates are reflected in the publication's version history the same way any other content change is; see [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md).

## Contact

Questions about this policy can be directed to [info@commonwaysystem.org](mailto:info@commonwaysystem.org).

---

Source: https://commonwaysystem.org/about/release-history/

# Release History & Roadmap

## How versioning works

The Commonway System uses CalVer, a version number built from the date rather than an arbitrary sequence: year, month, day (for example, 2026.08.28). The version shown in the publication's header is always the date of the most recent publish, and the most recently published version is the official current version of the guidebook. There is no separate "stable" or "beta" release; whatever is live is the current one.

This publication is statically generated. Publishing happens by pushing to GitHub, which triggers an automatic build. There's no manual deploy step and no delay between a push landing and the publication reflecting it, so the version number in the header updates the moment a change goes live.

The web version at commonwaysystem.org is canonical. Print editions of the Commonway System Guidebook are dated snapshots: each print copy carries the CalVer date it was produced under, and reflects the guidebook as it existed on that date. If something in a print copy conflicts with the current web version, the web version is the more current source.

If more than one push happens on the same calendar day, they share a single version number and a single changelog entry below. The changelog entry for that date covers everything that shipped that day, not just the first or last push.

## Current version

**2026.09.26**

The guidebook currently documents 112 Street Typology pattern pages across Local, Collector, Arterial, Freeway, and Intersections & Crossings. None are content stubs, every published pattern page carries real modal-hierarchy, density-applicability, and design-notes content, and every one now carries real citations rather than the "Unsourced claim" flag. Find Your Pattern is still the one remaining placeholder page in the Guide, pending its own diagnostic sequence. It is actively expanding, not a finished publication.

## Changelog

Entries run newest to oldest. Each entry covers everything published under that date, even if it shipped across more than one push.

**2026.09.26**

-   New Accessibility Policy page (About, under Terms and Policies; also linked from the footer): the WCAG 2.2 Level AA goal, what has and hasn't been tested, every display setting, the text-only pages, external-content limits, and how to report a barrier. The footer gained a distinct row with the copyright line (© current year Commonway System) and links to Terms and Conditions, Privacy Policy, AI Policy, and Accessibility Policy.
-   Full-site automated audit with axe-core across all 165 pages (desktop dark, desktop light, and 375px phone), and every issue it found was fixed: a `<main>` landmark on every page; names for the sidebar and "On this page" landmarks; Pattern ID and Retrofit Strategy card titles are no longer headings that skipped a level (Media Gallery cards are now proper `h2`s); the light-mode "Tip" and "Correct" label colors and the "Compact" density chip now meet the 4.5:1 contrast minimum; citation badges have a 24px tap target with no visual change; the Who/How/Why table has real header cells; and stray empty images in this changelog are gone (backtick spans now render as code). A later pass also fixed the muted note color inside expanded Layered guidance cells.
-   Skip link ("Skip to main content") as the first Tab stop on every page, and a compact sticky "On this page" bar on tablets and phones (below 1180px, where the right-hand rail is hidden): shows the current section, opens a list of headings with the on-screen ones emphasized, closes on selection, Escape, or an outside tap, and moves focus to the heading you jump to. Anchor jumps and keyboard focus now clear the sticky navbar and bar.
-   Homepage hero animation now has a Pause/Play button (WCAG 2.2.2). It freezes both the dot-halftone canvas and the glow, remembers the choice, and is hidden when the device is set to reduce motion.
-   New Display settings panel (an "Aa" button in the header, and a section in the mobile menu): text size in four steps up to 150% (scaled from the reader's own browser setting), high-contrast mode (also follows the device's "more contrast" setting when nothing is saved; pure black and white, solid borders, underlined links, and a text label for every classification color on index cards), simplified view (one column, plain font, no decoration or animation, all collapsed sections expanded), enhanced keyboard focus outline, large mouse pointer, and a translucent yellow pointer highlight. Choices are saved in the browser only and applied before first paint. The panel scrolls inside itself so it stays reachable at the largest text size or on a short screen.
-   Text-only version of every page: `pnpm run build` now runs `scripts/generate-text-pages.mjs` after the site build, writing a plain, unstyled version of each page to `/text/…` (165 pages plus an index at `/text/all-pages/`), built from the rendered page so components' content survives. No images, scripts, or animation; marked noindex with the full page as canonical. Linked as "Text-only version" under every page and from the Display settings panel. Adds one dev dependency (`node-html-parser`) and a prerender exception for `/text/` links in `svelte.config.js`.
-   Navbar now wraps onto a second row instead of overflowing the page when text is enlarged or the window is narrow (this also fixes an existing sideways overflow between 941px and about 1000px wide); its measured height feeds the sticky sidebar, "On this page" bar, and anchor clearance. The "Version" label shortens to "V." below 1100px to make room for the new button.
-   New pattern, INT-RGC-15 Railroad Grade Crossing (Intersections and Crossings, Situational), covering an at-grade crossing where a street meets an active rail line: its own geometry standard, warning devices, sight-distance rules, and low-clearance-vehicle risk. Industrial Collector gained a "Layered guidance across sources" table (several deliberate "Not researched" gaps). Curb Cut / Driveway Apron, Roundabout, Signal, and Protected Intersection each gained a truck-oriented section with citations: forward entry with no public backing, freight-priority roundabout sizing, and turning-truck risk to people walking and biking. The Pattern Index and sidebar list the new page (112 pattern pages). Every page touched in this release, including these, was scanned with axe in light and dark mode at desktop and 375px width with no violations.
-   Markdown version of every page for AI and LLM readers: each page's content is also written as a clean `.md` file at the same path (`/patterns/foo/` becomes `/patterns/foo.md`; the homepage is `/index.md`), generated after the build by the same script as the text-only pages, with a small header (title, URL, Pattern ID, last updated). Citation badges become `[N]` pointing at the numbered References list, and the Layered guidance table is flattened into headings since markdown tables can't hold its expandable cells. Every page advertises its markdown version with `<link rel="alternate" type="text/markdown">`, `llms.txt` now links to the `.md` versions, and a new `_headers` file serves them as `text/markdown` with `noindex` so search engines keep to the HTML pages. There is also an `llms-full.txt` at the site root with every page's markdown in one file, linked from `llms.txt`. Not built: serving markdown from the normal page URL via an `Accept: text/markdown` header (that needs an edge function or Worker).
-   Site search: a Search button in the header (and in the mobile menu, and Ctrl/Cmd+K anywhere) opens a search dialog covering every Pattern, Retrofit Strategy, Guide, About, Blog and Reference page and every Media Gallery item as its own result. Filter by section and by Pattern type, search a Pattern ID directly (LOC-DEF-01), and see the headings on a page that also match. The same search is also a full page at `/search/`, where a search can be linked (`/search/?q=roundabout`). It is built with Pagefind, indexed at build time and run entirely in the browser: nothing typed is sent anywhere, and the index only downloads the first time someone searches. A media result opens the Media Gallery filtered to that item. There is deliberately no single-key shortcut such as "/", since those need a way to be turned off. Not yet tested with a screen reader; see the Accessibility Policy.
-   Removed the italic "Working assessment: this pattern's status reflects a preliminary Commonway System judgment call, pending final review" note from the 69 pattern pages that carried it (the Network, Corridor, Facility, and Element pages plus a few later additions). Their statuses are unchanged; only the note came off.
-   New Site Map page (About, right after Overview; also linked from the footer, the search dialog and the search page): every page in the publication in one list, grouped and ordered exactly like the navigation, with Pattern and Retrofit Strategy IDs beside their links, plus an "Other ways to browse" section (search, the text-only pages, the XML sitemap, `llms.txt` and `llms-full.txt`). It is generated at build time from the sidebar and every page's own title, so a new page appears on its own; a page missing from the sidebar is listed under "Other pages" and logged in the build output instead of going missing.
-   Search results now show a thumbnail for Patterns, Retrofit Strategies, Blog posts and Media items (any other page, such as a Guide or About page, gets one only when it sets its own `image:` in its front matter; otherwise it shows none). Pages get their image from a new optional `image:` field in their own frontmatter, which also now supplies the social-share preview image (`og:image` and `twitter:image`) and the page's structured data; the Pattern and Retrofit index cards read the same field instead of a hand-typed value on each card, and pages without an image still show the placeholder. Small copies of every content image are pre-made (160px and 480px WebP, `pnpm run thumbs`) and committed, so search results and the index and gallery cards no longer load 1 MB originals. The 21 Media Gallery preview images are now hosted on this site rather than loaded from YouTube and Strong Towns, so search shows them without contacting a third party. In the search dialog the filters now fold into a "Filters" disclosure so results stay in view.
-   Display settings gained three more options. Reading font: Lexend, Atkinson Hyperlegible Next, or OpenDyslexic replace the publication's fonts (all three self-hosted, never loaded from an outside font service, and only downloaded once chosen; the panel and policy say plainly that research has not shown dyslexia-specific fonts read faster, so it is offered as a preference). Color symbols: a small cream tab with ColorSym symbols (the free color-identification system by Chris Eastridge and Luis Francisco, CC BY-SA 4.0, used unmodified) in the bottom-left of colored index cards and of the Pattern ID and Retrofit ID cards, so hues are not the only cue; each of the nine Scale hues has its own symbol or a two-symbol pair joined by a slash (dominant hue first) where ColorSym has no matching color, and a key is on the Brand Guide under "Color symbols". Reading ruler: shades the page except a clear window of one to three lines that follows the mouse, a finger or keyboard focus (Alt plus Up or Down also moves it), with adjustable window height and shading; it does nothing in forced-colors mode or print and turns off Pointer highlight.
-   Display settings panel: it now shows a scrollbar, edge shadows, and a "Scroll for more" arrow at the bottom while there are more options below (the arrow disappears once you scroll). Fixed a bug where the visible radio buttons (text size, and the new reading font) could show as unchecked because the panel exists twice on the page and both copies shared radio names. Large pointer now really is large everywhere: a large arrow, a large hand over anything clickable, and a large text cursor over text and text boxes (it previously fell back to the small native pointer over form controls and the search button).
-   Two new npm dependencies for the reading fonts (@fontsource-variable/lexend, @fontsource-variable/atkinson-hyperlegible-next, @fontsource/opendyslexic, all SIL Open Font License) and the ColorSym symbols in `static/color-symbols/`, both credited in `THIRD-PARTY-NOTICES`. The Accessibility Policy page lists all three new settings. Axe-core was clean on the Pattern Index, a pattern page, the Retrofit index and a Retrofit Strategy page, the Brand Guide and the policy page, in both themes at desktop and 375px, with the new settings switched on. Not tested: screen readers, real touch devices, forced-colors mode, or how the two-symbol Color symbols pairs read to someone with color vision deficiency; the ShareAlike term on the ColorSym symbols is flagged for the attorney review.
-   Known incomplete: no full keyboard-only, screen reader (NVDA, VoiceOver, JAWS), 200/400% zoom, or forced-colors testing has been done, so the policy page does not claim conformance. At the largest text size the header is about 180px tall on wide screens (and taller when wrapped on phones), which leaves less room for content. Text-only pages exist only in built output, so their links 404 under `pnpm run dev`. Contrast and pointer settings were verified with axe and measured values, not a full manual review. The new search dialog, Search page and Site Map have been scanned with axe (both themes, phone and desktop, and the Display settings modes) but not tested with a screen reader. The rule that serves the markdown versions as `text/markdown` and keeps them out of search engines (`static/_headers`) can only be confirmed once deployed. The Media Gallery cards still load channel logos from another website. Retrofit Strategies and the blog post have no featured image yet, so they show the placeholder.

**2026.09.25**

-   New Retrofit Strategy, RFT-CDR-11 ("2+1 road with cable median barrier"), the 18th entry and 11th Corridor strategy: converts an undivided rural two-lane road into a continuous three-lane cross section with an alternating passing lane and a cable median barrier. Cited to Swedish (VTI), FHWA, Kentucky, Missouri, and Colorado sources, including Colorado's own caveat that the crash-reduction estimate is uncertain and a limited pilot is advised. Added to the Retrofit Index and sidebar.
-   New "Layered guidance across sources" section on Default (Standard Collector) and Rural Collector / Farm-to-Market Road: an expandable table comparing federal/state baseline, NACTO, Complete Streets, and Dutch practice against the Commonway System answer, one row per design element (nine rows on each). Each cell shows a short summary and expands to the full text with citations. Default (Standard Collector) gained references 2 through 19; Rural Collector now has 16.
-   Rural Collector / Farm-to-Market Road: speed rule changed from 30 to 35 mph, with a terrain-by-volume design-speed table (level, rolling, mountainous by traffic volume) in the speed box; cells above 45 mph link to the new 2+1 retrofit. Bicycle, pedestrian, separation, lane-width, and intersection guidance now split at 45 mph (shoulder below, separated path above; mini-roundabout below, roundabout or enhanced stop control above), and intersection treatment is broken out by what the road meets (Local, Collector, Arterial, Freeway).
-   Default (Standard Collector): separation/buffer guidance corrected so the 3 ft parking-adjacent minimum applies only where no rigid crash-protective barrier separates bicycles from the car lanes, and a Property access row added.
-   New `GuidanceTable` component (expandable cells, row and expand-all controls, labeled tiers, a Commonway System column twice the width of the others, built-in default columns) and `SpeedTerrainTable`. Intended as a standard section for every Local, Collector, Arterial, and Intersections & Crossings pattern page; only the two pages above carry it so far.
-   Media items can now carry a per-page endorsement status. MED-013 (Safe By Design, 2+1 roads) is Aligned on the new retrofit and Context-only on Rural Collector, whose typical case it doesn't describe.
-   Sitewide color reorganization (landed 2026.09.23): every Scale now has its own real 6-tier color ramp (Network through Element, hues in Scale order), replacing the shared Freeway-gray placeholder on the newest four; Freeway's ramp deliberately departs from the Brand Guide's neutral gray at the site owner's direction. Pattern, Retrofit, and Modal Hierarchy components updated; Brand Guide's Scale ramps and Accessibility notes updated to match. The Roadmap's color-reorganization and ecosystem-map items were removed, both now shipped.
-   Known incomplete: the Rural Collector table has several deliberate open gaps (NACTO and Complete Streets intersection cells, Dutch pedestrian cell, lane count outside the Commonway column). The separated-facility gap width for speeds of 45 mph and above is not yet specified anywhere in the publication. Four sources could not be independently verified: the Green Book Table 6-1 values beyond the highest-volume column, the AASHTO bike guide's wider-shoulder-above-50-mph figure, the Missouri 12 to 24 percent passing-lane figure, and the Dutch 60 km/h access-road speed. The 2+1 retrofit's applicability to Default (No Parking, No Direct Property Access) and Scenic Highway / Byway is by reasoning, not yet researched on those pages.

**2026.09.22**

-   Pattern Index illustration coverage expanded from 11 to 26 of 111 patterns. 15 patterns wired up with a real illustration for the first time: all 4 Network patterns (Grid, Dendritic / Hierarchical, Radial, Organic / Irregular), all 6 Corridor patterns (Density Step-Down / Step-Up, Rural-to-Town Gateway, Character Transect, Rail-With-Trail Corridor, Road-Adjacent Greenway, Transit Alignment Corridor), Bicycle Boulevard / Neighborhood Greenway and Shared-Use Path (Local Streets, completing that category), Bike Highway / Greenway (Collectors), Stroad (Arterials), Protected Intersection (Intersections & Crossings), and Sharrow plus Modal Filter / Point Closure (Elements). Artwork for 11 already-illustrated patterns (10 Local Street patterns plus Roundabout), the shared placeholder graphic, and the two Foundations-page diagrams was also refreshed with updated versions.
-   Kevin hand-placed every image file directly in `static/patterns/` outside of a session; each session's task was wiring the matching `image` prop into that pattern's card in `patterns/+page.md` and verifying it live. See CLAUDE.md for the updated convention, including a note that the extension isn't locked to `.png` (several new files are `.jpeg`) and a known filename typo (`net-den-02-dendritic-hierachical.png`) that's intentionally left as-is since the reference already matches it.
-   A 27th pattern illustration added: Turbo-Roundabout (Intersections & Crossings). Every Pattern Index, Retrofit Strategy Index, and Media Gallery card image now lazy-loads (`loading="lazy" decoding="async"`), confirmed live to only fetch images near the initial viewport rather than all of them at once.
-   New `GuideDiagram` component replaces the raw `<img>` tag on the four Foundations pages with a topic diagram (Density Tiers, Design Speed & Speed Limits, Scale Hierarchy, Street Types & Classifications), adding real width/height (for layout-shift prevention), an aspect-ratio fallback, and an optional caption via a real `<figure>`/`<figcaption>`, on top of the same lazy-loading. Documented on the Brand Guide. Building it surfaced a real sitewide bug, now fixed: `base.css`'s global image rule was missing `height: auto` alongside `max-width: 100%`, so any image carrying real width/height attributes had its height pinned to a fixed pixel value instead of scaling proportionally, visibly stretching it once the width was capped down to fit a narrower column. See CLAUDE.md for the full diagnosis.
-   New `AuthorPhoto` component adds a photo to the "About the author" section on `/about/commonway-system/`: a hardcoded 1:1 square crop, positioned beside the bio text on wider screens and stacked below it on narrow ones, with a "Kevin Young, Author, Commonway System" caption underneath. Internal links to that section were also added from two places that reference Kevin by name without one: the Acknowledgments page's opening line and the Project Governance page's opening line.
-   JSON-LD structured data now names Kevin as a co-author, not just the Commonway System Organization, on every pattern/guide/blog page's schema, alongside a `sameAs` set of his real profile links (personal site, LinkedIn, GitHub, Facebook, about.me) on the sitewide Organization's `founder` field too. A deliberate, requested reversal of this file's prior "Organization only, not a named author" stance for individual articles; the Organization stays the first author in the list, this only adds Kevin by name and profile links alongside it. See CLAUDE.md for the full reasoning.

**2026.09.14**

-   Four new Foundations pages gained a real illustration each: Scale Hierarchy, Density Tiers, Street Types & Classifications, and Design Speed & Speed Limits. Each is a single PNG, hand-placed directly in the page, styled automatically with a themed rounded-corner/border/shadow treatment so it reads as real content rather than a bare embed. See CLAUDE.md for the raw-`<img>`\-tag convention this follows.
-   New Media Gallery entry, MED-021 (Strong Towns, "The Key to Slowing Traffic is Street Design, Not Speed Limits"), tagged to the Design Speed & Speed Limits guide page. The Gallery's first `article`\-type entry, alongside its existing video and podcast items.
-   Retrofit Strategy Index section order changed from Corridor/Intersection/Network to Network/Corridor/Intersection, both in the sidebar and on the index page itself; the page's own intro text and frontmatter description were updated to match.
-   Homepage hero background tuning: the ink-halftone effect's dots now swell to a larger peak radius for a bolder look at full swell.

**2026.09.11**

-   New Guide page, "How the Transportation Ecosystem Fits Together" (guide/how-the-transportation-ecosystem-fits-together/), placed in Foundations directly after How to read a retrofit strategy. Explains the landscape of organizations that write street-design guidance, standards, and advocacy, MUTCD, PROWAG, NACTO, AASHTO, Strong Towns, CNU, Vision Zero Network, PPS, Complete Streets, Create Streets, CROW, SWOV, ITDP, grouped by how much binding authority each actually carries rather than by acronym or subject, and states plainly where Commonway System itself fits relative to all of it. 15 real, tiered citations, all sourced directly from each organization's own site or the governing federal regulation. Built from a written ticket; its raw `<sup class="citation">` markup was translated to the publication's real Citation/EvidenceChip components per the standing ticket-verification rule, and MED-013's Related Media tagging was extended to this new page.
-   New homepage hero background: the diagonal-line texture behind the hero title (`.hero-lines`) has been replaced with a native, from-scratch canvas animation, small halftone-style dots whose size swells and recedes in organic, varied-size clusters that drift gently rightward across the hero, evoking traffic flow along the roads and streets this guidebook is about. No third-party effects library, no purchased asset: built directly in Svelte with layered value noise, confined to a couple of curving path shapes so the motion itself reads as street-like rather than a generic background wipe. Respects reduced-motion preferences (a static, non-animated dot grid for anyone with that setting on) and leaves the hero's teal glow and dark background untouched. See CLAUDE.md for the full build and tuning writeup.

**2026.09.10**

-   Sitewide citation-link audit (Item 22) completed. All Pattern, Retrofit Strategy, and Guide pages with References sections now carry working outbound links to their primary sources, sourced and verified domain by domain across five batches: Guide pages plus all 17 Retrofit Strategy entries; the Design Speed guide page plus the Network, Corridor, Local Street, Collector, and Arterial pattern categories; Freeway, Intersection, and Facility patterns; Element patterns; and a final round of corrections (two citations updated to their current published editions, one retargeted to a federal source after its original NACTO page was retired).
-   Final tally, from a fresh sitewide crawl: 315 citations total across all Pattern, Retrofit, and Guide reference lists, 310 linked to a working source. The remaining 5 (not the 4 originally estimated) are the Network pattern citations marked "Print/ebook source, no persistent URL to monitor" across Grid, Dendritic / Hierarchical, and Organic / Irregular, intentionally unlinked per their own notes.
-   Pattern-count audit (Item 33): the live count is 111, not the 106 that had gone stale in a couple of places. Fixed in CLAUDE.md and in this page's own Roadmap section; every dated changelog entry below keeps its own historical count as written, per the standing rule that a changelog entry records the count at that date, not the current one. Found, but left for a separate decision: the 2026.08.28 launch entry's summary interpolates the live count instead of a fixed number, so it silently drifts and currently misstates what actually shipped that day.
-   Self-reference terminology audit and correction (Item 11): audited every `+page.md` and README.md for "website"/"site"/"book"/"guide" used as self-reference to this publication, then corrected roughly 106 instances across 21 files to the locked house style, "the publication" for format/medium self-reference and "the guidebook" for whole-publication content self-reference. "The Guide" naming this site's own `/guide/` section, every citation and external-document title, and a couple of generic analogies were confirmed as exemptions and left untouched. See CLAUDE.md for the full rule and its exemptions.
-   Public Roadmap section rebuilt as a direct mirror of the canonical Open Items table (tracked outside this repo), replacing a list that had drifted out of sync: nine grouped subheadings by area (New content, Structure changes, Existing content, Audits, New features, Design system, Standing / ongoing, External), one entry per Public item, no Private items and no internal-tracking detail. Kept in sync with the canonical table going forward per the standing Roadmap Sync process.

**2026.09.04**

-   New top-level Media Gallery section (`/media/`), added between Retrofits and Reference in the nav. A Media item is a small external reference, a YouTube video, podcast, or article, tagged with which Pattern pages, Retrofit Strategy pages, or Guide pages it relates to; the Gallery itself is a real, filterable/sortable index (search, plus checkbox filters for media type, source, and topic), not a static list. Launched with one seed entry (a Not Just Bikes video on continuous sidewalks); see below for same-day additions.
-   A companion "Related Media" section now appears on every Pattern page, every Retrofit Strategy page, and select Guide pages (Foundations, Make It Happen, and About → The Commonway System), showing only the media items tagged to that specific page. If nothing is tagged, the section renders nothing at all, no empty state, so it's live on all of those page types now even though only a handful currently show anything.
-   Two real gaps in the source ticket were found and resolved before building, rather than built around silently: the ticket described reusing "the existing Form Controls component pattern already used on the Pattern Index" for the Gallery's filters, but no working version of that exists anywhere on the publication (the closest match is an explicitly decorative, non-functional Brand Guide mockup); the Gallery's filtering is new, real client-side logic. Separately, the ticket's media-tagging field only supported Pattern IDs and Retrofit Strategy IDs, but Related Media was also specified for Guide/About pages, which have neither; that field now also accepts a page's own route path. See CLAUDE.md for the full writeup.
-   Data architecture note for future sessions: media items are the first "data record" content type in this publication, distinct from Patterns/Retrofit Strategies/Guide pages (which are full hand-authored content pages with no queryable structure behind them). Each media item is one small TypeScript file, checked by `pnpm run check` against a shared schema, not a markdown page — see CLAUDE.md's new "Media Gallery & Related Media" section for the reasoning, and for what a future session needs to hand over to add another item to the library.
-   Follow-up layout request: `/media/` was rebuilt from the sitewide 3-column template (sidebar, content, table of contents) into a page-specific 2-column layout, main content on the left, search/filter/sort controls stacked vertically on the right in place of the table of contents, since neither a sidebar nor page headings made sense for this page. A second follow-up capped Related Media's own card grid at 2 columns, decoupled from the Media Gallery page's own grid, which stays at 3.
-   Same-day second batch: four more Media Gallery entries added (MED-002 through MED-005, three City Beautiful videos and one BicycleDutch video), from a second written ticket. The Gallery now shows 5 items and 3 distinct sources; Related Media now shows real content on a much wider set of pages, including several tagged by more than one entry at once (Protected Intersection carries both a general "are streets too complicated" video and a Dutch protected-intersection design video, for instance). The ticket asked for one specific check before implementing: that all 47 `relatedTo` IDs across the four new entries actually resolve to live pages, rather than trusting the list as given. All 47 did; nothing needed flagging or fixing.
-   Mobile layout fix and redesign for the Media Gallery's filter panel: scrolling on a narrow screen used to make the filter panel visually overlap the results grid underneath it (a sticky-positioning bug, only surfaced once someone actually scrolled past it on a phone), and separately, the panel was permanently expanded there, pushing every result below the fold. Both are fixed: the panel is now a native, collapsible disclosure on mobile, collapsed by default, positioned right before the results count instead of above the page title, while desktop keeps the original always-expanded, non-collapsible panel with no changes to its behavior.
-   Third Media Gallery batch: 15 more entries (MED-006 through MED-020) from a batch explicitly submitted as an unfinished draft rather than a ready ticket, since it named patterns/retrofits by title only and needed the real ID codes looked up against this publication's own frontmatter. Four judgment calls the draft flagged for a human decision were confirmed before implementing: a Vision Zero-themed video with no clean pattern fit now tags the About page that discusses CS's philosophical grounding directly; a stroads/road-classification explainer now also tags the Guide page on Functional Classification; a turbo-roundabout video's endorsement was set to "context-only" rather than "aligned," since the video itself reports the design's documented pedestrian/cyclist tradeoffs; and a suggested new Retrofit Strategy for rural highway safety was deliberately held off as its own future ticket rather than folded into a media-only batch. The Gallery now holds 20 items across 7 sources.
-   One direct fix: MED-002's own `relatedTo` list was missing Cul-de-sac, despite the video itself being specifically about cul-de-sac subdivisions. Added on request.

**2026.09.03**

-   Retrofit Strategies Batch 1 scaffolding: five new Guide pages, built from a written ticket (an instructions file plus five content files), that lay the groundwork for the Retrofit Strategy catalog landing in Batch 2. No Retrofit Strategy entries exist yet, none of these pages have anything real to cross-link to as a catalog entry, they only build what a future entry will point at.
-   Four new pages published under Guide → Make It Happen: Legal & Planning Mechanisms (right-of-way control tools and policy mechanisms that make a retrofit possible in the first place), Funding & Financing Mechanisms (eight value-capture tools in a structured what-it-is/purpose/revenue/leveraging format), Decision & Evaluation Processes (Intersection Control Evaluation and the Road Safety Audit), and Construction Methodology & The Build Spectrum (the four-stage demonstration/pilot/quick-build/permanent framework, plus CS's own "test before you pour" position). All four carry real, tiered citations.
-   A fifth new page, How to read a retrofit strategy, was placed in Foundations directly under How to Read a Pattern rather than in Make It Happen. It documents the future `RFT-SCALE-##` ID format (SCALE is Corridor/Intersection/Network) and what each section of a Retrofit Strategy entry will contain, once real entries exist. Initially scaffolded into Make It Happen alongside its four batch-mates, then corrected once flagged: it's structurally How to Read a Pattern's sibling, not a Make It Happen tool, and pagination follows sidebar position. See CLAUDE.md for the full reasoning and the house rule this sets for future batches that mix structural roles.
-   How to Read a Pattern and How Road Changes Actually Happen both gained cross-references into the new pages at their existing natural attachment points (a corridor-preservation aside, an engineering-study/warrant discussion, a capital-project discussion), rather than a bolted-on "see also" list.
-   Citation format in the source ticket (italic evidence-tier labels, no inline markers in the prose) was translated to the publication's real `EvidenceChip`/`Citation` components rather than transcribed literally, per the standing ticket-verification rule; inline citation badges were added by hand at the closest topical match for each reference, so nothing in the four new References lists sits orphaned with no inline attachment point.
-   Retrofit Strategies Batch 2: the catalog itself. A new top-level Retrofits section (`/retrofits/`, sibling to Patterns in the navbar) now holds all 17 real `RFT-SCALE-##` entries, 10 Corridor, 4 Intersection, 3 Network, plus its own index page, built from a second written ticket (an instructions file plus 23 content files). A new `RetrofitCard` component gives each entry the same visual ID-card treatment Patterns use, with a Corridor/Intersection/Network scale label in place of a status badge, since Retrofit Strategies are never endorsed or discouraged, only applicable or not.
-   Six new patterns landed alongside the catalog, needed as real destinations for the new strategies: Modal Filter / Point Closure, Median Island, and Neighborhood Traffic Circle / Mini-Roundabout (Elements); Median U-Turn, Restricted Crossing U-Turn, and Displaced Left-Turn (Intersections & Crossings, all three Situational by design, a narrow-context fit rather than a broad default).
-   A new "Getting there: Retrofit path options" section, the piece deliberately deferred from Batch 1, is now live on 22 pattern pages, pointing each one at the Retrofit Strategy or Strategies that lead to it. Ten existing pages (Bollard, Curb Extension, Bicycle Boulevard, Pedestrian Safety Island/Refuge, Boulevard, Roundabout, All-Way Stop, Vertical Speed Control, Signal, Grade-Separated Interchange) also gained reciprocal Related Patterns links back to the six new patterns.
-   Verified against a real `pnpm run build`, not just `pnpm run check`: all 24 new pages' internal links and citation anchors resolved cleanly under strict prerendering on the first build. See CLAUDE.md for the full build, including the Network-scale "applies within, not leads to" phrasing rule and the mixed-scale Pattern-ID reference in the three protected-bike-lane retrofits.
-   Same-day follow-up: the Retrofit Strategy Index (`/retrofits/`) was rebuilt from a plain numbered list into a card grid matching the Pattern Index, via a new `RetrofitIndexCard` component. Coloring for both the new index card and the existing Retrofit Strategy ID card now follows each strategy's functional Pattern peer rather than a separate palette: Intersection strategies use the real Intersections & Crossings ramp, Corridor and Network strategies share Patterns' own still-placeholder Freeway-gray. Both components are now documented on the Brand Guide alongside their Pattern-catalog counterparts.

**2026.09.02**

-   Merged Commercial Arterial (ART-CAR-07) into Stroad (ART-STD-05). Commercial Arterial and Stroad were the same failure mode under two names; Stroad's page now covers both, with citations merged from both original pages. ART-CAR-07 is retired and not reassigned. 301 redirect in place.
-   All 11 Intersections & Crossings pattern pages gained a Recommended/Situational status badge, applied to both the page's own Pattern ID card and its Pattern Index row (Protected Intersection already had Recommended; the other 10 are new). Reverses the publication's prior documented convention that intersections carry no status; see CLAUDE.md. Uncontrolled's Design notes also gained one sentence pointing to Stop / Yield as the next control tier once volume rises past the point Uncontrolled stays safe.
-   New "Descriptive" status badge added for patterns documented as an existing condition rather than a design recommendation. Applied to Organic/Irregular (NET-ORG-04), resolving its previously flagged pending-decision callout. No other pattern currently qualifies.
-   New `static/_redirects` file added for a real Netlify-level 301 (the Commercial Arterial → Stroad merge above needed one, and `adapter-static` has no server-side way to produce a redirect on its own). CLAUDE.md updated throughout to document all of the above, including a new working-convention note on verifying a written ticket's concrete claims (citation markup, token values) against the actual code rather than transcribing them literally.
-   Bicycle Boulevard / Neighborhood Greenway (LOC-BBG-12) fully rewritten, dropping its "demonstrates the components" placeholder framing for real content: a Paired illustration, Modal hierarchy, Design notes with 2 real tiered citations, and a Related patterns section. It was the last of the 106 live pattern pages still carrying placeholder content or the "Unsourced claim" flag.
-   Four pattern pages converted off a non-standard "Why this pattern exists" / "Key considerations" template onto the publication's standard Modal hierarchy → Design notes structure: Parkway, Downtown Thoroughfare, Multi-Use Trail / Greenway, and Shared-Use Path. Existing citation numbers and their attachment points were preserved on all four; only the surrounding prose and headings changed.
-   New `Illustration` component system built for the Brand Guide's illustration spec (a Paired/Single-condition/Diagram/Descriptive/Conditional frame-and-callout renderer, standing in for real vector art until each pattern's illustration gets drawn) and applied to Local Default (LOC-DEF-01, replacing its old "no illustration yet" placeholder note, and adding a new NACTO reference) and Stroad (ART-STD-05, a required Single-condition illustration plus a justified plan-view supplemental). This is a sitewide component now available for every pattern page's Illustration section, but illustration content has only been authored for these 2 pages plus Bicycle Boulevard above; the other ~103 pattern pages still have none.
-   Fixed a cosmetic sidebar bug: the Patterns sidebar showed "Stroad / Commercial Arterial (Avoid)" for the Stroad entry, inconsistent with the page's own "Stroad (Commercial Arterial)" title set during the 2026.09.02 merge above. Now matches.
-   Related patterns rollout completed: the 35 pattern pages still missing a Related patterns section (11 Local, 5 Collector, 5 Arterial, 4 Freeway, 10 Intersections) all got one. Every one of the 105 live pattern pages now carries exactly one. Protected Bike Lane / Cycle Track (ELM-PBL-37) also gained a 4th Key Considerations bullet citing its existing NACTO reference, which had been listed but never cited inline.
-   How to Read a Pattern gained two new sections matching the publication's current pattern-page structure: "Illustrations," explaining the Paired/Single-condition/Diagram/Descriptive illustration forms in reader-facing terms, and "Related patterns," describing the cross-reference list every pattern page now ends with. Two stale cross-references on the same page were also fixed: the citation-example pointer and the Caution-admonition example both used to point at Bicycle Boulevard sections that no longer exist after its rewrite above; the Caution example now points at a real, verified example on One-Way Street instead.
-   Post-verification cleanup: a leaked instruction sentence ("Citation badge 1 also appears once more, in Illustration callout 3 above") was found rendering as live page text on Bicycle Boulevard, immediately after Design notes — meta-commentary from the drafting process that should never have been visible content. Removed; a sitewide scan turned up no other instances. The Pattern Index's Arterial table had a visible numbering gap (skipping straight from 6 to 8) left over from the Commercial Arterial retirement, since the Pattern Index card's number badge is drawn directly from the Pattern ID's own trailing digits. Closing it meant renumbering Parkway from ART-PKY-08 to ART-PKY-07, a one-time, explicitly authorized exception to the publication's normal "IDs are never reassigned" rule, made only because the publication is four days old and not yet public; see CLAUDE.md for the full reasoning and the house rule this sets for any future case. The Commercial Arterial → Stroad redirect itself was double-checked and confirmed already correctly in place from earlier the same day.
-   New Guide page, "Design Speed & Speed Limits" (guide/design-speed/, under Foundations): explains why design speed, operating speed, and posted speed limit diverge, and states the Commonway System's own rule, design speed always equals posted speed, with concrete numbers by Character Type. Built from a user-supplied ticket; its raw citation HTML was translated to this publication's real Citation/EvidenceChip components rather than transcribed literally.
-   New Speed & Modal Hierarchy card component system (SpeedModalHierarchyCard, SpeedLimitSection, ModalHierarchySection, ModalHierarchyRow, ModalHierarchyPill, SpeedLimitSign), replacing the old plain "Modal hierarchy" heading and list on all 23 automobile-allowing Local, Collector, and Arterial pattern pages, and extended in a Modal-Hierarchy-only form to the 4 patterns that exclude automobiles entirely (Pedestrian-only Street/Plaza, Shared-Use Path, Bike Highway/Greenway, Multi-Use Trail/Greenway). Section A renders one MUTCD-style speed-limit sign per applicable speed (stacked above the description on Arterial pages, which can carry up to 5 at once; side by side on Local/Collector); Section B renders one colored pill per mode, ">" between ranked modes and "=" for an explicit tie (a real case on Shared-Use Path and Multi-Use Trail/Greenway's own equal-priority Pedestrian/Bicycle pairing). Two further special cases: Stroad shows signs with no pill row at all, since it has no ranked hierarchy to show; Festival Street and School Street each show two labeled pill rows, since their hierarchy changes by time of day.
-   Pill icons are 5 exact icons from the Lucide icon set (person-standing, bike, tram-front, car, truck), supplied directly by the user and used under Lucide's ISC license. New THIRD-PARTY-NOTICES file added at the repo root for this and any future embedded (not npm-dependency) third-party asset, linked from the Terms and Conditions page's "Code and content licensing" section.
-   Arterial's pill color is a documented accessibility exception, not a silent pass: black technically clears WCAG contrast against Arterial's green in both light and dark mode, but reads far less legibly in practice than white, so Arterial pills are fixed white in both modes with a dark text-shadow/icon-shadow glow standing in for the missing contrast margin, a real, computed shortfall rather than an estimate. Documented as a "Fail (mitigated)" row in the Brand Guide's Accessibility notes table, the same treatment already given the publication's other known, flagged color exceptions.
-   How to Read a Pattern gained a new "The Speed & Modal Hierarchy card" section (between Density tiers and Admonitions) with a live rendered demo. Brand Guide's Components section gained two new entries, "Speed & Modal Hierarchy card" and "Modal hierarchy pills," plus 6 new Accessibility notes rows with contrast ratios computed directly against the real tokens.css values.

**2026.09.01**

-   Full citation sourcing completed for the rest of the guidebook: 93 pattern pages gained real References sections and inline citation badges (46 pages already had References from an earlier session but no inline badges, so those got badges only; 47 pages, mostly Corridor, Local Street, Collector, Arterial, Freeway, and Intersection typologies, got References and badges built from scratch). 105 of the 106 live pattern pages now carry real citations; only Bicycle Boulevard / Neighborhood Greenway remains flagged, a confirmed placeholder page left that way on purpose. Sources include AASHTO, MUTCD (11th Edition with Revision 1), NACTO, PROWAG, FHWA, NCHRP research reports, and CROW/SWOV for the Dutch Sustainable Safety citations, each tagged Legal/regulatory, Evidence-based, or Precedent-based.
-   Fixed a real bug in the navbar’s CalVer version number: it was computed from the build machine’s wall clock at build time, which isn’t always the same moment as the last real push, so re-running a Netlify build against an already-published commit (a manual redeploy, a cache-clear-and-rebuild, an automatic retry) silently advanced the version past the date anything was actually published, confirmed live when the navbar read one day ahead of every page’s own "Last updated" text. The version is now computed from the last commit’s own date instead (`src/routes/+layout.server.ts`), so it only changes when new content is actually pushed, and stays correct no matter how many times the same commit gets rebuilt. The development server is unaffected and still shows the live current date while editing.
-   New Pattern IDs page published under Guide → Foundations: the nine-prefix Scale table and status-badge explanation that used to live inline on How to Read a Pattern now have their own page, linked from How to Read a Pattern, Scale Hierarchy, and Street Types & Classifications. How to Read a Pattern's own Pattern ID card section is now shorter and leads with a live example card (reusing the Brand Guide's illustrative "Urban main street" sample) instead of the full reference table, so a reader sees a real card before reading about its parts.
-   Make It Happen chapter published under Guide, resolving the Roadmap's "Process-explainer chapter" item: "How Road Changes Actually Happen," a four-question method for finding out who has authority over a specific road and how to actually request a change, covering restoring vs. adding vs. changing a standard everywhere, public vs. private roads, splits in jurisdiction, and the seven ways a request gets processed once the right authority is found. A companion reference page, "When Jurisdiction Doesn't Follow the Pattern," catalogs real documented exceptions (consolidated city-counties, independent cities, tribal land overlaps, special districts, and more) that don't fit the general method cleanly. Both carry real citations. The Guide intro page and the Make It Happen sidebar group were updated to match.

**2026.08.31**

-   Pattern ID scheme corrected sitewide: Segment/Intersection (LOC/COL/ART/FRE/INT) was previously the only Scale documented as encoding Scale in its prefix. The full nine-prefix system is now in place and documented: NET (Network), CDR (Corridor), FAC (Facility), and ELM (Element) as flat, non-subdividing Scale prefixes, alongside the existing five Functional Classification prefixes at Segment/Intersection. How to Read a Pattern, Scale Hierarchy, and Street Types & Classifications all rewritten to describe the corrected scheme.
-   Three new live Segment/Intersection pattern pages: Shared-Use Path (LOC-SUP-13), Multi-Use Trail / Greenway (COL-MUT-06), and Protected Intersection (INT-PRI-11, the first new Intersections & Crossings entry since the original ten). Added to the Pattern Index card grid and sidebar; pattern count reached 40.
-   A new "On the Horizon" section was briefly added to the Pattern Index listing 63 named-and-scoped-but-not-yet-built patterns as descriptive reference tables; superseded later the same day, see below, once all 63 became real pattern pages.
-   Full Network/Corridor/Facility/Element pattern batch built out: all 63 previously-scoped patterns (4 Network, 6 Corridor, 10 Facility, 43 Element) now have real pattern pages, plus 3 more new Segment/Intersection patterns resolving every item on the old "under review" list: Downtown Thoroughfare (COL-DTH-07), Commercial Arterial (ART-CAR-07, a documented anti-pattern), and Parkway (ART-PKY-08). Live pattern count is now 106. Avenue and the Downtown One-Way/Two-Way Street cluster, also once "under review," were deliberately not built: Downtown One-Way is just the existing One-Way Street (ART-OWS-06), and Avenue was dropped from consideration.
-   Pattern Index page fully restructured: the old five-classification-plus-two-appendix layout (Local/Collector/Arterial/Freeway/Intersections, "Under review," "On the Horizon") is now nine Scale-ordered sections (Network, Corridor, Local street, Collector street, Arterial street, Freeway, Intersections and crossings, Facility level, Element level), every section a full card grid, no more plain-bullet or table-only appendix sections. Sidebar restructured to match, 9 groups in the same order. JSON-LD Pattern Index ItemList now reflects all 106 patterns automatically, since it derives from the sidebar tree rather than being hand-counted.
-   PatternCard and PatternIndexCard gained four new classification values (network, corridor, facility, element), all sharing Freeway’s existing neutral-gray ramp as a placeholder color pending real Brand Guide colors for those Scales, flagged inline in both components. Organic/Irregular (NET-ORG-04) renders without a status badge, a flagged, not-yet-confirmed treatment for its own descriptive (not prescriptive) case, since the publication’s Recommended/Situational/Avoid system doesn’t have an equivalent value; see the page’s own note callout and this file’s Known gaps section.
-   Brand Guide’s illustrative "Urban main street" PatternCard demo renumbered from ART-UMS-07 to ART-UMS-09: the collision this file had been flagging as a future risk actually happened once Commercial Arterial and Parkway became real 7th/8th Arterial Typologies.

**2026.08.30**

-   Homepage rebuilt from scaffold placeholder text into a real Hero / differentiator-strip / features-grid page, with three new components (Hero, EvidenceStrip, FeatureGrid) and two new PageLayout frontmatter flags (hideTitle, wide) for pages that need their own custom-placed h1 or a wider-than-prose content column.
-   Homepage hero redesigned to be full-bleed edge to edge and permanently dark regardless of the publication’s own light/dark toggle, with a subtle animated lane-line texture and a teal glow behind the logomark (both respecting prefers-reduced-motion), and a 60vh minimum height. New GlobalLayout mechanism (isHome) collapses the sidebar/toc grid to a single full-width column on the homepage only, since neither ever has content there.
-   Differentiator strip (the "why this guidebook is different" evidence-tier callout) redesigned from an amber box, which read as a warning notice, to a teal feature-highlight treatment matching the evidence chips’ own palette; its "learn more" link now uses the publication’s standard hyperlink styling instead of a custom color.
-   Differentiator strip and feature grid widened to match the navbar’s own 88rem measure, instead of the narrower 46rem prose column every article page uses.
-   /about/credits/ moved for real to /about/acknowledgments/ (route, not just display title this time), with every cross-link updated to match.
-   Guide section rebuilt: sidebar regrouped into Foundations, Find Your Pattern, and Make It Happen (the Introduction page now an ungrouped "Start Here" entry at the top, same idea as About’s own Overview item). New Scale Hierarchy page split out of the Introduction page’s old content. Two new placeholder pages, Find Your Pattern and Make It Happen, each with real explanatory copy and the standing "planned but not yet written" callout, one per new sidebar group so nothing has to move once each becomes a real page sequence.
-   JSON-LD structured data added publication-wide: an Organization and WebSite block on every page, plus a BreadcrumbList and a template-appropriate schema.org type (TechArticle for Guide/Reference/pattern pages, CollectionPage for the Pattern Index, AboutPage/WebPage for About, Blog/BlogPosting for the blog) generated from each page’s own frontmatter, no per-page authoring. Every page’s frontmatter gained a date field (datePublished, backfilled from its existing "last updated" date) and every pattern page gained a patternId field, now the single source for the Pattern ID card’s id instead of a hardcoded literal.
-   Pattern Index page (/patterns/) rebuilt from a plain bulleted list into a card grid: a new PatternIndexCard component per Street Typology, with a recolored image area (classification-ramp tint, swappable per-pattern illustration once one exists), a number badge, and a status badge for Situational/Avoid entries. A new shared StatusBadge component now backs both this and the existing Pattern ID card’s own status pill. Real illustrations added for 11 of the 37 patterns so far, all of Local Streets except Bicycle Boulevard, plus Roundabout. Added to the Brand Guide’s component showcase. The classification section intros on this page were also rewritten into plainer-language prose.
-   New Intersections & Crossings color ramp (six tiers, built from #8A5A13), resolving the classification’s old single-color placeholder the same way the guidebook’s other four ramps work; documented on the Brand Guide alongside them. Flagged, not resolved: this hue sits within about a degree of the publication’s reserved warning amber.
-   Mobile navbar layout fixed: below 940px, the version date, GitHub icon, and theme toggle used to clump on the left with empty space on the right once the primary nav links collapsed into the hamburger drawer. All five elements (logo, hamburger, version, GitHub, toggle) now space evenly edge to edge, with icon tap targets kept at their full size and the wordmark logo shrunk to make room on the narrowest phones.
-   Known incomplete: the new Scale Hierarchy page’s Network/Corridor/Facility/Element definitions carry over wording from an earlier planning session that was never formally re-confirmed as final; pending a maintainer read-through. Separately, found but did not fix a pre-existing bug: the mobile hamburger button doesn’t actually open the sidebar drawer on any viewport, confirmed on an unmodified copy of the publication, so the drawer’s nav links and page sidebar are currently unreachable on mobile.

**2026.08.29**

-   Pattern ID format finalized as CLASS-CTXCODE-## (e.g. LOC-BBG-12), replacing the old SCALE-CTXCODE-### scheme. Applied across every pattern page, the Pattern Index, and every illustrative example, confirmed with a full-repo search for zero remaining old-format IDs.
-   Bicycle Boulevard’s placeholder ID resolved to LOC-BBG-12; the Brand Guide’s separate "Urban main street" demo card migrated to ART-UMS-07.
-   PatternCard gained a status badge (Recommended, Situational/Discouraged, Avoid), applied to every Local, Collector, Arterial, and Freeway pattern page. Intersections & Crossings entries intentionally carry no status, matching the master reference.
-   Default (Standard Local Street) rewritten with real content and cross-links to every other Local Typology and to Continuous Sidewalk/Raised Junction.
-   New Release History & Roadmap page published under About, with a live pattern-page count and current-version date computed from the publication’s own routes rather than hardcoded.
-   Google Analytics wired up (GA4), loading only in production builds, never during local development.
-   sitemap.xml added and submitted to Google Search Console; robots.txt now points crawlers at it.
-   Fixed a mobile navigation bug: the hamburger drawer only ever showed a page’s own sidebar tree, never the navbar’s primary links (Guide, Pattern Index, About), which made them unreachable on narrow viewports, including the homepage.
-   Density Tiers and Street Types & Classifications published under Guide: the six density tiers with their ITE/CNU transect equivalents and unit-per-acre ranges, and what a Functional Classification and a Street Typology actually are, indexing every Typology by classification.
-   How to Read a Pattern rewritten with real content: the Pattern ID format, classification colors and status badges, all five admonition kinds, and how citation badges work.
-   Citation badges now link down to their numbered source entry publication-wide, instead of being plain unlinked numbers.
-   About section filled in with real content: Contributing / Volunteering, Governance, Reporting, and a new Credits page (a data-driven contributor list, currently empty pending the first real contribution). New Terms and Conditions, Privacy Policy, and AI Policy pages published alongside them.
-   Added the GitHub-side contributor infrastructure those About pages point to: issue templates (factual error, missing citation, dead link, accessibility), a pull request template, and a CODE\_OF\_CONDUCT.md. Added a root LICENSE (MIT, covering the publication’s code only) and documented the code/content license split in the README.
-   Every page now shows a real "Last updated" date next to its edit link, sourced from git history at build time rather than filesystem metadata (which a fresh deploy checkout would otherwise reset on every file).
-   Added "Share" buttons (X, Facebook, LinkedIn, Reddit, Bluesky, email, copy-link) to every page: plain outbound links only, no third-party share-button script or tracking, consistent with the Privacy Policy.
-   The version number in the navbar is now a link to this page.
-   Fixed a real production-build failure: the Brand Guide’s illustrative citation demo linked to a citation anchor that doesn’t exist, which `adapter-static`’s strict prerendering treats as a hard build error rather than a soft dead link.
-   Street Types & Classifications gained 10 real citations (Stroad, Street Typology, Living Street/Woonerf, Yield Street, Turbo-Roundabout, plus the three sources behind the Dutch CROW comparison table), mph conversions alongside every km/h speed figure, and working links from that comparison table straight to each pattern’s real CS equivalent page.
-   Wide tables now scroll horizontally in their own box instead of overflowing the page: a themed edge-fade shadow, a thin scrollbar, and a “scroll for more” hint shown only once a table actually overflows. Applied publication-wide through a new rehype plugin, not hand-added per table, and built as a wrapper around the table rather than changing the table’s own CSS display, so screen readers keep the table’s native semantics.
-   Evidence-tier chips (Legal/regulatory, Evidence-based, Precedent-based) rolled out to every citation on Density Tiers and Street Types & Classifications, and made a standing house rule going forward: every new citation gets one. The Contributing page’s review checklist now says so explicitly.
-   Sitewide URL restructure: the navbar is now Home / Guide / Patterns / Reference / Blog / About. All 37 pattern pages and the Pattern Index moved out of Guide into their own Patterns section; Guide now holds only its 4 remaining non-pattern pages. Two new sections launched: Reference (explaining the technical-detail layer planned beneath pattern pages, not yet populated) and Blog (a dynamically generated index, one welcome post so far).
-   About’s sidebar split into three groups, About/Development/Terms and Policies, and four of its pages got new display titles without changing their URLs: Governance → Project Governance, Contributing / Volunteering → Submit a Change, Reporting → Report a Problem, Credits → Acknowledgments.
-   Fixed this page’s own live pattern-page count, which had silently dropped to 0 after the Patterns move since the script computing it still pointed at the old guide/ path.

**2026.08.28**

Initial public launch of commonwaysystem.org, deployed through Netlify with a custom SveltePress theme. Guide structure established: Introduction, Pattern Index, How to Read a Pattern, and the first 37 Street Typology pattern pages across Local, Collector, Arterial, Freeway, and Intersections & Crossings.

## Publishing checklist and build notes

Before pushing a batch of work to GitHub, draft a short build note summarizing what changed since the last push. This does two things: it gives the changelog entry above something accurate to draw from, and it gives a checkpoint to review the work before it goes live.

A build note doesn't need to be long. Cover:

-   What content changed (new pattern pages, edits to existing ones, corrected data)
-   What structural or publication changes shipped (new components, navigation changes, styling updates)
-   Anything left in a known-incomplete state (a page that's live but flagged with an unsourced claim, a section still under review)

## Roadmap

Work that's planned but not yet built, grouped by area.

### New content

-   **Induced Demand page.** A new Guide page on induced demand, connected to the patterns, retrofit strategies, and Media Gallery entries it relates to.
-   **Traffic Calming page.** A new Guide page on traffic calming, connected to the patterns and retrofit strategies it relates to.
-   **Hoofdnet/Plusnet methodology page.** A new Guide page on the Dutch Hoofdnet/Plusnet road-network methodology.

### Structure changes

-   **Classification overview pages.** Landing pages for Local, Collector, Arterial, and Freeway, sitting between the Pattern Index and individual Street Typology pages, which currently jump straight from one to the other.
-   **Dutch CROW reconciliation.** Folding an internal CROW-comparison reference into the actual Commonway System patterns.

### Existing content

-   **Commonway System page update.** A refresh of `/about/commonway-system/` with clearer information for a first-time visitor.
-   **Brand Guide page update.** Finalizing `/about/brand-guide/` as the canonical brand reference, including documentation for components not yet covered there.
-   **Related Media placement decision.** Finalizing which page a specific Related Media item currently tagged to the Commonway System page actually belongs on.

### Audits

-   **Website specification audit.** A full audit of the publication against the checklist at specification.website.

### New features

-   **Find Your Pattern tool.** A two-part diagnostic tool plus an interactive, clickable hotspot map.
-   **Photo Gallery feature.** A new media type usable on any page: ordinary photos, before/after comparison sliders, and map-based street-level photos.
-   **Related Media refinements.** Improvements to how the Related Media component displays.

### Standing / ongoing

-   **Illustration system rollout.** Extending real illustration content beyond the handful of pattern pages that currently have it.
-   **Bike Highway / Downtown Thoroughfare content pass.** A future revision pass on these two pattern pages.
-   **Binding-adoption template.** A future, separate model template for formal municipal adoption.
-   **More media items.** Ongoing additions to the Media Gallery as new sources come up.

### External

-   **Rosetta Places citation.** Rosetta Places will cite the Commonway System by name once it reaches a citable state.

---

Source: https://commonwaysystem.org/about/reporting/

# Report a Problem

Noticed something wrong but don't want to fix it yourself? This is the fast path: no writing, no pull request, just flag it and someone else takes it from here.

If you'd rather submit the actual fix yourself, correcting the text, adding the missing citation, see [Submit a Change](https://commonwaysystem.org/about/contributing.md) instead.

## What to report here

-   **A factual error**: a wrong figure, an outdated rule, a description that no longer matches the current guidance
-   **An unsourced claim**: something that should carry the unsourced-claim flag⚠ but doesn't, or something flagged that you believe now has a source available
-   **A dead citation link**: a source URL that no longer resolves or redirects somewhere unexpected
-   **An accessibility issue**: anything that makes the publication harder to use with a screen reader, keyboard navigation, or at different zoom levels

## How to report it

Open a GitHub issue using the [issue template that matches what you're reporting](https://github.com/Commonway-System/commonwaysystem.org/issues/new/choose): Factual error, Missing citation, Dead link, or Accessibility issue. Each template asks for the page URL and what's wrong, so a report can be triaged without back-and-forth. If your report doesn't fit any of those, a blank issue works too. You don't need a GitHub account to read an issue, but you do need one to open one, since that's how the maintainer can follow up with you if there are questions.

## What happens after you report something

A reported error is checked against the same evidence-tier system used everywhere else in the guidebook: legal/regulatory sources outrank evidence-based sources, which outrank precedent-based ones. A dead citation link gets one of two treatments: if the source moved, the link is updated and an archive snapshot is kept as a backup; if the source is genuinely gone, the citation is re-flagged with the unsourced-claim flag until a replacement is found.

Reports don't require a response window or a guaranteed timeline, since this is a single-maintainer project, but every report is read and triaged.

## Safety-relevant errors

If you're reporting something you believe could lead someone to make an unsafe real-world design decision, say so explicitly in the issue, the Factual error, Missing citation, and Dead link templates each ask directly. Those get looked at first.

---

Source: https://commonwaysystem.org/about/sitemap/

# Site Map

Every page of the publication in one place, grouped the same way as the navigation. This list is built from the site itself each time it is published, so a new page appears here automatically. To find something by topic instead, use [Search](https://commonwaysystem.org/search/). For the ways to browse without this page, see [Other ways to browse](#other-ways-to-browse) at the end.

## Home

-   [Commonway System](https://commonwaysystem.org/index.md)

## Guide

-   [Start Here](https://commonwaysystem.org/guide.md)

### Foundations

-   [How to read a pattern](https://commonwaysystem.org/guide/how-to-read-a-pattern.md)
-   [How to read a retrofit strategy](https://commonwaysystem.org/guide/how-to-read-a-retrofit-strategy.md)
-   [How the Transportation Ecosystem Fits Together](https://commonwaysystem.org/guide/how-the-transportation-ecosystem-fits-together.md)
-   [Pattern IDs](https://commonwaysystem.org/guide/pattern-ids.md)
-   [Density Tiers](https://commonwaysystem.org/guide/density-tiers.md)
-   [Street Types & Classifications](https://commonwaysystem.org/guide/street-types.md)
-   [Scale Hierarchy](https://commonwaysystem.org/guide/scale-hierarchy.md)
-   [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md)

### Find Your Pattern

-   [Find Your Pattern](https://commonwaysystem.org/guide/find-your-pattern.md)

### Make It Happen

-   [How Road Changes Actually Happen](https://commonwaysystem.org/guide/make-it-happen.md)
-   [When Jurisdiction Doesn't Follow the Pattern](https://commonwaysystem.org/guide/make-it-happen/jurisdiction-variants.md)
-   [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md)
-   [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md)
-   [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md)
-   [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md)

## Patterns

-   [Pattern Index](https://commonwaysystem.org/patterns.md)

### Network

-   [Grid](https://commonwaysystem.org/patterns/network/grid.md) `NET-GRD-01`
-   [Dendritic / Hierarchical](https://commonwaysystem.org/patterns/network/dendritic-hierarchical.md) `NET-DEN-02`
-   [Radial](https://commonwaysystem.org/patterns/network/radial.md) `NET-RAD-03`
-   [Organic / Irregular](https://commonwaysystem.org/patterns/network/organic-irregular.md) `NET-ORG-04`

### Corridors

-   [Density Step-Down / Step-Up](https://commonwaysystem.org/patterns/corridors/density-step-down-step-up.md) `CDR-DSD-01`
-   [Rural-to-Town Gateway](https://commonwaysystem.org/patterns/corridors/rural-to-town-gateway.md) `CDR-RTG-02`
-   [Character Transect](https://commonwaysystem.org/patterns/corridors/character-transect.md) `CDR-CTR-03`
-   [Rail-With-Trail Corridor](https://commonwaysystem.org/patterns/corridors/rail-with-trail-corridor.md) `CDR-RWT-04`
-   [Road-Adjacent Greenway](https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway.md) `CDR-RAG-05`
-   [Transit Alignment Corridor](https://commonwaysystem.org/patterns/corridors/transit-alignment-corridor.md) `CDR-TAC-06`

### Local Streets

-   [Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md) `LOC-DEF-01`
-   [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md) `LOC-ALY-02`
-   [Cul-de-sac](https://commonwaysystem.org/patterns/local-streets/cul-de-sac.md) `LOC-CDS-03`
-   [Frontage / Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md) `LOC-FSR-04`
-   [Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md) `LOC-MST-05`
-   [Living Street / Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md) `LOC-LSW-06`
-   [Yield Street](https://commonwaysystem.org/patterns/local-streets/yield-street.md) `LOC-YLD-07`
-   [Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md) `LOC-FES-08`
-   [Pedestrian-only Street / Plaza](https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza.md) `LOC-PED-09`
-   [Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) `LOC-LTR-10`
-   [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) `LOC-BBG-12`
-   [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md) `LOC-SCH-11`
-   [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md) `LOC-SUP-13`

### Collectors

-   [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) `COL-DEF-01`
-   [Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) `COL-FTM-02`
-   [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) `COL-IND-03`
-   [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) `COL-BHG-04`
-   [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) `COL-CTR-05`
-   [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) `COL-MUT-06`
-   [Downtown Thoroughfare](https://commonwaysystem.org/patterns/collectors/downtown-thoroughfare.md) `COL-DTH-07`

### Arterials

-   [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) `ART-DEF-01`
-   [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) `ART-BLV-02`
-   [Scenic Highway / Byway](https://commonwaysystem.org/patterns/arterials/scenic-highway-byway.md) `ART-SCB-03`
-   [Arterial Transit (BRT/LRT)](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) `ART-ATR-04`
-   [Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md) `ART-STD-05`
-   [One-Way Street](https://commonwaysystem.org/patterns/arterials/one-way-street.md) `ART-OWS-06`
-   [Parkway](https://commonwaysystem.org/patterns/arterials/parkway.md) `ART-PKY-07`

### Freeways

-   [Default (Freeway)](https://commonwaysystem.org/patterns/freeways/default.md) `FRE-DEF-01`
-   [Expressway](https://commonwaysystem.org/patterns/freeways/expressway.md) `FRE-EXP-02`
-   [Beltway / Ring Road](https://commonwaysystem.org/patterns/freeways/beltway-ring-road.md) `FRE-BLT-03`
-   [Freeway-scale Transit (Commuter/Heavy Rail)](https://commonwaysystem.org/patterns/freeways/freeway-transit.md) `FRE-FTR-04`

### Intersections and Crossings

-   [Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) `INT-RAB-01`
-   [Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md) `INT-TRB-02`
-   [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) `INT-SIG-03`
-   [All-Way Stop](https://commonwaysystem.org/patterns/intersections/all-way-stop.md) `INT-AWS-04`
-   [Stop / Yield (Two-Way)](https://commonwaysystem.org/patterns/intersections/stop-yield.md) `INT-SYD-05`
-   [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md) `INT-CSJ-06`
-   [Uncontrolled](https://commonwaysystem.org/patterns/intersections/uncontrolled.md) `INT-UNC-07`
-   [Midblock Pedestrian Crossing](https://commonwaysystem.org/patterns/intersections/midblock-crossing.md) `INT-MPC-08`
-   [Driveway / Curb Cut](https://commonwaysystem.org/patterns/intersections/driveway-curb-cut.md) `INT-DCC-09`
-   [Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md) `INT-GSI-10`
-   [Protected Intersection](https://commonwaysystem.org/patterns/intersections/protected-intersection.md) `INT-PRI-11`
-   [Median U-Turn (MUT)](https://commonwaysystem.org/patterns/intersections/median-u-turn.md) `INT-MUT-12`
-   [Restricted Crossing U-Turn (RCUT)](https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn.md) `INT-RCU-13`
-   [Displaced Left-Turn (DLT)](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) `INT-DLT-14`
-   [Railroad Grade Crossing](https://commonwaysystem.org/patterns/intersections/railroad-grade-crossing.md) `INT-RGC-15`

### Facilities

-   [Transit Shelter](https://commonwaysystem.org/patterns/facilities/transit-shelter.md) `FAC-TSH-01`
-   [Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md) `FAC-TPL-02`
-   [Transit Hub / Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) `FAC-THS-03`
-   [Surface Parking Lot](https://commonwaysystem.org/patterns/facilities/surface-parking-lot.md) `FAC-SPL-04`
-   [Parking Garage / Structure](https://commonwaysystem.org/patterns/facilities/parking-garage-structure.md) `FAC-PGS-05`
-   [Park-and-Ride](https://commonwaysystem.org/patterns/facilities/park-and-ride.md) `FAC-PNR-06`
-   [Plaza / Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md) `FAC-PLZ-07`
-   [Bike Parking Corral](https://commonwaysystem.org/patterns/facilities/bike-parking-corral.md) `FAC-BPC-08`
-   [Bike-Share Station](https://commonwaysystem.org/patterns/facilities/bike-share-station.md) `FAC-BSS-09`
-   [Secure Bike Parking / Bike Station](https://commonwaysystem.org/patterns/facilities/secure-bike-parking-bike-station.md) `FAC-SBP-10`

### Elements

-   [Curb](https://commonwaysystem.org/patterns/elements/curb.md) `ELM-CRB-01`
-   [Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md) `ELM-CBE-02`
-   [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) `ELM-CRP-03`
-   [Curb Cut / Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md) `ELM-CCA-04`
-   [Wheel Stop](https://commonwaysystem.org/patterns/elements/wheel-stop.md) `ELM-WHS-05`
-   [Vertical Speed Control](https://commonwaysystem.org/patterns/elements/vertical-speed-control.md) `ELM-VSC-06`
-   [Rumble Strip](https://commonwaysystem.org/patterns/elements/rumble-strip.md) `ELM-RMS-07`
-   [Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) `ELM-CRW-08`
-   [Pedestrian Safety Island / Refuge](https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge.md) `ELM-PSI-09`
-   [Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md) `ELM-DWS-10`
-   [Regulatory Sign](https://commonwaysystem.org/patterns/elements/regulatory-sign.md) `ELM-RGS-11`
-   [Warning Sign](https://commonwaysystem.org/patterns/elements/warning-sign.md) `ELM-WNS-12`
-   [Guide Sign](https://commonwaysystem.org/patterns/elements/guide-sign.md) `ELM-GDS-13`
-   [Traffic Signal](https://commonwaysystem.org/patterns/elements/traffic-signal.md) `ELM-TFS-14`
-   [Pedestrian Signal](https://commonwaysystem.org/patterns/elements/pedestrian-signal.md) `ELM-PDS-15`
-   [Bicycle Signal](https://commonwaysystem.org/patterns/elements/bicycle-signal.md) `ELM-BCS-16`
-   [RRFB](https://commonwaysystem.org/patterns/elements/rrfb.md) `ELM-RRF-17`
-   [Pedestrian Hybrid Beacon](https://commonwaysystem.org/patterns/elements/pedestrian-hybrid-beacon.md) `ELM-PHB-18`
-   [Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md) `ELM-BIO-19`
-   [Flow-Through Planter](https://commonwaysystem.org/patterns/elements/flow-through-planter.md) `ELM-FTP-20`
-   [Pervious Strip](https://commonwaysystem.org/patterns/elements/pervious-strip.md) `ELM-PVS-21`
-   [Pervious Pavement](https://commonwaysystem.org/patterns/elements/pervious-pavement.md) `ELM-PVP-22`
-   [Traffic Barrier](https://commonwaysystem.org/patterns/elements/traffic-barrier.md) `ELM-TRB-23`
-   [Crash Cushion / End Terminal](https://commonwaysystem.org/patterns/elements/crash-cushion-end-terminal.md) `ELM-CCT-24`
-   [Bollard](https://commonwaysystem.org/patterns/elements/bollard.md) `ELM-BOL-25`
-   [Street Light](https://commonwaysystem.org/patterns/elements/street-light.md) `ELM-STL-26`
-   [Pedestrian-scale Lighting](https://commonwaysystem.org/patterns/elements/pedestrian-scale-lighting.md) `ELM-PSL-27`
-   [Street Tree](https://commonwaysystem.org/patterns/elements/street-tree.md) `ELM-STT-28`
-   [Tree Pit / Tree Trench](https://commonwaysystem.org/patterns/elements/tree-pit-tree-trench.md) `ELM-TPT-29`
-   [Landscaped Buffer Strip](https://commonwaysystem.org/patterns/elements/landscaped-buffer-strip.md) `ELM-LBS-30`
-   [Bench](https://commonwaysystem.org/patterns/elements/bench.md) `ELM-BCH-31`
-   [Trash / Recycling Receptacle](https://commonwaysystem.org/patterns/elements/trash-recycling-receptacle.md) `ELM-TRR-32`
-   [Drinking Fountain](https://commonwaysystem.org/patterns/elements/drinking-fountain.md) `ELM-DRF-33`
-   [Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) `ELM-CBL-34`
-   [Buffered Bike Lane](https://commonwaysystem.org/patterns/elements/buffered-bike-lane.md) `ELM-BBL-35`
-   [Advisory Bike Lane](https://commonwaysystem.org/patterns/elements/advisory-bike-lane.md) `ELM-ABL-36`
-   [Protected Bike Lane / Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) `ELM-PBL-37`
-   [Green Pavement / Conflict Marking](https://commonwaysystem.org/patterns/elements/green-pavement-conflict-marking.md) `ELM-GPM-38`
-   [Sharrow (Avoid)](https://commonwaysystem.org/patterns/elements/sharrow.md) `ELM-SHR-39`
-   [Bike Parking / Rack](https://commonwaysystem.org/patterns/elements/bike-parking-rack.md) `ELM-BPR-40`
-   [Transit Boarding Island](https://commonwaysystem.org/patterns/elements/transit-boarding-island.md) `ELM-TBI-41`
-   [Bike Box](https://commonwaysystem.org/patterns/elements/bike-box.md) `ELM-BKB-42`
-   [Two-Stage Turn Queue Box](https://commonwaysystem.org/patterns/elements/two-stage-turn-queue-box.md) `ELM-TSQ-43`
-   [Modal Filter / Point Closure](https://commonwaysystem.org/patterns/elements/modal-filter-point-closure.md) `ELM-MFP-44`
-   [Median Island](https://commonwaysystem.org/patterns/elements/median-island.md) `ELM-MDI-45`
-   [Neighborhood Traffic Circle / Mini-Roundabout](https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout.md) `ELM-NTC-46`

## Retrofits

-   [Retrofit Strategy Index](https://commonwaysystem.org/retrofits.md)

### Network

-   [Modal filtering / Low Traffic Neighborhood retrofit](https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit.md) `RFT-NET-01`
-   [Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md) `RFT-NET-02`
-   [Barrier-crossing / network reconnection retrofit](https://commonwaysystem.org/retrofits/network/barrier-crossing-network-reconnection-retrofit.md) `RFT-NET-03`

### Corridor

-   [Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) `RFT-CDR-01`
-   [Five-plus lane reallocation](https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation.md) `RFT-CDR-02`
-   [Lane diet](https://commonwaysystem.org/retrofits/corridor/lane-diet.md) `RFT-CDR-03`
-   [One-way to two-way conversion](https://commonwaysystem.org/retrofits/corridor/one-way-to-two-way-conversion.md) `RFT-CDR-04`
-   [Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md) `RFT-CDR-05`
-   [Transit priority lane retrofit](https://commonwaysystem.org/retrofits/corridor/transit-priority-lane-retrofit.md) `RFT-CDR-06`
-   [Protected bike lane retrofit via lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md) `RFT-CDR-07`
-   [Protected bike lane retrofit via lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md) `RFT-CDR-08`
-   [Protected bike lane retrofit via parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) `RFT-CDR-09`
-   [Depaving / pavement-to-gravel conversion](https://commonwaysystem.org/retrofits/corridor/depaving-pavement-to-gravel.md) `RFT-CDR-10`
-   [2+1 road with cable median barrier](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md) `RFT-CDR-11`

### Intersection

-   [Signal-to-roundabout conversion](https://commonwaysystem.org/retrofits/intersection/signal-to-roundabout-conversion.md) `RFT-INT-01`
-   [Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md) `RFT-INT-02`
-   [Restricted Crossing U-Turn (RCUT) retrofit](https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit.md) `RFT-INT-03`
-   [Displaced Left-Turn (DLT) retrofit](https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit.md) `RFT-INT-04`

## Media

-   [Media Gallery](https://commonwaysystem.org/media.md)

## Reference

-   [Reference](https://commonwaysystem.org/references.md)

## Blog

-   [Blog](https://commonwaysystem.org/blog.md)
-   [Welcome to the Commonway System](https://commonwaysystem.org/blog/welcome.md)

## About

### About

-   [Overview](https://commonwaysystem.org/about.md)
-   [Site Map](https://commonwaysystem.org/about/sitemap.md)
-   [The Commonway System](https://commonwaysystem.org/about/commonway-system.md)
-   [Brand Guide](https://commonwaysystem.org/about/brand-guide.md)

### Development

-   [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md)
-   [Project Governance](https://commonwaysystem.org/about/governance.md)
-   [Submit a Change](https://commonwaysystem.org/about/contributing.md)
-   [Report a Problem](https://commonwaysystem.org/about/reporting.md)
-   [Acknowledgments](https://commonwaysystem.org/about/acknowledgments.md)

### Terms and Policies

-   [Terms and Conditions](https://commonwaysystem.org/about/terms-and-conditions.md)
-   [Privacy Policy](https://commonwaysystem.org/about/privacy-policy.md)
-   [AI Policy](https://commonwaysystem.org/about/ai-policy.md)
-   [Accessibility Policy](https://commonwaysystem.org/about/accessibility-policy.md)

## Other ways to browse

-   [Search](https://commonwaysystem.org/search/): search every Pattern, Retrofit Strategy, Guide page, and media item, with filters. Also opens from the Search button in the header, or Ctrl+K (Cmd+K on a Mac).
-   [Text-only pages](https://commonwaysystem.org/text/all-pages/): a plain, unstyled version of every page with no images, scripts, or animation.
-   [XML sitemap](https://commonwaysystem.org/sitemap.xml): the list of pages for search engines.
-   [llms.txt](https://commonwaysystem.org/llms.txt): an index of the guidebook's pages as markdown, for AI tools.
-   [llms-full.txt](https://commonwaysystem.org/llms-full.txt): the whole guidebook as one markdown file, for AI tools.

---

Source: https://commonwaysystem.org/about/terms-and-conditions/

# Terms and Conditions

**Effective date:** August 29, 2026

By using this publication, you agree to the terms below. If you don't agree with them, don't use the publication.

## What this publication is

Commonway System is a reference guidebook to street and road design patterns, compiled by an enthusiast and researcher, not a licensed engineer or planner. Every prescriptive claim in the guidebook is meant to trace back to a cited source; where it doesn't yet, the claim carries an unsourced-claim flag⚠. See [The Commonway System](https://commonwaysystem.org/about/commonway-system.md) for the full explanation of how and why it's built this way.

## Not professional advice

Nothing on this publication is engineering advice, legal advice, or a substitute for a licensed professional. Real construction and policy changes require a licensed engineer's review, government approval, and local jurisdiction compliance, none of which this publication provides or is a substitute for. Any application of the patterns described here, in design, construction, policy, or advocacy, is done at your own risk.

## No warranty, information may be incomplete or wrong

This publication is provided "as is," without warranty of any kind. We do not guarantee that any information on this publication is accurate, current, or complete. Mistakes happen, sources go out of date, and unsourced claims exist and are labeled as such, but a claim carrying a citation is not a guarantee that the citation was applied correctly or that the underlying source itself is error-free. Verify anything you intend to rely on against the original source, and against a licensed professional where relevant, before acting on it.

## Limitation of liability

To the fullest extent permitted by law, Commonway System and its maintainer are not liable for any damages, direct or indirect, arising from your use of this publication or reliance on its content. This includes, without limitation, damages resulting from errors, omissions, outdated information, or decisions made based on anything published here.

## Brand, trademark, and visual identity

The Commonway System name, logo, wordmark, color system, and overall visual identity are not covered by the publication's code license or by the content-contribution terms described on the [Submit a Change](https://commonwaysystem.org/about/contributing.md) page. They remain the property of the Commonway System project and are reserved. Nothing in this publication's code license, content terms, or the act of contributing to the guidebook grants any right to use, reproduce, modify, or create derivative versions of the Commonway System name, logo, or brand identity without prior written permission.

## Code and content licensing

The publication's underlying code is open source under the MIT License; see the [LICENSE file](https://github.com/Commonway-System/commonwaysystem.org/blob/main/LICENSE) in the repository. A small number of icons are reproduced from the third-party [Lucide](https://lucide.dev/) icon set under its own license; see [THIRD-PARTY-NOTICES](https://github.com/Commonway-System/commonwaysystem.org/blob/main/THIRD-PARTY-NOTICES). The guidebook's written content is licensed separately: Commonway System retains the rights to the compiled guidebook, and contributors grant a license to use their submissions as described on the [Submit a Change](https://commonwaysystem.org/about/contributing.md) page. These are two different licenses covering two different things, and neither extends to the brand elements described above.

## Contributions

Submitting a correction, citation, or new pattern proposal through the project's GitHub repository is governed by the terms on the [Submit a Change](https://commonwaysystem.org/about/contributing.md) page and the repository's [Code of Conduct](https://github.com/Commonway-System/commonwaysystem.org/blob/main/CODE_OF_CONDUCT.md). We reserve the right to decline, edit, or remove any contribution.

## External links

The guidebook cites and links to external sources throughout: government manuals, published studies, agency websites. We don't control those sites and aren't responsible for their content, accuracy, or availability.

## Governing law

These terms are governed by the laws of the State of South Carolina, United States, without regard to conflict-of-law principles. Any dispute arising from this publication is subject to the jurisdiction of the courts of Horry County, South Carolina.

## Changes to these terms

These terms may be updated as the project develops. Updates are reflected in the publication's version history; see [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md). Continued use of the publication after a change means you accept the updated terms.

## Severability

If any part of these terms is found unenforceable, the rest remains in effect.

## Contact

Questions about these terms can be directed to [info@commonwaysystem.org](mailto:info@commonwaysystem.org).

---

Source: https://commonwaysystem.org/blog/

# Blog

Notes on how the Commonway System gets built: research, structural decisions, new patterns as they're added, and corrections when something earlier turns out to be wrong. Newest first.

1.  [Welcome to the Commonway System](https://commonwaysystem.org/blog/welcome.md) August 29, 2026
    
    The first post in an ongoing record of how the Commonway System gets built.

---

Source: https://commonwaysystem.org/blog/welcome/

# Welcome to the Commonway System

This is the first post on what will be an ongoing record of how the Commonway System gets built: research notes, structural decisions, new patterns as they're added, and the occasional correction when something earlier turns out to be wrong.

If you're new here: Commonway System is a pattern language for roads and streets, a reference guidebook organized by Functional Classification and Street Typology, with every prescriptive claim traced back to a cited source wherever one exists. Start with the [Guide](https://commonwaysystem.org/guide.md) if you want to understand how the system is put together, or the [Patterns](https://commonwaysystem.org/patterns.md) section if you want to jump straight to a specific kind of street.

This blog isn't part of the guidebook itself, it won't carry prescriptive claims or citations the way a pattern page does. It's the place for everything adjacent to the guidebook: why a decision was made, what changed and when, what's coming next. The [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md) page remains the authoritative changelog; this is more room to explain the reasoning behind it.

More to come.

---

Source: https://commonwaysystem.org/guide/

# Introduction

## Where to start

The Guide is where you start **when you have a problem**, not a curiosity.

**If you already know what you are after**, like a Local Alley or a Turbo-Roundabout, go to [Patterns](https://commonwaysystem.org/patterns.md) and look it up.

**If you're trying to figure out** why the street outside your house feels dangerous, what it's supposed to be called, or how to actually get something changed, **start here**.

## What is in this guide?

The Patterns section describes what a good street looks like. **This Guide is for deciding what to do about the street you've got.** Use this guide to determine which pattern fits your situation, and how to move it through the process that actually builds or changes a street.

### Learn how streets actually get built

That second part, the part where a plan turns into pavement, runs through your local government: whoever authorizes the change, approves the budget, and schedules the work. Most people never learn how that works, which is a large part of why streets that everyone agrees are unsafe can sit unfixed for years. The Guide is meant to close that gap, in plain language.

## This section is built in three parts:

-   **[Foundations](https://commonwaysystem.org/guide/how-to-read-a-pattern.md)** — the vocabulary and classification system used throughout the rest of the Commonway System. Start here if terms like Functional Classification, Street Typology, or pattern scale are new to you.
-   **[Find Your Pattern](https://commonwaysystem.org/guide/find-your-pattern.md)** — a short diagnostic that turns a plain description of a street into the pattern that fits it.
-   **[Make It Happen](https://commonwaysystem.org/guide/make-it-happen.md)** — a walkthrough of how local road decisions actually get made, who to ask, and how to push one forward.

---

Source: https://commonwaysystem.org/guide/construction-methodology-spectrum/

# Construction Methodology & The Build Spectrum

A Retrofit Strategy can be built in more than one way. The same road diet can appear overnight as cones and paint, or arrive years later as full curb-to-curb reconstruction. Neither is more legitimate than the other. This page locks CS's position on how these approaches relate, when each is appropriate, and why the choice matters as much as the design itself.

This page sits alongside [How Road Changes Actually Happen](https://commonwaysystem.org/guide/make-it-happen.md) because the build method is as much a part of getting something done as the jurisdictional process is. Knowing who can approve a change matters less if you don't also know what kind of change you can ask for first.

## The four stages

Practitioners in this field, most consistently the Street Plans Collaborative[1] and cities like Burlington, Vermont,[2] describe a four-stage build spectrum. CS adopts this framing directly, since it's already well-tested in practice and gives a shared vocabulary for talking about how much commitment a given installation represents.[3]

**Demonstration.** Hours to about a week. Low-cost, temporary materials: chalk, tape, cones, planters. Often led by residents, a business district, or a nonprofit rather than the public agency itself. The purpose is to show a possibility, not to test performance rigorously.

**Pilot.** Roughly thirty days. Typically led by the public agency, using slightly more durable temporary materials. The purpose shifts from demonstration to genuine testing, gathering real data on how a design performs before committing further.

**Quick-build.** One to five years. Semi-permanent materials, durable enough to function as real infrastructure while still being reversible if the design doesn't work. This stage is where most of a project's real-world evidence gets generated, since it lasts long enough for genuine before-and-after comparison.[4]

**Permanent.** Full capital construction: concrete, signal equipment, complete reconstruction. The final stage, typically undertaken once a design has been tested and proven, or where the strategy's scale makes anything short of full construction impractical from the outset.[5]

## CS's position: test before you pour

Where a Retrofit Strategy can move through this spectrum, CS holds that it should. Skipping directly to permanent construction on an unproven design commits money, political capital, and years of construction disruption to a configuration that hasn't been tested against how people actually use the street. A pilot or quick-build stage costs a fraction of that, is reversible if wrong, and produces the evidence a permanent version will need to justify itself anyway.

This isn't a claim that every project must pass through all four stages in sequence. A jurisdiction with strong existing evidence for a given design, or a strategy too small in scope to warrant a formal pilot, can reasonably move faster. The position is narrower than that: skipping the testing stages should be a deliberate choice made with reasons, not a default.

## Not every strategy can move through this spectrum

Some Retrofit Strategies genuinely cannot be piloted with paint and cones. An Intersection-scale strategy involving new median construction, signal relocation, or significant grading, a Median U-Turn retrofit, for instance, requires real construction to exist at all. There's no meaningful demonstration version of moving a signal head.

Each Retrofit Strategy page states plainly, in its Getting it built section, whether it can move through the full spectrum or effectively requires starting at Permanent. This page explains the spectrum itself; it doesn't repeat, strategy by strategy, which stage each one starts at.

## Materials change by stage, not just duration

The distinction between stages isn't only how long an installation lasts. It's also what it's built from. A demonstration uses materials meant to be removed by hand: chalk, tape, delineators. A quick-build uses materials meant to survive years outdoors but still be pulled up if needed: modular curbs, durable paint systems, movable planters. A permanent installation uses materials that assume the design is final: poured concrete, underground conduit, fixed signal infrastructure.

This matters because a design that looks identical at the pilot and permanent stages can represent very different levels of commitment underneath. Reading a strategy's stage tells you not just how new it is, but how easily it could still change.

## References

1.  Precedent-based [Street Plans Collaborative. "Tactical Urbanist's Guide to Materials and Design."](https://street-plans.com/tactical-urbanists-guide-to-materials-and-design/)
2.  Precedent-based [City of Burlington, Vermont. "Quick Build Design + Materials Standards."](https://www.burlingtonvt.gov/331/Quick-Build-Projects)
3.  Precedent-based [Congress for the New Urbanism. "Merging Tactical Urbanism with Public Works."](https://www.cnu.org/publicsquare/2019/02/07/merging-tactical-urbanism-public-works)
4.  Evidence-based [PeopleForBikes. "Quick Builds for Better Streets: A New Project Delivery Model for U.S. Cities."](https://www.peopleforbikes.org/reports/quick-builds-for-better-streets-a-new-project-delivery)
5.  Precedent-based [Global Designing Cities Initiative. "From Pop-Up to Permanent: Five Lessons in Tactical Urbanism."](https://globaldesigningcities.org/update/from-pop-up-to-permanent-five-lessons-in-tactical-urbanism/)

---

Source: https://commonwaysystem.org/guide/decision-evaluation-processes/

# Decision & Evaluation Processes

Not every tool in this publication is a design or a piece of legislation. Some are procedures, formal, staged processes a jurisdiction follows to decide which design to build in the first place, or to check a design's safety before or after it's built. This page catalogs two of the most established: Intersection Control Evaluation and the Road Safety Audit.

Both are procedural rather than physical or legal. Neither one is a Retrofit Strategy, and neither is a legal or funding mechanism. They're the process a jurisdiction runs before or alongside using one. See [How Road Changes Actually Happen](https://commonwaysystem.org/guide/make-it-happen.md) for how these processes typically fit into a project's broader timeline.

## Intersection Control Evaluation (ICE)

**What it is.** A staged, documented process for comparing intersection control and geometric alternatives, using quantifiable performance measures alongside qualitative community and multimodal considerations, before committing to a design.[4]

**Who conducts it.** Public agency staff, typically state DOT or MPO engineers and planners, sometimes with consultant support. A growing number of agencies have adopted formal ICE policies requiring the process for defined project types.[6]

**When it's used.** During planning and schematic development, before an intersection design is finalized, whenever a project presents a genuine choice between control types, for instance a signal versus a roundabout versus a Restricted Crossing U-Turn.

**The process:**

1.  **Scoping.** Identify the full range of intersection types that could plausibly serve the location, based on traffic volumes, crash history, and surrounding context.
2.  **Stage I screening.** Narrow the full range to a short list of alternatives that meet organizational goals and project needs and are practical to pursue. Alternatives that fail basic feasibility are screened out here.
3.  **Stage II analysis.** Evaluate the short-listed alternatives in detail, using quantifiable measures, safety performance, capacity, and cost, alongside qualitative measures like multimodal accommodation and community goals.[5]
4.  **Comparison and documentation.** Compare alternatives side by side using a transparent, traceable method. Some agencies use a dedicated tool for this step; the Safety Performance for Intersection Control Evaluation (SPICE) tool is one example, drawing on Highway Safety Manual crash prediction methods to compare predicted crash frequency and severity across control types.[7]
5.  **Selection.** Choose a preferred alternative, documented well enough that the reasoning is legible to anyone reviewing the decision later, including the public.

**Why it matters here.** ICE is the formal version of a question this publication raises informally throughout the Pattern catalog: given a choice of intersection control, which one actually performs better for this specific location. ICE is how a jurisdiction answers that question with evidence rather than habit.[8]

## Road Safety Audit (RSA)

**What it is.** A formal safety performance examination of an existing or planned road or intersection, conducted by an independent, multidisciplinary team, resulting in a written report of safety issues and improvement opportunities.[1]

**Who conducts it.** A team independent of the project's own designers, deliberately drawn from multiple disciplines, so the review isn't checking its own work.

**When it's used.** RSAs can be run at any project stage: pre-construction (planning and design), during construction, or post-construction (operations and maintenance). They can also be run on existing roads with no active project at all, simply to surface safety issues on infrastructure already in service.

**The process:**

1.  **Identify the project or existing road to be audited.**
2.  **Select the audit team**, chosen specifically for independence from the original design work and for a range of relevant disciplines.
3.  **Conduct a pre-audit meeting** to review available project information, data, and materials with the audit team before fieldwork begins.
4.  **Perform a field review**, examining the site under relevant conditions, which may include different times of day or weather.
5.  **Conduct the audit analysis** and prepare a formal report documenting identified safety issues, organized by topic or by risk priority depending on project size.
6.  **Present the findings** to the project owner and design team.
7.  **Prepare a formal response** addressing each identified issue.
8.  **Incorporate accepted findings** into the project or into a plan for the existing road, as appropriate.[2]

**Why it matters here.** An RSA is one of the few tools in this publication that can be applied to a street that has no active project at all. It's how a safety issue on an existing Pattern gets surfaced in the first place, often the actual trigger that starts a jurisdiction looking at a Retrofit Strategy.[3]

## References

1.  Legal / regulatory [Federal Highway Administration. "Road Safety Audits (RSA)."](https://highways.dot.gov/safety/proven-safety-countermeasures/road-safety-audit)
2.  Legal / regulatory [Federal Highway Administration. "FHWA Road Safety Audit Guidelines."](https://highways.dot.gov/safety/data-analysis-tools/rsa/fhwa-road-safety-audit-guidelines)
3.  Legal / regulatory [Federal Highway Administration. "Conducting Road Safety Audits."](https://highways.dot.gov/safety/data-analysis-tools/rsa/fhwa-road-safety-audit-guidelines/40-conducting-road-safety-audits)
4.  Legal / regulatory [Texas Department of Transportation. "Intersection Control Evaluation (ICE) — Context."](https://www.txdot.gov/manuals/des/tsp/chapter-10-intersection-analysis/10-2-intersection-control-evaluation--ice----conte.html)
5.  Legal / regulatory [Texas Department of Transportation. "Intersection Control Evaluation — Process and Analysis."](https://www.txdot.gov/manuals/des/tsp/chapter-10-intersection-analysis/10-3-intersection-control-evaluation---process-and.html)
6.  Legal / regulatory [Federal Highway Administration. "Primer on Intersection Control Evaluation (ICE)," FHWA-SA-18-076.](https://highways.dot.gov/safety/intersection-safety/ice/primer-intersection-control-evaluation-ice)
7.  Evidence-based [Jenior, P., Butsick, A., Haas, P., and Ray, B. "Safety Performance for Intersection Control Evaluation (SPICE) Tool User Manual," FHWA-SA-18-026.](https://www.pooledfund.org/Document/Download/8250)
8.  Evidence-based [Federal Highway Administration. "Intersections for Pedestrians and Bicyclists: An Informational Guide."](https://highways.dot.gov/sites/fhwa.dot.gov/files/2022-06/fhwasa22017.pdf)

---

Source: https://commonwaysystem.org/guide/density-tiers/

# Density Tiers

Every pattern page in this guidebook notes which density tiers it's typical for, using chips like Suburban shown on the [How to Read a Pattern](https://commonwaysystem.org/guide/how-to-read-a-pattern.md) page. This page explains what those six tiers mean, where the names and numbers come from, and how to read them.

\[Image: Commonway System density tiers diagram showing six levels of development from Undeveloped to Core.\]

Density here means how much housing and activity sit on the land around a given street, not the street itself. The same Street Typology can look different at different densities, and the tier system exists so the guidebook can say precisely which context it's describing without a paragraph of throat-clearing every time.

## The six tiers

| Tier | Code | ITE/CNU equivalent | What it looks like |
| --- | --- | --- | --- |
| Undeveloped | UND | C1 Natural | Natural or unused land. |
| Rural | RRL | C2 Rural | Agricultural land or scattered development. |
| Suburban | SUB | C3 Suburban | Single-family residential, landscape-dominant. |
| Compact | CPT | C4 General Urban | A tighter grid, mixed use, walkable, often an older or denser built form. |
| Urban | URB | C5 Urban Center | Higher density, taller buildings, an active mixed-use core. |
| Core | COR | C6 Urban Core | The highest density in the system, downtown-scale, continuous urban fabric. |

The six-zone structure itself, and the C1-C6 naming, comes from a joint ITE and CNU practice guide.[1]

## How the numbers work

Each tier also carries an approximate density range, measured in housing units per acre. These numbers are diagnostic, not regulatory: they help a reader place a real segment of street into the right tier, they don't set a zoning cap or a legal limit anywhere in this guidebook.

| Tier | Units per acre |
| --- | --- |
| Undeveloped | 0 |
| Rural | 0-2 |
| Suburban | 2-8 |
| Compact | 6-20 |
| Urban | 15-40 |
| Core | 25-100+ |

The Suburban through Core figures come directly from the CNU transect methodology this system is adapted from.[2] Rural's ceiling is set to match Suburban's floor, keeping all six tiers connected with no gap between them. Within that range, the U.S. Census Bureau's own housing-unit density threshold for what counts as urban at all works out to roughly 0.3 units per acre,[3] which lands well inside Rural's range and supports genuinely rural land sitting at the low end of it.

These ranges intentionally overlap between adjacent tiers, the same way the underlying methodology does. Density is a gradient, not a hard cutoff, so a segment sitting in an overlap is genuinely borderline. When that happens, the plain-language description in the table above is the primary way to tell tiers apart; the numeric range is a secondary check, not the deciding factor.

One tier has a firmer numeric anchor than the rest. The Urban-to-Core boundary is also marked by a persons-per-acre or jobs-per-acre threshold, 20 persons per acre or 45 jobs per acre, adapted from a Florida Department of Transportation formula that distinguishes those two tiers specifically.[4] It doesn't appear elsewhere in the table on purpose: applying a precise persons-per-acre number to every tier would suggest a level of certainty the underlying sources don't actually support.

## A real-world reference point

Miami's own zoning code is built on the same six-zone transect concept and reaches noticeably higher densities than the ranges above: Suburban 9-18 units per acre, Compact up to 36, Urban up to 65, and Core as high as 150 by right, with bonus-area provisions allowing over 1,000 units per acre in parts of downtown Miami.[5] It's included here as a real, adopted example of how high a major US city has actually calibrated these tiers, not as the source the ranges above are built from.

## Why these names

The six tiers, in order, are Undeveloped, Rural, Suburban, Compact, Urban, and Core. One other name was considered and set aside during development: "Streetcar" was an early candidate for the tier that became Compact, but it assumed a streetcar-era origin that doesn't hold for every neighborhood the tier needs to describe, plenty of Compact-tier places never had a streetcar line running through them. Compact does the job without that baked-in assumption: denser and tighter than Suburban, but not yet large enough or continuous enough to count as Urban.

There's no separate tier for a small town. A small town's Main Street often reads as a pocket of Urban or Compact intensity sitting inside an otherwise Rural surrounding area, and that's fine: density tiers are assigned to a specific segment of street, not to an entire town or region, so a single block can carry a different tier than the land around it.

## How this connects to the rest of the guidebook

Every Street Typology page in the guidebook lists which density tiers it's typical for, using the same six tiers and codes described here. A pattern marked typical at Suburban, Compact, and Urban is telling you it shows up as the normal choice in those contexts; a tier marked as an edge case means it happens but isn't the norm; a tier marked unlikely means the pairing rarely occurs in practice. See the [Street Typology Pattern Index](https://commonwaysystem.org/patterns.md) for the full list.

## References

1.  Precedent-based Institute of Transportation Engineers and Congress for the New Urbanism, _Designing Walkable Urban Thoroughfares: A Context Sensitive Approach_, 2010. Available at: [https://19january2017snapshot.epa.gov/smartgrowth/designing-walkable-urban-thoroughfares-context-sensitive-approach](https://19january2017snapshot.epa.gov/smartgrowth/designing-walkable-urban-thoroughfares-context-sensitive-approach)
2.  Precedent-based Congress for the New Urbanism, "The Transect," _Public Square: A CNU Journal_, by Robert Steuteville, published June 10, 2009, updated January 22, 2016. Available at: [https://www.cnu.org/publicsquare/transect](https://www.cnu.org/publicsquare/transect)
3.  Legal / regulatory U.S. Census Bureau, "Urban Area Criteria for the 2020 Census, Final Criteria," _Federal Register_, March 24, 2022. Available at: [https://www.federalregister.gov/documents/2022/03/24/2022-06180/urban-area-criteria-for-the-2020-census-final-criteria](https://www.federalregister.gov/documents/2022/03/24/2022-06180/urban-area-criteria-for-the-2020-census-final-criteria)
4.  Legal / regulatory Florida Department of Transportation, _Context Classification Guide_, Chapter 2, "Step-by-Step Guide for Determining Context Classification," October 2024. Available at: [https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/roadway/completestreets/files/fdot-context-classification.pdf](https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/roadway/completestreets/files/fdot-context-classification.pdf)
5.  Legal / regulatory City of Miami, _Miami 21 Code_, Article 4, "Standards and Tables," Table 4, "Density, Intensity and Parking," as adopted May 2010. Available at: [https://www.miami21.org/PDFs/FinalDocumentsMay2010/FULLDOCUMENT-May2010.pdf](https://www.miami21.org/PDFs/FinalDocumentsMay2010/FULLDOCUMENT-May2010.pdf)

---

Source: https://commonwaysystem.org/guide/design-speed/

# Design Speed & Speed Limits

\[Image: Commonway System design speed diagram showing the relationship between design speed, operating speed, and posted speed limit.\]

## What design speed is

Design speed is a selected speed used to determine a roadway's geometric design features: curve radii, sight distance, lane width, and similar elements.[1] It is an input to the drawing board, not a number posted on a sign. A road's actual geometry, its curves, its lane widths, its sightlines, can support a much higher speed than the design speed on the plans, because geometric standards are written with a built-in safety margin for near-worst-case conditions.[3] Engineers call the highest speed a road's geometry can actually support its _inferred design speed_, and it is frequently higher than the design speed the road was drawn to.[5]

## What a posted speed limit is

A posted speed limit is the legal maximum speed for a section of road, set by a state or local transportation authority. In conventional US practice, posted limits are commonly derived from the 85th-percentile operating speed: the speed at or below which 85 percent of drivers travel in free-flow conditions.[2] This method sets the limit to match how people already drive, not to match what the road's geometry was designed for.

## Why these two numbers diverge

Design speed, operating speed, and posted speed limit are three different measures, set by three different parties, for three different reasons: designers set design speed to establish geometric features, operators set posted limits they judge safe for the road, and drivers pick their own speed based on how safe the road feels to them. These three numbers are frequently incompatible with each other.[4]

The mismatch has a specific origin. A 1985 FHWA memorandum establishing the controlling criteria for federal-aid design stated that design speed should be selected to equal or exceed the posted speed limit. In 2001, AASHTO's Green Book dropped that link. The Green Book now defines design speed purely as a geometric design input and gives no guidance connecting it to posted speed limits.[5] Since then, US roads are routinely built with generous, above-minimum geometry, then posted below what that geometry actually invites. The result: streets whose curves, lane widths, and sightlines all say "drive faster" while the sign says otherwise. Drivers overwhelmingly follow the road, not the sign. Documented cases show 85th-percentile operating speeds and posted speed limits both exceeding the road's own designated design speed, on roads whose geometry was never checked for consistency against the number on the plans.[6]

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [What is the "Correct" Speed Limit?](https://www.youtube.com/watch?v=JRbnBc-97Ps)

Not Just Bikes

Makes the physics and data case for 30 km/h (roughly 20 mph) as the safe default urban speed, the same logic behind CS's own Local street speed cap.

Aligned

### [The Key to Slowing Traffic is Street Design, Not Speed Limits](https://archive.strongtowns.org/journal/2021/8/6/the-key-to-slowing-traffic-is-street-design-not-speed-limits)

Strong Towns

Makes the case, with side-by-side street photos, that a posted number on a sign does not change driver behavior the way lane width, block length, and sightlines do, the same self-enforcing-design principle behind CS's own design-speed-equals-posted-speed rule.

## Why it matters

A posted number does not change how a driver feels behind the wheel. Geometry does. A driver's comfortable, "natural" speed is set by what the road communicates: lane width, curvature, sightlines, and roadside friction, regardless of what the sign says.[7] Design speed decoupled from posted speed limit is design speed decoupled from what actually happens on the road. A pattern book that treats posted speed as the safety mechanism, while leaving geometry free to invite something higher, is solving the wrong problem.

## The Commonway System's rule

**Design speed always equals posted speed limit.**

This is CS's foundational speed rule, and every Local, Collector, and Arterial pattern in this publication is built to it. It follows FHWA's own self-enforcing roadway framework: the roadway's physical design should make the target speed the comfortable, natural driving speed, not just the legal one.[7] A CS street is not "20 mph" or "30 mph" because a sign says so. It is that speed because its geometry makes any faster speed feel wrong to drive.

This is not a target. It is not aspirational. Where a CS pattern specifies a speed, that speed is the design speed, the posted speed, and the intended operating speed, all at once, by design.

## Applying the rule, by street type

### Local: 20 mph hard maximum, no exceptions

CS holds Local streets to 20 mph with no exceptions clause, a stricter standard than the Stockholm Declaration's own 30 km/h (≈20 mph) carve-out for areas where motor vehicles and vulnerable road users mix.[8] The number is not arbitrary. Pedestrian severe-injury risk from a vehicle impact reaches 10 percent at 17.1 mph and death risk reaches 10 percent at 24.1 mph.[9] Pedestrian survival exceeds 90 percent in collisions at or below 20 mph, and falls below 50 percent at 30 mph and above.[10] Local street geometry must make 20 mph the comfortable driving speed. No Local pattern in this publication is designed to a higher inferred speed than its posted number.

### Collector: 30 mph standard, 35 mph only with rigid separation

CS holds Collectors to 30 mph as the standard maximum. 35 mph is permitted only where bicycle facilities carry rigid, crash-protective separation, a concrete barrier or permanent curb, not flexible delineator posts. This distinction is FHWA's own: flexible delineators and rigid barriers are not treated as equivalent separation.[11] The 30 mph threshold matches Dutch distributor-road practice, where roads at this speed class require physical separation between cars and bicycles.[12] It is also a real safety cliff: bicyclist fatality risk in a collision roughly doubles at 30 mph relative to lower speeds.[13] Seattle's own Streets Illustrated design guidance independently arrives at the same 30 mph threshold.[14]

### Arterial: density-tiered baseline, with two non-stacking modifiers

No existing framework prescribes Arterial design speed the way CS needs it prescribed, so this is original CS synthesis, built from FHWA's density principle, NACTO's speed guidance, Dutch noise policy, and VDOT's access-spacing logic. Every piece is cited below.

**Baseline, set by density tier.** FHWA is explicit that arterial design speed should fall as land-use density rises: an urban collector or arterial passing through a dense area should carry an appreciably lower design speed than the same functional class in a rural setting.[15] NACTO's own Design Speed guidance goes further: design criteria should sit at or below a street's target speed, and higher speeds are inappropriate on urban streets, including urban arterials, with higher speeds reserved for limited-access freeways and highways.[16] CS's six density tiers (see [Density Tiers](https://commonwaysystem.org/guide/density-tiers.md)) give this principle a structured baseline:

| Density Tier | Baseline Arterial Speed |
| --- | --- |
| Undeveloped / Rural | 55 mph |
| Suburban | 45 mph |
| Compact | 40 mph |
| Urban | 35 mph |
| Core | 30 mph |

Core's baseline meets Collector's ceiling by design. At CS's highest density tier, an Arterial's surrounding context is closer to a Collector's than to a rural Arterial's, even though it still carries a through-traffic function.

**Noise modifier: −5 mph.** Where an Arterial segment runs adjacent to noise-sensitive land uses (residential, schools, healthcare), subtract 5 mph from the baseline. This has direct precedent on both sides of the Atlantic. The Netherlands' Noise Pollution Act sets statutory road-noise limits and mandates abatement where they're exceeded,[21] and the N325 Pleyroute corridor had its speed limit set specifically for noise and environmental reasons under that framework.[22] In the US, speed reduction is a federally recognized highway noise abatement measure in its own right: FHWA's traffic noise regulation, 23 CFR Part 772, which governs every state DOT's noise policy, lists reducing speed limits among the traffic management measures available to control highway noise, noting that roughly a 20 mph reduction produces a perceptible (5 dBA) decrease.[23] AASHTO's own environmental guidance repeats the same finding.[24] CS's 5 mph step is smaller than FHWA's ~20 mph figure for a _perceptible_ reduction because it is one of two contributing modifiers in a cumulative framework, not a standalone noise-abatement measure sized to solve noise on its own.

**"Noise-sensitive adjacency" is a distance, defined the way the Dutch define it, not the way FHWA defines it.** Article 74 of the Dutch Noise Pollution Act gives every road a statutory noise zone, measured from the inside edge of its outermost travel lane on both sides, sized by lane count and by whether the road sits in an urban or rural area:[26]

| Lanes | Urban zone | Rural zone |
| --- | --- | --- |
| 1-2 | 660 ft (200 m) | 820 ft (250 m) |
| 3-4 | 1,150 ft (350 m) | 1,310 ft (400 m) |
| 5+ | 1,150 ft (350 m) | 1,970 ft (600 m) |

A noise-sensitive land use inside this zone qualifies for the modifier; one outside it doesn't. Roads posted at 30 km/h and woonerven carry no zone at all under Dutch law, since they're already slow enough that noise isn't the binding constraint,[26] the same logic behind CS restricting this modifier to Arterials only. CS adopts this table directly, converted to feet and keyed to the Arterial segment's own lane count.

FHWA's approach is not a distance rule at all. Under 23 CFR 772, highway agencies must model predicted noise levels in decibels at specific receptor points using the Traffic Noise Model, and abatement is only triggered once a receptor's predicted level approaches or exceeds the federal Noise Abatement Criteria.[23] That's a case-by-case standard requiring an acoustic model for each project, not a bright-line rule a pattern-book user can check with a tape measure.

CS deliberately takes the Dutch rule over the FHWA standard here, and the choice has real backing beyond convenience. The foundational law-and-economics treatment of this exact tradeoff concludes that standards are more costly for individuals to interpret when deciding how to act and for an adjudicator to apply after the fact, while rules make outcomes predictable without requiring case-by-case precedent or specialized interpretation each time.[27] The same conclusion holds specifically for noise regulation: quantitative, rule-based noise ordinances are capable of providing non-discretionary, objective, and predictable standards, while qualitative, discretionary approaches are more prone to inconsistent enforcement and vagueness.[28] Enforcement research reaches the same conclusion in general terms: rules are cheaper to enforce than standards precisely because they don't require case-specific information to apply.[29] A pattern book meant to be usable without commissioning an acoustic study for every Arterial segment is exactly the situation this literature describes. CS chooses the version of this rule that produces the same answer every time it's applied.

**Access modifier: −5 mph.** Where local streets tie into the Arterial more frequently than a defined spacing threshold, subtract 5 mph from the baseline. This inverts VDOT's own logic tying minimum intersection spacing to speed class: VDOT requires wider spacing at higher speeds because more conflict points at speed raise crash risk.[25] CS applies the same relationship in reverse: tighter local-street spacing is itself evidence that the speed should come down.

**The two modifiers do not stack.** If a segment qualifies for both, only the single larger reduction applies, not both added together. This is not an arbitrary simplification. It follows the same logic used across three independent fields that all study what happens when overlapping risk-reduction factors are combined:

-   NACTO's City Limits methodology evaluates conflict density and activity level jointly, in a risk matrix, rather than summing them into a single additive number.[17]
-   AASHTO's Green Book treats design speed as one of a small set of governing controlling criteria, with deviations handled through a documented design-exception process rather than compounding penalties across every applicable factor.[18]
-   FHWA's own Highway Safety Manual guidance on combining multiple Crash Modification Factors cautions that unless countermeasures act completely independently, multiplying several together is likely to overestimate their combined effect, with the risk of overestimation growing as more factors are combined.[19] The standard correction for exactly this situation is the _dominant effect method_: apply only the single most effective (largest) factor, the simplest and most conservative approach, used when the applicable factors overlap rather than act independently.[20]

CS's noise and access modifiers are not independent, both are proxies for the same underlying thing: how much a road's context, not its through-traffic function, should be pulling its design speed down. Applying the dominant one, not both, follows the same conservative logic transportation safety practice already uses when two risk factors point the same direction.

**Floor: 30 mph, with a documented-exception process.** The baseline minus the applicable modifier never exceeds the Step 1 baseline, and the result is not permitted below 30 mph except through a documented exception, following the same default-plus-documented-exception architecture CS already uses for roundabout-first intersection control and the crash-investigation lifecycle.

### Freeway: governed by existing systems

CS does not set a speed rule for Freeways. An extensive federal and state regulatory system, spanning AASHTO's own Interstate design standards and each state DOT's speed-setting authority, already governs freeway speed comprehensively. CS respects that existing system rather than duplicating or second-guessing it.

## References

1.  Legal / regulatory [AASHTO. _A Policy on Geometric Design of Highways and Streets_, 7th ed. Washington, DC: American Association of State Highway and Transportation Officials, 2018.](https://store.transportation.org/Item/PublicationDetail?ID=4127)
2.  Legal / regulatory Federal Highway Administration. "Relationship Between Design Speed, Operating Speed, and Posted Speed." Available at: [https://www.fhwa.dot.gov/planning/css/resources/speed](https://www.fhwa.dot.gov/planning/css/resources/speed)
3.  Evidence-based [Texas Transportation Institute / Federal Highway Administration. _Compatibility of Design Speed and Posted Speed for Texas Highways_. Report FHWA/TX-95/1465-1.](https://static.tti.tamu.edu/tti.tamu.edu/documents/1465-2F.pdf)
4.  Legal / regulatory [Toole, Joseph S. Foreword to _Speed Concepts: Informational Guide_. FHWA-SA-10-001. Washington, DC: Federal Highway Administration, 2009.](https://highways.dot.gov/safety/speed-management/speed-concepts-informational-guide-0)
5.  Legal / regulatory Federal Highway Administration. Memorandum from E. Dean Carlson establishing the thirteen controlling criteria for design, April 15, 1985, and subsequent guidance on the 2001 AASHTO Green Book redefinition of design speed. Available at: [https://www.fhwa.dot.gov/design/standards/151007.cfm](https://www.fhwa.dot.gov/design/standards/151007.cfm)
6.  Legal / regulatory Federal Highway Administration. "Chapter 6: Government Roles Related to Traffic Speeds." _Speed Concepts: Informational Guide_. Available at: [https://highways.dot.gov/safety/speed-management/speed-concepts-informational-guide/chapter-6-government-roles-related](https://highways.dot.gov/safety/speed-management/speed-concepts-informational-guide/chapter-6-government-roles-related)
7.  Legal / regulatory [Federal Highway Administration. _Self-Enforcing Roadways: A Guidance Report_. FHWA-HRT-17-098, 2018.](https://highways.dot.gov/research/publications/safety/FHWA-HRT-17-098)
8.  Precedent-based [Third Global Ministerial Conference on Road Safety. _Stockholm Declaration_. Stockholm, 2020.](https://www.roadsafetysweden.com/about-the-conference/stockholm-declaration/)
9.  Evidence-based [Tefft, Brian C. _Impact Speed and a Pedestrian's Risk of Severe Injury or Death_. Washington, DC: AAA Foundation for Traffic Safety, 2011.](https://aaafoundation.org/impact-speed-pedestrians-risk-severe-injury-death/)
10.  Evidence-based [Peden, Margie, et al. _World Report on Road Traffic Injury Prevention_. Geneva: World Health Organization, 2004, as cited by the Federal Highway Administration.](https://iris.who.int/handle/10665/42871)
11.  Legal / regulatory [Federal Highway Administration. _Separated Bike Lane Planning and Design Guide_.](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/separated_bikelane_pdg/page00.cfm)
12.  Precedent-based [CROW. Dutch Sustainable Safety design guidance on distributor-road separation requirements.](https://crowplatform.com/product/design-manual-for-bicycle-traffic/)
13.  Evidence-based [Federal Highway Administration / National Transportation Safety Board. Bicyclist fatality risk data by impact speed.](https://highways.dot.gov/safety/pedestrian-bicyclist/bikeway-selection-guide)
14.  Precedent-based [Seattle Department of Transportation. _Streets Illustrated_.](https://streetsillustrated.seattle.gov/overview/vision-for-seattles-new-streets/)
15.  Legal / regulatory Federal Highway Administration. "Design Speed." Available at: [https://www.fhwa.dot.gov/planning/css/resources/dspeed](https://www.fhwa.dot.gov/planning/css/resources/dspeed)
16.  Precedent-based National Association of City Transportation Officials. "Design Speed." _Urban Street Design Guide_. Available at: [https://nacto.org/publication/urban-street-design-guide/design-controls/design-speed/](https://nacto.org/publication/urban-street-design-guide/design-controls/design-speed/)
17.  Precedent-based [National Association of City Transportation Officials. _City Limits: Setting Safe Speed Limits on City Streets_, 2020.](https://nacto.org/publication/city-limits/)
18.  Legal / regulatory [AASHTO. _A Policy on Geometric Design of Highways and Streets_, 7th ed., controlling criteria and design exception guidance.](https://store.transportation.org/Item/PublicationDetail?ID=4127)
19.  Evidence-based Federal Highway Administration, CMF Clearinghouse. _Combining Multiple CMFs_. Available at: [https://www.cmfclearinghouse.fhwa.dot.gov](https://www.cmfclearinghouse.fhwa.dot.gov)
20.  Evidence-based [Texas Department of Transportation. "5.4 Crash Modification Factors (CMFs)," dominant effect method. _Roadway Design Manual_.](https://www.txdot.gov/manuals/des/tsp/chapter-5-safety-analysis-concepts/5-4-crash-modification-factors--cmfs-.html)
21.  Legal / regulatory [Netherlands. _Wet geluidhinder_ \[Noise Pollution Act\].](https://wetten.overheid.nl/BWBR0003227)
22.  Precedent-based [N325 Pleyroute corridor speed-setting precedent, as documented in Dutch noise policy literature.](https://en.wikipedia.org/wiki/Provincial_road_N325_\(Netherlands\))
23.  Legal / regulatory [Federal Highway Administration. 23 CFR Part 772, _Procedures for Abatement of Highway Traffic Noise and Construction Noise_.](https://www.ecfr.gov/current/title-23/chapter-I/subchapter-H/part-772)
24.  Precedent-based AASHTO Center for Environmental Excellence. "Noise Overview." Available at: [https://environment.transportation.org/focus-areas/noise/noise-overview/](https://environment.transportation.org/focus-areas/noise/noise-overview/)
25.  Precedent-based [Virginia Department of Transportation. Intersection and access spacing standards by design speed class.](https://snowplowing.vdot.virginia.gov/doing-business/technical-guidance-and-support/land-use-and-development/access-management-standards/)
26.  Legal / regulatory [Netherlands. _Wet geluidhinder_ \[Noise Pollution Act\], Article 74 (statutory noise zone widths by lane count and urban/rural context).](https://wetten.overheid.nl/BWBR0003227)
27.  Evidence-based [Kaplow, Louis. "Rules Versus Standards: An Economic Analysis." _Duke Law Journal_ 42, no. 3 (1992): 557-629.](https://scholarship.law.duke.edu/cgi/viewcontent.cgi?article=3207&context=dlj)
28.  Evidence-based [Malone, Linda A. _Environmental Regulation of Land Use_, §11.06\[2\], as summarized in "Guidelines for Drafting Municipal Noise Control Ordinances," FindLaw.](https://corporate.findlaw.com/law-library/guidelines-for-drafting-municipal-noise-control-ordinances.html)
29.  Evidence-based ["Enforcement and Learning Under Rules and Standards." Cambridge University Press, 2026.](https://www.cambridge.org/core/journals/legal-theory/article/enforcement-and-learning-under-rules-and-standards/9653BA18A57733B64CA3243714896BB2)

---

Source: https://commonwaysystem.org/guide/find-your-pattern/

# Find Your Pattern

A short set of plain-language questions about a specific street or intersection, how people use it, how fast traffic moves through it, what's around it, will eventually turn a reader's answers into the Functional Classification and Street Typology that fits.

That tool isn't built yet. In the meantime, browse [Street Types & Classifications](https://commonwaysystem.org/guide/street-types.md) directly and match your street to the closest description, or look through [Patterns](https://commonwaysystem.org/patterns.md) by Functional Classification if you already have a rough sense of whether you're dealing with a Local street, a Collector, an Arterial, or an intersection.

Tip

This page is planned but not yet written. Check the [Release History & Roadmap](https://commonwaysystem.org/about/release-history.md) for progress.

---

Source: https://commonwaysystem.org/guide/funding-financing-mechanisms/

# Funding & Financing Mechanisms

[Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) answers whether a jurisdiction can control the land or commit to a policy. This page answers a different question: how the money for a retrofit actually gets raised. The two are often confused because a single project uses both, but they're handled by different staff, different processes, and different legislative authority.

Unlike that page, most of these mechanisms are described consistently across their primary sources using the same four attributes, so this page uses a structured format throughout rather than free-form profiles.

## Special assessment district

**What it is.** A fee charged to property owners within a defined district whose properties are the primary beneficiaries of a transportation improvement. Also called a Local Improvement District or Benefit Assessment District depending on the state.[1]

**Applicable purpose.** Captures the value a specific, identifiable group of properties gains from a nearby improvement and returns it to fund that improvement.

**Revenue potential.** Moderate to high, scaled to the size and value of the assessed district.

**Use of funds.** Capital construction and, in many states, ongoing operating and maintenance costs.

**Leveraging.** Can serve as the local match for federal or state grants, or as security for bonds, letting a district borrow against future assessment revenue.

## Tax increment financing (TIF)

**What it is.** A district in which the incremental growth in property tax revenue, above a fixed baseline, is redirected to fund the improvement believed to have driven that growth.[2]

**Applicable purpose.** Captures future value growth attributable to the improvement, without imposing a new direct fee on property owners.

**Revenue potential.** High, and can compound over the life of the district as property values continue rising.

**Use of funds.** Typically capital costs; operating and maintenance funding varies by state enabling legislation.

**Leveraging.** Frequently used to back long-term debt, since the revenue stream is projected over the life of the TIF district.

## Development impact fee

**What it is.** A one-time charge imposed on new development to fund the public infrastructure that development's added demand requires.[3]

**Applicable purpose.** Shifts the cost of capacity expansion onto the development generating the new demand, rather than existing taxpayers.

**Revenue potential.** Tied directly to the pace of new development, so it fluctuates with the local building cycle rather than providing a steady stream.

**Use of funds.** Capital costs for the specific facilities the fee is calculated against; state law typically restricts use to a defined nexus between the fee and the improvement.

**Leveraging.** Can be pledged against bonds where a jurisdiction has a predictable development pipeline.

## Transportation utility fee

**What it is.** A periodic fee charged to property owners or renters, based on estimated trip generation, functioning more like a utility bill than a property tax.[4]

**Applicable purpose.** Establishes an ongoing, dedicated revenue stream tied to system use rather than property value.

**Revenue potential.** Moderate, and highly dependent on the fee structure and rate chosen locally.

**Use of funds.** Commonly used for maintenance and operations, since the fee recurs regularly rather than arriving as a lump sum.

**Leveraging.** Weaker as bond security than TIF or special assessments, since courts in some states have limited how these fees can be structured and challenged.

## Joint development

**What it is.** A cost- or revenue-sharing partnership between a public agency and a private developer to build infrastructure and adjacent private development together.[5]

**Applicable purpose.** Aligns public infrastructure investment directly with private development that benefits from it, sharing both cost and upside.

**Revenue potential.** Variable, dependent on the specific deal structure and the real estate market at the time.

**Use of funds.** Typically capital costs for the shared or adjacent infrastructure.

**Leveraging.** Can bring private capital into a project that public funding alone couldn't support, in exchange for shared control or revenue.

## Parking benefit district

**What it is.** A district in which revenue from paid on-street parking is returned to that same district for local improvements, rather than going to a general fund.[6]

**Applicable purpose.** Builds local support for paid parking by visibly tying the revenue to nearby, tangible benefits.

**Revenue potential.** Moderate, scaled to parking demand and pricing within the district.

**Use of funds.** Often streetscape, sidewalk, and other public realm improvements within the district boundary.

**Leveraging.** Limited on its own, but frequently paired with other mechanisms on this page for a larger project.

## Transportation reinvestment zone

**What it is.** A defined zone, similar in mechanism to TIF, specifically authorized in some states for transportation-related revenue capture and reinvestment.[7]

**Applicable purpose.** Provides a transportation-specific alternative where general TIF authority is unavailable or restricted from transportation use.

**Revenue potential.** High, similar to TIF, dependent on the growth captured within the zone.

**Use of funds.** Transportation capital projects within the zone, per the enabling legislation.

**Leveraging.** Can back bonds the same way TIF does, where state law authorizes it.

## Naming rights and sponsorship

**What it is.** The sale of naming or sponsorship rights for a piece of infrastructure to a private company or institution.[8]

**Applicable purpose.** A supplementary revenue source rather than a primary funding mechanism for most projects.

**Revenue potential.** Low relative to the other mechanisms on this page, though notable for requiring no new fee or tax.

**Use of funds.** Varies by agreement; often directed to the specific asset being named.

**Leveraging.** Minimal, given the modest and often one-time nature of the revenue.

## References

1.  Legal / regulatory [Federal Highway Administration, Center for Innovative Finance Support. "Value Capture Strategies Toolkit for Practitioners."](https://www.fhwa.dot.gov/ipd/value_capture/toolkit/)
2.  Evidence-based [Federal Highway Administration. "Filling Funding Gaps." _Public Roads_, Autumn 2019.](https://highways.dot.gov/public-roads/autumn-2019/filling-funding-gaps)
3.  Legal / regulatory [Federal Highway Administration. "Value Capture Revenue Tools: An Introduction."](https://www.fhwa.dot.gov/ipd/pdfs/fact_sheets/program_value_cap_introduction.pdf)
4.  Precedent-based [Federal Highway Administration. "Value Capture Techniques in Practice."](https://www.fhwa.dot.gov/ipd/value_capture/strategies_in_practice/)
5.  Legal / regulatory [Federal Transit Administration. "Value Capture."](https://www.transit.dot.gov/valuecapture)
6.  Precedent-based [New Jersey Transit-Oriented Development. "Value Capture Implementation Manual."](https://www.njtod.org/value-capture-manual/)
7.  Precedent-based [Buro Happold. "Capturing the Value of Public Transit."](https://www.burohappold.com/news/value-capture-financing-solution-americas-transit-infrastructure-problem/)
8.  Evidence-based [Federal Highway Administration. "Managing Economic Shocks to Value Capture-Funded Projects," March 2022.](https://www.fhwa.dot.gov/ipd/pdfs/value_capture/managing_economic_shocks.pdf)

---

Source: https://commonwaysystem.org/guide/how-the-transportation-ecosystem-fits-together/

# How the Transportation Ecosystem Fits Together

Most people don't end up here because they're curious about street design. They arrive because something specific bothers them: a crosswalk that isn't there, a corner that feels dangerous to cross, a road that seems built for cars and nothing else. The instinct is simple. _I just want this fixed. Why is that complicated?_

It's complicated because "fixing a road" runs into two separate landscapes at once, and almost nobody explains the difference between them before dropping you into either one.

The first landscape is legal authority: which government can actually approve a change, and what process it requires. That's a real question with a real answer for your specific location, and [How Road Changes Actually Happen](https://commonwaysystem.org/guide/make-it-happen.md) is the chapter dedicated to it. If you haven't read it yet, that's where the "who do I call and what do they need from me" question gets answered.

This page is about the other landscape: the world of organizations that write the guidance, standards, and advocacy that shape what a _good_ fix looks like in the first place. NACTO, AASHTO, Strong Towns, the MUTCD, PROWAG. If you've spent any time researching your own street, you've probably run into a few of these names already, usually without anyone explaining what they are, whether they matter, or why there are so many of them.

That's the actual, specific problem this page exists to solve. It's not just that the landscape is unfamiliar. It's that even people who've been at this a while often can't say which organization actually has the authority to make something happen versus which one is just publishing an opinion, however well-researched. Two organizations can both put out a document called a "design guide," and one of them is federal law by way of state adoption while the other is a respected but entirely voluntary recommendation. Nothing about the name tells you which is which.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why America Won't Copy Sweden's Cheap Highway Fix](https://www.youtube.com/watch?v=jyNEnYaBszk)

Safe By Design

Explains Sweden's 2+1 alternating-passing-lane cable-barrier retrofit and the specific AASHTO Green Book barriers (literally) that have kept the same fix from scaling in the US.

## Who does what, and how much weight it actually carries

The organizations below are grouped by the kind of authority they hold, not by acronym or subject matter, because that's the distinction that actually answers "does this matter for my situation."

### Binding regulation

These aren't recommendations. If a jurisdiction is subject to them, compliance isn't optional.

**The Manual on Uniform Traffic Control Devices (MUTCD), and the Federal Highway Administration that maintains it.** The MUTCD is a genuine national standard for traffic control devices, stop signs, signals, pavement markings, and more, issued under federal regulation.[1] States don't get to ignore it, but they do get to choose how they adopt it: as-is, with a state supplement, or as their own state MUTCD written in substantial conformance.[1] If you're a professional who already knows the MUTCD, the useful thing to know here isn't what it is, it's that Commonway's patterns are built to be consistent with it, not to substitute for it. A Commonway pattern that specifies a device covered by the MUTCD assumes you'll still confirm your state's specific adoption of it.

**PROWAG (Public Right-of-Way Accessibility Guidelines) and the U.S. Access Board.** This one's worth being precise about, because its legal status has changed recently and in stages. The Access Board issued PROWAG as a final rule in August 2023, covering accessibility for sidewalks, curb ramps, crosswalks, and pedestrian signals.[2] On its own, a Board guideline isn't yet an enforceable standard. It becomes one only once another federal agency formally adopts it, which is exactly what happened next: the General Services Administration adopted it in July 2024, and the Department of Transportation adopted it for transit stops effective January 2025.[2] That two-step structure (guideline, then adoption) is common enough across this landscape that it's worth recognizing as a pattern in itself, not a PROWAG-specific quirk.

**The EPA, for the stormwater and green infrastructure side of street design.** Green infrastructure, permeable pavement, bioswales, rain gardens, isn't just a nice-to-have design choice. It's frequently how a jurisdiction complies with Clean Water Act stormwater requirements it's already legally bound to.[3] If a Commonway retrofit strategy touches stormwater management, that's the regulatory backdrop it sits on top of, even when nobody mentions the Clean Water Act by name.

### Professional guidance, not law

These organizations shape what "good practice" looks like across the profession, and cities widely adopt their guidance voluntarily, but none of it is binding on its own.

**NACTO (National Association of City Transportation Officials).** NACTO is a coalition of city and transit agency transportation departments, not a government body itself, that publishes street design guidance built specifically for dense urban conditions.[4] Its Urban Street Design Guide and Urban Bikeway Design Guide are widely cited throughout Commonway System because they fill a real gap: guidance written for cities, not just highways. For a professional already fluent in NACTO, the relevant CS distinction is scope, not competition. NACTO guidance is one of several sources Commonway System draws on and synthesizes into a single common set of patterns, rather than a separate parallel system you'd need to reconcile with NACTO yourself.

**AASHTO (American Association of State Highway and Transportation Officials).** AASHTO represents the state DOTs themselves, and its publications, the Green Book above all, function as the de facto national standard for highway geometric design, even though AASHTO is an organization of the states, not a federal agency, and its policies aren't federal law.[5] States adopt AASHTO guidance into their own standards at their own discretion, which is exactly why "AASHTO says so" and "it's the law here" aren't automatically the same statement. A professional will recognize AASHTO immediately; what's worth flagging is that Commonway's patterns lean on AASHTO's geometric and safety guidance for vehicle-facing design while drawing on NACTO and the Dutch sources below for everything AASHTO's highway-first origins don't cover well.

**ITE (the community formerly known as the Institute of Transportation Engineers).** ITE is a professional membership association for transportation engineers and planners, not a standards-setting government body, that advances shared knowledge and recommended practices across the field through its members, publications, and conferences.[6] Where Commonway System cites an ITE Recommended Practice, that's professional consensus among practitioners, not regulation.

### Advocacy and movements

These organizations aren't publishing engineering standards. They're building public will and political pressure toward a different default way of building streets, and their influence shows up in which projects get funded and which get demanded, not in a codebook.

**Strong Towns.** A nonprofit and media organization built around the argument that most postwar suburban development, streets included, is a financially unsustainable pattern, and that the fix runs through incremental, locally-driven change rather than another master plan.[7] If you've heard someone argue that a wide arterial road is bankrupting their city rather than serving it, that argument traces back here.

**Congress for the New Urbanism (CNU).** A membership nonprofit that's spent over three decades advancing walkable, mixed-use urban design as the explicit alternative to sprawl, articulated through its founding Charter of the New Urbanism.[8] Where Strong Towns argues mainly from municipal finance, CNU argues mainly from design and urban form, and the two movements overlap heavily in practice.

**Vision Zero Network.** A nonprofit campaign, not a design-standards body, helping communities adopt Vision Zero: the goal of eliminating traffic deaths and serious injuries entirely, built on the premise that people will inevitably make mistakes and the road system should be designed so those mistakes don't kill anyone.[9] Several Commonway patterns that prioritize forgiving design over driver-behavior enforcement draw directly on Vision Zero's underlying safe-systems thinking, even on pages that don't mention Vision Zero by name.

**Project for Public Spaces (PPS).** Since 1975, PPS has led "placemaking," a community-driven, bottom-up approach to designing public spaces, plazas, markets, streets, around how people actually use them rather than how a plan assumes they will.[10] Where the other movements here focus on the street as a transportation problem, PPS treats it as a public space problem first, which is a genuinely different lens worth having.

**The National Complete Streets Coalition (a program of Smart Growth America).** Complete Streets is the specific, named movement behind the idea that a street's design should serve pedestrians, cyclists, transit riders, and drivers together, not motor vehicles by default.[11] Over 1,600 U.S. jurisdictions have adopted some form of Complete Streets policy, which is why the phrase itself has become close to a household term in this field even though it's not a technical standard.

**Create Streets.** A UK-based social enterprise, design practice, and think tank founded by Nicholas Boys Smith in 2012, built around the idea of "gentle density," street-based, low-rise, high-density neighborhoods, and it's had genuine influence on British national planning policy, including through the government's Building Better, Building Beautiful Commission.[12] Where the rest of this bucket is largely American, Create Streets is a useful reminder that the same underlying argument, dense and walkable beats sprawl, shows up internationally with its own vocabulary and its own political wins. Its own focus sits closer to building form and architectural character than to road engineering itself, which is a genuinely different scope from Commonway's own density tiers, worth keeping distinct rather than treating the two as interchangeable.

### International frameworks

**The Dutch CROW system.** CROW is the Dutch nonprofit that develops the design guidelines, standards, and manuals used to plan Netherlands infrastructure, including the Design Manual for Bicycle Traffic, widely regarded internationally as the most complete bicycle infrastructure design reference in existence.[13] A meaningful share of Commonway's cycling and low-speed street patterns are directly informed by CROW's published guidance, adapted for U.S. jurisdictional and legal context rather than copied wholesale.

**SWOV (Institute for Road Safety Research).** SWOV is the Netherlands' national scientific research institute for road safety, independent of CROW, focused on generating and disseminating research rather than writing design standards itself.[14] Where CROW tells you how to build something, SWOV is closer to the evidence for why building it that way actually reduces crashes. Commonway System draws on both, and treats them as distinct roles rather than interchangeable Dutch sources.

### Adjacent, with a tangential role

**ITDP (Institute for Transportation and Development Policy).** A global nonprofit focused on sustainable and equitable transportation, best known for its work on bus rapid transit systems worldwide.[15] ITDP's core focus, transit systems and global development contexts, sits mostly outside Commonway System's scope, but its research occasionally informs the transit-adjacent patterns here.

## Where Commonway actually fits

None of the organizations above are wrong, and Commonway System isn't trying to out-rank any of them. FHWA still sets the binding rules it sets. AASHTO's Green Book is still the geometric baseline most engineers were trained on. Strong Towns is still right that street decisions are financial decisions. Commonway doesn't compete with any of that authority, and claiming otherwise would be exactly the kind of overpromise this page is trying to help you see through.

What Commonway actually does is narrower and, we'd argue, more useful for exactly the confusion this page opened with: it takes the guidance these organizations already publish, separately, in their own formats, aimed at their own audiences, and reorganizes it into one common set of patterns. You don't need to already know that curb ramp requirements come from PROWAG, that bikeway geometry comes from NACTO and CROW, and that the underlying safety philosophy traces back to Vision Zero, before you can find a usable answer. The pattern already did that reconciliation for you.

That's the honest version of "solution." Not a new authority layered on top of the existing ones, but a legibility layer over guidance that already exists and that these organizations have spent decades getting right. If you're a newcomer, that means you get to start with a pattern instead of a research project. If you're a professional who already knows this landscape well, that means Commonway is worth your time not because it replaces what you know, but because it's already done the cross-referencing you'd otherwise do by hand.

## Once you've found your pattern

Understanding this landscape answers "what does a good fix look like." It doesn't answer "how do I get it approved where I live," because that's a separate question about government jurisdiction, not design guidance. That's exactly what [How Road Changes Actually Happen](https://commonwaysystem.org/guide/make-it-happen.md) walks through next.

## References

1.  Legal / regulatory [23 CFR 655.603, MUTCD as the national standard for traffic control devices, state adoption options.](https://www.law.cornell.edu/cfr/text/23/655.603)
2.  Legal / regulatory [U.S. Access Board, Public Right-of-Way Accessibility Guidelines (PROWAG) overview, including the August 2023 final rule and the July 2024 (GSA) and December 2024 (DOT, effective January 2025) enforceable adoptions.](https://www.access-board.gov/prowag/)
3.  Legal / regulatory [U.S. EPA, About Green Infrastructure, stormwater management and Clean Water Act compliance context.](https://www.epa.gov/green-infrastructure/about-green-infrastructure)
4.  Precedent-based [NACTO, About page, coalition structure and mission.](https://nacto.org/about/)
5.  Precedent-based [AASHTO, About page, state DOT membership, standards-setting role, and non-federal legal status.](https://transportation.org/about/)
6.  Precedent-based [ITE, About ITE, professional membership association structure and mission.](https://www.ite.org/about-ite/about-ite/)
7.  Precedent-based [Strong Towns, About page, mission and organizational structure.](https://www.strongtowns.org/about)
8.  Precedent-based [Congress for the New Urbanism, Who We Are, mission and Charter of the New Urbanism.](https://www.cnu.org/who-we-are)
9.  Precedent-based [Vision Zero Network, About page, mission and safe-systems approach.](https://visionzeronetwork.org/about/vision-zero-network/)
10.  Precedent-based [Project for Public Spaces, About page, placemaking history and mission since 1975.](https://www.pps.org/about)
11.  Precedent-based [Smart Growth America, National Complete Streets Coalition program page, mission and policy adoption count.](https://www.smartgrowthamerica.org/programs-and-coalitions/national-complete-streets-coalition/)
12.  Precedent-based [Create Streets, Our Story page, founding, mission, and policy influence including the Building Better, Building Beautiful Commission.](https://www.createstreets.com/front-page-2/our-story/)
13.  Precedent-based [CROW Platform, official site, role in developing Dutch infrastructure design guidance.](https://crowplatform.com/)
14.  Precedent-based [SWOV Institute for Road Safety Research, official site.](https://swov.nl/en)
15.  Precedent-based [ITDP, About Us page, mission and history.](https://itdp.org/about/)

---

Source: https://commonwaysystem.org/guide/how-to-read-a-pattern/

# How to Read a Pattern

Every pattern in this guidebook is built from the same handful of parts, repeated consistently: a Pattern ID card, density tier chips, admonition blocks, and citations. This page walks through what each one means, so the rest of the guidebook can be read without re-explaining itself on every page.

## The Pattern ID card

`ART-UMS-09`

Recommended Arterial

Urban main street

An Urban main street is an Arterial typology combining retail frontage access with continuous pedestrian priority along both edges.

Each pattern opens with a card naming its ID, title, [Functional Classification](https://commonwaysystem.org/guide/street-types.md), and (for most classifications) a status. The colored left edge matches the classification, Local, Collector, Arterial, Freeway, or Intersections & Crossings, so a reader flipping through the guidebook can tell at a glance what kind of pattern they're looking at, even before reading the title.

The ID itself follows a fixed format, `[PREFIX]-[CTXCODE]-[##]`, like `LOC-BBG-12`, with an optional trailing `(DENSITY)` suffix once more than one page exists for the same Typology at different density tiers.

The label in the upper right corner shows the pattern's Functional Classification when one applies: Local, Collector, Arterial, Freeway, or Intersections & Crossings. For the four Scales that don't subdivide by classification, Network, Corridor, Facility, and Element, that same corner shows the Scale name itself instead. See [Scale Hierarchy](https://commonwaysystem.org/guide/scale-hierarchy.md) for what each of the nine Scale prefixes covers.

Read the [Pattern IDs](https://commonwaysystem.org/guide/pattern-ids.md) page for what each part of the ID means, the full nine-prefix Scale breakdown, and what each status badge means.

## Illustrations

Every pattern now opens with an illustration, placed right after the ID card and before the page's main text. Most patterns show a pair: a grayscale "Typical condition" alongside a "Commonway recommendation" with the specific fix highlighted. A few patterns use a different form instead:

-   Avoid patterns show a single flagged condition, with an "Instead, see" pointing to the alternative.
-   Network-scale patterns show a plan-view diagram rather than a cross-section.
-   A small number of patterns that document an existing condition without recommending for or against it show one plain illustration with no verdict implied.
-   One or two hard-to-classify patterns use whichever form fits best.

Most patterns need just one illustration. A few carry a second when the main illustration's format can't show something the page depends on, a driveway-spacing claim that only reads clearly from above, for instance, rather than in cross-section.

Illustrations still being drawn show as a placeholder: a bordered box with a caption describing the scene and numbered callouts pointing to what matters, standing in for the finished artwork.

## Density tiers

Density tiers appear as a small chip next to any guidance that changes by context:

Suburban Urban Core

Six tiers run from Undeveloped to Core, describing how much housing and activity sit on the land around a street, not the street itself. Read the [Density Tiers](https://commonwaysystem.org/guide/density-tiers.md) page for what each tier means, where the names and unit-per-acre ranges come from, and how to handle a segment that falls between two tiers.

## The Speed & Modal Hierarchy card

Every Local, Collector, and Arterial pattern that allows automobiles carries a second card, split into two parts: Section A, Design Speed & Speed Limit, and Section B, Modal Hierarchy. A handful of patterns exclude automobiles entirely, Shared-Use Path and Bike Highway / Greenway among them, and show Section B on its own, with no speed section at all, since [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md) has nothing to say about a street with no cars on it.

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local Character Type's rule: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Bicycle > Transit > Vehicle > Freight

No override: this Typology follows the Local base order.

**Section A, Design Speed & Speed Limit,** shows one MUTCD-style speed-limit sign per applicable speed, paired with a short line stating whether the pattern inherits its Character Type's rule as written or carries a documented override, and a link to [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md) for the full rule and its citations. Arterial cards stack the sign(s) above that text instead of running them side by side, since an Arterial pattern can carry up to five signs, one per density tier, where Local always shows one and Collector shows at most two.

**Section B, Modal Hierarchy,** shows a row of pills, one per mode, each pairing a small icon with the mode's name, left to right in ranked order. A ">" between two pills means the left one outranks the right; an "=" means the two are explicitly tied, [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md)'s Pedestrian = Bicycle pairing is a real example. Pill color follows the pattern's own Functional Classification, the same color family as the Pattern ID card's left edge above.

Two patterns bend this format further. [Stroad](https://commonwaysystem.org/patterns/arterials/stroad.md) shows Section A's signs with no pill row underneath at all, since it's an explicit Avoid pattern with no ranked hierarchy to show. [Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md) and [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md) each show two labeled pill rows instead of one, since their modal hierarchy changes by time of day.

## Admonitions

Callout blocks flag content that needs to stand apart from the surrounding text. Five kinds exist, each with its own color and label:

Note

A note adds background or context that isn't itself an instruction.

Tip

A tip is a specific, actionable recommendation worth calling out on its own.

Caution

Renders with the label "Caution." Flags a real risk or a rule that's easy to get wrong, like the speeding risk called out on the [One-Way Street](https://commonwaysystem.org/patterns/arterials/one-way-street.md) page.

Avoid

Renders with the label "Avoid." Marks a pattern or approach the Commonway System recommends against outright, stronger than a Situational status badge.

Unsourced claim

Flags a claim that still needs a citation before publication. The amber color is reserved for this and for pattern highlighting, so it never doubles as a general-purpose warning color elsewhere in the system.

## Citations

Citations are numbered, superscript badges that link down to a source list at the end of the page, under a `## References` heading. Clicking a badge jumps straight to its numbered entry. A claim still waiting on a source is flagged inline instead of cited, using the same amber as the `:::unsourced` block above but sized for a single word or number rather than a whole paragraph⚠.

See the [Bicycle Boulevard](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) page's Design notes section for numbered citations linking to a real References list in action.

## Related patterns

Every pattern page ends with a short Related Patterns list before its References, pointing to the other patterns most worth reading alongside it: a companion, an override, or a lower or higher tier of the same idea. Not every pattern in the same family is listed, only the ones with something specific to add.

Patterns describe what a street should be. If you're trying to figure out how to move an existing street toward one, see [How to read a retrofit strategy](https://commonwaysystem.org/guide/how-to-read-a-retrofit-strategy.md).

---

Source: https://commonwaysystem.org/guide/how-to-read-a-retrofit-strategy/

# How to Read a Retrofit Strategy

Retrofit Strategies answer a different question than Patterns do. A Pattern describes what a street should be. A Retrofit Strategy describes how to move an existing street toward that destination. This page explains how each part of a Retrofit Strategy entry works.

If you haven't read [How to Read a Pattern](https://commonwaysystem.org/guide/how-to-read-a-pattern.md) yet, start there first. Retrofit Strategies borrow several conventions from Patterns directly, and this page assumes you already know them.

## The ID card

Every Retrofit Strategy has an ID in the format `RFT-SCALE-##`, for example `RFT-CDR-01`.

-   **RFT** marks this as a Retrofit Strategy, not a Pattern.
-   **SCALE** is one of three values: **CDR** (Corridor), **INT** (Intersection), or **NET** (Network). This tells you what level the strategy operates at, a single street segment, a single intersection, or an area-wide network.
-   **##** is a sequential number within that scale. Numbers are never renumbered or reused, matching how Pattern IDs work.

The scale appears directly on the ID card, the same place Patterns display their own identifying information. There is no separate scale badge. If you're used to reading a Pattern's ID card, reading a Retrofit Strategy's works the same way.

Retrofit Strategies do not carry status badges (Recommended, Situational, Discouraged, and so on). A Pattern's badge tells you whether CS endorses that destination. A Retrofit Strategy isn't endorsed or discouraged in that sense, it's either applicable to your situation or it isn't. That judgment lives in the Applicability and thresholds section below, not in a badge.

## Overview

A short, word-lite explanation of what the strategy physically or procedurally involves. If you've never heard of a road diet or a Restricted Crossing U-Turn, this is where you find out what it actually is, in plain language, before anything else.

## Where this leads: Target patterns

Every Retrofit Strategy exists to move a street toward one or more destinations. This section lists the Pattern or Patterns this strategy typically produces. A four-to-three lane road diet, for instance, usually leads toward a Collector or Arterial pattern with added bike facilities, so that Pattern is listed and linked here.

This section is the mirror image of a Pattern page's own "Getting there: Retrofit path options" section, which lists the strategies that lead to that Pattern. Read together, the two sections let you navigate in either direction, start from where you are and find out where you could go, or start from a destination and find out how to get there.

## Applicability and thresholds

The conditions under which this strategy is actually appropriate. Traffic volume ceilings, existing lane count, context type, and similar thresholds live here. This is the section to read before proposing anything, since it tells you whether the strategy even fits your street.

Thresholds here are evidence-based and cited, not judgment calls. Where research gives a specific number, for instance a volume ceiling above which a road diet stops being appropriate, that number appears here with its source.

## Evidence and effectiveness

The measured outcomes: crash reduction percentages, safety findings, and other studied effects. Every citation carries its evidence-tier chip, Legal / regulatory Evidence-based Precedent-based, the same standard used across every citation sitewide.

## Getting it built

Two questions, answered briefly:

1.  **Where does this strategy fall on the construction spectrum?** Some strategies can move through demonstration, pilot, and quick-build stages before becoming permanent. Others, because of their scale or complexity, effectively require full capital construction from the start. This section says which, and links to the Guide's [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md) page rather than re-explaining the spectrum here.
2.  **Does this strategy typically require a formal decision process first?** Some strategies, particularly at the Intersection scale, are commonly preceded by an Intersection Control Evaluation or a Road Safety Audit. This section notes that and links to the Guide's [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md) page rather than re-explaining the process here.

## Who can move this

A compact note on jurisdiction and leverage. Not a full treatment of legal or funding mechanisms, just enough to tell you whether this is a city council conversation, a state DOT conversation, or something a neighborhood group can push for directly. Links out to [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md) for the deeper detail.

This section exists because Retrofit Strategies, unlike Patterns, are things someone has to actually go do. Knowing what tool exists is only useful if you also know whose hands it's in.

## Related retrofit strategies

Some strategies belong to a family. The three approaches to retrofitting a protected bike lane, reallocating lane width, removing a lane, or reducing on-street parking, are distinct strategies with distinct tradeoffs, but they're solving the same underlying problem in different ways. This section cross-references the other members of that family so you can compare approaches before choosing one.

This section only appears when a genuine family relationship exists. It follows the same inclusion standard as a Pattern's Related patterns section: a stated relationship, a defined structural connection, or a genuinely non-obvious pairing, never inclusion just because two strategies happen to share a scale.

## References

Primary sources only, evidence-tier tagged, in the same citation format used throughout the publication.

## The short version

If you remember nothing else from this page: a Pattern is a destination, a Retrofit Strategy is a path. Start with Where this leads if you're standing at a strategy and want to know what it produces. Start with Getting there if you're standing at a Pattern and want to know how to reach it. Everything else on a Retrofit Strategy page exists to help you judge whether that path is the right one for your street, and who needs to help you walk it.

---

Source: https://commonwaysystem.org/guide/legal-planning-mechanisms/

# Legal & Planning Mechanisms

Retrofit Strategies change a street's physical form. That change usually depends on something happening first: land being controlled, a policy being adopted, a classification being changed. This page catalogs the legal and planning tools that make retrofit strategies possible in the first place.

These tools don't specify a design. They specify who controls the ground a design would sit on, or what a jurisdiction has committed itself to doing. A road diet is a design decision. A corridor preservation ordinance is what keeps the right-of-way for that road diet from being built over before anyone gets around to it.

This page is a catalog of the existing menu of tools. See [How Road Changes Actually Happen](https://commonwaysystem.org/guide/make-it-happen.md) for how these tools typically enter a project's timeline, and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md) for the related question of how a project actually gets paid for.

## Right-of-way control tools

These tools reserve or acquire land for a future transportation use, typically well before construction funding exists.[1][5]

### Official map

**What it is.** A map, adopted by ordinance, that designates the future location of a planned street or right-of-way expansion. Property within the mapped area can be restricted from development that would conflict with the future facility.[4]

**Who controls it.** Local government, by ordinance, usually tied to a comprehensive or master plan.

**When it's used.** Early, well before a project has funding or a design. An official map is a placeholder that prevents the land from being built out of reach.

### Option to purchase

**What it is.** An agreement giving a public agency the right, but not the obligation, to buy a specific parcel or easement at a later date, at a price set now.[2]

**Who controls it.** The agency and the property owner, negotiated individually.

**When it's used.** When a specific parcel is known to be needed but the agency isn't ready to commit funds yet. Lower-cost than outright acquisition, since it defers payment.

### Comprehensive or master plan corridor designation

**What it is.** Formally naming a corridor in a jurisdiction's adopted comprehensive plan as a future transportation priority.[3]

**Who controls it.** The local legislative body, through the plan adoption process.

**When it's used.** As the first formal step in corridor preservation, since most other tools in this section reference the comprehensive plan as their legal basis.

### Concurrency ordinance

**What it is.** A requirement that infrastructure capacity, including transportation capacity, must exist or be committed before new development is approved.

**Who controls it.** Local government, by ordinance, often required or enabled by state growth management law.

**When it's used.** To prevent development from outpacing a corridor's planned capacity, indirectly protecting the case for future right-of-way.

### Voluntary developer reservation

**What it is.** A developer voluntarily sets aside land for a future transportation facility as part of a project, often in exchange for a density bonus or other incentive.

**Who controls it.** Negotiated between the developer and the local government during project review.

**When it's used.** When a parcel is being developed before the transportation need is fully funded, and outright dedication isn't legally required.

### Density transfer

**What it is.** Development rights are shifted from the portion of a parcel needed for a future right-of-way to the remaining buildable portion, so the owner doesn't lose overall development capacity.

**Who controls it.** Local zoning code, applied parcel by parcel.

**When it's used.** As a lighter-weight alternative to a full transfer of development rights program, when only a single parcel's right-of-way need is being addressed.

### Setback and building-line reservation

**What it is.** Zoning or subdivision requirements that keep new construction set back far enough to leave room for a future roadway widening or facility.

**Who controls it.** Local zoning and subdivision ordinances.

**When it's used.** Routinely, as a background requirement on any parcel adjacent to a corridor with a known future need, rather than as a standalone action.

## Policy mechanisms

These tools don't reserve land. They commit a jurisdiction to a design approach, which in turn shapes what happens the next time a street is touched.

### Complete Streets policy

**What it is.** A formal commitment, by ordinance, departmental policy, or executive order, to design and operate streets for all users rather than motor vehicles alone.[6][9][10]

**Who controls it.** Varies by form. An ordinance requires legislative action; a departmental policy or executive order can be issued without it, but carries less durable force.

**When it's used.** As a standing policy rather than a per-project decision, meaning its main effect is on projects that haven't been scoped yet.

### Arterial retrofit ordinance

**What it is.** An ordinance that specifically mandates retrofit treatment, rather than leaving it discretionary, on arterials meeting defined criteria.

**Who controls it.** Local or state legislative action, sometimes tied to a state Complete Streets act.

**When it's used.** Where a jurisdiction wants retrofit to happen on a schedule rather than opportunistically. This is a policy mechanism whose entire purpose is to compel a Retrofit Strategy from the Corridor scale catalog.

### Functional classification reclassification

**What it is.** Changing a street's official functional class, which in turn changes which design standards and treatments are eligible or required.[7]

**Who controls it.** The state DOT or MPO typically holds final authority, though local government can petition for reclassification.

**When it's used.** When a street's actual function and use no longer match its classification, commonly after a corridor has already transitioned in practice from a through-route to a local destination street or vice versa.

### Context classification

**What it is.** A design-standards system that ties requirements to the surrounding land use context rather than to functional class alone, letting the same street type receive different treatment in a downtown versus a rural setting.[8]

**Who controls it.** State DOT, when adopted as a statewide system; can also be adapted locally.

**When it's used.** As an alternative or supplement to functional classification, in jurisdictions that have found classification alone too blunt an instrument for context-sensitive design.

## References

1.  Legal / regulatory [Florida Department of Transportation. "What is Corridor Management?" Center for Urban Transportation Research.](https://www.cutr.usf.edu/oldpubs/news_let/articles/spring96/am.htm)
2.  Legal / regulatory [Salt Lake County Office of Regional Development. "Corridor Preservation Fund."](https://www.saltlakecounty.gov/regional-development/planning-transportation/corridor-preservation-fund)
3.  Precedent-based [CONNECT Our Future. "Transportation Corridor Preservation."](https://connectourfuture.org/tools/transportation-corridor-preservation/)
4.  Legal / regulatory [Utah Code Title 72, Chapter 5, Part 4, Section 403. "Transportation Corridor Preservation Powers."](https://le.utah.gov/xcode/Title72/Chapter5/72-5-S403.html)
5.  Legal / regulatory [Federal Highway Administration, Office of Real Estate Services. "Corridor Management."](https://www.fhwa.dot.gov/real_estate/right-of-way/corridor_management/index.cfm)
6.  Precedent-based [CRTPO. "Complete Streets Policy."](https://crtpo.org/resources/complete-streets/complete-streets-policy/)
7.  Evidence-based [NACTO Urban Street Design Guide. "Functional Classification."](https://nacto.org/publication/urban-street-design-guide/design-controls/functional-classification/)
8.  Legal / regulatory [Florida Department of Transportation. "Context Classification Guide," October 2024.](https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/roadway/completestreets/files/fdot-context-classification.pdf)
9.  Legal / regulatory [MRSC. "Complete Streets." Washington state code compilation.](https://mrsc.org/explore-topics/facilities/rights-of-way/complete-streets)
10.  Legal / regulatory [Washington Revised Code of Washington 47.04.320-.340. "Complete Streets Act."](https://app.leg.wa.gov/rcw/default.aspx?cite=47.04.320)

---

Source: https://commonwaysystem.org/guide/make-it-happen/

# How Road Changes Actually Happen

Getting a street pattern built is rarely just a design question. It's a process question: who has the authority to approve a change, how that authority typically handles a request like yours, and what actually has to happen before anything gets painted, signed, or poured.

That process varies by city, county, and state, sometimes down to the individual road. This page can't give you the phone number to call. What it can give you is a method: four questions that will get you to the right authority and the right kind of request, wherever you are.

This page doesn't cover private roads or homeowners' association jurisdiction beyond a short note under Question 2 below, since that's a routine branch of the method rather than an exception to it. It also doesn't cover Corridor Preservation, a separate, opt-in program for reserving right-of-way for a distant future facility, which has almost nothing to do with the everyday process covered here. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) for the tools that reserve land and commit a jurisdiction to a policy, including corridor preservation, ahead of a request like the one this page walks through.

## Question 1: What are you trying to do?

Start here, because the answer changes everything downstream.

**A. Restore or maintain something that already exists in its current, already-approved form.** A faded stripe, a broken sign, a pothole. The need for this was already established when it was first installed, so it doesn't need to be justified again.

**B. Add or change something at a specific location that isn't there today, or that currently works differently.** A new stop sign, a new crosswalk, a changed signal, a road diet. This is new, so someone will need to justify it before it happens.

**C. Change the underlying design standard everywhere this situation occurs, not just at one location.** This is the one genuinely location-independent path on this page. It skips the rest of this method entirely and routes straight to your local government's comprehensive plan or ordinance process, the same process that would apply to any other proposed change in local law or policy.

If you picked A or B, keep going. If you picked C, this page's remaining questions won't apply to you the way they apply to a single-location request.

## Question 2: Is the road public or private?

**Private roads have no government jurisdiction at all.** Authority sits with the HOA board or the private owner, governed by the community's declaration and bylaws, not by any public process. But two things are worth knowing if you're dealing with a private road:

Traffic control devices an HOA installs without real engineering backing have been challenged and thrown out in court as unenforceable, in at least one case tied to a fatality dispute.[1] A private road isn't a free pass to install whatever seems reasonable.

And in some states, that private status can be partly, deliberately lifted. Florida is one example: a board majority vote can convert enforcement (not ownership) so that state traffic law and police authority apply, as an all-or-nothing election.[2] The road stays privately owned, but it starts behaving like a public one for enforcement purposes.

**Public roads continue to Question 3.** If you're not sure whether a road is public or private, check for a blue street sign (a private-road marker in some jurisdictions), look up your jurisdiction's own road ownership map if it publishes one, or call your local public works department and ask. Several jurisdictions' own published guidance tells residents to do exactly this rather than guess.

## Question 3: Which government has authority?

This is not a single clean lookup, and it's the question most likely to surprise a newcomer. It has four parts.

**3a. Start with ownership, but don't stop there.** City, county, state, tribal, or federal ownership is the obvious first check, but which layer of government owns which roads is itself inconsistent from place to place. A state highway running through a small town might be state property in every sense except that the town controls its traffic signals below a certain population size.[3] Ownership tells you where to start looking, not necessarily where the request ends up.

**3b. Check whether authority splits by function on this exact road.** Signal timing, road grade, underground utilities, and sidewalks can each belong to a different authority on the same physical stretch of road, even when one government clearly owns the pavement itself. Don't assume the entity that owns the road controls every part of a request about it.

**3c. Check for overlapping sovereignty.** Tribal land crossed by a state highway is the clearest example: a change may require joint approval from two authorities, with neither one able to act alone.

**3d. If more than one authority holds a piece of your request, contact each one for its specific piece.** Don't assume one call covers everything once you've found more than one authority involved.

Jurisdiction can fracture in ways well beyond what these four steps anticipate: by a population threshold, by a city that consolidated with its county but left specific municipalities out, by a route number that means something different once you cross into a particular city's limits. If your situation feels unusual once you start asking around, the [reference page on jurisdiction variants](https://commonwaysystem.org/guide/make-it-happen/jurisdiction-variants.md) catalogs the specific, documented structures that don't follow this page's general method cleanly.

## Question 4: How does that government process this?

Once you know which government (or governments) actually holds the authority, the request itself follows one of several tracks, depending on what you're asking for.

**4a. Direct service request.** Fits routine maintenance authority. Staff can act without a study, because the need was already established when the thing was first installed. This is the track for most of what Question 1 sorted into "restore or maintain."

**4b. Engineering study or warrant.** Triggered by adding or changing something that isn't already there. For devices covered by the Manual on Uniform Traffic Control Devices (MUTCD), this is a genuine federal standard, applied through state adoption.[4] Every state must adopt the MUTCD as-is, adopt it with a state supplement, or write its own state MUTCD in substantial conformance, and the specific approach varies by state.[4]

This isn't bureaucracy for its own sake. It exists because research shows unwarranted devices actually reduce safety: drivers learn to treat unjustified signs and signals as optional, which lowers compliance even at nearby locations where a device really is warranted.[5] A warrant is proof of need, required before the device goes in, not after.

Not everything runs through MUTCD's warrant process, though. Speed humps are the clearest example: because MUTCD doesn't cover them, states and cities have each written their own separate petition and eligibility criteria, and these vary widely even within a single state.[6] Whatever number or percentage you find published for your own jurisdiction, treat it as that jurisdiction's own rule, not a national standard.

And a warrant, once required, isn't a formality that agreement among neighbors can skip. Unanimous neighborhood support does not exempt a request from this process. An engineering study can still be required, and a request can still be denied, even when every affected property owner agrees.[7]

At an intersection specifically, this engineering study can take a more formal, staged shape than a warrant lookup, an Intersection Control Evaluation comparing control alternatives, or a Road Safety Audit examining an existing location for safety issues. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md) for how each one works.

**4c. Capital project.** Needed once a request's cost exceeds routine maintenance authority, whether it's a new addition or a larger fix. Timeline depends heavily on the funding source. Projects using federal funds must go through a Metropolitan Planning Organization (MPO) and appear in that region's Transportation Improvement Program before federal money can be released, which can add years.[8] Residents cannot approach an MPO directly; a local government has to sponsor the project first.[9]

A capital project also raises two questions this page doesn't answer on its own: where the money actually comes from, beyond a federal grant, and whether "capital project" has to mean full permanent construction from day one. See [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md) for the first, and [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md) for the second, since a project can often move through a demonstration, pilot, or quick-build stage before committing to permanent construction.

**4d. Legislative or public-hearing action.** Required when state law or local code treats the change as carrying legal or political weight, independent of its physical scale. Installing or removing a mid-block crosswalk in some cities requires exactly this kind of legislative action, even though physically it's a small change.[10]

**4e. Already-adopted-plan implementation.** If the specific change you're asking about was already designated in a plan the city or county previously adopted, such as a bike master plan, it can often proceed as ordinary engineering work folded into a scheduled project, with no fresh public process.[11] The public input already happened when the plan itself was adopted.

**4f. Compliance-triggered work.** Some changes aren't requested by anyone at all. The clearest example is ADA curb ramps: federal law requires them whenever a street is "altered," such as during resurfacing, regardless of whether any resident asked.[12] If a qualifying project is already scheduled nearby, this kind of change may already be coming without a request from you.

**4g. Rights-based accommodation channel.** Separate from the ordinary public works request path, some jurisdictions maintain a dedicated process specifically for disability-related access barrier requests, evaluated on different terms and by a different office than a general request.[13] If your request is about a mobility or access barrier specifically, check whether your jurisdiction runs a channel like this before filing it as a general request.

## Jurisdiction can fracture in ways worth expecting

Even once you've worked through all four questions, it's worth knowing that "who's in charge here" can turn out to be genuinely surprising, not just unfamiliar. In Baltimore, the state highway administration maintains numbered state routes in every Maryland county except Baltimore City, where the city's own department of transportation maintains those same state highways instead, meaning a route number tells you nothing reliable about who to call once you're inside certain city boundaries.[14] In parts of Colorado, a newly built subdivision's roads can be financed and governed by a metropolitan district, an independent unit of government with its own elected board and taxing authority, created by the developer before residents ever moved in, layered underneath the city or county residents assume is in charge.[15]

These aren't edge cases invented for this page. They're real, documented structures, and there are more like them. The [reference page on jurisdiction variants](https://commonwaysystem.org/guide/make-it-happen/jurisdiction-variants.md) is where to look if your own situation doesn't fit the general method cleanly.

## A decision isn't always final

Whichever track above produced an answer, that answer isn't necessarily the end of the story. A decision reached through any of these tracks can be challenged, and potentially reversed, through the courts. This has happened with contested bike lanes and road diets in more than one city.[16] A denial, or an approval, is a decision made through a specific process. It isn't automatically the last word.

## References

1.  Precedent-based HOA Talk forum discussion, DIY stop signs ruled unenforceable after fatality dispute. [https://www.hoatalk.com/Forum/tabid/55/forumid/1/postid/229452/view/topic/Default.aspx](https://www.hoatalk.com/Forum/tabid/55/forumid/1/postid/229452/view/topic/Default.aspx)
2.  Legal / regulatory Florida Statute 316.006(2)(b)4 and (3)(b)5, HOA board election of state traffic law enforcement on private roads. Summary via LegalClarity: [https://legalclarity.org/florida-private-road-laws-traffic-regulations-explained/](https://legalclarity.org/florida-private-road-laws-traffic-regulations-explained/)
3.  Legal / regulatory Revised Code of Washington 47.24.020, state DOT authority over traffic signals in incorporated towns below a population threshold. [https://apps.leg.wa.gov/rcw/default.aspx?cite=47.24.020](https://apps.leg.wa.gov/rcw/default.aspx?cite=47.24.020)
4.  Legal / regulatory 23 CFR 655.603, MUTCD as the national standard for traffic control devices; state adoption options. [https://www.law.cornell.edu/cfr/text/23/655.603](https://www.law.cornell.edu/cfr/text/23/655.603) (Supplementary: Kittelson, "What You Need to Know About the New MUTCD," state adoption breakdown: [https://www.kittelson.com/ideas/what-you-need-to-know-about-the-new-mutcd/](https://www.kittelson.com/ideas/what-you-need-to-know-about-the-new-mutcd/))
5.  Evidence-based Research synthesis on unwarranted stop signs reducing driver compliance. [https://archive.rcgov.org/ca20120221/PW021412-16.pdf](https://archive.rcgov.org/ca20120221/PW021412-16.pdf)
6.  Evidence-based Iowa State University study on speed humps, confirming exclusion from MUTCD and resulting jurisdiction-by-jurisdiction criteria. [https://cityofpleasantridge.org/wp-content/uploads/2019/01/Study-on-Speed-Humps-Iowa-State-University.pdf](https://cityofpleasantridge.org/wp-content/uploads/2019/01/Study-on-Speed-Humps-Iowa-State-University.pdf)
7.  Precedent-based Kansas City reporting on engineering-study requirement despite unanimous neighborhood support. [https://thebeaconnews.org/stories/2024/11/18/request-crosswalk-stop-sign-in-kansas-city/](https://thebeaconnews.org/stories/2024/11/18/request-crosswalk-stop-sign-in-kansas-city/)
8.  Legal / regulatory 23 CFR Part 450, federal definition and requirements for the Transportation Improvement Program. [https://www.ecfr.gov/current/title-23/chapter-I/subchapter-E/part-450](https://www.ecfr.gov/current/title-23/chapter-I/subchapter-E/part-450)
9.  Precedent-based Indianapolis MPO, sponsor-to-TIP project process. [https://www.indympo.org/funding/irtip](https://www.indympo.org/funding/irtip)
10.  Precedent-based San Francisco Better Streets, public hearing and SFMTA Board action requirement for mid-block crosswalk installation/removal. [https://sfbetterstreets.org/find-project-types/pedestrian-safety-and-traffic-calming/crosswalks/index.html](https://sfbetterstreets.org/find-project-types/pedestrian-safety-and-traffic-calming/crosswalks/index.html)
11.  Precedent-based Sacramento example of plan-adoption absorbing future public process for bikeway implementation. [https://www.pedbikeinfo.org/resources/resources\_details.php?id=4693](https://www.pedbikeinfo.org/resources/resources_details.php?id=4693)
12.  Legal / regulatory DOJ/FHWA joint guidance on ADA Title II curb ramp requirements triggered by street alteration. [https://archive.ada.gov/doj-fhwa-ta.htm](https://archive.ada.gov/doj-fhwa-ta.htm)
13.  Precedent-based Los Angeles Access Request Program, disability-specific access barrier remediation process. [https://sidewalks.lacity.gov/access-request-program-frequently-asked-questions](https://sidewalks.lacity.gov/access-request-program-frequently-asked-questions)
14.  Precedent-based Maryland Department of Transportation State Highway Administration, road maintenance jurisdiction excluding Baltimore City. [https://roads.maryland.gov/mdotsha/pages/index.aspx?PageId=9](https://roads.maryland.gov/mdotsha/pages/index.aspx?PageId=9)
15.  Legal / regulatory Colorado Special District Act, Title 32, Article 1, C.R.S., governing metropolitan district formation and authority. Summary via Colorado Division of Local Government: [https://dlg.colorado.gov/special-districts-brief-review-for-residents](https://dlg.colorado.gov/special-districts-brief-review-for-residents)
16.  Precedent-based NYC Streetsblog reporting on court-ordered removal of a half-installed Queens bike lane under Article 78 challenge. [https://nyc.streetsblog.org/2025/12/05/queens-judge-orders-city-to-nix-half-installed-queens-bike-lane](https://nyc.streetsblog.org/2025/12/05/queens-judge-orders-city-to-nix-half-installed-queens-bike-lane)

---

Source: https://commonwaysystem.org/guide/make-it-happen/jurisdiction-variants/

# When Jurisdiction Doesn't Follow the Pattern

The [How Road Changes Actually Happen chapter](https://commonwaysystem.org/guide/make-it-happen.md) teaches a general method for finding out who has authority over a road and how that government processes a request. That method works for most readers most of the time. It does not work cleanly for everyone, because a small number of documented government structures depart from the ordinary city-county-state stack in ways the general method doesn't anticipate.

This page catalogs those structures. Each entry is a real, named, documented exception, not a hypothetical edge case. If your situation matches one of these, start here instead of the general method, since it will get you to the right authority faster.

This page does not cover private roads or homeowners' association jurisdiction. That topic is addressed directly in Question 2 of the [How Road Changes Actually Happen chapter](https://commonwaysystem.org/guide/make-it-happen.md), since it's a routine branch of the general method rather than an exception to it.

## Consolidated city-county governments

Some cities and counties have merged into a single government. Consolidation is almost never total, though. Specific municipalities or functions are routinely carved out even after a formal merger.

Jacksonville and Duval County, Florida consolidated in 1968, but four municipalities (Baldwin, Jacksonville Beach, Neptune Beach, and Atlantic Beach) declined to join and remain fully independent cities inside the consolidated county today.[1]

Indianapolis and Marion County, Indiana consolidated under Unigov in 1970, combining administration, planning and zoning, parks, and infrastructure development.[2] Police, fire, and school districts were explicitly left out of that consolidation. Four municipalities were also excluded by a population threshold written into the enabling legislation, yet their residents still vote for the consolidated mayor and council and receive countywide services.[3]

Roads and infrastructure appear to be among the functions most likely to be pulled into a consolidation even when other functions stay separate, but this is a pattern, not a guarantee, and needs to be verified for each consolidated city individually.

## Independent cities

Virginia has 38 independent cities that are not part of any county at all. They are legal equals to counties, not subdivisions of them. Only three other independent cities exist anywhere else in the country: Baltimore, St. Louis, and Carson City.[4]

Virginia inverts the usual national pattern in a specific way: except for Arlington and Henrico counties, Virginia's counties do not maintain their own roads at all. The state DOT maintains secondary roads directly.[5] Virginia's independent cities, by contrast, own and maintain their own roads and receive a fixed state funding allocation for it, while counties compete for a share of the state DOT's budget instead.

Virginia also has a distinct request category worth knowing about if you're dealing with an independent city: its Rural Addition Policy lets a resident petition to have a private or informally public road formally accepted into the state-maintained system, generally requiring at least 20 years of public use and 24-hour public availability.[6] This is a different kind of request than fixing or adding something to a road the state already maintains. It's a request that the state take on the road at all.

## Dillon's Rule states

This variant is different in kind from the others on this page. It doesn't change which government has jurisdiction. It changes whether a government that clearly has jurisdiction is legally free to act on its own initiative.

Under Dillon's Rule, which originates from an 1868 court decision, a local government only has the powers explicitly granted to it by the state, plus powers necessarily or fairly implied from an express grant.[7] A Dillon's Rule city or county that needs new authority to do something has to lobby the state legislature for it.

Home Rule flips that presumption: a local government can act unless the state has explicitly withdrawn that authority.[8] Most states fall somewhere between the two, sometimes granting home rule only above a population threshold, which means two towns in the same state can have genuinely different authority to act on an identical request.

This matters directly for the How Road Changes Actually Happen chapter's Question 4 tracks. In a Dillon's Rule jurisdiction, a government telling you "we can't do that" may be legally accurate rather than simply unwilling, and the real next step is lobbying the state legislature, not applying more local pressure. Virginia, already covered above under independent cities, is a strict Dillon's Rule state.

## Tribal land overlaps

Tribal roads are maintained by a tribe's own transportation department or by the federal Bureau of Indian Affairs (BIA). This is not a variant of local government. It's a genuinely separate sovereign layer alongside federal, state, and local government. Tribes prepare their own five-year Tribal Transportation Improvement Program, submitted to the BIA for approval, running parallel to the state and MPO planning system rather than through it.[9]

Where a state highway crosses reservation land, authority can require joint approval from both governments, with neither able to act alone. In Washington State, for example, tribal authorities can adjust speed limits on a state highway within reservation boundaries, but the change isn't effective until the state DOT also approves it and signs are posted.[10] If the road in question is a city or county road instead of a state highway, the tribal change additionally needs that local government's approval too.

## Special districts and metropolitan districts

In Colorado and some other states, roads inside a new development can be financed, and sometimes maintained, by a special district rather than the city or county a resident would normally assume is in charge. Colorado's metropolitan districts are genuine, independent units of local government under the state's Special District Act, with elected boards, property tax authority, and the power to issue bonds.[11]

These districts are often created by the developer before residents ever move in, specifically to work around state tax limitation laws that restrict how much a city or county can raise taxes for new infrastructure.[12] A resident can end up paying off a 30-year infrastructure bond to a government entity they've never heard of, layered directly underneath the city or county they assumed owned the road. Colorado also has several narrower single-purpose variants of this same idea, with different governance models depending on the district type.

## Interstate compact authorities

A small number of roads and crossings are governed by an authority that belongs to two states jointly, created through a formal interstate compact rather than through either state's ordinary government structure. The Port Authority of New York and New Jersey is the clearest example: a joint corporate entity created by a 1921 interstate compact that required congressional consent, governed by twelve commissioners split evenly between the two states' governors.[13]

Its jurisdiction is defined geometrically, by a 25-mile radius from lower Manhattan, rather than by any political boundary, and it operates its own police department with authority to enforce motor vehicle law specifically at the bridges and tunnels it controls.[14] A road authority like this exists entirely outside the normal city, county, and state stack, because it belongs to two states at once.

## States without a functioning county layer

A few states have no active county government at all, though they arrived there by different paths. Connecticut abolished county government entirely in 1960.[15] Unlike Puerto Rico, which never had counties in the first place, Connecticut's county lines still appear on some maps and in some statutes, but there is no government behind them today. The state replaced counties administratively with regional planning councils and councils of governments, mainly for federal grant purposes.

In practice, this creates a direct town-versus-state road split at the level of individual streets. Some Connecticut towns publish street-by-street guides showing which segments are town-maintained and which are state-maintained.[16] Connecticut also formalizes the split-by-function pattern seen elsewhere on this page: a state Office of State Traffic Administration holds authority over traffic control devices statewide, working through a locally designated Local Traffic Authority in each town, whose exact form (a board of selectmen, a police commission, a mayor, or a police chief) depends on that town's own structure.[17]

Connecticut additionally recognizes a distinct legal path from private to public road status: if an owner deliberately allows sustained public use over a significant period of time, a court can later find the road became public through this use, called implicit dedication, without any formal petition process ever having occurred.[18]

## Michigan-style road commissions

Michigan townships have no jurisdiction over roads at all, which runs counter to how townships function in most other states.[19] Instead, Michigan created county road commissions: legally distinct, single-purpose government bodies that are not part of general county government, except in Wayne County, which uses its own department of public services instead.[20]

These commissions have jurisdiction over all roads in their county except state highways, hold no taxing authority of their own, and are funded entirely through state and federal road funds. Roughly three-quarters of Michigan's road mileage falls under county road commission jurisdiction, with the rest split between the state highway system and cities and villages.[21] Road commissions also contract with the state DOT to maintain thousands of miles of state roads, meaning the entity responsible for the physical work and the entity that sets the design standard can be two different bodies even on a single stretch of state highway.

## Federal-agency-embedded roads

Some ordinary, daily-commute roads inside a city are managed by a federal land agency rather than the city's own transportation department. In Washington, D.C., the district's own transportation department manages most of the city's roads, but several major corridors, including Rock Creek Parkway, the George Washington Parkway, and the roads around the National Mall and Tidal Basin, are managed by the National Park Service instead.[22] These are not confined to park land at the city's edge. They function as ordinary commuting routes threaded through the middle of the city.

The National Park Service also follows a distinct federal compliance pathway for traffic control devices, operating under a specific memorandum of understanding with the Federal Highway Administration rather than adopting the MUTCD directly.[23] The Park Service's own sign system is deemed to be in substantial conformance with the MUTCD rather than a direct adoption of it. Major event closures in the district, such as a marathon or a presidential inauguration, typically require coordination across the district's own transportation department, the Metropolitan Police, the U.S. Park Police, and the Secret Service, since no single agency holds full authority over the affected corridors.

## Puerto Rico and territorial structure

Puerto Rico has no county layer at all. It is organized directly into 78 municipios, each functioning as a combined city and county.[24] Its state-equivalent layer is itself split in two: the Department of Transportation and Public Works is the cabinet-level department, while actual highway construction and maintenance sits with a separate, semi-independent public corporation, the Puerto Rico Highways and Transportation Authority, which functions as a child agency of the department rather than a division inside it.[25]

For federal-aid highway purposes, Puerto Rico is treated like a state, with its own Federal Highway Administration division office.[26] That federal funding relationship holds even though Puerto Rico's basic governmental structure doesn't match the mainland county-city-state stack this page's other entries are built around.

Other US territories, including Guam, the US Virgin Islands, American Samoa, and the Northern Mariana Islands, were not individually researched for this page. Each likely has its own variant of a non-standard county layer paired with a federally recognized DOT-equivalent, broadly similar in kind to Puerto Rico's, but this has not been verified and should not be treated as confirmed.

## References

1.  Precedent-based Government of Jacksonville overview, including the four independent municipalities that declined 1968 consolidation. [https://en.wikipedia.org/wiki/Government\_of\_Jacksonville](https://en.wikipedia.org/wiki/Government_of_Jacksonville)
2.  Precedent-based Unigov overview (Indianapolis/Marion County consolidation scope). [https://en.wikipedia.org/wiki/Unigov](https://en.wikipedia.org/wiki/Unigov)
3.  Legal / regulatory Indiana Code 36-3-1-7, excluded cities and included towns under Unigov. [https://law.justia.com/codes/indiana/title-36/article-3/chapter-1/section-36-3-1-7/](https://law.justia.com/codes/indiana/title-36/article-3/chapter-1/section-36-3-1-7/)
4.  Precedent-based LegalClarity, overview of Virginia's independent cities (38 cities, count of 41 nationwide). [https://legalclarity.org/virginia-independent-cities-what-they-are-and-how-they-work/](https://legalclarity.org/virginia-independent-cities-what-they-are-and-how-they-work/)
5.  Precedent-based Virginia Department of Transportation, contact and jurisdiction FAQ confirming the Arlington/Henrico exception. [https://www.vdot.virginia.gov/contact/](https://www.vdot.virginia.gov/contact/)
6.  Precedent-based Virginia Department of Transportation, "How Roads Qualify for Improvements," Rural Addition Policy criteria. [https://www.vdot.virginia.gov/projects/roads-qualify/](https://www.vdot.virginia.gov/projects/roads-qualify/)
7.  Legal / regulatory Cornell Law School Legal Information Institute, Wex definition of home rule, including Dillon's Rule origin. [https://www.law.cornell.edu/wex/home\_rule](https://www.law.cornell.edu/wex/home_rule)
8.  Legal / regulatory FiscalNote, overview of Dillon's Rule versus Home Rule. [https://fiscalnote.com/blog/dillons-rule-vs-home-rule](https://fiscalnote.com/blog/dillons-rule-vs-home-rule)
9.  Legal / regulatory Bureau of Indian Affairs, Tribal Transportation Program overview. [https://www.bia.gov/bia/ois/division-transportation/operations](https://www.bia.gov/bia/ois/division-transportation/operations)
10.  Legal / regulatory Washington State Legislature, bill report on tribal authority to adjust speed limits on state highways within reservation boundaries. [https://lawfilesext.leg.wa.gov/biennium/2009-10/Htm/Bill%20Reports/Senate/5331%20SBR%20TRAN%2009.htm](https://lawfilesext.leg.wa.gov/biennium/2009-10/Htm/Bill%20Reports/Senate/5331%20SBR%20TRAN%2009.htm)
11.  Legal / regulatory Colorado Special District Act, Title 32, Article 1, C.R.S. Summary via Colorado Division of Local Government: [https://dlg.colorado.gov/special-districts-brief-review-for-residents](https://dlg.colorado.gov/special-districts-brief-review-for-residents)
12.  Precedent-based Colorado Association of Homebuilders, metro districts explained (developer financing model, TABOR context). [https://www.hbacolorado.com/colorado-metro-districts/](https://www.hbacolorado.com/colorado-metro-districts/)
13.  Precedent-based Ballotpedia, New York-New Jersey Port Authority Compact of 1921. [https://ballotpedia.org/New\_York-New\_Jersey\_Port\_Authority\_Compact\_of\_1921](https://ballotpedia.org/New_York-New_Jersey_Port_Authority_Compact_of_1921)
14.  Precedent-based Wikipedia, Port Authority of New York and New Jersey Police Department, jurisdiction at specific bridges and tunnels. [https://en.wikipedia.org/wiki/Port\_Authority\_of\_New\_York\_and\_New\_Jersey\_Police\_Department](https://en.wikipedia.org/wiki/Port_Authority_of_New_York_and_New_Jersey_Police_Department)
15.  Precedent-based Wikipedia, local government in Connecticut, county abolition history (1960 Public Act 152). [https://en.wikipedia.org/wiki/Local\_government\_in\_Connecticut](https://en.wikipedia.org/wiki/Local_government_in_Connecticut)
16.  Precedent-based Town of Glastonbury, Connecticut, town-versus-state road guide. [https://www.glastonburyct.gov/departments/department-directory-a-h/highway/streets-transportation/town-vs-state-roads](https://www.glastonburyct.gov/departments/department-directory-a-h/highway/streets-transportation/town-vs-state-roads)
17.  Legal / regulatory Connecticut Department of Transportation, Local Traffic Authority role description. [https://portal.ct.gov/dot/osta/local-traffic-authority](https://portal.ct.gov/dot/osta/local-traffic-authority)
18.  Legal / regulatory Connecticut Office of Legislative Research, report on towns taking over roads within special taxing districts, including implicit dedication case law. [https://www.cga.ct.gov/2002/rpt/2002-R-1015.htm](https://www.cga.ct.gov/2002/rpt/2002-R-1015.htm)
19.  Precedent-based Michigan Townships Association, "What Townships Do," explicit statement that townships lack road authority. [https://michigantownships.org/about-townships/what-townships-do/](https://michigantownships.org/about-townships/what-townships-do/)
20.  Legal / regulatory Road Commission for Oakland County, jurisdiction breakdown and 1909 enabling law (Public Act 51), Wayne County exception. [https://rcocweb.org/177/What-Is-the-Road-Commission](https://rcocweb.org/177/What-Is-the-Road-Commission)
21.  Precedent-based Canton, Michigan, FAQ on statewide road ownership breakdown by percentage. [https://www.cantonmi.gov/m/faq?cat=28#question-169](https://www.cantonmi.gov/m/faq?cat=28#question-169)
22.  Precedent-based District Department of Transportation, National Park Service traffic advisory reporting on Beach Drive/Rock Creek Parkway management. [https://ddot.dc.gov/release/national-park-service-traffic-advisory-report-february-2](https://ddot.dc.gov/release/national-park-service-traffic-advisory-report-february-2)
23.  Legal / regulatory Federal Highway Administration and National Park Service, memorandum of understanding on traffic control devices (UniGuide substantial conformance). [https://mutcd.fhwa.dot.gov/resources/policy/moutcd/index.htm](https://mutcd.fhwa.dot.gov/resources/policy/moutcd/index.htm)
24.  Precedent-based Wikipedia, Puerto Rico Department of Transportation and Public Works, municipio structure. [https://en.wikipedia.org/wiki/Puerto\_Rico\_Department\_of\_Transportation\_and\_Public\_Works](https://en.wikipedia.org/wiki/Puerto_Rico_Department_of_Transportation_and_Public_Works)
25.  Precedent-based Wikipedia, Puerto Rico Highways and Transportation Authority, child-agency relationship to DTOP. [https://en.wikipedia.org/wiki/Puerto\_Rico\_Highways\_and\_Transportation\_Authority](https://en.wikipedia.org/wiki/Puerto_Rico_Highways_and_Transportation_Authority)
26.  Legal / regulatory Federal Highway Administration, Puerto Rico/USVI Division office overview. [https://highways.dot.gov/field-offices/puerto-rico](https://highways.dot.gov/field-offices/puerto-rico)

---

Source: https://commonwaysystem.org/guide/pattern-ids/

# Pattern IDs

Every pattern in this guidebook carries a unique ID, shown on its Pattern ID card as described on the [How to Read a Pattern](https://commonwaysystem.org/guide/how-to-read-a-pattern.md) page. This page explains what each part of that ID means, why it's structured the way it is, and what the status badge next to it tells you.

## The ID format

Every pattern ID follows a fixed format:

**`[PREFIX]-[CTXCODE]-[##]`**

For example, `LOC-BBG-12`, with an optional trailing `(DENSITY)` suffix once more than one page exists for the same Typology at different density tiers.

-   **PREFIX** encodes Scale, covered in full below.
-   **CTXCODE** is a short mnemonic for the specific Typology. `BBG` stands for Bicycle Boulevard / Neighborhood Greenway, for example. `DEF` is reserved for each classification's baseline default entry.
-   **\[##\]** is a two-digit number assigned once, in the order the pattern was added to the guidebook. It never changes later, even if the pattern's position in the Pattern Index does.

## Scale prefixes

PREFIX is where the ID encodes Scale, one of nine values:

| Prefix | Meaning | Scale |
| --- | --- | --- |
| `NET` | Network | Network |
| `CDR` | Corridor | Corridor |
| `LOC` | Local | Segment/Intersection |
| `COL` | Collector | Segment/Intersection |
| `ART` | Arterial | Segment/Intersection |
| `FRE` | Freeway | Segment/Intersection |
| `INT` | Intersections & Crossings | Segment/Intersection |
| `FAC` | Facility | Facility |
| `ELM` | Element | Element |

Network, Corridor, Facility, and Element each get exactly one flat prefix, with no further subdivision. Segment/Intersection is the one Scale that subdivides, into five prefixes, because Functional Classification carries real design implications, speed, modal hierarchy, that the other four Scales don't yet have an equivalent for. That's also why every pattern page live in the guidebook today is a Segment/Intersection pattern: `LOC`, `COL`, `ART`, `FRE`, or `INT`.

See [Scale Hierarchy](https://commonwaysystem.org/guide/scale-hierarchy.md) for what each of the nine Scale prefixes actually covers, and [Street Types & Classifications](https://commonwaysystem.org/guide/street-types.md) for what each Functional Classification and Typology means in plain language.

## Status badges

Where a status applies, it appears as a small badge next to the classification label on the Pattern ID card.

-   **Recommended** is the quiet default, no color emphasis, since it's the unremarkable normal case.
-   **Situational** reuses the amber warning color, meaning the pattern is real but context-dependent.
-   **Avoid** reuses the rose danger color, meaning the Commonway System actively recommends against it.

Status is omitted entirely on Intersections & Crossings entries, since the master Typology reference doesn't track a status for those.

## How this connects to the rest of the guidebook

See [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) for a full worked example of a Pattern ID card in context, and the [Pattern Index](https://commonwaysystem.org/patterns.md) for every pattern currently in the guidebook.

---

Source: https://commonwaysystem.org/guide/scale-hierarchy/

# Scale Hierarchy

\[Image: Commonway System scale hierarchy diagram showing five levels: Network, Corridor, Segment or Intersection, Facility, and Element, arranged from top to bottom with arrows connecting each scale, on a clean white background with the text Commonway System Scale Hierarchy\]

Every pattern in the Commonway System exists at one of five scales:

**Network → Corridor → (Segment / Intersection) → Facility → Element**

-   **Network.** The whole connected system, or a defined sub-system within it. Patterns here are about topology and system-wide structure rather than any single physical place: a grid versus a radial street layout, how a transit network integrates with the road network, or a classification system itself. You wouldn't stand in one spot and see a Network pattern, you'd see it on a map.
-   **Corridor.** A linear stretch of the network connecting two places, often crossing multiple contexts along the way. This is the level where "the road's character changes as it moves from farmland into town" patterns live.
-   **Segment or Intersection.** Siblings, not nested; the network is made of segments connected by intersections. This is where most patterns in the system live: a specific stretch of street between two intersections, or the intersection itself.
-   **Facility.** Something that attaches to a segment or intersection rather than being one: a bus shelter, a parking garage, a plaza. Internally complex enough to have its own element-level layout inside it.
-   **Element.** The physical components a segment, intersection, or facility is built from: curbs, medians, signage, striping, signals, street trees, lighting.

A pattern's ID starts with a prefix naming its Scale: `NET` for Network, `CDR` for Corridor, `FAC` for Facility, `ELM` for Element, and one of `LOC`/`COL`/`ART`/`FRE`/`INT` for Segment/Intersection, the one Scale that also subdivides by Functional Classification. `LOC-BBG-12`, for example, is a Segment/Intersection-scale pattern, specifically a Local pattern in the back-of-block/alley context. See [Pattern IDs](https://commonwaysystem.org/guide/pattern-ids.md) for the full nine-prefix breakdown. Knowing where a pattern sits on this scale, alongside its classification, is what makes the rest of the Guide, and the diagnostic and process walkthrough still to come, make sense.

---

Source: https://commonwaysystem.org/guide/street-types/

# Street Types & Classifications

Every pattern page in this guidebook is sorted two ways: by its Functional Classification and by its Street Typology. Those aren't everyday words, so this page explains what they mean, in plain language, before you run into them everywhere else in the guidebook.

\[Image: Commonway System functional classification diagram showing four classes of streets and roadways: Freeways, Arterials, Collectors, and Local Streets, while describing their differences.\]

## The question every street has to answer

Every street is pulled between two competing jobs: helping people move through quickly, and helping people access the homes and businesses along it. A street can't fully do both at once. A road built for fast through-traffic works badly as a place with driveways and parked cars every few feet; a residential street built for slow, safe access to houses works badly as a high-speed route across town.

**Functional Classification is just naming where a street sits on that trade-off.** Commonway System uses four, the same categories used to classify roads across the US highway system:[1]

| Classification | Job it's built to do |
| --- | --- |
| **Local** | All access, no through-traffic. Getting to your house or a nearby business is the entire point. |
| **Collector** | A middle step. Gathers traffic from Local streets and feeds it onto bigger roads. Some access, some movement. |
| **Arterial** | Mostly movement. Built to carry traffic efficiently across a larger area, not to serve driveways directly. |
| **Freeway** | Pure movement. High speed, no direct access to anything at all, not even a single driveway. |

There's a real-world example of what goes wrong when a street tries to do both jobs badly at once: it's called a **Stroad**[2], a road that tries to move fast traffic and serve strip-mall driveways and parking lots at the same time. It ends up dangerous for the same reason a car can't be a good boat: trying to do two very different jobs at once usually means doing neither one well. Commonway System flags Stroad as a pattern to avoid, and most of what a Collector or Arterial page in this guidebook recommends is really just a way of keeping those two jobs from colliding.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Stroads are Ugly, Expensive, and Dangerous](https://www.youtube.com/watch?v=ORzNZUeUHAM)

Not Just Bikes

The definitive explainer on stroads, and lays out the Dutch three-tier road/street classification system that CS's own Functional Classification structure closely mirrors.

## Why a bike path or a bus route gets a car-sounding label

You'll run into pattern names like "Collector" attached to a bike path, or "Local" attached to a bus route, and that can look like a mistake at first. It isn't. Functional Classification isn't really about cars, it's about the job being done, and any mode of travel can do any of these jobs.

A dedicated bike path connecting one neighborhood to another is doing exactly the job a car Collector does, just for bikes instead of cars, so it's classified as a Collector. A car-free plaza that exists purely so people can walk to shops and linger is doing the same job a residential street does, just without cars, so it's classified as Local. The same logic sorts transit: a neighborhood bus loop plays a Local role, a bus route feeding a larger transit line plays a Collector role, a light-rail spine crossing a whole city plays an Arterial role, and commuter or heavy rail plays a Freeway-scale role. Once you're thinking in terms of the job rather than the vehicle, the classification makes sense for any mode.

## From classification to a specific street

Knowing a street's Functional Classification tells you its general job. It doesn't tell you the specific situation it's handling. That's what a **Street Typology**[3] is: a named, specific pattern within a classification, built for one clear purpose.

Think of it like this: Functional Classification answers "what job is this street doing?" Street Typology answers "what particular kind of street is doing that job?" An Alley and a Main Street are both Local, both are pure access with no through-traffic, but they're built for completely different situations: one is a service lane behind buildings, the other is a shopping street meant for browsing on foot. Same classification, very different street.

Every classification has a **Default** Typology: the standard, ordinary version of that classification, with no special situation attached. A pattern only gets its own named Typology when it's built around something specific enough to deserve a name of its own, a particular access pattern, a particular land use, or a single mode getting full priority.

## Every Street Typology in the guidebook

Most of the names below aren't invented for this guidebook. Many trace to established American design guides, particularly NACTO's Urban Street Design Guide,[4] cross-referenced against how each pattern is actually used in the field.

### Local

| Typology | What it is |
| --- | --- |
| [Default](https://commonwaysystem.org/patterns/local-streets/default.md) | The standard neighborhood street. No special job beyond getting people to and from home. |
| [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md) | A narrow service lane behind buildings, mainly for deliveries, trash pickup, and driveway access. |
| [Cul-de-sac](https://commonwaysystem.org/patterns/local-streets/cul-de-sac.md) | A dead-end residential street that loops back on itself. |
| [Frontage/Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md) | A quiet local street running alongside a busier road, keeping people out of fast through-traffic. |
| [Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md) | A local street lined with shops and restaurants, built for browsing on foot as much as driving. |
| [Living Street/Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md)[5] | A street where people walking and biking always have the right of way, and cars are guests, not the priority. |
| [Yield Street](https://commonwaysystem.org/patterns/local-streets/yield-street.md)[6] | A low-traffic street with no dedicated travel lanes; whoever's already there has the right of way. |
| [Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md) | A street that closes to cars for markets or events, and behaves like a normal local street the rest of the time. |
| [Pedestrian-only Street/Plaza](https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza.md) | Closed to vehicles entirely, built just for walking and sometimes biking. |
| [Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) | A street built around a neighborhood bus or streetcar route. |
| [Bicycle Boulevard/Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) | A quiet residential street specifically designed to prioritize bikes over car traffic. |
| [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md) | A street that closes to car traffic during drop-off and pickup to keep kids safe. |

### Collector

| Typology | What it is |
| --- | --- |
| [Default](https://commonwaysystem.org/patterns/collectors/default.md) | A standard street that gathers traffic from Local streets and feeds it onto bigger roads. |
| [Rural Collector/Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) | A collector serving farms and rural areas, carrying both people and agricultural traffic. |
| [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) | A collector built to handle truck traffic serving warehouses and industrial sites. |
| [Bike Highway/Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) | A dedicated, physically separated path built specifically for bikes over real distance. |
| [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) | A collector street built around a dedicated bus route. |

### Arterial

| Typology | What it is |
| --- | --- |
| [Default](https://commonwaysystem.org/patterns/arterials/default.md) | A major road built to move traffic efficiently across a larger area, without driveways or on-street parking interrupting the flow. |
| [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) | A grand arterial, often with a landscaped median and sometimes separate slower side lanes for local access. |
| [Scenic Highway/Byway](https://commonwaysystem.org/patterns/arterials/scenic-highway-byway.md) | An arterial through a scenic or rural landscape, where the drive itself matters as much as the destination. |
| [Arterial Transit](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) | A major road built around dedicated bus rapid transit or light rail. |
| [Stroad](https://commonwaysystem.org/patterns/arterials/stroad.md) | A hybrid that tries to be both a fast through-road and a shopping strip at once, and does neither safely. This is the pattern Commonway System is built to help communities move away from. |
| [One-Way Street](https://commonwaysystem.org/patterns/arterials/one-way-street.md) | Traffic moves in one direction only. Tends to encourage speeding, so it's discouraged except in specific situations. |

### Freeway

| Typology | What it is |
| --- | --- |
| [Default](https://commonwaysystem.org/patterns/freeways/default.md) | A limited-access, high-speed road with no traffic lights or driveways, built purely to move large volumes of vehicles. |
| [Expressway](https://commonwaysystem.org/patterns/freeways/expressway.md) | A slightly less restricted freeway variant, still built purely for movement. |
| [Beltway/Ring Road](https://commonwaysystem.org/patterns/freeways/beltway-ring-road.md) | A freeway that loops around a city rather than cutting through its center. |
| [Freeway-scale Transit](https://commonwaysystem.org/patterns/freeways/freeway-transit.md) | Heavy or commuter rail running at the same scale as a freeway corridor. |

### Intersections & Crossings

Every classification above describes a stretch of street. Intersections & Crossings is different: it describes how two streets meet, and it applies across all four classifications rather than belonging to just one.

| Typology | What it is |
| --- | --- |
| [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) | A circular intersection that keeps traffic moving continuously instead of stopping. Commonway System's default choice for busier intersections. |
| [Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md)[7] | A larger, multi-lane roundabout for high-volume intersections between two major roads. |
| [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) | A traditional traffic light, used only when a roundabout genuinely isn't practical. |
| [All-Way Stop](https://commonwaysystem.org/patterns/intersections/all-way-stop.md) | A four-way stop. |
| [Stop/Yield](https://commonwaysystem.org/patterns/intersections/stop-yield.md) | A basic two-way stop or yield-controlled intersection. |
| [Continuous Sidewalk/Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md) | A crossing where the sidewalk stays level and uninterrupted, and cars ramp up over it, rather than the sidewalk dipping down for cars. |
| [Uncontrolled](https://commonwaysystem.org/patterns/intersections/uncontrolled.md) | An intersection with no signs or signals at all, appropriate only where traffic is very light. |
| [Midblock Pedestrian Crossing](https://commonwaysystem.org/patterns/intersections/midblock-crossing.md) | A marked crossing placed in the middle of a block rather than at an intersection. |
| [Driveway/Curb Cut](https://commonwaysystem.org/patterns/intersections/driveway-curb-cut.md) | Where a driveway meets the street. |
| [Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md) | A freeway-scale interchange where roads cross at different heights entirely, like an overpass. |

## Why this matters once you're reading a pattern page

Every Segment/Intersection-scale pattern's ID starts with its Functional Classification (`LOC`, `COL`, `ART`, `FRE`, or `INT`), follows with a code for its specific Typology, and ends with a number, for example `LOC-DEF-01` for the standard Local street. These five prefixes apply specifically to the Segment/Intersection scale, alongside four other flat Scale prefixes (`NET`, `CDR`, `FAC`, `ELM`) covering Network, Corridor, Facility, and Element patterns, which don't subdivide by classification. See [Pattern IDs](https://commonwaysystem.org/guide/pattern-ids.md) for the full nine-prefix ID scheme, [Scale Hierarchy](https://commonwaysystem.org/guide/scale-hierarchy.md) for what each Scale covers, and [Density Tiers](https://commonwaysystem.org/guide/density-tiers.md) for the other axis every pattern page is sorted by, alongside classification and typology.

## For readers coming from Dutch (CROW) practice

If you're familiar with Dutch road design, Duurzaam Veilig, or CROW's manuals, you'll recognize a lot of the underlying thinking here even though the categories don't map cleanly onto each other. Commonway System sorts streets by the job they do, movement versus access. Dutch practice sorts primarily by design speed and how completely different modes are physically separated. There's no perfect one-to-one translation, but most CS patterns have a close Dutch relative worth knowing.

| Source Manual | Category/Type | Closest CS equivalent | Area | Cross-section | Speed | Mode separation | Other differentiator |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Duurzaam Veilig | Nationale stroomweg | [Default](https://commonwaysystem.org/patterns/freeways/default.md) (Freeway) / [Expressway](https://commonwaysystem.org/patterns/freeways/expressway.md) | Outside built-up | Min. 2×2, full physical lane separation | 120 km/h (~75 mph) | Full (grade-separated) | National-scale |
| Duurzaam Veilig | Regionale stroomweg | [Expressway](https://commonwaysystem.org/patterns/freeways/expressway.md) / [Beltway / Ring Road](https://commonwaysystem.org/patterns/freeways/beltway-ring-road.md) | Outside built-up | 2×1 to 2×2, physical direction separation | 100 km/h (~60 mph) | Full | Connects regions |
| Duurzaam Veilig | Gebiedsontsluitingsweg I | [Default](https://commonwaysystem.org/patterns/arterials/default.md) (Arterial) | Outside built-up | 2×2, physical separation | 80 km/h (~50 mph) | Bikes banned, routed elsewhere | No erf access |
| Duurzaam Veilig | Gebiedsontsluitingsweg II | [Default](https://commonwaysystem.org/patterns/arterials/default.md) (Arterial) | Outside built-up | 2×1, paint separation | 80 km/h (~50 mph) | Bikes banned | Priority-road rules |
| Duurzaam Veilig | GOW50 | [Default](https://commonwaysystem.org/patterns/arterials/default.md) (Arterial) | Inside built-up | 1 to 2 lanes/direction | 50 km/h (~30 mph) | Separated bike paths | Standard urban distributor |
| Duurzaam Veilig | GOW30 (hybrid) | [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (loose match) | Inside built-up | Same as GOW50 | 30 km/h (~20 mph) | Bike separation often reduced | Emerging (Amsterdam) |
| Duurzaam Veilig | Erftoegangsweg I | [Frontage / Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md), [Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) | Outside built-up | 1 shared carriageway | 60 km/h (~35 mph) | Marked bike strip/path |  |
| Duurzaam Veilig | Erftoegangsweg II | [Default](https://commonwaysystem.org/patterns/local-streets/default.md) (Local) | Outside built-up | 1 shared carriageway | 60 km/h (~35 mph) | None, bikes ride in road | Equal-priority junctions |
| Duurzaam Veilig | ETW-30 (urban) | [Default](https://commonwaysystem.org/patterns/local-streets/default.md) (Local) | Inside built-up | 1 shared carriageway | 30 km/h (~20 mph) | Mixed traffic | Destination traffic only |
| Duurzaam Veilig | Woonerf | [Living Street / Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md) | Inside built-up | No marked lanes, shared surface | 15 km/h (~10 mph) | None, peds have priority | No roadway/sidewalk distinction |
| Ontwerpwijzer Fietsverkeer | Fietssnelweg (bicycle expressway) | [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) | Any, own alignment | 4m+ two-way path | 20 to 30 km/h design (~10 to 20 mph) | Full, bikes only | Long-distance, minimal stops, built for e-bike speeds |
| Ontwerpwijzer Fietsverkeer | Solitair fietspad | [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) | Any, own alignment | 2 to 4m path | n/a | Full, bikes only (or +mopeds) | Independent of the road network (park, shortcut) |
| Ontwerpwijzer Fietsverkeer | Vrijliggend fietspad | Cross-section attribute, not a discrete CS typology | Alongside a road | 2 to 2.5m one-way, wider two-way | n/a | Physical curb/median separation from cars | Mandatory alongside GOW roads under Duurzaam Veilig |
| Ontwerpwijzer Fietsverkeer | Fietsstraat | [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) | Inside built-up, local streets | Shared carriageway, bike-priority markings | 30 km/h (~20 mph) | Shared, cars are guests | Cars permitted but bikes are the primary user |
| Ontwerpwijzer Fietsverkeer | Fiets(suggestie)strook | Cross-section attribute, not a discrete CS typology | On-street, any tier | Painted stripe, no barrier | n/a | Paint only, cars can cross/park over it | Lowest protection level, used where space is tight |
| Richtlijn inpassing tram | Tram (mixed traffic) | [Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) / [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) | Inside built-up | Shares the traffic lane | Matches host road | None | Runs in-lane with cars |
| Richtlijn inpassing tram | Tram (reserved lane/median) | [Arterial Transit](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) | Inside built-up | Dedicated median or curb lane | Higher than mixed | Physical separation | Common on GOW-scale streets |
| Richtlijn inpassing tram | Tram (tunnel/grade-separated) | [Freeway-scale Transit](https://commonwaysystem.org/patterns/freeways/freeway-transit.md) | Any | Dedicated tunnel or elevated | Highest | Full | Same treatment as heavy/light rail |

Sourced from CROW's own categorization framework,[8] bicycle design manual,[9] and tram integration guideline.[10]

Two things this table can't capture cleanly. Vrijliggend fietspad and fiets(suggestie)strook don't get a real CS equivalent, since CS treats bike separation as a cross-section detail layered onto Local, Collector, or Arterial, while Dutch practice treats the separation level itself as the classifying feature. And tram doesn't get its own dedicated Dutch ladder the way roads do. CROW classifies the physical integration method instead, mixed, reserved, or grade-separated, which is what maps onto CS's Transit typologies here, by degree of separation rather than by a named category.

## References

1.  Legal / regulatory Federal Highway Administration, "Highway Functional Classification: Concepts, Criteria and Procedures," 2013 Edition, updated 2015. Available at: [https://www.fhwa.dot.gov/planning/processes/statewide/related/highway\_functional\_classifications/section01.cfm](https://www.fhwa.dot.gov/planning/processes/statewide/related/highway_functional_classifications/section01.cfm)
2.  Precedent-based Charles Marohn and Asia Mieleszko, "What's a STROAD and Why Does It Matter?" Strong Towns, term coined by Marohn in 2013. Available at: [https://www.strongtowns.org/journal/2018-3-1-whats-a-stroad-and-why-does-it-matter](https://www.strongtowns.org/journal/2018-3-1-whats-a-stroad-and-why-does-it-matter)
3.  Legal / regulatory City of Minneapolis, Street Design Guide, "Street Types" section, explicitly built on and crediting NACTO's street typology framework. Available at: [https://sdg.minneapolismn.gov/street-types/introduction](https://sdg.minneapolismn.gov/street-types/introduction)
4.  Legal / regulatory National Association of City Transportation Officials (NACTO), _Urban Street Design Guide_, 2013. Available at: [https://nacto.org/publication/urban-street-design-guide/](https://nacto.org/publication/urban-street-design-guide/)
5.  Evidence-based Annenies Kraaij et al., "Communal versus Private: The Unfinished Search for the Ideal Woonerf," DASH: Delft Architectural Studies on Housing, TU Delft. Origin credited to Niek de Boer and Joost Vahl, Delft, late 1960s/1970s. Available at: [https://journals.open.tudelft.nl/dash/article/view/4579](https://journals.open.tudelft.nl/dash/article/view/4579)
6.  Legal / regulatory National Association of City Transportation Officials (NACTO), "Yield Street," Urban Street Design Guide. Available at: [https://nacto.org/publication/urban-street-design-guide/streets/yield-street/](https://nacto.org/publication/urban-street-design-guide/streets/yield-street/)
7.  Legal / regulatory Federal Highway Administration, Office of International Programs, "Turbo Roundabouts: Support Safety, Efficiency, and Increased Capacity." Origin credited to Dr. Lambertus Fortuijn, Delft University of Technology, 1996. Available at: [https://international.fhwa.dot.gov/programs/tbp/docs/35976\_FHWA\_HPIP\_Turbo\_Roundabout\_Factsheet\_v05\_Release\_508.pdf](https://international.fhwa.dot.gov/programs/tbp/docs/35976_FHWA_HPIP_Turbo_Roundabout_Factsheet_v05_Release_508.pdf)
8.  Legal / regulatory CROW, _Basiskenmerken wegontwerp: Categorisering en inrichting van wegen_ (CROW-publicatie 315), Ede, 2012, updating the original 1997 Duurzaam Veilig categorization handbook. Available at: [https://kennisbank.crow.nl/public/gastgebruiker/WOBU/Handboek\_Verkeersveiligheid/Duurzaam\_Veilig/20998](https://kennisbank.crow.nl/public/gastgebruiker/WOBU/Handboek_Verkeersveiligheid/Duurzaam_Veilig/20998)
9.  Legal / regulatory CROW, _Ontwerpwijzer fietsverkeer_ (CROW-publicatie 230), 2006, revised 2016; published in English as _CROW Design Manual for Bicycle Traffic_, 2016. Available at: [https://kennisbank.crow.nl/public/WOBI/Ontwerpwijzer\_fietsverkeer/Woord\_vooraf/33096](https://kennisbank.crow.nl/public/WOBI/Ontwerpwijzer_fietsverkeer/Woord_vooraf/33096)
10.  Legal / regulatory CROW, _Richtlijn inpassing tram in stedelijke omgeving_, commissioned by Expertisecentrum Rail, superseding the 2007 _Leidraad inpassing tram in stedelijk gebied_. Available at: [https://www.crow.nl/kennisproducten/richtlijn-inpassing-tram-in-stedelijke-omgeving/](https://www.crow.nl/kennisproducten/richtlijn-inpassing-tram-in-stedelijke-omgeving/)

Unsourced claim

Sources 8 through 10 were located and verified against CROW's and Fietsberaad's public knowledge-base pages, not against the primary paywalled publications themselves, and still need verification against a primary copy before this page is considered fully sourced.

---

Source: https://commonwaysystem.org/media/

# Media Gallery

External videos, podcasts, and articles related to Commonway System content: real examples, explainers, interviews, and news coverage from outside the guidebook. Each item's blurb explains how it relates to CS content, not a neutral summary of the item itself, and its endorsement label says whether CS agrees with it, includes it for background only, or includes it as a counterexample.

21 of 21 media items

Aligned

## [The Key to Slowing Traffic is Street Design, Not Speed Limits](https://archive.strongtowns.org/journal/2021/8/6/the-key-to-slowing-traffic-is-street-design-not-speed-limits)

Strong Towns

Makes the case, with side-by-side street photos, that a posted number on a sign does not change driver behavior the way lane width, block length, and sightlines do, the same self-enforcing-design principle behind CS's own design-speed-equals-posted-speed rule.

Aligned

## [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

Aligned

## [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

Aligned

## [Why do so many U.S. cities have gridded streets?](https://www.youtube.com/watch?v=KUDVP6aRS1Y)

City Beautiful

Traces how the grid became the default American street pattern, from William Penn's Philadelphia through Jefferson's Midwest land ordinances, historical background for why the Grid network topology pattern is so dominant in U.S. contexts.

Aligned

## [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

## [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

Aligned

## [Why Aren't Dangerous Drivers Punished?](https://www.youtube.com/watch?v=dHRfClVJg70)

Global Cycling Network

Traces why traffic law rarely punishes road violence proportionally, then makes the case CS already builds on: infrastructure should be designed so mistakes aren't fatal, rather than relying on punishment after the fact.

Aligned

## [You've Been Lied To About Roads For 60 Years](https://www.youtube.com/watch?v=CVq7XOXkg1U)

Global Cycling Network

Covers "junk roads," traffic-model incentives to overbuild, and the trillion-dollar cost of designing roads around growth projections that the roads themselves inflate.

Aligned

## [More Lanes Are (Still) A Bad Thing](https://www.youtube.com/watch?v=CHZwOAIect4)

Not Just Bikes

Lays out induced demand, Braess's Paradox, and traffic evaporation with real case studies (LA 405, Houston Katy Freeway, Cheonggyecheon), then shows the Dutch one-lane-plus-transit cross-section as the actual fix.

Aligned

## [Why Amsterdam is Removing 10,000 Parking Spaces](https://www.youtube.com/watch?v=mXLqrMljdfU)

Not Just Bikes

Documents Amsterdam's on-street parking reduction through permit attrition and street redesigns, including the tradeoff of a large replacement garage inducing more driving nearby.

Aligned

## [Why the Dutch Wait Less at Traffic Lights](https://www.youtube.com/watch?v=knbVWXzL4-4)

Not Just Bikes

Breaks down Dutch traffic-responsive signal timing, independent phasing, transit signal priority, and no-right-turn-on-red as a pedestrian/cyclist safety measure.

Aligned

## [Stroads are Ugly, Expensive, and Dangerous](https://www.youtube.com/watch?v=ORzNZUeUHAM)

Not Just Bikes

The definitive explainer on stroads, and lays out the Dutch three-tier road/street classification system that CS's own Functional Classification structure closely mirrors.

Aligned

## [Can we make cities car free?](https://www.youtube.com/watch?v=g9-9CxCxrVE)

City Beautiful

Covers Oslo's parking-elimination approach, Barcelona's superblocks, and Houten's ring-road-with-car-free-interior model, each a different route to the same modal-filtering goal.

Aligned

## [Why America Won't Copy Sweden's Cheap Highway Fix](https://www.youtube.com/watch?v=jyNEnYaBszk)

Safe By Design

Explains Sweden's 2+1 alternating-passing-lane cable-barrier retrofit and the specific AASHTO Green Book barriers (literally) that have kept the same fix from scaling in the US.

Context only

## [America Built the Wrong Roundabout (The Dutch Didn't)](https://www.youtube.com/watch?v=CKjTkXljhWc)

Safe By Design

Traces the turbo roundabout's origin and safety data, but also reports the Fietsersbond's documented cyclist/pedestrian crossing hazards at turbo roundabouts directly, worth noting since it complicates a clean "aligned" label.

Aligned

## [Are Roundabouts Actually Better Than Traffic Lights?](https://www.youtube.com/watch?v=012fMI3TdRo)

Streetcraft

A real head-to-head test (Carmel, IN) backing the case for roundabouts on time, fuel efficiency, and crash severity, while being upfront about roundabouts' accessibility gap for blind pedestrians.

Aligned

## [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

Aligned

## [What is the "Correct" Speed Limit?](https://www.youtube.com/watch?v=JRbnBc-97Ps)

Not Just Bikes

Makes the physics and data case for 30 km/h (roughly 20 mph) as the safe default urban speed, the same logic behind CS's own Local street speed cap.

Aligned

## [South Carolina's Freeway for Bikes](https://www.youtube.com/watch?v=NxGYs8kHxw4)

Road Guy Rob

The Swamp Rabbit Trail's rail-to-trail history and its treatment as genuine transportation infrastructure, plus the Travelers Rest Main Street road diet that reallocated car lanes to parking and bike parking.

Aligned

## [Roads don't have to be FAT to be FAST](https://www.youtube.com/watch?v=UV0x2hNRYnU)

Road Guy Rob

Explains the interrupted-flow/platooning physics behind signalized-arterial congestion, then covers Carmel's Keystone Parkway conversion to a limited-access road using compact elevated roundabout interchanges instead of a full diamond interchange.

Aligned

## [Let's FIX the HIGH SCHOOL (with 152 ROUNDABOUTS!)](https://www.youtube.com/watch?v=1ZUZA76L09M)

Road Guy Rob

The origin story of Carmel's roundabout program, starting with a contentious school-zone traffic-calming project, and the engineering fix (tightened entries, fatter center island) that made the design work.

---

Source: https://commonwaysystem.org/patterns/

# Pattern Index

Every pattern currently in the Commonway System, grouped by Scale: Network, Corridor, Segment/Intersection (the one Scale that further subdivides by Functional Classification), Facility, and Element. See [Scale Hierarchy](https://commonwaysystem.org/guide/scale-hierarchy.md) for what each Scale covers and how they relate.

## Network level patterns

Network patterns describe the topology of a whole connected system, or a defined sub-system within it, not any single physical place. You would not stand in one spot and see a Network pattern, you would see it on a map: a grid versus a radial layout, how branching or connectivity shapes route choice across an entire area.

1

### [Grid](https://commonwaysystem.org/patterns/network/grid.md)

`NET-GRD-01`

2

### [Dendritic / Hierarchical](https://commonwaysystem.org/patterns/network/dendritic-hierarchical.md)

`NET-DEN-02` Situational / Discouraged

3

### [Radial](https://commonwaysystem.org/patterns/network/radial.md)

`NET-RAD-03` Situational / Discouraged

4

### [Organic / Irregular](https://commonwaysystem.org/patterns/network/organic-irregular.md)

`NET-ORG-04` Descriptive

## Corridor level patterns

Corridor patterns describe a linear stretch of the network connecting two places, often crossing multiple contexts along the way. This is the level where transitions get designed on purpose, a road's character changing as it moves from farmland into town, or a fixed transit alignment shaping a cross-section for miles at a stretch, rather than being left to happen segment by segment with no coordination.

1

### [Density Step-Down / Step-Up](https://commonwaysystem.org/patterns/corridors/density-step-down-step-up.md)

`CDR-DSD-01`

2

### [Rural-to-Town Gateway](https://commonwaysystem.org/patterns/corridors/rural-to-town-gateway.md)

`CDR-RTG-02`

3

### [Character Transect](https://commonwaysystem.org/patterns/corridors/character-transect.md)

`CDR-CTR-03`

4

### [Rail-With-Trail Corridor](https://commonwaysystem.org/patterns/corridors/rail-with-trail-corridor.md)

`CDR-RWT-04` Situational / Discouraged

5

### [Road-Adjacent Greenway](https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway.md)

`CDR-RAG-05`

6

### [Transit Alignment Corridor](https://commonwaysystem.org/patterns/corridors/transit-alignment-corridor.md)

`CDR-TAC-06` Situational / Discouraged

## Local street patterns

Local streets have many access points and short trips, so keeping speeds under 20 mph, no exceptions, matters more than moving vehicles quickly. Walking and biking come first, then transit, then vehicles and freight.

1

### [Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md)

`LOC-DEF-01`

2

### [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md)

`LOC-ALY-02`

3

### [Cul-de-sac](https://commonwaysystem.org/patterns/local-streets/cul-de-sac.md)

`LOC-CDS-03` Situational / Discouraged

4

### [Frontage / Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md)

`LOC-FSR-04`

5

### [Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md)

`LOC-MST-05`

6

### [Living Street / Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md)

`LOC-LSW-06`

7

### [Yield Street](https://commonwaysystem.org/patterns/local-streets/yield-street.md)

`LOC-YLD-07`

8

### [Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md)

`LOC-FES-08`

9

### [Pedestrian-only Street / Plaza](https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza.md)

`LOC-PED-09` Situational / Discouraged

10

### [Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md)

`LOC-LTR-10`

11

### [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md)

`LOC-SCH-11`

12

### [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md)

`LOC-BBG-12`

13

### [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md)

`LOC-SUP-13`

## Collector street patterns

Collectors link local streets to the arterial network, carrying more through traffic while still running past homes and storefronts. Speeds top out at 30 mph, 35 only behind rigid crash-protective separation, with walking, biking, and transit still taking priority.

1

### [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md)

`COL-DEF-01`

2

### [Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md)

`COL-FTM-02`

3

### [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md)

`COL-IND-03`

4

### [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md)

`COL-BHG-04`

5

### [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md)

`COL-CTR-05`

6

### [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md)

`COL-MUT-06`

7

### [Downtown Thoroughfare](https://commonwaysystem.org/patterns/collectors/downtown-thoroughfare.md)

`COL-DTH-07` Situational / Discouraged

## Arterial street patterns

Arterials move higher volumes of through traffic over longer distances, so the core rule is separation: no on-street parking or driveway access competing with through movement. Posted speed always matches the road's actual design speed. Transit takes priority here, ahead of people walking and biking.

1

### [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md)

`ART-DEF-01`

2

### [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md)

`ART-BLV-02`

3

### [Scenic Highway / Byway](https://commonwaysystem.org/patterns/arterials/scenic-highway-byway.md)

`ART-SCB-03`

4

### [Arterial Transit (BRT/LRT)](https://commonwaysystem.org/patterns/arterials/arterial-transit.md)

`ART-ATR-04`

5

### [Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md)

`ART-STD-05` Avoid

6

### [One-Way Street](https://commonwaysystem.org/patterns/arterials/one-way-street.md)

`ART-OWS-06` Situational / Discouraged

7

### [Parkway](https://commonwaysystem.org/patterns/arterials/parkway.md)

`ART-PKY-07` Situational / Discouraged

## Freeway patterns

Freeways sit outside the Commonway System's detailed design scope entirely. They're listed here for completeness, not because the system sets rules for them: no modal hierarchy, no speed regulation.

1

### [Default (Freeway)](https://commonwaysystem.org/patterns/freeways/default.md)

`FRE-DEF-01`

2

### [Expressway](https://commonwaysystem.org/patterns/freeways/expressway.md)

`FRE-EXP-02`

3

### [Beltway / Ring Road](https://commonwaysystem.org/patterns/freeways/beltway-ring-road.md)

`FRE-BLT-03`

4

### [Freeway-scale Transit (Commuter / Heavy Rail)](https://commonwaysystem.org/patterns/freeways/freeway-transit.md)

`FRE-FTR-04`

## Intersections and crossings

Intersections aren't tied to one Functional Classification, since any two street types can meet at a corner. The default is a roundabout wherever a Collector-or-larger street is involved, stepping up to a turbo-roundabout at busy Arterial-to-Arterial junctions. Signals are a documented last resort, and a continuous sidewalk is the default where a Local street meets a Collector.

1

### [Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md)

`INT-RAB-01`

2

### [Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md)

`INT-TRB-02`

3

### [Signal](https://commonwaysystem.org/patterns/intersections/signal.md)

`INT-SIG-03` Situational / Discouraged

4

### [All-Way Stop](https://commonwaysystem.org/patterns/intersections/all-way-stop.md)

`INT-AWS-04` Situational / Discouraged

5

### [Stop / Yield (Two-Way)](https://commonwaysystem.org/patterns/intersections/stop-yield.md)

`INT-SYD-05` Situational / Discouraged

6

### [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md)

`INT-CSJ-06`

7

### [Uncontrolled](https://commonwaysystem.org/patterns/intersections/uncontrolled.md)

`INT-UNC-07` Situational / Discouraged

8

### [Midblock Pedestrian Crossing](https://commonwaysystem.org/patterns/intersections/midblock-crossing.md)

`INT-MPC-08`

9

### [Driveway / Curb Cut](https://commonwaysystem.org/patterns/intersections/driveway-curb-cut.md)

`INT-DCC-09` Situational / Discouraged

10

### [Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md)

`INT-GSI-10` Situational / Discouraged

11

### [Protected Intersection](https://commonwaysystem.org/patterns/intersections/protected-intersection.md)

`INT-PRI-11`

12

### [Median U-Turn (MUT)](https://commonwaysystem.org/patterns/intersections/median-u-turn.md)

`INT-MUT-12` Situational / Discouraged

13

### [Restricted Crossing U-Turn (RCUT)](https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn.md)

`INT-RCU-13` Situational / Discouraged

14

### [Displaced Left-Turn (DLT)](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md)

`INT-DLT-14` Situational / Discouraged

15

### [Railroad Grade Crossing](https://commonwaysystem.org/patterns/intersections/railroad-grade-crossing.md)

`INT-RGC-15` Situational / Discouraged

## Facility level patterns

Facility patterns describe something that attaches to a segment or intersection rather than being one: a bus shelter, a parking garage, a plaza. Each is internally complex enough to have its own element-level layout inside it.

1

### [Transit Shelter](https://commonwaysystem.org/patterns/facilities/transit-shelter.md)

`FAC-TSH-01`

2

### [Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md)

`FAC-TPL-02`

3

### [Transit Hub / Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md)

`FAC-THS-03`

4

### [Surface Parking Lot](https://commonwaysystem.org/patterns/facilities/surface-parking-lot.md)

`FAC-SPL-04` Situational / Discouraged

5

### [Parking Garage / Structure](https://commonwaysystem.org/patterns/facilities/parking-garage-structure.md)

`FAC-PGS-05` Situational / Discouraged

6

### [Park-and-Ride](https://commonwaysystem.org/patterns/facilities/park-and-ride.md)

`FAC-PNR-06` Situational / Discouraged

7

### [Plaza / Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md)

`FAC-PLZ-07`

8

### [Bike Parking Corral](https://commonwaysystem.org/patterns/facilities/bike-parking-corral.md)

`FAC-BPC-08`

9

### [Bike-Share Station](https://commonwaysystem.org/patterns/facilities/bike-share-station.md)

`FAC-BSS-09` Situational / Discouraged

10

### [Secure Bike Parking / Bike Station](https://commonwaysystem.org/patterns/facilities/secure-bike-parking-bike-station.md)

`FAC-SBP-10` Situational / Discouraged

## Element level patterns

Element patterns describe the physical components a segment, intersection, or facility is built from: curbs, medians, signage, striping, signals, street trees, lighting. This is the most granular Scale in the system, and the level most other patterns eventually point down to.

1

### [Curb](https://commonwaysystem.org/patterns/elements/curb.md)

`ELM-CRB-01`

2

### [Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md)

`ELM-CBE-02`

3

### [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md)

`ELM-CRP-03`

4

### [Curb Cut / Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md)

`ELM-CCA-04` Situational / Discouraged

5

### [Wheel Stop](https://commonwaysystem.org/patterns/elements/wheel-stop.md)

`ELM-WHS-05` Situational / Discouraged

6

### [Vertical Speed Control](https://commonwaysystem.org/patterns/elements/vertical-speed-control.md)

`ELM-VSC-06`

7

### [Rumble Strip](https://commonwaysystem.org/patterns/elements/rumble-strip.md)

`ELM-RMS-07` Situational / Discouraged

8

### [Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md)

`ELM-CRW-08`

9

### [Pedestrian Safety Island / Refuge](https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge.md)

`ELM-PSI-09`

10

### [Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md)

`ELM-DWS-10`

11

### [Regulatory Sign](https://commonwaysystem.org/patterns/elements/regulatory-sign.md)

`ELM-RGS-11`

12

### [Warning Sign](https://commonwaysystem.org/patterns/elements/warning-sign.md)

`ELM-WNS-12`

13

### [Guide Sign](https://commonwaysystem.org/patterns/elements/guide-sign.md)

`ELM-GDS-13`

14

### [Traffic Signal](https://commonwaysystem.org/patterns/elements/traffic-signal.md)

`ELM-TFS-14` Situational / Discouraged

15

### [Pedestrian Signal](https://commonwaysystem.org/patterns/elements/pedestrian-signal.md)

`ELM-PDS-15`

16

### [Bicycle Signal](https://commonwaysystem.org/patterns/elements/bicycle-signal.md)

`ELM-BCS-16` Situational / Discouraged

17

### [RRFB](https://commonwaysystem.org/patterns/elements/rrfb.md)

`ELM-RRF-17`

18

### [Pedestrian Hybrid Beacon](https://commonwaysystem.org/patterns/elements/pedestrian-hybrid-beacon.md)

`ELM-PHB-18` Situational / Discouraged

19

### [Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md)

`ELM-BIO-19`

20

### [Flow-Through Planter](https://commonwaysystem.org/patterns/elements/flow-through-planter.md)

`ELM-FTP-20` Situational / Discouraged

21

### [Pervious Strip](https://commonwaysystem.org/patterns/elements/pervious-strip.md)

`ELM-PVS-21` Situational / Discouraged

22

### [Pervious Pavement](https://commonwaysystem.org/patterns/elements/pervious-pavement.md)

`ELM-PVP-22` Situational / Discouraged

23

### [Traffic Barrier](https://commonwaysystem.org/patterns/elements/traffic-barrier.md)

`ELM-TRB-23` Situational / Discouraged

24

### [Crash Cushion / End Terminal](https://commonwaysystem.org/patterns/elements/crash-cushion-end-terminal.md)

`ELM-CCT-24`

25

### [Bollard](https://commonwaysystem.org/patterns/elements/bollard.md)

`ELM-BOL-25`

26

### [Street Light](https://commonwaysystem.org/patterns/elements/street-light.md)

`ELM-STL-26`

27

### [Pedestrian-scale Lighting](https://commonwaysystem.org/patterns/elements/pedestrian-scale-lighting.md)

`ELM-PSL-27`

28

### [Street Tree](https://commonwaysystem.org/patterns/elements/street-tree.md)

`ELM-STT-28`

29

### [Tree Pit / Tree Trench](https://commonwaysystem.org/patterns/elements/tree-pit-tree-trench.md)

`ELM-TPT-29`

30

### [Landscaped Buffer Strip](https://commonwaysystem.org/patterns/elements/landscaped-buffer-strip.md)

`ELM-LBS-30`

31

### [Bench](https://commonwaysystem.org/patterns/elements/bench.md)

`ELM-BCH-31`

32

### [Trash / Recycling Receptacle](https://commonwaysystem.org/patterns/elements/trash-recycling-receptacle.md)

`ELM-TRR-32`

33

### [Drinking Fountain](https://commonwaysystem.org/patterns/elements/drinking-fountain.md)

`ELM-DRF-33` Situational / Discouraged

34

### [Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md)

`ELM-CBL-34` Situational / Discouraged

35

### [Buffered Bike Lane](https://commonwaysystem.org/patterns/elements/buffered-bike-lane.md)

`ELM-BBL-35`

36

### [Advisory Bike Lane](https://commonwaysystem.org/patterns/elements/advisory-bike-lane.md)

`ELM-ABL-36` Situational / Discouraged

37

### [Protected Bike Lane / Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md)

`ELM-PBL-37`

38

### [Green Pavement / Conflict Marking](https://commonwaysystem.org/patterns/elements/green-pavement-conflict-marking.md)

`ELM-GPM-38`

39

### [Sharrow](https://commonwaysystem.org/patterns/elements/sharrow.md)

`ELM-SHR-39` Avoid

40

### [Bike Parking / Rack](https://commonwaysystem.org/patterns/elements/bike-parking-rack.md)

`ELM-BPR-40`

41

### [Transit Boarding Island](https://commonwaysystem.org/patterns/elements/transit-boarding-island.md)

`ELM-TBI-41`

42

### [Bike Box](https://commonwaysystem.org/patterns/elements/bike-box.md)

`ELM-BKB-42`

43

### [Two-Stage Turn Queue Box](https://commonwaysystem.org/patterns/elements/two-stage-turn-queue-box.md)

`ELM-TSQ-43`

44

### [Modal Filter / Point Closure](https://commonwaysystem.org/patterns/elements/modal-filter-point-closure.md)

`ELM-MFP-44`

45

### [Median Island](https://commonwaysystem.org/patterns/elements/median-island.md)

`ELM-MDI-45`

46

### [Neighborhood Traffic Circle / Mini-Roundabout](https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout.md)

`ELM-NTC-46`

---

Source: https://commonwaysystem.org/patterns/arterials/arterial-transit/

# Arterial Transit (BRT/LRT)

`ART-ATR-04`

Recommended Arterial

Arterial Transit (BRT/LRT)

An Arterial with dedicated bus rapid transit or light rail infrastructure, most often a separated running way or exclusive lane.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [More Lanes Are (Still) A Bad Thing](https://www.youtube.com/watch?v=CHZwOAIect4)

Not Just Bikes

Lays out induced demand, Braess's Paradox, and traffic evaporation with real case studies (LA 405, Houston Katy Freeway, Cheonggyecheon), then shows the Dutch one-lane-plus-transit cross-section as the actual fix.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\] \[SPEED LIMIT 35\] \[SPEED LIMIT 40\]

Follows the Arterial density-tiered baseline for its typical Compact, Urban, and Core contexts. Transit priority in the modal hierarchy below does not change the vehicle speed cap.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

Unlike Local Transit and Collector Transit, this ordering reinforces the Arterial base order rather than overriding it, since Transit already sits at the top of the Arterial base hierarchy.

## Design notes

Arterial is the one Functional Classification where the base modal hierarchy already puts Transit first, ahead of Pedestrian. Dedicated BRT or LRT treatment strengthens that existing priority with physical infrastructure rather than reordering it.[1]

## Related patterns

[Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) (LOC-LTR-10) and [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) (COL-CTR-05) (explicitly contrasted on this page: those two override their base order for Transit priority, while this pattern reinforces an order where Transit is already first)

## Getting there: Retrofit path options

[Transit priority lane retrofit](https://commonwaysystem.org/retrofits/corridor/transit-priority-lane-retrofit.md) (RFT-CDR-06)

## References

1.  Precedent-based [NACTO, _Transit Street Design Guide_ (2016).](https://nacto.org/publication/transit-street-design-guide/)

---

Source: https://commonwaysystem.org/patterns/arterials/boulevard/

# Boulevard

`ART-BLV-02`

Recommended Arterial

Boulevard

An Arterial with a wide, pedestrian-first frontage alongside through traffic lanes, typically featuring a planted median or landscaped buffer. Includes the Multiway Boulevard variant, where frontage roads are separated from through lanes by planted medians, such as Octavia Boulevard.[1]

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\] \[SPEED LIMIT 35\] \[SPEED LIMIT 40\]

Follows the Arterial density-tiered baseline for its typical Compact, Urban, and Core contexts.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Transit > Bicycle > Vehicle > Freight

A judgment call reasoned from the Typology's purpose rather than derived cleanly from a listed override trigger, and open for correction.

## Design notes

Multiway Boulevard is confirmed as a named variant folded into this single entry rather than split into its own Typology, since both share the same underlying logic: separating slower, frontage-facing movement from faster through traffic within one right-of-way.

## Related patterns

[Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the base Arterial rule this pattern applies pedestrian-first frontage to), [Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md) (ART-STD-05) (named in Stroad's own "Instead, see" list as one of its two replacement patterns), [Median Island](https://commonwaysystem.org/patterns/elements/median-island.md) (ELM-MDI-45) (the Element pattern this corridor most often carries)

## Getting there: Retrofit path options

[Five-plus lane reallocation](https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation.md) (RFT-CDR-02)

## References

1.  Precedent-based [Jacobs, A., Macdonald, E., and Rofé, Y., _The Boulevard Book_ (MIT Press, 2002).](https://mitpress.mit.edu/9780262100908/the-boulevard-book/)

---

Source: https://commonwaysystem.org/patterns/arterials/default/

# Default (No Parking, No Direct Property Access)

`ART-DEF-01`

Recommended Arterial

Default (No Parking, No Direct Property Access)

The baseline Arterial: a through-movement road that never mixes on-street parking or direct property access with through traffic. Any access need along the corridor is served by a separate Local or Frontage/Service Road instead.

Typical at: Rural Suburban Compact Urban Core

Undeveloped is an edge case.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\] \[SPEED LIMIT 35\] \[SPEED LIMIT 40\] \[SPEED LIMIT 45\] \[SPEED LIMIT 55\]

Design speed always equals posted speed, following FHWA's self-enforcing roadway framework.[2] The baseline is set by density tier, running from 55 mph at Undeveloped and Rural down to 30 mph at Core, matching Collector's own ceiling at that tier. Two modifiers can each subtract 5 mph from the baseline where they apply: adjacency to noise-sensitive land uses within a lane-count-based distance, and local-street access more frequent than a defined spacing threshold, the same access-density logic behind why frequent driveway cuts raise crash risk.[3] The two modifiers do not stack: where both apply, only the single larger reduction is used, not both added together. The result never falls below a 30 mph floor except through a documented exception.

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

Modal hierarchy follows the Arterial base order. This gives vehicles and freight movement-priority, but Vision Zero evidence keeps pedestrians and cyclists from dropping to the bottom on account of traffic volume alone. Freight moves above Vehicle only where a Typology's whole purpose is freight-specific.

## Design notes

The no-parking, no-direct-access rule is the load-bearing distinction between this entry and Stroad. It positions the Commonway System closer to the Dutch functional-homogeneity principle than to conventional NACTO or ITE-CNU practice, where Arterials more commonly do mix through traffic with driveway access and curbside parking.[1]

## Related patterns

[Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md) (ART-STD-05) (explicitly named on this page as the pattern this rule exists to prevent becoming), [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01) (the equivalent baseline one Functional Classification down)

## Getting there: Retrofit path options

[Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) (RFT-CDR-01), [Five-plus lane reallocation](https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation.md) (RFT-CDR-02), [Lane diet](https://commonwaysystem.org/retrofits/corridor/lane-diet.md) (RFT-CDR-03), [One-way to two-way conversion](https://commonwaysystem.org/retrofits/corridor/one-way-to-two-way-conversion.md) (RFT-CDR-04), [Protected bike lane retrofit via lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md) (RFT-CDR-08)

## References

1.  Precedent-based [SWOV, "Principles for a Safe Road Network" (CROW Sustainable Safety).](https://sustainablesafety.nl/)
2.  Legal / regulatory [FHWA, "Self-Enforcing Roadways: A Guidance Report."](https://highways.dot.gov/research/publications/safety/FHWA-HRT-17-098)
3.  Evidence-based [Gluck, J., Levinson, H. S., and Stover, V., NCHRP Report 420 (1999).](http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_420.pdf)

---

Source: https://commonwaysystem.org/patterns/arterials/one-way-street/

# One-Way Street

`ART-OWS-06`

Situational / Discouraged Arterial

One-Way Street

An Arterial operating one direction of travel only, typically paired with a second one-way Arterial carrying the opposite direction nearby.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings.

Caution

One-Way Street carries Situational/Discouraged status. It tends to encourage speeding, since drivers no longer need to watch for oncoming traffic.[1]

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\] \[SPEED LIMIT 35\] \[SPEED LIMIT 40\]

Follows the Arterial density-tiered baseline for its typical Compact, Urban, and Core contexts.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

The modal hierarchy is retained at the Arterial base order rather than reassigned, a deliberate choice that signals the conflict between the pattern's real-world speeding effect and its nominal priority order, rather than papering over it with a different hierarchy.

## Design notes

Discouraged status here does not mean the pattern is banned; it means adopting it requires weighing the speeding tendency against whatever benefit, often traffic flow or signal progression, motivated the one-way conversion in the first place.

## Related patterns

[Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the two-way form this page's own citation, Riggs and Gilderbloom's evidence-based research on two-way conversion's livability gains, supports converting to, rather than the base order this pattern deliberately retains without reassigning)

## References

1.  Evidence-based [Riggs, W. and Gilderbloom, J., "Two-Way Street Conversion: Evidence of Increased Livability in Louisville," _Journal of Planning Education and Research_ 36(1), 2016.](https://www.urbanismnext.org/resources/two-way-street-conversion-evidence-of-increased-livability-in-louisville)

---

Source: https://commonwaysystem.org/patterns/arterials/parkway/

# Parkway

`ART-PKY-07`

Situational / Discouraged Arterial

Parkway

A roadway historically designed as a scenic, landscaped route, typically featuring a planted median and limited access, whose modern implementations vary widely between two distinct traditions: a limited-access, freeway-like facility, and a slower, arterial-scale boulevard-like facility running through or alongside parkland.

Typical at: Rural Suburban Compact Urban

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 35\] \[SPEED LIMIT 40\] \[SPEED LIMIT 45\] \[SPEED LIMIT 55\]

Follows the Arterial density-tiered baseline for its typical Rural, Suburban, Compact, and Urban contexts. A Parkway meeting genuine freeway design standards should be read as a Freeway pattern instead, which carries no speed rule at all.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

Follows the Arterial base order without an override. A Parkway meeting genuine freeway design standards should be read as a Freeway pattern instead, which carries no modal hierarchy at all.

## Design notes

The term "parkway" carries genuinely conflicting meanings across American road-building history, spanning a limited-access freeway-like facility and a slower boulevard-like facility through or alongside parkland.[1] A Parkway built to genuine freeway standards falls outside CS's Functional Classification system entirely and should be read as a Freeway pattern instead; this page's guidance does not apply to it. The more historically common case, a Parkway that does not meet freeway standards, must be classified and designed as an Arterial, subject to all Arterial standards including the no-direct-access, no-on-street-parking rule, since AASHTO's own functional classification system carries no separate parkway category.[2] The scenic, landscaped character historically associated with parkways can and should be retained through median plantings, tree canopy, and generous right-of-way, but character alone does not exempt the facility from Arterial access-management rules. This classification ambiguity, not a design tradeoff, is why the pattern carries the stronger Discouraged caution rather than an ordinary Situational one; it renders under the publication's combined Situational/Discouraged badge since Discouraged is not yet a distinct status value.

## Related patterns

[default Freeway pattern](https://commonwaysystem.org/patterns/freeways/default.md) (FRE-DEF-01) (redirect target for freeway-standard parkways); [default Arterial pattern](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the standards a non-freeway parkway must follow); [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (ART-BLV-02), [Scenic Highway/Byway](https://commonwaysystem.org/patterns/arterials/scenic-highway-byway.md) (ART-SCB-03) (related but distinct Arterial subtypes)

## References

1.  Precedent-based [National Park Service, _Park Roads and Parkways: A History_. Documents the freeway-standard vs. boulevard-standard tension in American parkway design, and the National Trust for Historic Preservation's unsuccessful push to AASHTO's own Task Force on Geometric Design for a distinct parkway classification.](https://www.nps.gov/parkhistory/online_books/roads/shs4.htm)
2.  Legal / regulatory [American Association of State Highway and Transportation Officials, _A Policy on Geometric Design of Highways and Streets_ ("Green Book").](https://store.transportation.org/Item/PublicationDetail?ID=4127)

---

Source: https://commonwaysystem.org/patterns/arterials/scenic-highway-byway/

# Scenic Highway / Byway

`ART-SCB-03`

Recommended Arterial

Scenic Highway / Byway

An Arterial through a low-development, often scenic landscape, where vehicle movement is prioritized and pedestrian, bicycle, and transit demand are minimal.[1]

Typical at: Undeveloped Rural

Suburban is an edge case. Compact, Urban, and Core are unlikely pairings.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 55\]

Follows the Arterial density-tiered baseline for its typical Undeveloped/Rural context.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Vehicle > Bicycle > Pedestrian > Transit > Freight

Whether Freight should be excluded outright rather than simply ranked last is an open call.

## Design notes

This entry follows the same shape as Rural Collector/Farm-to-Market Road: a low-density, low-development-pressure pattern that is the norm where it applies and effectively disappears as density rises.

## Related patterns

[Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) (COL-FTM-02) (explicitly named on this page as following the same shape)

## References

1.  Legal / regulatory [23 U.S.C. § 162, National Scenic Byways Program.](https://www.law.cornell.edu/uscode/text/23/162)

---

Source: https://commonwaysystem.org/patterns/arterials/stroad/

# Stroad (Commercial Arterial)

`ART-STD-05`

Avoid Arterial

Stroad (Commercial Arterial)

A street and Arterial hybrid, known under two common names, Stroad (coined by Strong Towns) and Commercial Arterial: through traffic mixed with on-street parking, frequent direct commercial driveway access, or both, along the same corridor.[1] This is the exact combination the Arterial core safety rule prohibits: arterials should carry through traffic without direct property access or on-street parking competing for the same space.[2]

Occurs most often at: Rural Suburban Compact

Undeveloped and Urban are edge cases. Core is an unlikely pairing.

Avoid

Stroad is an explicit **Avoid** pattern within the Commonway System, not a Typology to design toward. No default modal order is assigned, since the pattern itself is the anti-pattern being flagged.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 40\] \[SPEED LIMIT 45\] \[SPEED LIMIT 55\]

Stroad mixes through traffic with on-street parking and direct driveway access, the exact combination the Arterial core safety rule prohibits. No single design speed is safe for this mismatch; the signs above show the density-tiered baseline this pattern violates, not a speed to design toward.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

No default modal order is assigned, since the pattern itself is the anti-pattern being flagged.

## Illustration

**Type:** Single-condition. **Format:** Segment / cross-section (~2.8:1).

Typical condition

Mixed on-street parking and a through-traffic lane, with no protected crossing; the entire condition is amber-flooded, per the Single-condition rule for Avoid patterns.

Callouts

1.  (Physical) On-street parking beside through lanes.
2.  (Physical) No protected or signalized midblock crossing despite pedestrian-generating land use.

**Instead, see:** [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (ART-BLV-02), [Default Arterial](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) + [Frontage / Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md) (LOC-FSR-04)

**Supplemental illustration**, justified: the driveway-spacing claim below is longitudinal, and the required cross-section format above is lateral and can't show it.

**Type:** Supplemental (plan-view). **Format:** Wide (16:9 or wider).

Plan view

Direct driveway cuts spaced every 100–200 ft along the corridor, with no parallel frontage or service road to aggregate access points.

Callouts

1.  (Physical) Direct driveway cuts every 100–200 ft.[3]
2.  (Physical) No parallel frontage/service road to aggregate access points.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [You've Been Lied To About Roads For 60 Years](https://www.youtube.com/watch?v=CVq7XOXkg1U)

Global Cycling Network

Covers "junk roads," traffic-model incentives to overbuild, and the trillion-dollar cost of designing roads around growth projections that the roads themselves inflate.

Aligned

### [More Lanes Are (Still) A Bad Thing](https://www.youtube.com/watch?v=CHZwOAIect4)

Not Just Bikes

Lays out induced demand, Braess's Paradox, and traffic evaporation with real case studies (LA 405, Houston Katy Freeway, Cheonggyecheon), then shows the Dutch one-lane-plus-transit cross-section as the actual fix.

Aligned

### [Stroads are Ugly, Expensive, and Dangerous](https://www.youtube.com/watch?v=ORzNZUeUHAM)

Not Just Bikes

The definitive explainer on stroads, and lays out the Dutch three-tier road/street classification system that CS's own Functional Classification structure closely mirrors.

## Design notes

The density figures above track how often this pattern actually occurs in the built environment, not whether it should. It is most common from Rural through Compact density, matching the typical state-highway-turned-suburban-corridor problem: a road built for through movement that gradually accumulates driveways and curb cuts as adjacent land develops.

Every direct driveway or curb cut along the corridor is a conflict point undermining both through-traffic flow and safety: access-point density correlates directly with crash rate, with high-density segments running roughly three times the crash rate of well-managed comparison segments.[3]

This page exists to help readers identify a Stroad and replace it, with Boulevard where a pedestrian-first frontage fits the corridor, or with Default Arterial paired with a separate Local or Frontage/Service Road where it does not.

## Related patterns

[Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (ART-BLV-02), [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01), [Frontage / Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md) (LOC-FSR-04)

## References

1.  Precedent-based [Marohn, C., "What's a STROAD and Why Does It Matter?", Strong Towns.](https://www.strongtowns.org/journal/2018-3-1-whats-a-stroad-and-why-does-it-matter)
2.  Legal / regulatory [American Association of State Highway and Transportation Officials, _A Policy on Geometric Design of Highways and Streets_ ("Green Book").](https://store.transportation.org/Item/PublicationDetail?ID=4127)
3.  Evidence-based [Gluck, J., Levinson, H.S., and Stover, V., _Impacts of Access Management Techniques_, NCHRP Report 420, Transportation Research Board, 1999. Crash rates rise consistently with access-point density; high-density segments show crash rates approximately 3x well-managed comparison segments.](http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_420.pdf)

---

Source: https://commonwaysystem.org/patterns/collectors/bike-highway-greenway/

# Bike Highway / Greenway

`COL-BHG-04`

Recommended Collector

Bike Highway / Greenway

A dedicated, physically separated bicycle path operating at Collector scale, prioritizing continuous, higher-speed bicycle through-movement over other modes.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [South Carolina's Freeway for Bikes](https://www.youtube.com/watch?v=NxGYs8kHxw4)

Road Guy Rob

The Swamp Rabbit Trail's rail-to-trail history and its treatment as genuine transportation infrastructure, plus the Travelers Rest Main Street road diet that reallocated car lanes to parking and bike parking.

Typical at: Undeveloped Rural Suburban Compact Urban

Core is an edge case, since a dedicated separated path competes for limited right-of-way with other demands at the highest density tier.

## Modal hierarchy

Modal hierarchy

Bicycle > Pedestrian > Transit > Vehicle > Freight

An override justified because the Typology's stated purpose is dedicated bicycle through-movement. Design Speed & Speed Limits doesn't apply here, since this pattern excludes automobiles entirely.

## Design notes

Distinct from Local's Bicycle Boulevard, which shares the roadway with calmed vehicle traffic, this Typology is physically separated infrastructure, closer in function to a linear park path or a rail-trail than to a shared street. It is realistic across nearly the full density range, since a separated path is not dependent on the surrounding street grid the way a shared-roadway Typology is.[1]

## Related patterns

[Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12) (explicitly distinguished on this page: shared calmed roadway vs. this pattern's physical separation), [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) (COL-MUT-06) (a similarly-named Collector-scale pattern this one is specifically distinct from)

## Getting there: Retrofit path options

[Protected bike lane retrofit via lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md) (RFT-CDR-07), via [lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md) (RFT-CDR-08), via [parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) (RFT-CDR-09)

## References

1.  Precedent-based [CROW, _Design Manual for Bicycle Traffic_, English ed. (2016), Ch. 4.5 "Bicycle highways."](https://crowplatform.com/product/design-manual-for-bicycle-traffic/)

---

Source: https://commonwaysystem.org/patterns/collectors/collector-transit/

# Collector Transit

`COL-CTR-05`

Recommended Collector

Collector Transit

A Collector street carrying a fixed transit route, where transit priority is layered onto the base pedestrian and bicycle priority rather than replacing it.

Typical at: Suburban Compact Urban Core

Rural is an edge case. Undeveloped is an unlikely pairing.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\]

Follows the Collector default: 30 mph standard. Transit priority in the modal hierarchy below does not change the vehicle speed cap.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

An override of the Collector base order justified by the Typology's stated purpose, a designated transit route.

## Design notes

This entry is the Collector-scale sibling of Local Transit and Arterial Transit, following the same override logic across all three Functional Classifications.[1]

## Related patterns

[Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) (LOC-LTR-10) and [Arterial Transit (BRT/LRT)](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) (ART-ATR-04) (this pattern's siblings across Functional Classification, per this page's own Design notes)

## Getting there: Retrofit path options

[Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md) (RFT-CDR-05), [Transit priority lane retrofit](https://commonwaysystem.org/retrofits/corridor/transit-priority-lane-retrofit.md) (RFT-CDR-06)

## References

1.  Precedent-based [NACTO, _Transit Street Design Guide_ (2016).](https://nacto.org/publication/transit-street-design-guide/)

---

Source: https://commonwaysystem.org/patterns/collectors/default/

# Default (Standard Collector)

`COL-DEF-01`

Recommended Collector

Default (Standard Collector)

The baseline Collector street. No special land use, freight function, or dedicated mode gives it a name of its own, so it carries the base Collector modal hierarchy and speed rule unmodified.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

Typical at: Suburban Compact Urban Core

Rural is an edge case. Undeveloped is an unlikely pairing.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\] \[SPEED LIMIT 35\]

30 mph standard. 35 mph is permitted only with rigid crash-protective separation, a concrete barrier rather than delineator posts, following FHWA's own distinction between the two.[1]

Modal hierarchy

Pedestrian > Bicycle > Transit > Vehicle > Freight

Modal hierarchy follows the Collector base order, the same shape as Local. The higher speed tier loosens the practical design treatment, crossing spacing and separation, without changing the rank order.

## Layered guidance across sources

The Commonway System column comes first: it is the answer. The four columns after it show the layered sources it was built from, from the federal and state baseline through NACTO, Complete Streets, and Dutch practice. The number-of-lanes and on-street-parking rows are a first pass, less fully resolved than the others.

Collector street design guidance by source, from federal and state baseline through the Commonway System answer

### Travel lane width

#### Commonway System

**10 ft lanes.**

10 ft. The federal range is a binding mandate, so nothing below 10 ft is legally available. NACTO's 10 ft sits at the safe end of that mandated range, so it is simultaneously the floor and the best available option.

#### Federal / State baseline

**10 to 12 ft range.**

10 to 12 ft, the AASHTO Green Book's Collector range.[2]

#### NACTO enhancement

**10 ft urban, avoid over 11.**

10 ft recommended in urban contexts; lanes over 11 ft discouraged.[3]

#### Complete Streets layer

**Narrower lanes.**

Narrower travel lanes listed as a typical element.[4]

#### Dutch / Sustainable Safety

**Not regulated separately.**

Not a separately regulated dimension. Folded into overall speed-and-separation design instead.

### Number of travel lanes

#### Commonway System

**Two lanes, one each way.**

Two lanes, one per direction, as the standard cross-section. Additional lanes are a documented exception requiring a stated volume threshold, not a default. Unmatched lane capacity without matching access control is exactly the failure mode [Stroad](https://commonwaysystem.org/patterns/arterials/stroad.md) describes.

#### Federal / State baseline

**Set by volume and level of service.**

AASHTO's Green Book bases lane count on projected traffic volume and level-of-service analysis rather than fixing one number, in the same Collector chapter that sets the lane-width range.[2] Needs verification: that source was read for width guidance, not confirmed for lane-count methodology.

#### NACTO enhancement

**Favors narrower over more lanes.**

Favors narrower lanes over more of them.[3] Open gap: NACTO's position on lane count itself was not separately sourced.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.[4]

#### Dutch / Sustainable Safety

**Typically 2×1 to 2×2 lanes.**

Dutch distributor roads, the closest functional peer, typically run 2×1 to 2×2 lanes. See the [CROW comparison table](https://commonwaysystem.org/guide/street-types.md#for-readers-coming-from-dutch-crow-practice).

### Bicycle facility

#### Commonway System

**Protected bike lane.**

Protected bike lane / cycle track, not merely buffered. This page's own Collector speed rule runs 30 to 35 mph, above the Dutch mixing threshold, so NACTO's enhanced recommendation is not optional here. It is what the speed rule already requires for internal consistency.

#### Federal / State baseline

**Not mandated; FHWA guide applies.**

Not mandated by default. FHWA's Separated Bike Lane Planning and Design Guide is the federal design reference for when one is provided.[1]

#### NACTO enhancement

**Protected over painted.**

Protected bike lane / cycle track recommended over a painted lane.[5]

#### Complete Streets layer

**Bike lanes or wide shoulders.**

Bicycle lanes or wide paved shoulders listed as a typical element.[4]

#### Dutch / Sustainable Safety

**Separate above 30 km/h.**

Physical separation required above a 30 km/h (about 19 mph) design speed. Cycle tracks measured 50 to 60% fewer bicycle crashes than painted lanes or mixed traffic on comparable roads.[6]

### Pedestrian facility

#### Commonway System

**Sidewalks both sides, NACTO widths.**

Sidewalk required on both sides, sized to NACTO's range, not PROWAG's floor. PROWAG's 4 ft is an accessibility minimum, not a comfort or capacity target, so it is the legal floor here, not the design target.

#### Federal / State baseline

**4 ft minimum, sidewalk not required.**

PROWAG requires a 4 ft minimum clear pedestrian access route where a sidewalk exists, 5 ft at medians and refuge islands, but does not require that a sidewalk be built in the first place.[7]

#### NACTO enhancement

**5 to 7 ft residential, 8 to 12 ft downtown.**

Pedestrian through zone of 5 to 7 ft in residential settings, 8 to 12 ft in downtown and commercial areas.[8]

#### Complete Streets layer

**Sidewalks always included.**

Sidewalks listed as the first typical element, on the premise a street is not complete without one.[4]

#### Dutch / Sustainable Safety

**Separate above 30 km/h.**

Follows the same 30 km/h separation logic as the bicycle row above.[6]

### Speed management

#### Commonway System

**30 mph; 35 only with rigid barrier.**

30 mph standard, 35 mph only with rigid crash-protective separation, as locked in [Speed and modal hierarchy](https://commonwaysystem.org/patterns/collectors/default.md#speed-and-modal-hierarchy) above. 35 mph sits well above the Dutch 30 km/h threshold, so that rigid-separation requirement is functionally the Dutch safety principle already built into this page's speed rule, just never labeled that way before.

#### Federal / State baseline

**Set from 85th-percentile speed.**

Traditionally set from the 85th-percentile observed speed.[12]

#### NACTO enhancement

**Narrower lanes calm traffic.**

Narrower lanes as the primary calming lever, same source as the lane-width row.[3]

#### Complete Streets layer

**Narrow lanes, curb extensions, roundabouts.**

Narrower lanes, curb extensions, and roundabouts listed as typical calming elements.[4]

#### Dutch / Sustainable Safety

**Separate above 30 km/h.**

30 km/h (about 19 mph) is the explicit threshold above which separation, not just marking, is required.[9]

### Intersection treatment

#### Commonway System

**Roundabout first; raised junction at Local streets.**

Depends on what the Collector meets. Collector to Local: [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md). Collector to Collector: [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md). Collector to Arterial: prefer [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md), falling back to [Protected Intersection](https://commonwaysystem.org/patterns/intersections/protected-intersection.md) or, only when neither works, [Signal](https://commonwaysystem.org/patterns/intersections/signal.md). A Collector connecting directly to a Freeway gets no treatment, since that combination should not occur in this publication's network hierarchy.

#### Federal / State baseline

**Roundabouts favored over signals.**

FHWA identifies roundabouts as a Proven Safety Countermeasure, a 37 to 90% reduction across collision types depending on severity, and recommends considering them ahead of signals on federally funded projects.[10] MUTCD's signal-warrant standard supports the same choice: an engineering study is required before installing a signal, and satisfying a warrant does not by itself require installing one.[14] A jurisdiction that meets a warrant and still chooses a roundabout is acting inside federal doctrine, not deviating from it.

#### NACTO enhancement

**Depends on what the street meets.**

Two different answers depending on what meets the Collector. Collector to Local: "gateway" treatments, curb extensions, raised crossings, and tight curb radii mark the transition.[15] Collector to Collector or Arterial: geometry, signal timing, and pedestrian islands are weighed against each other rather than one control type being endorsed.[16] NACTO does not take FHWA's explicit "prefer roundabouts" position. Its Traffic Circle treatment is scoped to small, uncontrolled minor intersections for calming, not a substitute for a multi-lane roundabout at a major intersection.[17]

#### Complete Streets layer

**Roundabouts and curb extensions.**

Roundabouts and curb extensions listed as typical elements.[4]

#### Dutch / Sustainable Safety

**Raised intersections.**

Raised intersections. See [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md), which documents the concept with its own citations.

### Separation / buffer between modes

#### Commonway System

**Rigid barrier: no minimum. Otherwise 3 ft.**

Where a rigid crash-protective barrier separates bicycles from the car lanes, no minimum buffer width is required. Where there is no such barrier, use NACTO's 3 ft parking-adjacent minimum, which clears the door-swing zone. The barrier does the separating job the buffer would otherwise do, and NACTO's number is the best-sourced answer for the case without one.[5]

#### Federal / State baseline

**Buffers permitted, no minimum width.**

MUTCD permits buffered preferential lane markings but sets no minimum buffer width itself.[11]

#### NACTO enhancement

**2 ft minimum, 3 ft beside parking.**

2 ft minimum buffer, wider preferred. 3 ft minimum adjacent to on-street parking, to clear the door-swing zone.[5]

#### Complete Streets layer

**Not specified.**

Not separately specified. Folded into the general infrastructure list.[4]

#### Dutch / Sustainable Safety

**Full separation, not paint.**

Not a separate step. Once a street crosses the 30 km/h threshold, Dutch practice moves straight to full physical separation rather than a painted buffer.[6]

### On-street parking

#### Commonway System

**Optional; 8 ft if provided.**

Optional and context-dependent, not a required element. Where provided, use AASHTO's 8 ft desirable width rather than the 7 ft minimum, since the extra width also protects the door-swing zone the bicycle-facility answer depends on.

#### Federal / State baseline

**7 ft minimum, 8 ft desirable.**

Most vehicles park 6 to 12 inches from the curb and occupy roughly 7 ft. The Green Book recommends a 7 ft minimum on urban streets and 8 ft as the desirable width where parking is provided.[13]

#### NACTO enhancement

**Not yet sourced.**

Open gap: not independently sourced.

#### Complete Streets layer

**Not treated as essential.**

Absent from the typical-elements list. On-street parking is not treated as a completeness requirement the way sidewalks and bike facilities are.[4]

#### Dutch / Sustainable Safety

**None on distributor roads.**

Not separately cited. A distributor-class road carries no direct property access by design, which excludes on-street parking from the through carriageway itself. Parking belongs on the local access streets Dutch classification keeps separate.

### Property access

#### Commonway System

**One driveway per block face, shared where possible.**

Minimal, consolidated access, not zero access. No more than one driveway per block face, with shared or cross-access driveways used instead of new individual ones wherever multiple parcels front the same block. A block-face count rather than a fixed distance scales to whatever the local block length already is, so it stays a usable target in a tight urban grid and a long suburban block alike, without this page inventing a distance that would only fit some jurisdictions. The Arterial sibling, [Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md), already draws the hard line at zero. A Collector's answer sits between that zero and a Local street's assumption of open frontage access: restrictive, but not absolute.

#### Federal / State baseline

**No single number; crash reduction proven.**

No single federal number. Driveway spacing follows the Transportation Research Board's Access Management Manual methodology, which ties spacing to speed and volume rather than fixing one distance, and states and localities adopt their own numbers from it. What is concrete and federal: FHWA designates Corridor Access Management, reducing driveway density along a roadway, as a Proven Safety Countermeasure, with a documented 25 to 31% reduction in fatal and injury crashes on urban and suburban arterials and a measurable benefit on two-lane roads as well.[18]

#### NACTO enhancement

**Limit driveways; one per block face at most.**

The Minneapolis Street Design Guide, built directly on NACTO's framework, is explicit: new driveways should be limited to locations without alley or cross-street access in the first place, and where one is unavoidable, no more than one curb cut per block face, sited midblock.[19]

#### Complete Streets layer

**Not specified.**

Absent from the typical-elements list. Property access is not treated as a completeness requirement.[4]

#### Dutch / Sustainable Safety

**No direct property access on distributor roads.**

Distributor roads, the Dutch functional peer to a Collector, carry no direct property access at all. It is a defining structural rule of the classification, not a discouraged practice. See the [CROW comparison table](https://commonwaysystem.org/guide/street-types.md#for-readers-coming-from-dutch-crow-practice).

## Design notes

This entry is the standard against which every other Collector Typology is defined as an override, the same role Default plays within Local.

## Related patterns

[Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md) (LOC-DEF-01) and [Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the equivalent baseline reference point one Functional Classification down and up, completing the three-tier chain)

## Getting there: Retrofit path options

[Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) (RFT-CDR-01), [Lane diet](https://commonwaysystem.org/retrofits/corridor/lane-diet.md) (RFT-CDR-03), [Protected bike lane retrofit via lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md) (RFT-CDR-07), [Protected bike lane retrofit via parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) (RFT-CDR-09)

## References

1.  Legal / regulatory [FHWA, _Separated Bike Lane Planning and Design Guide_.](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/separated_bikelane_pdg/page00.cfm)
2.  Legal / regulatory [AASHTO, _A Policy on Geometric Design of Highways and Streets_ ("Green Book"), Collector lane width range, as summarized in Washington State DOT's own AASHTO-comparison reference.](https://wsdot.wa.gov/publications/fulltext/ProjectDev/ProjectSummary/Compare_AASHTO-08.pdf)
3.  Precedent-based [NACTO, "Lane Width," _Urban Street Design Guide_.](https://nacto.org/publication/urban-street-design-guide/street-design-elements/lane-width/)
4.  Precedent-based [Smart Growth America, National Complete Streets Coalition, "About" page, typical Complete Street elements.](https://www.smartgrowthamerica.org/programs-and-coalitions/national-complete-streets-coalition/about/)
5.  Precedent-based [NACTO, "Designing Protected Bike Lanes," _Urban Bikeway Design Guide_.](https://nacto.org/publication/urban-bikeway-design-guide/designing-bikeways-for-all-ages-and-abilities/protected-bike-lanes/designing-protected-bike-lanes/)
6.  Evidence-based [J.W.H. van Petegem, P. Schepers & G.J. Wijlhuizen, "The safety of physically separated cycle tracks compared to marked cycle lanes and mixed traffic conditions in Amsterdam," SWOV Institute for Road Safety Research / TU Delft, _European Journal of Transport and Infrastructure Research_ 21(3), 2021.](https://journals.open.tudelft.nl/ejtir/article/download/5283/5126)
7.  Legal / regulatory [U.S. Access Board, PROWAG Chapter R3, Technical Requirements, pedestrian access route width.](https://www.access-board.gov/prowag/proposed/chapter-r3-technical-requirements/)
8.  Precedent-based [NACTO, "Sidewalk Zones," _Urban Street Design Guide_.](https://nacto.org/publication/urban-street-design-guide/street-design-elements/sidewalks/sidewalk-zones/)
9.  Evidence-based [TU Delft, _European Journal of Transport and Infrastructure Research_, Dutch road classification table (access/distributor/through roads, speed limits, and cyclist placement by class).](https://journals.open.tudelft.nl/ejtir/article/download/3000/3187/8330)
10.  Legal / regulatory [FHWA, "Roundabouts," CSS Design Tactics, Office of Planning, Environment, & Realty.](https://www.fhwa.dot.gov/planning/css/design/tactics/chap23.cfm)
11.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 3D, Section 3D.01, buffered preferential lane markings.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
12.  Legal / regulatory [Federal Highway Administration. "Relationship Between Design Speed, Operating Speed, and Posted Speed."](https://www.fhwa.dot.gov/planning/css/resources/speed)
13.  Legal / regulatory [AASHTO, _A Policy on Geometric Design of Highways and Streets_ ("Green Book"), on-street parking lane width, as quoted directly in a NACTO-hosted research citation.](https://nacto.org/wp-content/uploads/Part-III-Section-2-Citation-16_-Furth-and-Dulaski.pdf)
14.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 4C, Section 4C.01, traffic signal needs studies. An engineering study and warrant analysis are required, but satisfying a warrant does not itself require installing a signal.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
15.  Precedent-based [NACTO, "Intersections of Major and Minor Streets," _Urban Street Design Guide_.](https://nacto.org/publication/urban-street-design-guide/intersections/intersections-of-major-and-minor-streets/)
16.  Precedent-based [NACTO, "Major Intersections," _Urban Street Design Guide_.](https://nacto.org/publication/urban-street-design-guide/intersections/major-intersections/)
17.  Precedent-based [NACTO, "Traffic Circle," _Urban Street Design Guide_.](https://nacto.org/publication/urban-street-design-guide/intersections/traffic-circle/)
18.  Legal / regulatory [Federal Highway Administration, "Corridor Access Management," Proven Safety Countermeasures.](https://highways.dot.gov/sites/fhwa.dot.gov/files/2022-06/12_Corridor%20Access%20Management_508.pdf)
19.  Precedent-based [City of Minneapolis, Street Design Guide, "Driveways" section (Boulevards and Furnishings).](https://sdg.minneapolismn.gov/design-guidance/boulevards-and-furnishings/driveways)

---

Source: https://commonwaysystem.org/patterns/collectors/downtown-thoroughfare/

# Downtown Thoroughfare

`COL-DTH-07`

Situational / Discouraged Collector

Downtown Thoroughfare

A collector-scale street running through a dense downtown or town-center context, carrying meaningful through-traffic volume while also serving frequent pedestrian activity, on-street parking, and ground-floor commercial frontage along its length.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

Aligned

### [More Lanes Are (Still) A Bad Thing](https://www.youtube.com/watch?v=CHZwOAIect4)

Not Just Bikes

Lays out induced demand, Braess's Paradox, and traffic evaporation with real case studies (LA 405, Houston Katy Freeway, Cheonggyecheon), then shows the Dutch one-lane-plus-transit cross-section as the actual fix.

Typical at: Compact Urban Core

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\]

Follows the Collector default: 30 mph standard.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Bicycle > Transit > Vehicle > Freight

Follows the Collector base order without an override. The downtown context sharpens the pedestrian emphasis in the design treatment without changing which mode ranks first, since Pedestrian is already first in the Collector base order.

## Design notes

Distinct from Main Street (LOC-MST-05), a Local-scale, slower, retail-frontage-first pattern, and from Default Collector (COL-DEF-01), which doesn't assume a downtown context, Downtown Thoroughfare balances meaningful through-traffic volume against the frequent pedestrian activity, crossings, and access needs of a dense commercial core. This is a recognized NACTO street type distinct from both.[1] On-street parking is typically retained here, unlike the Arterial no-parking rule, since Collector classification carries no such restriction. Crossing frequency and intersection treatment should prioritize pedestrian activity given the downtown context, even while accommodating through-traffic volume.

## Related patterns

[Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md) (LOC-MST-05) (related Local-scale pattern, distinct in speed and priority); [default Collector pattern](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01); relevant Intersection patterns for frequent pedestrian crossings

## Getting there: Retrofit path options

[Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) (RFT-CDR-01), [One-way to two-way conversion](https://commonwaysystem.org/retrofits/corridor/one-way-to-two-way-conversion.md) (RFT-CDR-04)

## References

1.  Precedent-based [National Association of City Transportation Officials, _Urban Street Design Guide_, "Downtown Thoroughfare."](https://nacto.org/publication/urban-street-design-guide/streets/downtown-thoroughfare/)

---

Source: https://commonwaysystem.org/patterns/collectors/industrial-collector/

# Industrial Collector

`COL-IND-03`

Recommended Collector

Industrial Collector

A Collector road serving warehouses, freight yards, or manufacturing land use, designed around truck movement and loading rather than the base Collector priority order.

Typical at: Suburban Compact Urban

Undeveloped, Rural, and Core are edge cases.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 30\]

Follows the Collector default: 30 mph standard. Freight priority in the modal hierarchy below does not change the vehicle speed cap.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Freight > Vehicle > Pedestrian > Bicycle > Transit

An override justified because the Typology's stated purpose is freight movement to and from industrial land use.

## Layered guidance across sources

The Commonway System column comes first: it is the answer. The four columns after it show the layered sources it was built from. Open gaps are marked in the cells rather than guessed at.

Industrial Collector design guidance by source, from the Commonway System answer through federal and state baseline, NACTO, Complete Streets, and Dutch practice

### Travel lane width

#### Commonway System

**12 ft.**

12 ft. Truck volume is the reason: this is the width freight movement needs, not a rural or comfort-driven choice.

#### Federal / State baseline

**10 to 12 ft; 12 ft in industrial zones.**

10 to 12 ft depending on volume and speed, with industrial zones specifically built to 12 ft where truck volume is significant. Portland's industrial-zone cross-section uses two 12 ft travel lanes.[1] Minneapolis names the WB-62 design vehicle for highly industrialized streets.[2]

#### NACTO enhancement

**Not applicable at these volumes.**

NACTO's general guidance narrows lanes where feasible, but notes 10 ft lanes still support truck uses only at 35 mph and under. Industrial Collector truck volumes exceed that threshold, so the narrowing guidance does not carry over.[3]

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Number of travel lanes

#### Commonway System

**Two lanes, plus turn lanes as needed.**

Two lanes, one each way, with additional turn lanes as needed at intersections to accommodate slow-turning trucks.

#### Federal / State baseline

**Two to four lanes, plus turn lanes.**

Two to four lanes are typical for industrial roads, with additional turning lanes as needed.[4]

#### NACTO enhancement

**Not researched.**

Not researched.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Bicycle facility

#### Commonway System

**Required within a 3 mi bike / 0.5 mi walk catchment; must be physically separated.**

A bicycle facility is required, not contingent on a master plan naming this corridor, whenever any population that could plausibly use this street segment for any purpose falls within a 3-mile bicycle catchment or a 0.5-mile pedestrian catchment of it.[22] Measure the catchment against the street segment as a whole, not against any single business or job site along it. This is public right-of-way, and the relevant population is whoever could use it, not only people employed at adjacent industrial land uses.[22][24] Only in the genuine edge case, an isolated segment with no population within either catchment at all, does the facility become context-dependent rather than required. Once required, it must be physically separated, not a painted or buffered-only lane, per the Separation / buffer row below.

#### Federal / State baseline

**FTA 0.5 mi walk / 3 mi bike distances; FHWA selects by context, not plan status.**

FTA's adopted eligibility policy treats pedestrian improvements within one-half mile, and bicycle improvements within three miles, of a public transportation stop or station as having a de facto relationship to public transportation. Those are transit-funding thresholds, and this page borrows the same distances as its catchment.[22] Separately, FHWA's Bikeway Selection Guide selects bikeway facility type from roadway speed and volume, truck mix, and land use context, not from whether a corridor appears in an adopted bicycle plan.[23]

#### NACTO enhancement

**Coordinate truck and bike routes up front.**

Truck route designation should be coordinated with bicycle network mapping up front, rather than resolved after the fact. Bollards are recommended at truck-route corners because of a documented pattern of truck wheels overrunning curbs and striking people nearby.[6] Seattle's freight standards go further: a protected bicycle lane is recommended where a bicycle facility is planned on a truck street, though the standard's first preference is routing the bicycle network away from major truck streets where an alternative exists.[13]

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Pedestrian facility

#### Commonway System

**Sidewalk both sides, about 6 ft.**

Sidewalk on both sides, roughly a 6 ft pedestrian through-zone, with a minimal (roughly 0.5 ft) frontage zone. Driveway and curb-cut count is the real design lever here, not sidewalk width.

#### Federal / State baseline

**PROWAG width applies.**

PROWAG's general minimum access-route width applies regardless of adjacent land use.[7]

#### NACTO enhancement

**Not researched.**

Not researched.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Speed management

#### Commonway System

**30 mph, unchanged from base Collector.**

30 mph, unchanged from the base Collector rule. See [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md).

#### Federal / State baseline

**Design speed equals posted speed.**

FHWA's design-speed-equals-posted-speed framework, the same source cited across this publication.[8]

#### NACTO enhancement

**Narrower lanes calm traffic.**

The same logic as Default (Standard Collector): narrower lanes calm traffic. Here that logic is limited by the 12 ft truck lane width above, so speed is held by the 30 mph rule and geometry at intersections instead.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Intersection treatment

#### Commonway System

**Local: stop control. Collector or Arterial: roundabout.**

**Meets a Local street** Stop / Yield on the Local approach. Low volume does not justify a roundabout. The curb radius on the Industrial Collector's own approach still follows freight-street sizing, not a normal Local-street radius, since the truck is still turning even where the cross street is minor.[9]

**Meets another Collector** A [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) is preferred, sized per NCHRP Research Report 1043's current large-vehicle guidance with a truck apron for the occasional oversize check vehicle. The everyday design vehicle should clear the roundabout without off-tracking onto the apron.[10] Confirm actual vehicle-classification counts before defaulting to the largest conceivable design vehicle everywhere. Oversizing has its own safety and cost consequences.[11][12]

**Meets an Arterial** A [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) is preferred, with a [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) only where volume genuinely warrants one, the same logic as Default (Standard Collector). Size it at the higher end, since both legs likely carry freight designation.

**Meets a Freeway** Not applicable. A Collector does not connect to a Freeway at grade. That is an interchange condition and belongs to [Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md).

#### Federal / State baseline

**NCHRP Research Report 1043.**

NCHRP Research Report 1043 is the current national roundabout guide and supersedes NCHRP Report 672.[10]

#### NACTO enhancement

**Design vehicle vs. check vehicle.**

NACTO separates the design vehicle from the check vehicle, and favors rerouting truck routes over reconstructing a corner to fit the largest possible truck.[6]

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Separation / buffer between modes

#### Commonway System

**Physical separation required: 3 ft minimum buffer plus a durable vertical element, not paint alone.**

Physical separation is required on this Typology, not merely preferred: a minimum 3 ft buffer plus a durable vertical element (a curb, planter, or bollard), not a painted line alone, and not flexible delineator posts alone given the truck volumes this street carries. This is not a sliding scale on this page. Industrial Collector's speed is fixed at 30 mph (see Speed management above), and FHWA's bikeway-selection guidance calls for a fully separated facility once a street's speed and volume reach roughly 30 mph and/or approximately 7,000 vehicles per day.[23] A Collector carrying freight-level truck volume meets or exceeds that threshold as a matter of course, so there is no lower tier of separation available on this Typology to fall back to.

#### Federal / State baseline

**FHWA: full separation above ~30 mph / ~7,000 vpd; 3 ft minimum buffer, curb, planter, or bollard.**

FHWA's Bikeway Selection Guide generally recommends a separated bike lane or shared-use path, not a painted or buffered-only lane, once a street's motor vehicle speed and volume exceed roughly 30 to 35 mph and/or approximately 6,000 to 7,000 vehicles per day.[23] FHWA's separate Separated Bike Lane Planning and Design Guide sets a 3 ft minimum buffer width for maneuvering and door-opening clearance, and documents curbs, planters, bollards, and flexible delineator posts as vertical-element options, with a 3 inch mountable curb as the standard detail where street-sweeper access is needed.[5]

#### NACTO enhancement

**Setback stop bars; bicycle signal phasing.**

Seattle's freight standards describe stop bars that can be set back from the intersection and crosswalk to leave room for a turning truck's swept path, and bicycle signals that can separate bicycle and truck movements in time. Both are offered as design tools, not requirements.[13]

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### On-street parking

#### Commonway System

**Discouraged; buffered lane if unavoidable.**

Discouraged; off-street is always preferred. Where unavoidable, a buffered lane (10 to 14 ft plus a 2 to 4 ft painted buffer), never bare curbside. No parking or loading within 20 ft of a marked crosswalk.

#### Federal / State baseline

**20 ft crosswalk setback.**

A 20 ft setback before a marked crosswalk keeps sight distance clear and stops drivers pulling forward onto a raised crossing to back into the first space.[14]

#### NACTO enhancement

**Not researched.**

Not researched.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

### Property access

#### Commonway System

**Curb cuts limited by code; forward entry.**

Curb cuts limited by code, not "as needed." The driveway and on-site apron are sized so the design vehicle enters forward and never backs across the public sidewalk to reach a loading position. See [Curb Cut / Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md).

#### Federal / State baseline

**Curb-cut counts capped; no backing into the street.**

Curb-cut counts are limited by land use code.[15] Backing onto a public street or sidewalk to leave a site is prohibited in multiple adopted jurisdictions: Knightdale, NC bars loading areas from relying on backing movements into the right-of-way,[17] and Bakersfield, CA bars vehicles backing onto any street to leave a site, explicitly once the street is classified arterial or collector.[18] Houston bars back-in loading berths on a major thoroughfare and, where a back-out berth is used, requires it to be deep enough that no part of the vehicle protrudes over the property line.[16]

#### NACTO enhancement

**Confirm the actual truck mix.**

Confirm actual truck mix before assuming the largest design vehicle at every driveway.[19]

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not researched.

## Design notes

Industrial land use exists across a wide density range, which is why this Typology's realistic range is broader than most Collector entries, spanning Suburban through Urban with Undeveloped, Rural, and Core all plausible as edge cases rather than clean exclusions.[6]

The corner and driveway geometry on this page is driven by more than fit. Federal analysis has found that large trucks are involved in a disproportionate share of fatal pedestrian and cyclist crashes relative to their share of the vehicle fleet, and that turning maneuvers carry far higher odds of a fatal outcome than going straight, largely because a truck's off-tracking during a turn puts a person standing or riding alongside the trailer in a blind zone with no escape path.[20][21] That is why curb-cut minimization and intersection design on this page are treated as life-safety measures, not just access-management or geometry problems. The general pattern for turning-vehicle risk is on the [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) page, and this street is the acute case of it.

Two cautions apply when sizing anything on this page to the largest design vehicle. Designing every movement for the largest conceivable truck degrades safety and comfort for other users without a demonstrated need, and oversized intersections carry their own costs: more crash exposure, more confusion, more right-of-way, and longer pedestrian crossing distances.[11][12] Confirm actual vehicle mix before defaulting to the worst case.

**Bicycle facility catchment.** The 3-mile bike and 0.5-mile walk threshold above borrows the distances in FTA's own adopted eligibility policy for pedestrian and bicycle improvements, which are themselves reasoned from equivalent travel time at each mode's typical speed: roughly a 15-to-30-minute walk at 2 mph, and the same time budget at a bicycle's roughly 10 mph average commute speed.[22] The trigger is population, not land use classification. An industrial designation for this street does not mean its only legitimate users are people employed at businesses along it, and it should not be read as excusing the facility just because a bicycle plan has not caught up to the corridor. Industrial and logistics employment also skews toward a workforce with lower vehicle ownership and higher walk and bicycle mode share than the general population, including shift-work schedules that raise their own visibility and lighting needs. That is a reason to apply this trigger generously here, not a reason to scope it down to only the workers on-site.[24]

Where this pattern's street crosses an active rail spur, an increasingly common condition on industrial land, see [Railroad Grade Crossing](https://commonwaysystem.org/patterns/intersections/railroad-grade-crossing.md) (INT-RGC-15), which covers the geometry and warning devices this page does not.

## Related patterns

[Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01) (the base order this pattern overrides for Freight priority), [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md) (LOC-ALY-02) (the other cross-Classification pattern overriding to a Vehicle/Freight-first order for a specific access purpose), [Roundabout (Single / Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) (this pattern's intersection answer depends on that page's freight-street sizing note), [Curb Cut / Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md) (ELM-CCA-04) (this pattern's property-access answer depends on that Element's forward-entry requirement), [Railroad Grade Crossing](https://commonwaysystem.org/patterns/intersections/railroad-grade-crossing.md) (INT-RGC-15) (where an active rail spur crosses this street)

## References

1.  Legal / regulatory [City of Portland Bureau of Transportation, _PBOT Development Review Manual_, industrial-zone cross-section standard (44 ft curb-to-curb, two 12 ft travel lanes).](https://www.portland.gov/transportation/permitting/documents/pbot-development-review-manual-creating-public-streets-and/download)
2.  Legal / regulatory [City of Minneapolis, _Street Design Guidance_ 3.7B, "Design and Control Vehicles" (WB-62 named for highly industrialized streets).](https://sdg.minneapolismn.gov/application/files/4116/1256/7848/3.7B_Design_and_control_vehicles.pdf)
3.  Precedent-based [NACTO, _Urban Bikeway Design Guide_, "Protected Bike Lanes" (10 ft lanes support truck uses at 35 mph and under).](https://nacto.org/latest/urban-bikeway-design-guide-protected-bike-lanes/)
4.  Precedent-based [City of Portland Bureau of Transportation, StreetsPDX, "Industrial Roads" street type (two to four lanes plus turn lanes as needed).](https://pbotapps.portland.gov/streets-pdx/street-types/industrial-road)
5.  Legal / regulatory [Federal Highway Administration, _Separated Bike Lane Planning and Design Guide_, vertical separation type selection.](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/separated_bikelane_pdg/page08.cfm)
6.  Precedent-based [NACTO, _Urban Street Design Guide_, "Design Vehicle" (truck route coordination with bike, transit, and pedestrian mapping; bollards at truck-route corners).](https://nacto.org/publication/urban-street-design-guide/design-controls/design-vehicle/)
7.  Legal / regulatory [U.S. Access Board, PROWAG Chapter R3, Technical Requirements, pedestrian access route width.](https://www.access-board.gov/prowag/proposed/chapter-r3-technical-requirements/)
8.  Legal / regulatory [Federal Highway Administration. "Relationship Between Design Speed, Operating Speed, and Posted Speed."](https://www.fhwa.dot.gov/planning/css/resources/speed)
9.  Precedent-based Seattle Streets Illustrated, [3.9 Intersections](https://streetsillustrated.seattle.gov/design-standards/intersections/) and [2.13 Industrial Access](https://streetsillustrated.seattle.gov/street-type-standards/industrial-access/) (curb radius by connection type: 25 to 30 ft for truck-street intersections versus a 20 ft citywide default).
10.  Legal / regulatory [Transportation Research Board, _Guide for Roundabouts_, NCHRP Research Report 1043 (2023). Supersedes NCHRP Report 672.](https://www.nationalacademies.org/publications/27069)
11.  Legal / regulatory [Delaware Department of Transportation, _Design Guidance Memorandum_ (DGM) 1-26, "Roundabouts" (design vehicle versus check vehicle, and the caution against over-designing for the largest possible truck).](https://deldot.gov/Publications/manuals/dgm/pdfs/1-26_Roundabouts.pdf)
12.  Legal / regulatory [Wisconsin Department of Transportation, _Facilities Development Manual_, FDM 11-25 (costs of oversized truck-accommodating intersections).](https://wisconsindot.gov/rdwy/fdm/fd-11-25.pdf)
13.  Precedent-based [Seattle Streets Illustrated, 3.11 "Freight" (protected bicycle lane recommended on truck streets; setback stop bars and bicycle signals as tools against large-truck turning movements).](https://streetsillustrated.seattle.gov/design-standards/freight/)
14.  Legal / regulatory [Ohio Department of Transportation, _Location and Design Manual_ Volume 1, pedestrian facilities (20 ft parking and loading restriction before a marked crosswalk).](https://www.transportation.ohio.gov/working/engineering/roadway/manuals-standards/multimodal/04)
15.  Legal / regulatory [City of Seattle, Land Use Code § 23.54.030, "Parking space and access standards" (curb-cut counts per lot frontage).](http://seattle-wa.elaws.us/code/mc_title23_subtitleiii_ch23.54_sec23.54.030)
16.  Legal / regulatory [City of Houston, _Houston Building Code_ (2021), Chapter 31, § 3116.4.6 "Loading Berth" (§ 3112 in the 2015 edition).](https://up.codes/viewer/houston/ibc-2021/chapter/31/special-construction)
17.  Legal / regulatory [Town of Knightdale, NC, _Unified Development Ordinance_, Chapter 7, "Development Standards" (loading areas may not rely on backing movements into public rights-of-way).](https://www.knightdalenc.gov/sites/default/files/uploads/developmentservices/udo/07-development-standards-052226.pdf)
18.  Legal / regulatory [City of Bakersfield, _Zoning Code_, Chapter 32 (vehicles may not back onto any street or thoroughfare to leave a site, binding once a street is classified arterial or collector).](https://www.zoneomics.com/code/bakersfield-CA/chapter_32)
19.  Legal / regulatory [Los Angeles Department of Transportation, _Driveway Design Guide_ (2024) (on-site reservoir and maneuvering space; confirm truck mix by turning-movement path evaluation).](https://ladot.lacity.gov/sites/default/files/2026-04/driveway-design-guide-march-2024.pdf)
20.  Evidence-based [U.S. Government Accountability Office, _Pedestrian and Cyclist Safety: DOT Should Take Steps to Address Risks Related to Limited Driver Visibility_, GAO-26-107954 (2026).](https://www.gao.gov/products/gao-26-107954)
21.  Evidence-based [Wang, Q. et al., "Exploring the Influencing Factors and Formation of the Blind Zone of a Semitrailer Truck in a Right-Turn Collision," _Sustainability_ 14(16), 9805 (2022).](https://doi.org/10.3390/su14169805)
22.  Legal / regulatory [Federal Transit Administration, "Final Policy Statement on the Eligibility of Pedestrian and Bicycle Improvements Under Federal Transit Law," _Federal Register_ 76(161), p. 52046 (August 19, 2011) (one-half mile pedestrian and three-mile bicycle distances from a transit stop or station).](https://www.federalregister.gov/documents/2011/08/19/2011-21273/final-policy-statement-on-the-eligibility-of-pedestrian-and-bicycle-improvements-under-federal)
23.  Legal / regulatory [Federal Highway Administration, _Bikeway Selection Guide_, FHWA-SA-18-077 (2019) (facility type by speed, volume, truck mix, and land use context; separated facility thresholds).](https://safety.fhwa.dot.gov/ped_bike/tools_solve/docs/fhwasa18077.pdf)
24.  Evidence-based [Chandra, S., Jimenez, J., and Radhakrishnan, R., "Accessibility evaluations for nighttime walking and bicycling for low-income shift workers," _Journal of Transport Geography_ 64 (2017), pp. 97 to 108.](https://doi.org/10.1016/j.jtrangeo.2017.08.010)

---

Source: https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway/

# Multi-Use Trail / Greenway

`COL-MUT-06`

Recommended Collector

Multi-Use Trail / Greenway

An off-street path shared by pedestrians and bicyclists under roughly equal priority, similar to Shared-Use Path but longer-distance and often a destination in its own right, such as a rail-trail or linear park path.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

Typical at: Rural Suburban Compact Urban Core

Undeveloped contexts are an unlikely pairing.

## Modal hierarchy

Modal hierarchy

Pedestrian = Bicycle

Pedestrian and Bicycle share top priority under this pattern's own equal-priority definition, no ranking between the two. Transit, Vehicle, and Freight do not apply off-street; Design Speed & Speed Limits doesn't apply here, since this pattern excludes automobiles entirely.

## Design notes

Distinct from [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) (COL-BHG-04), which is bicycle-priority rather than equal-priority, and longer-distance than [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md) (LOC-SUP-13), with wayfinding and rest amenities mattering more at this length. Appropriate where the trail itself is a recreational or civic destination, not just a through-corridor. Where it runs parallel to a road for a meaningful stretch, see [Road-Adjacent Greenway](https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway.md) (CDR-RAG-05) for the corridor-scale relationship.[1]

## Related patterns

-   [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md) (LOC-SUP-13)
-   [Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) (COL-BHG-04)
-   [Road-Adjacent Greenway](https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway.md) (CDR-RAG-05)

## Getting there: Retrofit path options

[Barrier-crossing / network reconnection retrofit](https://commonwaysystem.org/retrofits/network/barrier-crossing-network-reconnection-retrofit.md) (RFT-NET-03) commonly takes this form where it crosses a highway, rail line, or disconnected cul-de-sac pattern.

## References

1.  Legal / regulatory [AASHTO, _Guide for the Development of Bicycle Facilities_, 5th Edition (2024).](https://store.transportation.org/item/collectiondetail/267)

---

Source: https://commonwaysystem.org/patterns/collectors/rural-collector/

# Rural Collector / Farm-to-Market Road

`COL-FTM-02`

Recommended Collector

Rural Collector / Farm-to-Market Road

A Collector road connecting low-density or agricultural land to the wider network, prioritizing vehicle and freight movement over pedestrian, bicycle, and transit use, which have little demand at this density.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Context only

### [Why America Won't Copy Sweden's Cheap Highway Fix](https://www.youtube.com/watch?v=jyNEnYaBszk)

Safe By Design

Explains Sweden's 2+1 alternating-passing-lane cable-barrier retrofit and the specific AASHTO Green Book barriers (literally) that have kept the same fix from scaling in the US.

Typical at: Undeveloped Rural

Suburban is an edge case. Compact, Urban, and Core are unlikely pairings.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 35\]

35 mph is this Typology's own set point for the common case (rolling terrain, low volume), not inherited from the base Collector rule. Matches Dutch Sustainable Safety's design speed for a rural access road carrying mixed traffic without full separation.[1] See the Layered guidance across sources section below for the full terrain-by-volume range and when a faster design requires a specific safety retrofit rather than just a higher number.

Design speed by terrain and traffic volume (ADT, vehicles per day)

| Terrain | ADT under 400 | ADT 400 to 2,000 | ADT over 2,000 |
| --- | --- | --- | --- |
| Level | 40 mph | 50 mph, [requires the retrofit](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md) | 60 mph, [requires the retrofit](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md) |
| Rolling | 35 mph | 40 mph | 50 mph, [requires the retrofit](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md) |
| Mountainous | 20 mph | 30 mph | 40 mph |

Every cell is either AASHTO's own permitted minimum for that terrain and volume combination, or, where real Dutch mixed-traffic evidence exists (rolling terrain, low volume), a number set by that evidence rather than AASHTO's minimum.[4] Cells above 45 mph need the 2+1 road with cable median barrier retrofit. Past that threshold, two vehicles closing head-on hit each other at roughly 90 mph or more combined, and collision energy scales with the square of closing speed, not linearly, so the safety answer changes qualitatively, not just numerically.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Vehicle > Freight > Pedestrian > Bicycle > Transit

A judgment call reasoned from the Typology's purpose rather than derived cleanly from a listed override trigger, and open for correction.

## Layered guidance across sources

The Commonway System column comes first: it is the answer. The four columns after it show the layered sources it was built from. Open gaps are marked in the cells rather than guessed at.

Rural Collector design guidance by source, from the Commonway System answer through federal and state baseline, NACTO, Complete Streets, and Dutch practice

### Travel lane width

#### Commonway System

**10 ft below 45 mph; 12 ft at 45+.**

**Below 45 mph** 10 ft. This is the specific low-speed, low-volume exception this Typology qualifies for at its typical case (rolling terrain, low volume), not a universal rural answer.[2]

**45 mph and above** 12 ft. This is the general rural collector standard, not a downgrade. The 10 ft figure was always the exception, so a design that crosses into the higher-speed tier returns to the standard.[2]

#### Federal / State baseline

**12 ft default; 10 ft at low volume.**

Rural collectors are generally designed to 12 ft, given the higher operating speeds typically found on them. 10 ft is permitted at operating speeds of 55 mph or below with future traffic under 400 vehicles per day.[2]

#### NACTO enhancement

**Not applicable.**

Scoped to urban streets.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not regulated separately.**

Not regulated as a separate dimension. Folded into overall speed-and-separation design instead.

### Number of travel lanes

#### Commonway System

**Two lanes, one each way.**

Two lanes, one per direction, the same as [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md). No change for rural context.

#### Federal / State baseline

**Not researched.**

Not separately researched for this Typology.

#### NACTO enhancement

**Not applicable.**

Scoped to urban streets.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Not researched.**

Not separately researched for this Typology.

### Bicycle facility

#### Commonway System

**Below 45 mph: 4+ ft shoulder. 45+: separated path.**

**Below 45 mph** Paved shoulder with a painted edge line, 4 ft minimum, widening toward the top of that range as speed and volume rise within the tier. Rumble strips are a real roadway-departure countermeasure, but they can make a shoulder unrideable for cyclists unless a clear, sufficiently wide gap is left, so do not add them here without that gap.[3]

**45 mph and above** A genuinely separated facility, a shared-use path or equivalent physical separation, not a shoulder. FHWA's Bikeway Selection Guide (2019) recommends exactly this, a separated path in place of a shoulder, above roughly 45 mph and/or 3,000 to 6,000 vehicles per day on a rural road.[8] Speeding is one of the most common factors in motor vehicle crashes,[10] which is why the answer at higher speeds is separation rather than a wider stripe.

#### Federal / State baseline

**Shoulders; separated path above ~45 mph.**

Paved shoulders are the standard rural bicycle accommodation. AASHTO's Guide for the Development of Bicycle Facilities calls for at least 4 ft, wider above 50 mph.[3] FHWA's Bikeway Selection Guide sets rural shoulder width by speed and volume and recommends a separated facility above approximately 45 mph and/or 3,000 to 6,000 vehicles per day.[8]

#### NACTO enhancement

**Not applicable; rural guide instead.**

Not applicable, scoped to urban streets. This is the exact context FHWA's Small Town and Rural Multimodal Networks guide (2016) exists to cover instead.[3]

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Marked bike strip or path at 60 km/h.**

This Typology's real counterpart, Erftoegangsweg (rural access road), uses a marked bike strip or path at the same 60 km/h design speed this page sets. See the [CROW comparison table](https://commonwaysystem.org/guide/street-types.md#for-readers-coming-from-dutch-crow-practice).

### Pedestrian facility

#### Commonway System

**Shoulder below 45 mph; separated path above.**

**Below 45 mph** No dedicated sidewalk required at this Typology's stated density tiers (Undeveloped, Rural). The paved shoulder is the fallback if pedestrian presence exists, which is defensible given negligible pedestrian demand.

**45 mph and above** Sharing a shoulder stops being defensible. A pedestrian's risk of death reaches 50% at 42 mph, 75% at 50 mph, and 90% at 58 mph, according to federal crash data analyzed for the AAA Foundation for Traffic Safety.[9] That is outcome data, not a design opinion. Provide the same separated facility the bicycle row calls for: one separated path serves both, so pedestrian and bicycle accommodation are one problem at this speed tier, not two.

#### Federal / State baseline

**PROWAG applies only if provided.**

PROWAG applies only if a pedestrian facility is actually provided, and one typically is not at this density and demand.

#### NACTO enhancement

**Not applicable.**

Scoped to urban streets.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Open gap.**

Not independently sourced for the pedestrian-specific case. Left as an open gap rather than extending the bicycle row's source.

### Speed management

#### Commonway System

**35 mph typical; up to 40 to 60 by terrain and volume.**

35 mph typical, up to 40 to 60 mph depending on terrain and volume. See the table in [Speed and modal hierarchy](https://commonwaysystem.org/patterns/collectors/rural-collector.md#speed-and-modal-hierarchy) above. Cells above 45 mph call for the [2+1 road with cable median barrier](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md) retrofit.[4]

#### Federal / State baseline

**Green Book minimums; Texas will not go below 40.**

AASHTO Green Book Table 6-1 sets minimum design speeds for rural collectors by terrain and traffic volume.[4] Real state practice commonly runs above that minimum: Texas's own manual will not go below 40 mph even in rolling terrain at low volume.[5]

#### NACTO enhancement

**Not applicable.**

Scoped to urban streets.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**60 km/h for rural access roads.**

60 km/h (about 35 mph) for Erftoegangsweg, the rural access-road tier, is the design speed at which mixed traffic continues without requiring full physical separation.[1] See the [CROW comparison table](https://commonwaysystem.org/guide/street-types.md#for-readers-coming-from-dutch-crow-practice).

### Intersection treatment

#### Commonway System

**Local: stop control. Collector or Arterial: roundabout.**

**Meets a Local street** Stop / Yield on the Local approach, always, regardless of the Collector's own speed tier. A rural Local street's volume is too low to justify a roundabout's cost or footprint under any condition this Typology covers. What changes with speed is how the stop control is built, not whether one exists.

**Below 45 mph** A plain, well-marked [Stop / Yield (Two-Way)](https://commonwaysystem.org/patterns/intersections/stop-yield.md).

**45 mph and above** FHWA's low-cost rural intersection research applies directly: rumble strips and a painted median island on the Collector's approach, and a channelizing island with a supplemental stop sign on the Local approach.[16]

This differs from the Collector-to-Local answer on [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md), [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md), because that is an urban, pedestrian-priority treatment. It does not fit this Typology's rural context or negligible pedestrian volume, so a different, speed-appropriate answer is correct here, not an inconsistency with the urban page.

**Meets another Collector**

**Below 45 mph** Prefer a mini-roundabout (see [Neighborhood Traffic Circle / Mini-Roundabout](https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout.md)) over a plain Stop / Yield where the intersection can physically support one. A North Carolina DOT-funded study developed crash modification factors from 25 real mini-roundabout conversions across eight states (Georgia, Iowa, Michigan, Minnesota, Missouri, North Carolina, Virginia, Washington), and its own scope targeted rural intersections at 35 mph and above, not urban ones.[14] Total crashes and fatal-and-injury crashes both decreased after conversion. The trade-off is real: property-damage-only crashes increased, meaning severe crashes are being converted into low-speed fender-benders, not vanishing. A mini-roundabout's central island is mountable, which suits this Typology's farm-equipment traffic better than a standard roundabout sized only for passenger-vehicle turning radii. Fall back to a well-marked [Stop / Yield (Two-Way)](https://commonwaysystem.org/patterns/intersections/stop-yield.md) only where geometry or right-of-way rules a mini-roundabout out.

**45 mph and above** A full [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) where volume justifies it, FHWA's enhanced stop-control treatment where it does not, never a plain uncontrolled crossing. The strongest matching evidence is a North Carolina DOT evaluation of 13 intersections, every one in a rural area, every one converted from a minor-road stop control, every one with at least one approach posted at 55 mph, with average major-road volume around 6,000 vehicles a day and minor-road volume around 3,600. It found 41% fewer total crashes, 79% fewer fatal-and-injury crashes, and 62% fewer frontal-impact crashes.[15] Those conditions, rural, high-speed, stop-to-roundabout, match this tier directly. Where volume does not justify a roundabout, FHWA's research on low-cost safety concepts for two-way stop-controlled rural intersections on high-speed two-lane roads applies: rumble strips on shoulders and painted median islands on the major approach, and channelizing islands with supplemental stop signs on the minor approach.[16]

**Meets an Arterial** A [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) is preferred, with a [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) only where volume genuinely warrants one. A rural Arterial is plausibly running 55 mph or faster, which is close to the exact condition the rural high-speed roundabout study cited on this page was built around.[15] This is not a new claim for this connection type, it is the same evidence this page already relies on, applied one tier up.

**Meets a Freeway** Not applicable. A Collector does not connect to a Freeway at grade. That is an interchange condition and belongs to [Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md), not a fifth case to solve here.

#### Federal / State baseline

**FHWA mini-roundabout guide; low-cost stop-control concepts.**

FHWA's Mini-Roundabouts Technical Summary is the federal design reference for the below-45 mph tier.[13] For the 45 mph and above tier, FHWA's research on low-cost safety concepts for two-way stop-controlled rural intersections on high-speed two-lane roads is the federal source.[16]

#### NACTO enhancement

**Not researched.**

Not independently researched for this row on this page.

#### Complete Streets layer

**Not researched.**

Not independently researched for this row on this page.

#### Dutch / Sustainable Safety

**Roundabouts where distributors meet.**

**Where two distributor roads meet** Sustainable Safety advises roundabouts.[11]

**Where an access road meets a distributor** SWOV research recommends either a well-controlled priority intersection or a driveway-like exit construction that forces the minor road to yield unambiguously.[12]

### Separation / buffer between modes

#### Commonway System

**Shoulder below 45 mph; physical gap above.**

**Below 45 mph** The paved shoulder is the buffer. There is no separate painted-buffer question, the way there is on the urban Default page.

**45 mph and above** Once the facility is a separated path rather than a shoulder, the relevant separation is the physical gap and/or barrier between the path and the roadway, not a painted stripe width. See [Road-Adjacent Greenway](https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway.md) and [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md). This publication does not yet specify a gap width for that separation, so none is stated here.

#### Federal / State baseline

**Not applicable.**

Not applicable in the same shape as the urban Default page's version of this row.

#### NACTO enhancement

**Not applicable.**

Not applicable in the same shape as the urban Default page's version of this row.

#### Complete Streets layer

**Not applicable.**

Not applicable in the same shape as the urban Default page's version of this row.

#### Dutch / Sustainable Safety

**Not applicable.**

Not applicable in the same shape as the urban Default page's version of this row.

### On-street parking

#### Commonway System

**None.**

Not applicable. No adjacent development generates curbside parking demand.

#### Federal / State baseline

**Not applicable.**

No curbside parking demand at this density.

#### NACTO enhancement

**Not applicable.**

No curbside parking demand at this density.

#### Complete Streets layer

**Not applicable.**

No curbside parking demand at this density.

#### Dutch / Sustainable Safety

**Not applicable.**

No curbside parking demand at this density.

### Property access

#### Commonway System

**Field access only, as needed.**

Minimal, consolidated field access: one driveway per parcel where feasible, with agricultural-equipment-use conditions on the permit. On the urban [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) page, minimal means working toward as little access as possible. Here, direct farm access is this Typology's functional purpose, so minimal means no more than legitimately needed, not an aspiration toward eliminating it.

#### Federal / State baseline

**One field driveway per property, minimum needed.**

TxDOT's current Access Management Standards treat field driveways specifically: permitted where a field has no other reasonable access, typically one per property under common ownership, kept to the minimum necessary, and conditioned on agricultural-equipment use.[6] FHWA's Corridor Access Management Proven Safety Countermeasure, also cited on Default (Standard Collector), applies here too.[7]

#### NACTO enhancement

**Not applicable.**

Scoped to urban streets.

#### Complete Streets layer

**Not specified.**

Not specified in the typical-elements list.

#### Dutch / Sustainable Safety

**Direct access is expected on access roads.**

This Typology's real Dutch counterpart is the access-road tier, where direct property access is the defining, expected feature, not something excluded. That differs from the distributor roads on the Default (Standard Collector) page, which carry no direct property access at all. See the [CROW comparison table](https://commonwaysystem.org/guide/street-types.md#for-readers-coming-from-dutch-crow-practice).

## Design notes

This entry is the mirror image of Main Street: the norm at Undeveloped and Rural density, and effectively disappearing past Suburban as land use shifts away from agricultural or undeveloped character. The speed rule, and the terrain-by-volume ranges behind it, are laid out in the Layered guidance across sources section above.

## Related patterns

[Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md) (LOC-MST-05) (explicitly named on this page as this pattern's mirror image), [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01) (the base order this pattern overrides)

## Getting there: Retrofit path options

[Depaving / pavement-to-gravel conversion](https://commonwaysystem.org/retrofits/corridor/depaving-pavement-to-gravel.md) (RFT-CDR-10), [2+1 road with cable median barrier](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md) (RFT-CDR-11) (for the terrain and volume combinations above 45 mph)

## References

1.  Precedent-based [SWOV, "Principles for a Safe Road Network" (CROW Sustainable Safety framework).](https://sustainablesafety.nl/)
2.  Legal / regulatory [Texas Department of Transportation, _Roadway Design Manual_, Chapter 6, Section 6.1.6, "Travel Lane Width and Number of Lanes" (rural collector lane widths by operating speed and traffic volume).](https://www.txdot.gov/manuals/des/rdw/chapter-6--collectors--4r-/6-1-design-considerations/6-1-6-travel-lane-width-and-number-of-lanes.html)
3.  Legal / regulatory [FHWA, _Small Town and Rural Multimodal Networks_ (2016), Chapter 3, paved shoulders.](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/small_towns/page00.cfm)
4.  Legal / regulatory [AASHTO, _A Policy on Geometric Design of Highways and Streets_ ("Green Book"), Table 6-1, minimum design speeds for rural collectors by terrain and traffic volume.](https://store.transportation.org/Common/DownloadContentFiles?id=1776)
5.  Legal / regulatory [Texas Department of Transportation, _Roadway Design Manual_, Chapter 6, Section 6.1.3, "Design Speed."](https://www.txdot.gov/manuals/des/rdw/chapter-6--collectors--4r-/6-1-design-considerations/6-1-3-design-speed.html)
6.  Legal / regulatory [Texas Department of Transportation, _Access Management Manual_, "Field Driveways."](https://www.txdot.gov/manuals/des/acm/chapter-2--access-management-standards/section-3--number--location--and-spacing-of-access/field-driveways.html)
7.  Legal / regulatory [Federal Highway Administration, "Corridor Access Management," Proven Safety Countermeasures.](https://highways.dot.gov/sites/fhwa.dot.gov/files/2022-06/12_Corridor%20Access%20Management_508.pdf)
8.  Legal / regulatory [Federal Highway Administration, _Bikeway Selection Guide_ (February 2019), rural shoulder width by speed and volume; separated facility recommended above approximately 45 mph and/or 3,000 to 6,000 ADT.](https://safety.fhwa.dot.gov/ped_bike/tools_solve/docs/fhwasa18077.pdf)
9.  Evidence-based [Tefft, B.C. (2011), "Impact Speed and a Pedestrian's Risk of Severe Injury or Death," AAA Foundation for Traffic Safety.](https://aaafoundation.org/research/impact-speed-pedestrians-risk-severe-injury-death/)
10.  Evidence-based [National Transportation Safety Board (2017), "Reducing Speeding-Related Crashes Involving Passenger Vehicles," Safety Study NTSB/SS-17/01.](https://www.ntsb.gov/safety/safety-studies/Pages/DCA15SS002.aspx)
11.  Evidence-based [SWOV, "Roundabouts and other intersections," fact sheet.](https://swov.nl/en/fact-sheet/roundabouts-and-other-intersections)
12.  Evidence-based [SWOV Report R-98-10 (1998), junction treatment recommendations where an access road meets a distributor road.](https://swov.nl/system/files/publication-downloads/r-98-10.pdf)
13.  Legal / regulatory [Federal Highway Administration, _Mini-Roundabouts Technical Summary_ (FHWA-SA-10-007, 2010).](https://safety.fhwa.dot.gov/intersection/innovative/roundabouts/fhwasa10007/fhwasa10007.pdf)
14.  Evidence-based [Pulugurtha, Mishra & Mathew, University of North Carolina at Charlotte, "Mini-Roundabout CMF Development" (NCDOT RP2020-32, 2021).](https://connect.ncdot.gov/projects/research/RNAProjDocs/RP2020-32_Final%20Report.pdf)
15.  Evidence-based [North Carolina Department of Transportation, "Evaluation of Roundabouts on High-Speed Roadways."](https://connect.ncdot.gov/resources/safety/TrafficSafetyResources/One%20Pager_Highspeed%20Roundabouts.pdf)
16.  Legal / regulatory [Federal Highway Administration, "Two Low-Cost Safety Concepts for Two-Way STOP-Controlled, Rural Intersections on High-Speed Two-Lane, Two-Way Roadways" (FHWA-HRT-08-063, 2008).](https://highways.dot.gov/sites/fhwa.dot.gov/files/FHWA-HRT-08-063.pdf)

---

Source: https://commonwaysystem.org/patterns/corridors/character-transect/

# Character Transect

`CDR-CTR-03`

Recommended Corridor

Character Transect

A corridor that deliberately passes through multiple Movement/Place contexts by design, for example a route that functions as a Highway at one end and a Main Street at the other, and the practice of sequencing the transitions between those contexts rather than treating the corridor as one uniform typology end to end.

## Why this pattern exists

Most corridor-planning guidance treats a road as belonging to one classification for its full length, but real corridors regularly earn different classifications at different points because the land use around them changes. Without an explicit pattern for this, a corridor either gets forced into a single ill-fitting classification, or each segment gets designed in isolation with no coordination between them, producing a road that feels disjointed or unpredictable to travel along.[1][2]

## Key considerations

-   Identify every context change point along the corridor before designing any single segment, so transitions are planned rather than discovered
-   Each individual context change should be handled by its own applicable pattern (Density Step-Down/Step-Up, Rural-to-Town Gateway); this pattern is the umbrella that recognizes the corridor needs that sequencing at all
-   A corridor with more than two or three context changes may indicate the corridor itself needs re-evaluation, not just better transitions

## Related patterns

[Density Step-Down/Step-Up](https://commonwaysystem.org/patterns/corridors/density-step-down-step-up.md) (CDR-DSD-01), [Rural-to-Town Gateway](https://commonwaysystem.org/patterns/corridors/rural-to-town-gateway.md) (CDR-RTG-02) (component transitions this pattern sequences); Movement/Place diagnostic (Guide)

## References

1.  Precedent-based [Jones, P., Boujenko, N., and Marshall, S. (2007), _Link and Place: A Guide to Street Planning and Design_.](https://www.semanticscholar.org/paper/Link-&-Place-A-guide-to-street-planning-and-design-Jones-Boujenko/58fd8fdf31e97674c45fa030d3f3504c2cf3a79e)
2.  Precedent-based [Duany Plater-Zyberk & Company, the rural-to-urban Transect (SmartCode, 2003).](https://transect.org/transect.html)

---

Source: https://commonwaysystem.org/patterns/corridors/density-step-down-step-up/

# Density Step-Down / Step-Up

`CDR-DSD-01`

Recommended Corridor

Density Step-Down / Step-Up

The pattern governing how a road’s cross-section, speed, and character adjust where the surrounding density tier changes along its length.

## Why this pattern exists

A road built to Urban-tier standards does not automatically become wrong when the buildings around it thin out, but it does need to change; a road that ignores the transition sends the wrong signal to drivers about what kind of place they are in. Density tiers already carry design implications (speed, cross-section, access spacing) at the Segment/Intersection scale; this pattern is what governs the handoff between two tiers along one continuous route, so the transition itself gets designed rather than left as an arbitrary jurisdictional boundary or abrupt lane-width jump.[1]

## Key considerations

-   The transition point should be marked by a deliberate, legible design change, not just a sign
-   Direction of change matters: stepping down (Urban to Rural) generally means widening/simplifying; stepping up (Rural to Urban) means narrowing/adding modal infrastructure
-   Transition length should scale with the speed differential between the two tiers (a bigger speed drop needs a longer, more gradual transition zone)

## Related patterns

[Rural-to-Town Gateway](https://commonwaysystem.org/patterns/corridors/rural-to-town-gateway.md) (CDR-RTG-02) (a special case of stepping down at a jurisdictional/settlement edge specifically, rather than a general tier change); relevant Segment-scale patterns at each density tier

## References

1.  Evidence-based [Theeuwes, J. and Godthelp, H. (1995), "Self-explaining roads," and Theeuwes, J. (2021), "Self-explaining roads: What does visual cognition tell us about designing safer roads?", _Cognitive Research: Principles and Implications_ 6(1).](https://cognitiveresearchjournal.springeropen.com/articles/10.1186/s41235-021-00281-6)

---

Source: https://commonwaysystem.org/patterns/corridors/rail-with-trail-corridor/

# Rail-With-Trail Corridor

`CDR-RWT-04`

Situational / Discouraged Corridor

Rail-With-Trail Corridor

A road or trail corridor running alongside an active rail line for some or all of its length, addressing crossing frequency, setback distance, and shared right-of-way concerns created by the parallel rail operation.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [South Carolina's Freeway for Bikes](https://www.youtube.com/watch?v=NxGYs8kHxw4)

Road Guy Rob

The Swamp Rabbit Trail's rail-to-trail history and its treatment as genuine transportation infrastructure, plus the Travelers Rest Main Street road diet that reallocated car lanes to parking and bike parking.

## Why this pattern exists

Active rail lines impose constraints (crossing safety, minimum setbacks, noise, at-grade conflict points) that do not apply to a corridor without a rail neighbor, and rail-with-trail is a well-documented category in its own right because the failure modes (unsafe informal crossings, inadequate setback, conflict at grade crossings) are specific and recurring enough to need a dedicated pattern rather than general guidance.[1]

## Key considerations

-   Grade crossings should be minimized and consolidated rather than left informal or frequent
-   Setback distance should account for rail speed and frequency, not a single fixed number
-   Where a parallel trail exists, connections back to the street network should be deliberate, not incidental gaps in a fence line

## Related patterns

[Road-Adjacent Greenway](https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway.md) (CDR-RAG-05) (related but distinct: no active rail involved); relevant Crossing-family Element patterns

## References

1.  Evidence-based [U.S. Department of Transportation / Federal Highway Administration, "Rails-with-Trails: Best Practices and Lessons Learned," 2021.](https://www.fhwa.dot.gov/environment/recreational_trails/publications/)

---

Source: https://commonwaysystem.org/patterns/corridors/road-adjacent-greenway/

# Road-Adjacent Greenway

`CDR-RAG-05`

Recommended Corridor

Road-Adjacent Greenway

A corridor where a multi-use trail or linear park runs parallel to, but physically separated from, a road for some or all of its length, without an active rail line involved, addressing connection points and crossing treatment between the two.

## Why this pattern exists

A greenway running beside a road is a common and valuable configuration, but it creates a specific design problem distinct from a road with no parallel path: where and how people move between the two, and how crossings of the road itself are handled where the greenway needs to cross it. Left unaddressed, this produces either a greenway that is disconnected from the destinations along the road, or unsafe informal crossing points.[1]

## Key considerations

-   Connection points between the road-side facilities and the greenway should be planned at regular, predictable intervals
-   Any point where the greenway needs to cross the road should use an appropriate Crossing-family Element pattern, not an ad hoc treatment
-   Distinguish this from Multi-Use Trail/Greenway (a Segment-scale pattern describing the trail itself); this pattern is about the trail’s relationship to the parallel road, not the trail’s own design

## Related patterns

[Rail-With-Trail Corridor](https://commonwaysystem.org/patterns/corridors/rail-with-trail-corridor.md) (CDR-RWT-04) (related but distinct: rail involved); [Multi-Use Trail/Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) (COL-MUT-06) (Segment scale, the trail itself); relevant Crossing-family Element patterns

## References

1.  Legal / regulatory [AASHTO, _Guide for the Development of Bicycle Facilities_, 5th Edition, 2024.](https://store.transportation.org/item/collectiondetail/267)

---

Source: https://commonwaysystem.org/patterns/corridors/rural-to-town-gateway/

# Rural-to-Town Gateway

`CDR-RTG-02`

Recommended Corridor

Rural-to-Town Gateway

The specific transition zone where a highway or rural road enters a town, village, or settlement edge, marked by deliberate physical cues (narrowing, street trees, lighting change, surface texture) that signal to drivers that the road’s character and behavior expectations have changed.

## Why this pattern exists

Drivers respond to the road they perceive, not the posted number.[1] A speed limit sign alone at a town line does little if the road geometry on both sides looks identical; self-explaining roadway research supports pairing regulatory changes with a visible physical change at the same point. This pattern is the specific, high-stakes case of Density Step-Down/Step-Up that occurs at a settlement’s edge, where the mismatch between rural approach speeds and in-town conditions (pedestrians, driveways, cross traffic) has real safety consequences.[2]

## Key considerations

-   Gateway treatment should combine at least two sensory cues (visual narrowing plus a surface or planting change), not rely on signage alone
-   Placement should give drivers enough sight distance to register and react to the change before reaching the area it protects
-   Distinguish gateway treatment (a point-scale cue at the transition) from the broader step-down it belongs to (which may extend well past the gateway itself)

## Related patterns

[Density Step-Down/Step-Up](https://commonwaysystem.org/patterns/corridors/density-step-down-step-up.md) (CDR-DSD-01) (parent pattern; this is the settlement-edge special case); relevant Local/Collector Segment patterns on the town side

## References

1.  Evidence-based [Theeuwes, J. and Godthelp, H. (1995), "Self-explaining roads," and Theeuwes, J. (2021), "Self-explaining roads: What does visual cognition tell us about designing safer roads?", _Cognitive Research: Principles and Implications_ 6(1).](https://cognitiveresearchjournal.springeropen.com/articles/10.1186/s41235-021-00281-6)
2.  Evidence-based [Hallmark, S., Knickerbocker, S., and Hawkins, N., "Evaluation of Low Cost Traffic Calming for Rural Communities," Iowa DOT / FHWA-SA-16-079.](https://publications.iowa.gov/15269/)

---

Source: https://commonwaysystem.org/patterns/corridors/transit-alignment-corridor/

# Transit Alignment Corridor

`CDR-TAC-06`

Situational / Discouraged Corridor

Transit Alignment Corridor

A corridor built around a fixed transit line (light rail, streetcar, or dedicated BRT) running parallel to or within the roadway, addressing how the transit alignment shapes the corridor’s whole cross-section for its full length.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Can we make cities car free?](https://www.youtube.com/watch?v=g9-9CxCxrVE)

City Beautiful

Covers Oslo's parking-elimination approach, Barcelona's superblocks, and Houten's ring-road-with-car-free-interior model, each a different route to the same modal-filtering goal.

## Why this pattern exists

A fixed transit alignment is not just another lane, it constrains cross-section width, access point spacing, and intersection design continuously along the corridor in a way that a bus running in mixed traffic does not. Treating each segment along a transit alignment independently risks a cross-section that works at one point and fails at the next (a dedicated lane that disappears and reappears, station spacing that does not match access needs).[1]

## Key considerations

-   Cross-section allocation for the transit alignment should be consistent for the corridor’s length, not renegotiated segment by segment
-   Station/stop placement should be planned as a corridor-wide sequence, not sited independently at each segment
-   Where the alignment shares the roadway with general traffic, note the applicable Modal Hierarchy exception justification this requires

## Related patterns

Transit Corridor (Segment-scale character type, the segment-level treatment this corridor pattern coordinates); Modal Hierarchy mechanism (Guide)

## References

1.  Precedent-based [NACTO, _Transit Street Design Guide_, 2016.](https://nacto.org/publication/transit-street-design-guide/)

---

Source: https://commonwaysystem.org/patterns/elements/advisory-bike-lane/

# Advisory Bike Lane

`ELM-ABL-36`

Situational / Discouraged Element

Advisory Bike Lane

A dashed-line bike lane marked on each side of a narrow, typically two-way, roadway with no dedicated centerline, where vehicles are expected to cross into the bike lane space temporarily to pass oncoming traffic, yielding to any cyclist present.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

On a roadway too narrow to accommodate a centerline plus two conventional bike lanes, an advisory bike lane provides a visual cue and priority framework for cyclists while allowing the roadway’s limited width to be shared flexibly by low-volume, low-speed traffic. This pattern exists to document this specific narrow-roadway treatment and its dependence on low traffic conditions to function safely.

## Key considerations

-   Appropriate only on lower-volume, lower-speed roadways where the shared-yielding mechanism can reasonably be expected to work[1]
-   Driver unfamiliarity with the treatment in areas where it is uncommon may require supporting signage or education
-   Not appropriate as traffic volumes or speeds increase beyond the range this pattern depends on

## Related patterns

[Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) (ELM-CBL-34) (a related but structurally distinct facility type); relevant Local Segment patterns where roadway width is most constrained

## References

1.  Precedent-based [NACTO, _Urban Bikeway Design Guide_, 3rd Ed., "Advisory Bike Lanes." Width thresholds: roadway under 28 ft, bike lane 5-6.5 ft, central travel space 10-15 ft.](https://nacto.org/publication/urban-bikeway-design-guide/designing-bikeways-for-all-ages-and-abilities/bikeways-on-low-speed-low-volume-streets/advisory-bike-lanes/)

---

Source: https://commonwaysystem.org/patterns/elements/bench/

# Bench

`ELM-BCH-31`

Recommended Element

Bench

A fixed or semi-fixed seating element installed along a sidewalk, plaza, or transit stop, providing a place to rest independent of any specific transit or commercial function.

## Why this pattern exists

Seating in the public realm extends how long and how comfortably people, particularly older adults, people with mobility limitations, and caregivers, can use a street or public space; this pattern exists to document siting and design considerations distinct from the seating that might be built into a transit shelter or plaza specifically.

## Key considerations

-   Placement should account for shade, sightlines, and proximity to activity; an isolated bench in full sun with nothing to observe sees little use
-   Should not obstruct the required pedestrian clear path of travel on the sidewalk it is placed along[1]
-   Design elements to prevent unwanted extended use (frequently discussed as "hostile architecture") raise genuine equity concerns and should be weighed carefully against basic comfort and accessibility for all users

## Related patterns

[Trash/Recycling Receptacle](https://commonwaysystem.org/patterns/elements/trash-recycling-receptacle.md) (ELM-TRR-32) (common companion element); [Plaza/Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md) (FAC-PLZ-07), [Transit Shelter](https://commonwaysystem.org/patterns/facilities/transit-shelter.md) (FAC-TSH-01) (Facility patterns commonly furnished with benches)

## References

1.  Legal / regulatory [PROWAG, Section R212, "Street Furniture," and Section R404, "Clear Spaces." Clear-space requirement (2.5 ft x 4.0 ft minimum) at benches.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/bicycle-signal/

# Bicycle Signal

`ELM-BCS-16`

Situational / Discouraged Element

Bicycle Signal

A signal indication, typically a bicycle-shaped symbol in red, yellow, and green, giving cyclists their own dedicated phase or right-of-way instruction distinct from vehicle and pedestrian signals.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

Aligned

### [Why the Dutch Wait Less at Traffic Lights](https://www.youtube.com/watch?v=knbVWXzL4-4)

Not Just Bikes

Breaks down Dutch traffic-responsive signal timing, independent phasing, transit signal priority, and no-right-turn-on-red as a pedestrian/cyclist safety measure.

## Why this pattern exists

Where a bicycle facility crosses or interacts with an intersection in a way that a shared vehicle or pedestrian phase does not safely accommodate, a dedicated bicycle signal resolves the conflict explicitly rather than leaving cyclists to interpret a signal meant for another mode. This pattern exists to document where that dedicated treatment is warranted.[1]

## Key considerations

-   Most appropriate where a protected bike lane or cycle track meets an intersection with a conflicting turning movement that a shared phase cannot resolve safely
-   Should be clearly distinguishable from the vehicle signal to avoid driver confusion about which indication applies to them
-   Leading bicycle intervals (giving cyclists a head start before conflicting vehicle movements) are a common and effective use of this pattern[2]

## Related patterns

[Traffic Signal](https://commonwaysystem.org/patterns/elements/traffic-signal.md) (ELM-TFS-14) (the vehicle control this pattern separates from); [Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37) (the facility type most commonly paired with this treatment)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 9D, "Signals for Bicycle Facilities." The current binding standard; bicycle signals existed only as FHWA Interim Approval IA-16 (2013) until the 11th edition made them standard.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Precedent-based [NACTO Urban Bikeway Design Guide, 3rd ed. (2025), "Bike Signal Design." Leading bicycle interval and actuation-versus-recall design guidance.](https://nacto.org/publication/urban-bikeway-design-guide/designing-safe-intersections/signal-phasing-and-timing-strategies/bike-signal-design/)

---

Source: https://commonwaysystem.org/patterns/elements/bike-box/

# Bike Box

`ELM-BKB-42`

Recommended Element

Bike Box

A designated waiting area marked at the head of a signalized intersection, positioned ahead of the vehicle stop line, allowing cyclists to position themselves in front of queued vehicles during a red signal for improved visibility and to enable a safer left turn or through movement.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

At a signalized intersection, a cyclist stopped alongside or behind queued vehicles has reduced visibility to drivers and a harder time making a turning movement across traffic once the signal changes; a bike box gives cyclists a visible head-start position ahead of the queue, addressing this specific intersection conflict. This pattern exists to document where and how that positioning treatment is applied.[1]

## Key considerations

-   Requires a "no turn on red" restriction for vehicles at that approach, since the box’s function depends on vehicles not entering the space during the cyclist’s queuing period
-   Most effective when paired with a bike lane leading into the box, so cyclists have a legible, protected path to reach it
-   Signal timing and driver awareness both affect real-world compliance; signage and clear markings help reinforce expected behavior

## Related patterns

[Green Pavement/Conflict Marking](https://commonwaysystem.org/patterns/elements/green-pavement-conflict-marking.md) (ELM-GPM-38) (often used to highlight the box itself); [Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37), [Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) (ELM-CBL-34) (the facilities that typically lead into a bike box)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Part 9. Intersection bicycle boxes formalized as standard, previously FHWA Interim Approval IA-18.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/bike-parking-rack/

# Bike Parking / Rack

`ELM-BPR-40`

Recommended Element

Bike Parking / Rack

A fixed rack or set of racks, most commonly an inverted-U or similar design, providing a place to lock a bicycle, typically installed on a sidewalk or in a dedicated on-street corral.

## Why this pattern exists

Reliable, well-designed bike parking is a necessary complement to any bike facility investment; without a secure place to park at the destination end of a trip, the quality of the route traveled matters less. This pattern exists to document rack design and placement considerations at the individual fixture level, distinct from the larger corral or secure-parking facility patterns it may be part of.[1]

## Key considerations

-   Rack design should support the bike frame at two points, an inverted-U or similar design, rather than a wheel-bender style that provides inadequate support and can damage wheels
-   Placement should avoid obstructing the sidewalk’s required pedestrian clear path of travel
-   Should be sited near actual destinations and entrances, not tucked away in low-visibility, low-security locations

## Related patterns

[Bike Parking Corral](https://commonwaysystem.org/patterns/facilities/bike-parking-corral.md) (FAC-BPC-08), [Secure Bike Parking/Bike Station](https://commonwaysystem.org/patterns/facilities/secure-bike-parking-bike-station.md) (FAC-SBP-10) (Facility-scale patterns this pattern is a component of)

## References

1.  Precedent-based [Association of Pedestrian and Bicycle Professionals (APBP), _Bicycle Parking Guidelines_, 2nd Ed. (2010). Inverted-U rack design standard, two-point frame support, placement near destinations.](https://www.apbp.org/Publications)

---

Source: https://commonwaysystem.org/patterns/elements/bioswale/

# Bioswale

`ELM-BIO-19`

Recommended Element

Bioswale

A vegetated, shallow channel designed to collect, convey, and filter stormwater runoff from an adjacent roadway or hard surface, using soil and plant material to slow flow and remove pollutants before water reaches a storm drain or waterway.

## Why this pattern exists

Conventional curb-and-gutter drainage moves runoff, and whatever pollutants it carries, directly into the storm system with no filtration; a bioswale intercepts that runoff at the source, reducing both the volume reaching the storm system and the pollutant load it carries. This pattern exists to document the design considerations that make a swale function as intended rather than as an underperforming ditch.[1]

## Key considerations

-   Sizing must be based on the contributing drainage area and expected runoff volume; an undersized swale simply overflows during real storm events[2]
-   Plant selection should tolerate both periodic inundation and dry periods, since swale conditions vary significantly between storm events
-   Inlet design (curb cuts or similar) should prevent sediment and debris from clogging the swale’s inlet point over time

## Related patterns

[Flow-Through Planter](https://commonwaysystem.org/patterns/elements/flow-through-planter.md) (ELM-FTP-20), [Pervious Strip](https://commonwaysystem.org/patterns/elements/pervious-strip.md) (ELM-PVS-21), [Pervious Pavement](https://commonwaysystem.org/patterns/elements/pervious-pavement.md) (ELM-PVP-22) (related green stormwater treatments); [Curb Cut/Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md) (ELM-CCA-04) (relevant where a curb cut serves as the swale’s inlet)

## References

1.  Legal / regulatory [U.S. Environmental Protection Agency, _Green Streets_ / _Green Street Design Manual_, 2021.](https://www.epa.gov/sites/default/files/2021-04/documents/green_streets_design_manual_feb_2021_web_res_small_508.pdf)
2.  Precedent-based [National Association of City Transportation Officials, _Urban Street Stormwater Guide_.](https://nacto.org/publication/urban-street-design-guide/street-design-elements/stormwater-management/bioswales/)

_"Legal / regulatory" here refers to the EPA guidance that municipal NPDES stormwater permits are legally built around, not a single mandatory design spec like MUTCD or PROWAG._

---

Source: https://commonwaysystem.org/patterns/elements/bollard/

# Bollard

`ELM-BOL-25`

Recommended Element

Bollard

A short, sturdy vertical post installed to block or control vehicle access to a specific area, protect pedestrians or infrastructure from vehicle intrusion, or delineate a boundary, ranging from fixed to removable or retractable designs.

## Why this pattern exists

Where a full barrier or curb is not warranted but vehicle access still needs to be controlled or blocked, a plaza edge, a bike facility entrance, a sidewalk protected from a nearby travel lane, bollards provide a lighter-weight, often more flexible solution. This pattern exists to document that distinct, smaller-scale protective and access-control role.

## Key considerations

-   Spacing must allow pedestrian, wheelchair, and stroller passage while still restricting vehicle entry[1]
-   Removable or retractable designs should be specified where emergency or service vehicle access is occasionally needed; where vehicle exclusion is the design driver, crash-rated bollards are spaced and tested to a recognized standard[2]
-   Visibility (reflective marking, contrasting color) matters for both drivers and pedestrians; an unmarked bollard is itself a collision hazard

## Related patterns

[Traffic Barrier](https://commonwaysystem.org/patterns/elements/traffic-barrier.md) (ELM-TRB-23), [Crash Cushion/End Terminal](https://commonwaysystem.org/patterns/elements/crash-cushion-end-terminal.md) (ELM-CCT-24) (related but functionally distinct safety hardware); [Plaza/Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md) (FAC-PLZ-07), [Bike Parking Corral](https://commonwaysystem.org/patterns/facilities/bike-parking-corral.md) (FAC-BPC-08) (Facility patterns commonly protected by bollards); [Modal Filter / Point Closure](https://commonwaysystem.org/patterns/elements/modal-filter-point-closure.md) (ELM-MFP-44) (the pattern this hardware is most commonly used to build)

## References

1.  Legal / regulatory [U.S. Access Board, Public Right-of-Way Accessibility Guidelines (PROWAG), 2023 final rule (adopted into DOT's ADA regulations effective January 17, 2025); 2010 ADA Standards for Accessible Design, Section 403.5.](https://www.access-board.gov/prowag/technical.html)
2.  Legal / regulatory [ASTM International, ASTM F2656/F2656M, standard test method for vehicle crash testing of perimeter barriers.](https://www.astm.org/Standards/F2656.htm)

---

Source: https://commonwaysystem.org/patterns/elements/buffered-bike-lane/

# Buffered Bike Lane

`ELM-BBL-35`

Recommended Element

Buffered Bike Lane

A striped bike lane with an additional painted buffer zone, typically hatched or cross-hatched markings, separating it from the adjacent vehicle travel lane or parking lane by more distance than a conventional bike lane alone provides.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

Adding painted buffer width increases the physical and perceived separation between cyclists and vehicle traffic without the cost or space demand of a physical barrier, addressing some of the comfort gap between a conventional bike lane and a fully protected facility. This pattern exists to document that intermediate option.[1]

## Key considerations

-   Buffer should be placed on the side of greater conflict risk, typically between the bike lane and the vehicle travel lane, or on both sides where a parking lane is also present[2]
-   Still relies on driver compliance with paint markings alone, and may not be sufficient comfort for all-ages-and-abilities ridership on higher-speed corridors
-   A reasonable default upgrade from a conventional bike lane where a full protected facility is not currently feasible

## Related patterns

[Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) (ELM-CBL-34) (the baseline this pattern improves on); [Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37) (the stronger-separation alternative)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Section 9C.02, "Buffered Bike Lane."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Precedent-based [NACTO, _Urban Bikeway Design Guide_, 3rd Ed. Buffer placement and sizing guidance.](https://nacto.org/publication/urban-bikeway-design-guide/)

---

Source: https://commonwaysystem.org/patterns/elements/conventional-bike-lane/

# Conventional Bike Lane

`ELM-CBL-34`

Situational / Discouraged Element

Conventional Bike Lane

A striped, dedicated on-street lane for bicycle travel, separated from the adjacent vehicle travel lane by paint markings alone, with no physical buffer or barrier.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

A conventional bike lane provides a clearly delineated, expected space for cyclists that a shared travel lane does not, improving predictability for both cyclists and drivers at a lower cost and space requirement than a buffered or protected facility. This pattern exists to document where this baseline level of separation is adequate versus where a stronger treatment is warranted.[1]

## Key considerations

-   Adequacy depends heavily on adjacent vehicle speed and volume; paint-only separation becomes less appropriate as speed and volume increase[2]
-   Lane width should accommodate safe passing distance from parked cars where relevant, to avoid the door-zone conflict
-   Should be considered a baseline treatment rather than the ceiling; upgrading to a buffered or protected facility should be the default aspiration on higher-stress corridors

## Related patterns

[Buffered Bike Lane](https://commonwaysystem.org/patterns/elements/buffered-bike-lane.md) (ELM-BBL-35), [Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37) (stronger-separation alternatives); [Sharrow](https://commonwaysystem.org/patterns/elements/sharrow.md) (ELM-SHR-39) (a lesser treatment for contexts where even this pattern is not feasible)

## References

1.  Legal / regulatory [AASHTO, _Guide for the Development of Bicycle Facilities_. Adopted by most state DOTs as the foundational lane-width and design standard.](https://store.transportation.org/item/publicationdetail/5371)
2.  Precedent-based [NACTO, _Urban Bikeway Design Guide_, 3rd Ed. (2025), "Design User, Design Speed, and Design Year." Protected lanes become the only all-ages-and-abilities-permissible option above 25 mph or 6,000 vehicles per day.](https://nacto.org/latest/urban-bikeway-design-guide-design-user-design-speed-and-design-year/)

---

Source: https://commonwaysystem.org/patterns/elements/crash-cushion-end-terminal/

# Crash Cushion / End Terminal

`ELM-CCT-24`

Recommended Element

Crash Cushion / End Terminal

An energy-absorbing device installed at the exposed end of a traffic barrier or in front of a fixed hazard, designed to decelerate an impacting vehicle gradually rather than presenting a rigid, unshielded end or face.

## Why this pattern exists

An unshielded barrier end or exposed fixed object can spear or abruptly stop an impacting vehicle, causing more severe injury than a properly designed energy-absorbing terminal would; this pattern exists specifically to address that exposure, since it is a distinct failure mode from the barrier’s general run.[1]

## Key considerations

-   Required wherever a traffic barrier’s end is exposed to head-on or angled impact from the direction of travel
-   Device selection must match the expected impact speed and angle for the specific location, not be applied as a generic default
-   Regular inspection and maintenance is necessary, since a damaged or improperly reset device may not perform as designed in a subsequent impact[2]

## Related patterns

[Traffic Barrier](https://commonwaysystem.org/patterns/elements/traffic-barrier.md) (ELM-TRB-23) (the element this pattern terminates); [Bollard](https://commonwaysystem.org/patterns/elements/bollard.md) (ELM-BOL-25) (a related but distinct safety hardware type)

## References

1.  Legal / regulatory [American Association of State Highway and Transportation Officials, _Manual for Assessing Safety Hardware_ (MASH), 2016.](https://store.transportation.org/item/publicationdetail/2707)
2.  Legal / regulatory [Federal Highway Administration / American Association of State Highway and Transportation Officials, Joint Implementation Agreement guidance on MASH transition deadlines.](https://rosap.ntl.bts.gov/view/dot/78583)

---

Source: https://commonwaysystem.org/patterns/elements/crosswalk/

# Crosswalk

`ELM-CRW-08`

Recommended Element

Crosswalk

A marked pedestrian crossing point, located at an intersection or midblock, delineated with pavement markings ranging from a simple two-line crosswalk to high-visibility continental or ladder striping.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

A crosswalk establishes a legally and visually defined place for pedestrians to cross, giving both pedestrians and drivers a shared, predictable expectation about where crossing will occur. This pattern exists to document marking types and the considerations that determine where and how a crossing should be marked, distinct from the signals or islands that may accompany it.[2]

## Key considerations

-   Marking visibility (continental/ladder striping vs. simple parallel lines) should scale with vehicle speed and pedestrian volume at the location
-   A marked crosswalk alone does not guarantee driver yielding; higher-speed or multi-lane crossings typically need a supporting treatment (signal, beacon, refuge island)[1]
-   Midblock crossings need particular care in sight-distance and driver expectation, since they occur outside the predictable intersection pattern

## Related patterns

[Pedestrian Safety Island/Refuge](https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge.md) (ELM-PSI-09), [Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md) (ELM-DWS-10), [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03) (companion elements at any crossing); [RRFB](https://commonwaysystem.org/patterns/elements/rrfb.md) (ELM-RRF-17), [Pedestrian Hybrid Beacon](https://commonwaysystem.org/patterns/elements/pedestrian-hybrid-beacon.md) (ELM-PHB-18) (supporting treatments for higher-speed or higher-volume crossings)

## References

1.  Evidence-based [Zegeer, C. et al., "Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations," FHWA-RD-01-075 (2002). A study of 1,000 marked and 1,000 unmarked sites, basis for the finding that markings alone aren't sufficient at higher speed, volume, or multi-lane crossings.](https://rosap.ntl.bts.gov/view/dot/15480/dot_15480_DS1.pdf)
2.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Part 3 (Markings). Governs marking types, including transverse lines and continental/ladder striping.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron/

# Curb Cut / Driveway Apron

`ELM-CCA-04`

Situational / Discouraged Element

Curb Cut / Driveway Apron

The break in a curb allowing vehicle access from the roadway to an adjacent driveway, typically formed with a sloped apron transitioning between street grade and driveway grade.

## Why this pattern exists

Every driveway crossing a sidewalk creates a conflict point between turning vehicles and pedestrians on that sidewalk, and the apron’s slope and width directly affect both vehicle turning ease and the sidewalk’s cross-slope and continuity for pedestrians passing through.[2] This pattern exists to document that conflict point’s design considerations distinct from a controlled crossing like a crosswalk.

## Key considerations

-   Sidewalk cross-slope through the apron should stay within accessible limits; the sidewalk should not tilt sharply to accommodate the driveway grade change[1]
-   Apron width should be sized to the driveway’s actual vehicle use; an oversized apron widens the pedestrian conflict zone without benefit
-   Frequency of curb cuts along a block face should be minimized where possible; each one is a point of reduced pedestrian priority and potential conflict

## Forward entry, no public backing

-   The design vehicle should enter and exit a driveway or loading apron forward, never backing onto a public street or sidewalk to leave the site.[3][4]
-   Where a back-out loading berth is used instead of forward-in access, the berth must be deep enough that no part of the vehicle protrudes over the property line during the maneuver. This is a geometry requirement, not a signage or policy fix.[4]
-   This rule is independently adopted in at least three U.S. jurisdictions' building or zoning codes (Houston, Knightdale NC, Bakersfield CA), so treat it as converged best practice rather than one city's idiosyncratic rule.[4][5][6]
-   Confirm the anticipated truck mix through a turning-movement-path evaluation before sizing the apron, rather than assuming the largest conceivable vehicle by default.[3]

## Related patterns

[Curb](https://commonwaysystem.org/patterns/elements/curb.md) (ELM-CRB-01), [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03) (related curb modifications); relevant sidewalk continuity guidance; [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) (COL-IND-03) (a freight-priority street whose property-access answer depends on the forward-entry requirement above)

## References

1.  Legal / regulatory [PROWAG (U.S. Access Board, 2023 final rule; adopted into DOT's ADA regulations effective January 17, 2025), Section R304. Cross-slope-through-apron limits.](https://www.access-board.gov/prowag/technical.html)
2.  Legal / regulatory [PROWAG (U.S. Access Board, 2023 final rule; adopted into DOT's ADA regulations effective January 17, 2025), Section R302, "Pedestrian Access Routes." Sidewalk continuity through a driveway crossing.](https://www.access-board.gov/prowag/technical.html)
3.  Legal / regulatory [Los Angeles Department of Transportation, _Driveway Design Guide_ (2024) (on-site reservoir and maneuvering space; confirm truck mix by turning-movement path evaluation).](https://ladot.lacity.gov/sites/default/files/2026-04/driveway-design-guide-march-2024.pdf)
4.  Legal / regulatory [City of Houston, _Houston Building Code_ (2021), Chapter 31, § 3116.4.6 "Loading Berth" (§ 3112 in the 2015 edition).](https://up.codes/viewer/houston/ibc-2021/chapter/31/special-construction)
5.  Legal / regulatory [Town of Knightdale, NC, _Unified Development Ordinance_, Chapter 7, "Development Standards" (loading areas may not rely on backing movements into public rights-of-way).](https://www.knightdalenc.gov/sites/default/files/uploads/developmentservices/udo/07-development-standards-052226.pdf)
6.  Legal / regulatory [City of Bakersfield, _Zoning Code_, Chapter 32 (vehicles may not back onto any street or thoroughfare to leave a site, binding once a street is classified arterial or collector).](https://www.zoneomics.com/code/bakersfield-CA/chapter_32)

---

Source: https://commonwaysystem.org/patterns/elements/curb-extension/

# Curb Extension

`ELM-CBE-02`

Recommended Element

Curb Extension

A widened curb that narrows the roadway at a crossing or parking zone, taking gateway, pinchpoint, chicane, bus bulb, or conventional form depending on its purpose and location.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

Aligned

### [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

## Why this pattern exists

Narrowing the effective roadway width at a specific point shortens pedestrian crossing distance, slows turning and through vehicles, and can reclaim space for other uses (a bus stop, plantings, a parklet), addressing several distinct problems (crossing safety, traffic calming, space reclamation) with one flexible physical treatment.[1]

## Key considerations

-   Form should match purpose: a bus bulb needs a different length and clearance than a corner pinchpoint or a mid-block chicane[2]
-   Drainage design at the extension point needs attention, since it interrupts the normal curb and gutter line
-   Sightlines for both drivers and pedestrians should be checked at the extension, especially near a crossing, since the extension changes sightline geometry

## Related patterns

[Curb](https://commonwaysystem.org/patterns/elements/curb.md) (ELM-CRB-01), [Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08) (typical pairing at a crossing); [Plaza/Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md) (FAC-PLZ-07) (Facility pattern this often anchors); [Transit Boarding Island](https://commonwaysystem.org/patterns/elements/transit-boarding-island.md) (ELM-TBI-41) (a related but distinct treatment for transit stops); [Modal Filter / Point Closure](https://commonwaysystem.org/patterns/elements/modal-filter-point-closure.md) (ELM-MFP-44) (an alternative geometry for narrowing or partially closing a street), [Median Island](https://commonwaysystem.org/patterns/elements/median-island.md) (ELM-MDI-45) (a center-of-roadway rather than lateral narrowing approach)

## References

1.  Precedent-based [NACTO Urban Street Design Guide, "Curb Extensions." Crossing-distance reduction and sizing guidance (length at least the crosswalk width, 1-2 ft narrower than the parking lane).](https://nacto.org/publication/urban-street-design-guide/street-design-elements/curb-extensions/)
2.  Evidence-based [Federal Highway Administration, "Install Curb Extensions at the Crosswalk" (Uncontrolled Pedestrian Crossing Treatment sheet). Identifies crash history, vehicle/pedestrian conflict, and speeding as the conditions this treatment addresses.](https://toolkits.ite.org/uiig/treatments/64%20Curb%20Extensions.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/curb-ramp/

# Curb Ramp

`ELM-CRP-03`

Recommended Element

Curb Ramp

A sloped transition cut into a curb, providing an accessible path between the sidewalk and street surface for wheelchair users, strollers, and anyone unable to step up or down a vertical curb face.

## Why this pattern exists

A curb that provides no ramped transition is an absolute barrier to wheelchair users and others who cannot step over a vertical curb face; this pattern exists because accessible curb transitions are both a baseline civil rights requirement and a foundational usability feature at every crossing point on the network.

## Key considerations

-   Slope must stay within accessible design limits; a ramp too steep defeats its own purpose[1]
-   Landing space at the top and bottom of the ramp must be clear of obstructions and large enough for a wheelchair to maneuver
-   Detectable Warning Surface should be present at every curb ramp reaching a street, not treated as a separate, optional add-on

## Related patterns

[Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md) (ELM-DWS-10) (required companion element); [Curb](https://commonwaysystem.org/patterns/elements/curb.md) (ELM-CRB-01), [Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08) (the elements this pattern connects)

## References

1.  Legal / regulatory [PROWAG (U.S. Access Board, 2023 final rule; adopted into DOT's ADA regulations effective January 17, 2025), Section R304, "Curb Ramps and Blended Transitions." Sets a 1:12 maximum running slope, a 1:48 maximum cross slope, and landing dimension and clear-area requirements.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/curb/

# Curb

`ELM-CRB-01`

Recommended Element

Curb

The raised edge separating the roadway from the sidewalk or shoulder, marking the physical boundary between space allocated to vehicles and space allocated to pedestrians or the roadway edge condition.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

The curb is the single most foundational physical element separating modes on a street; its height, material, and continuity determine drainage behavior, accessibility, and how legible the vehicle/pedestrian boundary reads to everyone using the street. Nearly every other Element pattern in this family (extensions, ramps, cuts) is a modification or interruption of this base condition, so it needs its own definition first.[1]

## Key considerations

-   Height should be sufficient to discourage casual vehicle encroachment onto the sidewalk while not creating a tripping hazard where pedestrians cross it
-   Material and profile should be durable against snowplow damage in climates where that applies
-   Continuity matters: an interrupted or inconsistent curb line undermines drainage design and the clarity of the mode boundary

## Related patterns

[Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md) (ELM-CBE-02), [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03), [Curb Cut/Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md) (ELM-CCA-04) (all modifications of this base element); [Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08) (a common interruption point)

## References

1.  Precedent-based [Federal Highway Administration, _Designing Sidewalks and Trails for Access_, Chapter 4, Section 4.4.11 ("Roadway Design"). Curb height and material guidance by roadway functional class (Table 4-1).](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/sidewalks/chap4b.cfm)

---

Source: https://commonwaysystem.org/patterns/elements/detectable-warning-surface/

# Detectable Warning Surface

`ELM-DWS-10`

Recommended Element

Detectable Warning Surface

A textured ground surface, typically a grid of truncated domes, installed at the edge of a curb ramp or platform to alert pedestrians with vision impairments to an approaching street edge or crossing point through underfoot texture.

## Why this pattern exists

A curb ramp removes the vertical cue (a step down) that traditionally signaled a street edge to a pedestrian using a cane or with low vision; the detectable warning surface restores that cue through texture instead of height. This pattern exists because it is a baseline accessibility requirement everywhere a curb ramp meets a street, not an optional accessory.

## Key considerations

-   Should be present at every curb ramp and transit platform edge reaching a vehicular way, without exception
-   Color contrast with the surrounding surface improves detectability for pedestrians with low vision, not just those who are fully blind[1]
-   Material must remain detectable underfoot over time; a worn-down or damaged surface fails its purpose even if visually still present

## Related patterns

[Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03) (required companion element); [Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md) (FAC-TPL-02) (Facility pattern where this also applies at platform edges)

## References

1.  Legal / regulatory [PROWAG (U.S. Access Board, 2023 final rule; adopted into DOT's ADA regulations effective January 17, 2025), Section R305, "Detectable Warning Surfaces." Dome size, spacing, visual contrast, and placement requirements.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/drinking-fountain/

# Drinking Fountain

`ELM-DRF-33`

Situational / Discouraged Element

Drinking Fountain

A fixed water fountain installed in the public right-of-way or an adjacent public space, providing free public access to drinking water, sometimes paired with a lower-height accessible basin or a pet-watering feature.

## Why this pattern exists

Public drinking water access supports comfort and public health, particularly in hot climates or along longer pedestrian corridors like trails and greenways, and its absence disproportionately affects people without ready access to bottled water. This pattern exists to document siting and accessibility considerations for this amenity.

## Key considerations

-   Accessible height and reach range must be provided, not just a single standard-height basin[1]
-   Freeze-proof design or seasonal shutoff is necessary in climates with winter freezing
-   Best sited near high pedestrian dwell locations (plazas, trailheads, transit hubs), rather than distributed evenly regardless of use pattern

## Related patterns

[Plaza/Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md) (FAC-PLZ-07), [Multi-Use Trail/Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) (COL-MUT-06) (contexts where this pattern is most relevant); [Bench](https://commonwaysystem.org/patterns/elements/bench.md) (ELM-BCH-31) (common companion amenity)

## References

1.  Legal / regulatory [PROWAG, Section R212, referencing ADA/ABA Accessibility Guidelines Sections 602.1-602.6 (36 CFR Part 1191, Appendix D). Binding accessible-height and knee-clearance requirements.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/flow-through-planter/

# Flow-Through Planter

`ELM-FTP-20`

Situational / Discouraged Element

Flow-Through Planter

A contained, structured planting box with an engineered soil and drainage layer that captures and filters stormwater runoff before releasing it through an underdrain, used where space or soil conditions do not allow for an open bioswale.

## Why this pattern exists

Many streetscape contexts, a narrow sidewalk zone, a site with contaminated or compacted native soil, cannot accommodate an open bioswale’s footprint or infiltration requirements; a flow-through planter delivers similar filtration benefits within a contained structure suited to tighter or more constrained sites. This pattern exists to document that structural alternative.[2]

## Key considerations

-   Underdrain design and outlet connection need to be planned as part of the site’s overall drainage system, not treated as self-contained
-   Maintenance access (removing debris, replacing plants, checking the underdrain) should be planned for at installation, since a neglected planter loses function quickly
-   Best suited to tight or constrained streetscape zones where an open bioswale’s footprint is not available[1]

## Related patterns

[Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md) (ELM-BIO-19) (the open-channel alternative this pattern substitutes for in constrained sites); [Tree Pit/Tree Trench](https://commonwaysystem.org/patterns/elements/tree-pit-tree-trench.md) (ELM-TPT-29) (a related structured planting element)

## References

1.  Precedent-based [National Association of City Transportation Officials, _Urban Street Stormwater Guide_, "Flow-Through Planters."](https://nacto.org/publication/urban-street-design-guide/street-design-elements/stormwater-management/flow-through-planters/)
2.  Legal / regulatory [U.S. Environmental Protection Agency, National Menu of Best Management Practices, "Site Design and Planning Strategies."](https://www.epa.gov/system/files/documents/2021-11/bmp-site-design-and-planning-strategies.pdf)

_"Legal / regulatory" here refers to the EPA guidance that municipal NPDES stormwater permits are legally built around, not a single mandatory design spec like MUTCD or PROWAG._

---

Source: https://commonwaysystem.org/patterns/elements/green-pavement-conflict-marking/

# Green Pavement / Conflict Marking

`ELM-GPM-38`

Recommended Element

Green Pavement / Conflict Marking

A colored pavement treatment, typically green, applied at a bike facility’s conflict point with a driveway, turn lane, or intersection, to increase driver awareness that a cyclist may be present or crossing through that space.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

At points where a bike facility’s path crosses or intersects with vehicle movement, a merging lane, a turn pocket, an intersection approach, the normal continuity of the bike facility’s visual cue breaks down; colored pavement restores visibility of the bike route through that conflict zone specifically. This pattern exists to document where and how this treatment should be applied.[1]

## Key considerations

-   Should be reserved for genuine conflict points rather than applied continuously along a facility; overuse dilutes its attention-getting value
-   Color and material should meet reflectivity and durability standards so the treatment remains visible and functional over time and weather exposure
-   Most effective when paired with clear lane markings and signage rather than deployed as a standalone fix for an unclear conflict area

## Related patterns

[Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37), [Buffered Bike Lane](https://commonwaysystem.org/patterns/elements/buffered-bike-lane.md) (ELM-BBL-35), [Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) (ELM-CBL-34) (the facilities this pattern supports at conflict points); [Bike Box](https://commonwaysystem.org/patterns/elements/bike-box.md) (ELM-BKB-42) (a related conflict-point treatment at intersections)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Part 9. Green colored pavement formalized as standard, previously FHWA Interim Approval IA-14.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/guide-sign/

# Guide Sign

`ELM-GDS-13`

Recommended Element

Guide Sign

A sign providing wayfinding or informational content, such as destination names, distances, route numbers, or facility identification, helping travelers navigate rather than regulating or warning them.

## Why this pattern exists

Travelers, whether driving, cycling, or walking, need to know where they are and how to reach their destination; guide signage is the network’s navigational layer, distinct from the rule-setting and hazard-alerting functions of the other two sign categories. This pattern exists to document its own legibility and placement considerations.[1][2]

## Key considerations

-   Message content should be concise and prioritized; a sign trying to convey too much information at once becomes unreadable at travel speed
-   Consistency in symbol and terminology use across the network helps build traveler trust and reduces confusion at decision points
-   Placement should occur far enough ahead of a decision point (an intersection, an exit) to allow safe lane positioning or route choice

## Related patterns

[Regulatory Sign](https://commonwaysystem.org/patterns/elements/regulatory-sign.md) (ELM-RGS-11), [Warning Sign](https://commonwaysystem.org/patterns/elements/warning-sign.md) (ELM-WNS-12) (related sign categories); wayfinding provisions in relevant Guide-level content

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Section 2A.03, "Classification of Signs."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 2D, "Guide Signs — Conventional Roads."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/landscaped-buffer-strip/

# Landscaped Buffer Strip

`ELM-LBS-30`

Recommended Element

Landscaped Buffer Strip

A planted zone running between the roadway and the sidewalk, providing separation, stormwater treatment opportunity, and space for street trees and other plantings, distinct from a hardscaped or paved separation.

## Why this pattern exists

A planted buffer between moving traffic and pedestrians provides psychological and physical separation beyond what a curb alone offers, while also creating usable space for trees, snow storage, and stormwater treatment that a fully paved streetscape does not accommodate. This pattern exists to document the width and design considerations that make this zone function well.[1]

## Key considerations

-   Width should be sufficient to support meaningful tree growth and planting; a strip too narrow limits both plant health and its buffering effect
-   Should account for a maintenance plan, since an unmaintained buffer can become an eyesore or a weed-choked liability rather than an asset
-   In snow climates, the strip may also serve as snow storage space, which should be planned for in plant and material selection

## Related patterns

[Street Tree](https://commonwaysystem.org/patterns/elements/street-tree.md) (ELM-STT-28), [Tree Pit/Tree Trench](https://commonwaysystem.org/patterns/elements/tree-pit-tree-trench.md) (ELM-TPT-29) (elements typically located within this zone); [Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md) (ELM-BIO-19), [Pervious Strip](https://commonwaysystem.org/patterns/elements/pervious-strip.md) (ELM-PVS-21) (stormwater treatments that may occupy this zone instead)

## References

1.  Precedent-based [NACTO Urban Street Design Guide, "Sidewalk Zones" (furnishing zone guidance). Width standards and the buffer's function separating pedestrians from traffic.](https://nacto.org/publication/urban-street-design-guide/street-design-elements/sidewalks/sidewalk-zones/)

---

Source: https://commonwaysystem.org/patterns/elements/median-island/

# Median Island

`ELM-MDI-45`

Recommended Element

Median Island

A raised or landscaped island placed along the center of a roadway to narrow the effective travel width and separate opposing traffic, without a pedestrian crossing function.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

## Why this pattern exists

Narrowing a roadway's visual and physical width slows traffic and reduces opposing-direction conflicts, independent of whether the median also serves a crossing purpose. Pedestrian Safety Island / Refuge documents the crossing-assistance case; this pattern documents the calming and access-management case, where a median exists to manage the corridor itself rather than to assist a specific crossing movement.[1][2]

## Key considerations

-   Access management benefits scale with how consistently the median precludes unsafe mid-block left turns and crossing movements along the corridor, not just at one isolated point
-   Landscaping and drainage design should account for maintenance access and sightlines, since a raised median interrupts both the roadway's drainage path and driver sightlines around it
-   Width should be sufficient to read visually as a real barrier rather than a painted gesture, while remaining consistent with the corridor's overall cross-section
-   Where a crossing is also needed nearby, coordinate with Pedestrian Safety Island / Refuge rather than assuming this pattern alone provides safe pedestrian passage

## Related patterns

[Pedestrian Safety Island / Refuge](https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge.md) (ELM-PSI-09) (a related but distinct treatment built specifically for two-stage pedestrian crossing), [Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md) (ELM-CBE-02) (a lateral narrowing approach rather than a center-of-roadway one), [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (ART-BLV-02) (the Arterial-scale corridor pattern this most often appears within)

## References

1.  Legal / regulatory [Federal Highway Administration, "Proven Safety Countermeasures: Corridor Access Management." Raised medians that preclude across-roadway movements as an access-management treatment.](https://highways.dot.gov/safety/proven-safety-countermeasures/corridor-access-management)
2.  Evidence-based [Gluck, J., Levinson, H.S., and Stover, V., _Impacts of Access Management Techniques_, NCHRP Report 420, Transportation Research Board, 1999.](http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_420.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/modal-filter-point-closure/

# Modal Filter / Point Closure

`ELM-MFP-44`

Recommended Element

Modal Filter / Point Closure

A physical closure placed mid-block or at an intersection leg that blocks through motor vehicle travel while preserving passage for pedestrians and bicyclists, using bollards, planters, partial curb extensions, or a similar barrier.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

## Why this pattern exists

A street network's permeability, how easily a route can be used for through travel, isn't the same for every mode. A modal filter exploits that difference on purpose: it removes a street's usefulness as a through route for motor vehicles while leaving it fully useful, often more pleasant, for anyone walking or biking.[1][2] This is the physical mechanism underneath both the [Modal filtering / Low Traffic Neighborhood retrofit](https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit.md) and [Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md) Retrofit Strategies at the Network scale; those Retrofit Strategies describe the area-wide pattern of closures, this pattern documents the closure itself.

## Key considerations

-   Passage width for pedestrians and bicyclists must be genuinely usable, not a minimum legal gap, and should account for cargo bikes, adaptive cycles, and mobility devices
-   Emergency vehicle access needs an explicit plan: a fixed closure without a removable, retractable, or otherwise overridable component can create a real response-time problem, not just a design inconvenience
-   Signage should state plainly that the street is closed to through motor traffic while remaining open to residents, deliveries, and emergency access where applicable, since an unmarked or ambiguous closure generates confusion and unauthorized attempts to pass
-   Materials can span the full construction spectrum, from a demonstration-stage planter arrangement to a permanent, engineered barrier; see [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md)

## Related patterns

[Bollard](https://commonwaysystem.org/patterns/elements/bollard.md) (ELM-BOL-25) (the hardware most commonly used to build a filter), [Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md) (ELM-CBE-02) (an alternative geometry for narrowing or partially closing a street), [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12) (the Local Street pattern this is most frequently paired with)

## Getting there: Retrofit path options

This Element is the direct physical product of [Modal filtering / Low Traffic Neighborhood retrofit](https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit.md) (RFT-NET-01), the Network-scale strategy that places a coordinated set of these closures across an area.

## References

1.  Evidence-based [Aldred, R. and Goodman, A., "Low Traffic Neighbourhoods, Car Use, and Active Travel: Evidence from the People and Places Survey of Outer London Active Travel Interventions," _Findings_, 2020.](https://findingspress.org/article/17128-low-traffic-neighbourhoods-car-use-and-active-travel-evidence-from-the-people-and-places-survey-of-outer-london-active-travel-interventions)
2.  Legal / regulatory [Federal Highway Administration, "Traffic Calming ePrimer," Module 3: Toolbox of Individual Traffic Calming Measures. Diagonal diverters and half closures as routing-restriction treatments.](https://highways.dot.gov/safety/speed-management/traffic-calming-eprimer/traffic-calming-eprimer-module-3)

---

Source: https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout/

# Neighborhood Traffic Circle / Mini-Roundabout

`ELM-NTC-46`

Recommended Element

Neighborhood Traffic Circle / Mini-Roundabout

A small raised or landscaped island placed at the center of a Local-to-Local intersection, around which traffic circulates at low speed, used for calming rather than volume control.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

## Why this pattern exists

Roundabout (Single / Multi-Lane) is sized to the volume it carries and is the default control wherever two Collector-or-higher streets meet; it isn't built for, and doesn't document, the much smaller intervention appropriate at a Local-to-Local intersection. This pattern exists to cover that gap: an intersection too low-volume to need a sized, engineered roundabout, but where an uncontrolled or minimally-controlled crossing still benefits from a physical feature that forces drivers to slow and negotiate rather than proceed straight through at speed.[1][2]

## Key considerations

-   Sizing is deliberately minimal compared to Roundabout, matching Local street volumes and speeds rather than being engineered for Collector-or-higher throughput
-   Sightlines around the circle must remain clear for all approaches, since the reduced scale means less margin for landscaping or signage to obstruct a driver's view of crossing traffic
-   Emergency vehicle and larger-vehicle turning movements should be checked, since a mountable apron around the circle is often needed to accommodate a fire truck or moving van without requiring a larger footprint for every vehicle
-   This pattern doesn't replace right-of-way rules at the intersection; signage or markings should make clear whether existing stop or yield control still applies

## Related patterns

[Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) (the sized, higher-volume analogue governed by different rules), [All-Way Stop](https://commonwaysystem.org/patterns/intersections/all-way-stop.md) (INT-AWS-04) (a control type this pattern sometimes replaces at a Local intersection), [Vertical Speed Control](https://commonwaysystem.org/patterns/elements/vertical-speed-control.md) (ELM-VSC-06) (an alternative Local-to-Local calming treatment)

## References

1.  Precedent-based [Delaware Department of Transportation, _Traffic Calming Design Manual_, 2025 edition, Section 3D, "Neighborhood Traffic Circles & Mini-Roundabouts."](https://deldot.gov/Publications/manuals/traffic_calming/pdfs/Delaware_TrafficCalmingDesignManual.pdf)
2.  Precedent-based [City of Auburn, Alabama, Engineering Services, _Design and Construction Manual_, Appendix J, "Examples of Traffic Calming Measures."](https://static.auburnalabama.org/media/apps/www/engineering-services/publications/design-and-construction-manual/12-30-19-App-J_App-I-Removed_FINAL.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/pedestrian-hybrid-beacon/

# Pedestrian Hybrid Beacon

`ELM-PHB-18`

Situational / Discouraged Element

Pedestrian Hybrid Beacon

A pedestrian-activated signal, sometimes called a HAWK beacon, that remains dark until activated, then displays a sequence progressing through flashing and solid indications to stop traffic and allow a pedestrian to cross, before returning to dark.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

## Why this pattern exists

A pedestrian hybrid beacon provides stronger, legally binding stop control than an RRFB while avoiding the ongoing delay a full traffic signal would impose on a corridor at a location that does not have enough pedestrian volume to justify constant signal timing. This pattern exists to document this middle-tier crossing treatment between an RRFB and a full signal.[1][2]

## Key considerations

-   Most appropriate at crossings with meaningful but intermittent pedestrian volume on a higher-speed or higher-volume roadway where an RRFB’s advisory-only nature is not sufficient
-   The dark-until-activated design should be paired with clear driver education or signage, since an unfamiliar driver may not immediately understand the sequence
-   Requires adequate signage and lighting so the beacon itself is visible and comprehensible well before the crossing point

## Related patterns

[RRFB](https://commonwaysystem.org/patterns/elements/rrfb.md) (ELM-RRF-17) (the lighter-control alternative this pattern exceeds); [Traffic Signal](https://commonwaysystem.org/patterns/elements/traffic-signal.md) (ELM-TFS-14) (the heavier-control alternative this pattern avoids); [Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08), [Pedestrian Safety Island/Refuge](https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge.md) (ELM-PSI-09) (companion crossing elements)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 4J, "Pedestrian Hybrid Beacons" (renumbered from the 2009 edition's Chapter 4F). Warrant conditions.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Evidence-based [Fitzpatrick, K. and Park, E.S., "Safety Effectiveness of the HAWK Pedestrian Crossing Treatment," FHWA-HRT-10-042 (2010). Tucson before/after study of 21 treatment sites versus 102 reference intersections: a 29% reduction in total crashes and a 69% reduction in pedestrian crashes.](https://www.fhwa.dot.gov/publications/research/safety/10042/10042.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge/

# Pedestrian Safety Island / Refuge

`ELM-PSI-09`

Recommended Element

Pedestrian Safety Island / Refuge

A protected median space within a roadway allowing a pedestrian to cross in two stages, stopping partway across to wait for a gap in the second direction of traffic rather than crossing the full width in one movement.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

## Why this pattern exists

Wide or multi-lane crossings ask a pedestrian to judge gaps in traffic across the full roadway width at once, a task that becomes harder and riskier as width and traffic volume increase; a refuge island breaks that judgment into two simpler, more manageable stages.[1] This pattern exists to document the sizing and placement considerations that make an island genuinely usable rather than a token gesture.

## Key considerations

-   Island width must be sufficient for a pedestrian, and ideally a pedestrian with a stroller or wheelchair, to wait comfortably, not just a painted sliver
-   Cut-through openings at grade (rather than requiring a step up) improve accessibility and should be the default[2]
-   Placement should align precisely with the crosswalk it serves; an offset island creates an awkward or unsafe crossing path

## Related patterns

[Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08) (the crossing this pattern supports); [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03), [Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md) (ELM-DWS-10) (companion accessibility elements at the island itself); [Median Island](https://commonwaysystem.org/patterns/elements/median-island.md) (ELM-MDI-45) (a related but distinct treatment built for calming and access management rather than crossing assistance)

## References

1.  Evidence-based [Zegeer, C. et al., "Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations," FHWA-RD-01-075 (2002). Documents a crash modification factor of 0.54 (a 46% crash reduction) for a raised median with a marked crosswalk compared to an unmarked comparison.](https://rosap.ntl.bts.gov/view/dot/15480/dot_15480_DS1.pdf)
2.  Legal / regulatory [PROWAG (U.S. Access Board, 2023 final rule; adopted into DOT's ADA regulations effective January 17, 2025), Section R306, "Pedestrian Street Crossings." Cut-through opening and accessibility requirements at medians and islands.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/pedestrian-scale-lighting/

# Pedestrian-scale Lighting

`ELM-PSL-27`

Recommended Element

Pedestrian-scale Lighting

A lower-mounted luminaire, typically 10-15 feet in height, providing illumination calibrated to serve pedestrians on a sidewalk, sized and spaced to support the pedestrian visual task rather than the vehicle-oriented task a standard street light serves.

## Why this pattern exists

Standard street lighting is mounted and spaced for vehicle sightlines, which often leaves the sidewalk under-illuminated or produces harsh, high-angle light poorly suited to a pedestrian’s closer-range visual needs (facial recognition, uneven surface detection, personal security). This pattern exists to document the distinct scale and spacing considerations pedestrian lighting requires.[1]

## Key considerations

-   Mounting height and spacing should be calibrated to the pedestrian visual task, not simply a shorter version of vehicle-scale fixture spacing
-   Light color and quality (warmth, glare control) affect both perceived safety and neighborhood character, and should be considered alongside pure illumination levels
-   Should be considered a standard companion to Street Light on any corridor with meaningful pedestrian activity, not an optional upgrade

## Related patterns

[Street Light](https://commonwaysystem.org/patterns/elements/street-light.md) (ELM-STL-26) (the companion vehicle-oriented lighting pattern); relevant Local and Collector Segment patterns where pedestrian activity is expected

## References

1.  Legal / regulatory [ANSI/IES RP-8-25, "Lighting Roadway and Parking Facilities." The same standard also sets pedestrian-volume-based illuminance criteria for sidewalks, distinct from its vehicle-oriented roadway tables, since this pattern serves a different visual task.](https://store.ies.org/product/recommended-practice-lighting-roadway-and-parking-facilities/)

---

Source: https://commonwaysystem.org/patterns/elements/pedestrian-signal/

# Pedestrian Signal

`ELM-PDS-15`

Recommended Element

Pedestrian Signal

A signal indication, typically a walking figure and countdown display, informing pedestrians when it is their turn to cross and how much time remains to do so at a signalized intersection or crossing.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why the Dutch Wait Less at Traffic Lights](https://www.youtube.com/watch?v=knbVWXzL4-4)

Not Just Bikes

Breaks down Dutch traffic-responsive signal timing, independent phasing, transit signal priority, and no-right-turn-on-red as a pedestrian/cyclist safety measure.

## Why this pattern exists

A vehicle-only signal phase gives pedestrians no explicit information about when or how long they have to cross; a pedestrian signal makes crossing timing an intentional, communicated part of the intersection’s operation. This pattern exists to document its own timing and placement considerations distinct from the vehicle signal it operates alongside.[1]

## Key considerations

-   Crossing time allotted must accommodate a range of pedestrian walking speeds, not just an average adult pace[2]
-   Should be provided at every signalized crossing where pedestrian activity is legal, not treated as optional
-   Countdown displays improve pedestrian decision-making at the crossing’s edge and should be the default over a simple walk/don’t-walk indication

## Related patterns

[Traffic Signal](https://commonwaysystem.org/patterns/elements/traffic-signal.md) (ELM-TFS-14) (the companion vehicle control this pattern coordinates with); [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03), [Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md) (ELM-DWS-10) (companion accessibility elements)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 4I, "Pedestrian Control Features" (renumbered from the 2009 edition's Chapter 4E), including Section 4D.02's leading pedestrian interval requirement.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Legal / regulatory [PROWAG (U.S. Access Board, 2023 final rule; adopted into DOT's ADA regulations effective January 17, 2025), Section R309, accessible pedestrian signal requirements.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/pervious-pavement/

# Pervious Pavement

`ELM-PVP-22`

Situational / Discouraged Element

Pervious Pavement

A load-bearing paving surface (permeable concrete, porous asphalt, or permeable interlocking pavers) engineered to allow stormwater to infiltrate directly through the pavement surface into a stone reservoir base below, rather than running off.

## Why this pattern exists

Applied across a full-width surface (a parking lot, a full travel lane, a plaza), pervious pavement addresses runoff at a larger scale than a pervious strip while still functioning as a normal load-bearing driving or walking surface. This pattern exists to document its own structural and maintenance requirements, which differ meaningfully from conventional pavement.[1]

## Key considerations

-   Requires periodic vacuum-sweeping or similar maintenance to prevent surface clogging from sediment, without which infiltration capacity degrades over time
-   Structural design (reservoir base depth, subgrade condition) must be engineered for the expected load, not treated as a simple material swap over standard pavement
-   Not appropriate in all climates or soil conditions; freeze-thaw cycles and poor native drainage both affect performance and should be evaluated before specifying[2]

## Related patterns

[Pervious Strip](https://commonwaysystem.org/patterns/elements/pervious-strip.md) (ELM-PVS-21) (a related, lower-scale treatment); [Surface Parking Lot](https://commonwaysystem.org/patterns/facilities/surface-parking-lot.md) (FAC-SPL-04) (Facility pattern where this often applies)

## References

1.  Legal / regulatory [U.S. Environmental Protection Agency, National Menu of Best Management Practices, "Permeable Pavements" fact sheet.](https://www.epa.gov/system/files/documents/2021-11/bmp-permeable-pavements.pdf)
2.  Precedent-based [National Association of City Transportation Officials, _Urban Street Stormwater Guide_, "Pervious Pavement."](https://nacto.org/publication/urban-street-design-guide/street-design-elements/stormwater-management/pervious-pavement/)

_"Legal / regulatory" here refers to the EPA guidance that municipal NPDES stormwater permits are legally built around, not a single mandatory design spec like MUTCD or PROWAG._

---

Source: https://commonwaysystem.org/patterns/elements/pervious-strip/

# Pervious Strip

`ELM-PVS-21`

Situational / Discouraged Element

Pervious Strip

A linear strip of permeable surface (gravel, permeable pavers, or open-graded aggregate), allowing stormwater to infiltrate directly into the ground rather than running off to a drain, typically installed within a parking lane, shoulder, or buffer zone.

## Why this pattern exists

A conventional impervious strip in this same location contributes runoff volume with no infiltration benefit; converting it to a pervious surface reduces runoff at a relatively low cost compared to a full bioswale or planter, without requiring a change in the strip’s basic use. This pattern exists to document that lower-intervention infiltration option.[1]

## Key considerations

-   Underlying soil infiltration rate needs to be verified before installation; a pervious surface over poorly-draining soil underperforms significantly
-   Surface material should be selected for the loads it will bear; a parking-lane application needs a different specification than a pedestrian-only buffer strip[2]
-   Periodic maintenance (removing sediment buildup) is required to keep the surface functioning as intended over time

## Related patterns

[Pervious Pavement](https://commonwaysystem.org/patterns/elements/pervious-pavement.md) (ELM-PVP-22) (a related but distinct full-surface treatment); [Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md) (ELM-BIO-19), [Flow-Through Planter](https://commonwaysystem.org/patterns/elements/flow-through-planter.md) (ELM-FTP-20) (higher-intervention alternatives)

## References

1.  Legal / regulatory [U.S. Environmental Protection Agency, National Menu of Best Management Practices, "Permeable Pavements" fact sheet.](https://www.epa.gov/system/files/documents/2021-11/bmp-permeable-pavements.pdf)
2.  Precedent-based [National Association of City Transportation Officials, _Urban Street Stormwater Guide_.](https://nacto.org/publication/urban-street-design-guide/street-design-elements/stormwater-management/pervious-strips/)

_"Legal / regulatory" here refers to the EPA guidance that municipal NPDES stormwater permits are legally built around, not a single mandatory design spec like MUTCD or PROWAG._

---

Source: https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track/

# Protected Bike Lane / Cycle Track

`ELM-PBL-37`

Recommended Element

Protected Bike Lane / Cycle Track

A bike facility physically separated from adjacent vehicle traffic by a barrier, curb, parked cars, bollards, or planters, rather than paint markings alone, providing the highest level of separation among on-street bike facility types.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

Physical separation removes the reliance on driver behavior and paint compliance that lower-tier bike facilities depend on, making cycling comfortable and accessible to a much broader range of riders, including children and less-confident adults, the core goal of an all-ages-and-abilities bike network.[1] This pattern exists to document the design considerations specific to physical separation.

## Key considerations

-   Intersection and driveway conflict points require particular design attention, since physical separation that continues uninterrupted mid-block can create visibility conflicts at any break in that separation
-   Should be the aspirational default treatment on higher-speed or higher-volume corridors where cycling is intended to be a viable, comfortable option for a broad range of riders
-   Maintenance access (snow removal, sweeping) needs to be planned for within a physically separated facility, since standard vehicle-lane equipment may not fit
-   Minimum rideable width is 6.5–7 ft (2–2.1 m) for a one-way facility, with 8–12.5 ft (2.5–3.8 m) preferred where volume supports side-by-side riding or passing.[2] Buffer width must be at least 3 ft (0.9 m) where adjacent to on-street parking, to clear the door-swing zone, or 2–3 ft (0.6–0.9 m) on streets without parking at 30 mph or below.[2]

## Related patterns

[Buffered Bike Lane](https://commonwaysystem.org/patterns/elements/buffered-bike-lane.md) (ELM-BBL-35), [Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) (ELM-CBL-34) (lower-separation alternatives); [Bicycle Signal](https://commonwaysystem.org/patterns/elements/bicycle-signal.md) (ELM-BCS-16) (a common companion treatment at intersections)

## Getting there: Retrofit path options

This Element is the direct product of all three protected bike lane retrofits: via [lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md) (RFT-CDR-07), via [lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md) (RFT-CDR-08), and via [parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) (RFT-CDR-09).

## References

1.  Evidence-based [Lusk, A.C. et al. (2011), "Risk of injury for bicycling on cycle tracks versus in the street," _Injury Prevention_ 17(2). Montreal study: 28% lower injury rate on cycle tracks compared to comparable streets.](https://pubmed.ncbi.nlm.nih.gov/21307080/)
2.  Precedent-based [NACTO, _Urban Bikeway Design Guide_, 3rd Ed., "Protected Bike Lanes." Design specifications.](https://nacto.org/publication/urban-bikeway-design-guide/designing-bikeways-for-all-ages-and-abilities/protected-bike-lanes/)

---

Source: https://commonwaysystem.org/patterns/elements/regulatory-sign/

# Regulatory Sign

`ELM-RGS-11`

Recommended Element

Regulatory Sign

A sign conveying a legally enforceable traffic rule, such as a stop sign, yield sign, speed limit sign, or turn restriction, whose message carries the force of law rather than merely advising or informing.

## Why this pattern exists

Regulatory signs are how a jurisdiction communicates enforceable rules to the traveling public; consistent placement, sizing, and messaging across the network is what allows a driver to trust and act on a sign without hesitation. This pattern exists to document the category as distinct from warning and guide signs, since its legal weight demands a different level of rigor in application.[1][2]

## Key considerations

-   Placement and sizing should follow established uniform standards so meaning is consistent and immediately recognizable across contexts
-   Overuse undermines effectiveness; a corridor with excessive regulatory signage trains drivers to tune out individual signs
-   A regulatory sign should reflect the roadway’s actual design and self-explaining cues, not attempt to compensate for a mismatched design through signage alone

## Related patterns

[Warning Sign](https://commonwaysystem.org/patterns/elements/warning-sign.md) (ELM-WNS-12), [Guide Sign](https://commonwaysystem.org/patterns/elements/guide-sign.md) (ELM-GDS-13) (related but functionally distinct sign categories); relevant Segment and Intersection patterns the sign is regulating

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Section 2A.03, "Classification of Signs."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 2B, "Regulatory Signs, Barricades, and Gates."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/rrfb/

# RRFB

`ELM-RRF-17`

Recommended Element

RRFB

A Rectangular Rapid Flashing Beacon, a pedestrian- or cyclist-activated warning device using bright, irregularly-flashing LED lights mounted near a crosswalk sign to increase driver yielding at an uncontrolled crossing.

## Why this pattern exists

An uncontrolled crosswalk relies entirely on driver attentiveness and willingness to yield; an RRFB gives the crossing a strong, attention-getting visual cue exactly when a pedestrian or cyclist is present, without the cost and delay of a full traffic signal. This pattern exists to document this lighter-weight treatment and where it fits relative to a full signal or hybrid beacon.[1]

## Key considerations

-   Most effective at midblock or lower-volume crossings where a full signal is not warranted but a marked crosswalk alone yields inconsistent results[2][3]
-   User-activated designs (push button or passive detection) should be reliable and low-friction to use; a device people cannot easily activate will not get used
-   Should be paired with adequate crosswalk marking and, where relevant, a refuge island rather than deployed as a standalone fix

## Related patterns

[Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08) (the crossing this pattern supports); [Pedestrian Hybrid Beacon](https://commonwaysystem.org/patterns/elements/pedestrian-hybrid-beacon.md) (ELM-PHB-18) (a stronger-control alternative for busier crossings); [Traffic Signal](https://commonwaysystem.org/patterns/elements/traffic-signal.md) (ELM-TFS-14) (the higher-control alternative this pattern is meant to avoid triggering)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026). Formerly Interim Approval IA-21, now standardized.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Evidence-based [NCHRP Research Report 841 (2017), "Development of Crash Modification Factors for Uncontrolled Pedestrian Crossing Treatments," Transportation Research Board. Documents a crash modification factor of 0.53 for vehicle-pedestrian crashes.](https://nap.nationalacademies.org/catalog/24627/development-of-crash-modification-factors-for-uncontrolled-pedestrian-crossing-treatments)
3.  Evidence-based [Fitzpatrick, K. et al., "Will You Stop for Me?," Report No. TTI-CTS-0010, Texas A&M Transportation Institute (2016). Driver-yielding research underlying its particular effectiveness at multilane crossings.](https://static.tti.tamu.edu/tti.tamu.edu/documents/TTI-CTS-0010.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/rumble-strip/

# Rumble Strip

`ELM-RMS-07`

Situational / Discouraged Element

Rumble Strip

A textured roadway surface, typically a series of shallow grooves or raised bars, that alerts drivers through vibration and sound when a vehicle crosses it.

## Why this pattern exists

Rumble strips address inattention and lane departure rather than speed directly, giving a driver an audible and tactile cue at a specific location or along a stretch of roadway, distinct from the speed-reduction goal of vertical deflection treatments. This pattern exists to document that separate function and its own siting considerations.[1]

## Key considerations

-   Placement near residences requires care, since the noise generated can create a livability conflict for adjacent properties
-   Not effective at reducing speed on its own; better suited to alerting for an upcoming change (stop condition, curve, edge of pavement) than as a substitute for vertical speed control
-   Should not be used where it may pose a hazard to bicyclists sharing the roadway without an alternative path around it[2]

## Related patterns

[Vertical Speed Control](https://commonwaysystem.org/patterns/elements/vertical-speed-control.md) (ELM-VSC-06) (related but functionally distinct calming treatment); [Warning Sign](https://commonwaysystem.org/patterns/elements/warning-sign.md) (ELM-WNS-12) (often paired to alert of an upcoming condition)

## References

1.  Evidence-based [Persaud, B., Lyon, C., Eccles, K., and Soika, J., "Safety Evaluation of Centerline Plus Shoulder Rumble Strips," FHWA-HRT-15-048 (Federal Highway Administration, 2015); NCHRP Report 641.](https://www.fhwa.dot.gov/publications/research/safety/15048/15048.pdf)
2.  Evidence-based [Federal Highway Administration, "Rumble Strips and Bicycle Accommodation," fact sheet.](https://highways.dot.gov/safety/rwd/keep-vehicles-road/rumble-strips/bicycles)

---

Source: https://commonwaysystem.org/patterns/elements/sharrow/

# Sharrow

`ELM-SHR-39`

Avoid Element

Sharrow

A shared-lane marking, a painted symbol combining a bicycle icon and chevron arrows, placed within a shared vehicle travel lane to indicate that cyclists may use the full lane and to suggest proper positioning within it.

## Why this pattern exists

On a roadway too narrow to provide any dedicated bike space, a sharrow at least communicates that cyclists are expected users of the lane and suggests where they should position themselves relative to parked cars and the travel lane’s edge; this pattern exists to document this lowest tier of bike accommodation and its real limitations.

## Key considerations

-   Provides no physical or even painted separation from vehicle traffic, and research has generally found it does little to improve comfort or safety for cyclists[1]
-   Should be treated as a last-resort or interim treatment rather than a target outcome; a corridor relying on sharrows is a candidate for future upgrade to a dedicated facility
-   May still hold value narrowly for wayfinding continuity between two stronger-facility segments where a short interruption cannot otherwise be avoided

## Related patterns

[Conventional Bike Lane](https://commonwaysystem.org/patterns/elements/conventional-bike-lane.md) (ELM-CBL-34), [Advisory Bike Lane](https://commonwaysystem.org/patterns/elements/advisory-bike-lane.md) (ELM-ABL-36) (facilities this pattern should generally be upgraded toward); [Stroad](https://commonwaysystem.org/patterns/arterials/stroad.md) (ART-STD-05) (the explicit Avoid-status pattern this shares status logic with)

## References

1.  Evidence-based [Ferenchak, N.N. and Marshall, W.E. (2019), "Advancing Healthy Cities Through Safer Cycling: An Examination of Shared Lane Markings," _International Journal of Transportation Science and Technology_ 8(2). Chicago before/after study: sharrows produced no statistically significant safety improvement, underperforming both bike lanes and no treatment on injury reduction.](https://www.sciencedirect.com/science/article/pii/S2046043018300583)

---

Source: https://commonwaysystem.org/patterns/elements/street-light/

# Street Light

`ELM-STL-26`

Recommended Element

Street Light

A pole-mounted luminaire providing illumination for the roadway, typically mounted at a height and spacing designed primarily to serve vehicle visibility and drivers, though its light also reaches the surrounding sidewalk and public realm.

## Why this pattern exists

Adequate roadway illumination reduces nighttime crash risk by improving driver visibility of the roadway edge, other vehicles, and pedestrians; this pattern exists to document the mounting height, spacing, and output considerations specific to vehicle-oriented lighting, distinct from the pedestrian-scale lighting that serves a different visual task.[1]

## Key considerations

-   Mounting height and spacing should follow established illumination standards for the roadway’s classification and speed, not a uniform default across all street types
-   Light spillover and glare onto adjacent properties should be minimized through fixture selection and shielding
-   Uniformity of illumination along a corridor matters more than peak brightness at any single point; dark gaps between light poles undermine the pattern’s purpose

## Related patterns

[Pedestrian-scale Lighting](https://commonwaysystem.org/patterns/elements/pedestrian-scale-lighting.md) (ELM-PSL-27) (the companion lighting pattern serving a different visual task and height); relevant Segment patterns this lighting serves

## References

1.  Legal / regulatory [ANSI/IES RP-8-25, "Lighting Roadway and Parking Facilities." Current American National Standard for mounting height, spacing, and illuminance-level tables by roadway classification.](https://store.ies.org/product/recommended-practice-lighting-roadway-and-parking-facilities/)

---

Source: https://commonwaysystem.org/patterns/elements/street-tree/

# Street Tree

`ELM-STT-28`

Recommended Element

Street Tree

A tree planted along a street, typically within the sidewalk zone or a landscaped buffer, providing shade, stormwater interception, visual buffering from traffic, and streetscape character.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

## Why this pattern exists

Street trees do measurable work beyond aesthetics, they reduce pedestrian-level heat, intercept a portion of rainfall before it reaches the storm system, and provide a visual and physical buffer between pedestrians and moving traffic; this pattern exists to document species selection, spacing, and root-space considerations that determine whether a tree thrives or struggles in a street environment.

## Key considerations

-   Adequate below-grade root space and soil volume must be planned for at installation; insufficient space is the leading cause of poor street tree survival and growth[1]
-   Species selection should account for mature canopy size relative to available overhead and sidewalk clearance, utility conflicts, and local climate tolerance
-   Spacing should balance canopy coverage goals against sightline requirements at driveways, crossings, and intersections

## Related patterns

[Tree Pit/Tree Trench](https://commonwaysystem.org/patterns/elements/tree-pit-tree-trench.md) (ELM-TPT-29) (the below-grade element supporting this pattern); [Landscaped Buffer Strip](https://commonwaysystem.org/patterns/elements/landscaped-buffer-strip.md) (ELM-LBS-30) (a common zone this pattern is planted within)

## References

1.  Evidence-based [Lindsey, J.P. and Bassuk, N. (1991), "Specifying Soil Volumes to Meet the Water Needs of Mature Urban Street Trees and Trees in Containers," _Journal of Arboriculture_ 17(6). Peer-reviewed formula (approximately 2 cubic ft of soil per sq ft of mature canopy) underlying the claim that insufficient space is the leading cause of poor street tree survival.](https://auf.isa-arbor.com/content/17/6/141)

---

Source: https://commonwaysystem.org/patterns/elements/traffic-barrier/

# Traffic Barrier

`ELM-TRB-23`

Situational / Discouraged Element

Traffic Barrier

A longitudinal barrier (guardrail, concrete barrier, or similar rigid or semi-rigid structure) installed to redirect an errant vehicle away from a roadside hazard or opposing traffic, rather than allowing the vehicle to travel further off-course.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why America Won't Copy Sweden's Cheap Highway Fix](https://www.youtube.com/watch?v=jyNEnYaBszk)

Safe By Design

Explains Sweden's 2+1 alternating-passing-lane cable-barrier retrofit and the specific AASHTO Green Book barriers (literally) that have kept the same fix from scaling in the US.

## Why this pattern exists

Certain roadside conditions (a steep slope, a fixed object, an opposing travel lane with no separation) pose a severe risk if an errant vehicle reaches them; a traffic barrier is deployed specifically to intercept and redirect the vehicle before it does, at the cost of introducing its own fixed-object risk if struck directly. This pattern exists to document when that tradeoff is justified.

## Key considerations

-   Should only be installed where the hazard being shielded is more severe than the barrier itself, since the barrier becomes a fixed object a vehicle can strike[1]
-   End treatments matter significantly; an unshielded or improperly terminated barrier end can be more dangerous than no barrier at all
-   Height and strength must be matched to the design vehicle and speed of the roadway it protects, crash-tested against current standards[2]

## Related patterns

[Crash Cushion/End Terminal](https://commonwaysystem.org/patterns/elements/crash-cushion-end-terminal.md) (ELM-CCT-24) (the treatment addressing this pattern’s exposed ends); [Bollard](https://commonwaysystem.org/patterns/elements/bollard.md) (ELM-BOL-25) (a related but functionally distinct barrier type)

## References

1.  Legal / regulatory [American Association of State Highway and Transportation Officials, _Roadside Design Guide_, 4th ed.](https://store.transportation.org/Item/PublicationDetail?ID=1802)
2.  Legal / regulatory [American Association of State Highway and Transportation Officials, _Manual for Assessing Safety Hardware_ (MASH), 2016.](https://store.transportation.org/item/publicationdetail/2707)

---

Source: https://commonwaysystem.org/patterns/elements/traffic-signal/

# Traffic Signal

`ELM-TFS-14`

Situational / Discouraged Element

Traffic Signal

A signal-controlled device using red, yellow, and green indications to assign right-of-way among conflicting vehicle movements at an intersection.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why the Dutch Wait Less at Traffic Lights](https://www.youtube.com/watch?v=knbVWXzL4-4)

Not Just Bikes

Breaks down Dutch traffic-responsive signal timing, independent phasing, transit signal priority, and no-right-turn-on-red as a pedestrian/cyclist safety measure.

## Why this pattern exists

Above a certain volume or conflict complexity, an uncontrolled or sign-controlled intersection can no longer safely and efficiently sort competing movements; a traffic signal imposes timed, positive control over who moves when. This pattern exists to document signal use as a documented departure from Commonway System’s roundabout-default intersection treatment, requiring its own justification.

## Key considerations

-   Consistent with Commonway System’s intersection defaults, signal installation should require documented burden-of-proof justification rather than being a default choice[1]
-   Timing and phasing should account for all modes present, not just vehicle throughput; pedestrian and bicycle phases need adequate crossing time
-   Signal coordination along a corridor affects speed and platooning behavior well beyond the single intersection where it is installed

## Related patterns

[Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) (the CS default this pattern is a documented departure from); [Pedestrian Signal](https://commonwaysystem.org/patterns/elements/pedestrian-signal.md) (ELM-PDS-15), [Bicycle Signal](https://commonwaysystem.org/patterns/elements/bicycle-signal.md) (ELM-BCS-16) (companion signal types at a signalized intersection)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 4C, "Traffic Control Signal Needs Studies." Establishes the nine signal warrants, and explicitly states that meeting a warrant does not itself require installation.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/transit-boarding-island/

# Transit Boarding Island

`ELM-TBI-41`

Recommended Element

Transit Boarding Island

A raised platform positioned between a bike lane and the vehicle travel lane at a transit stop, allowing bus or streetcar passengers to board and alight without crossing the bike lane at grade, and without the transit vehicle needing to merge across the bike lane to reach the curb.

## Why this pattern exists

Where a protected bike lane runs along a curb that also serves transit stops, a standard curbside stop forces either the bus to cross the bike lane to reach the curb, or passengers to cross the bike lane to board, both creating a recurring conflict point. A boarding island resolves this by placing the stop between the two facilities, letting each operate without crossing the other. This pattern exists to document that specific, well-defined conflict and its resolution.[1]

## Key considerations

-   Island width must accommodate expected passenger volume and any accessibility equipment (wheelchairs, strollers) waiting to board
-   The bike lane routing around the island needs clear delineation so cyclists understand they are expected to yield to boarding and alighting passengers crossing their path
-   Most relevant wherever a protected bike lane and a transit stop coincide on the same corridor; not a general-purpose treatment outside that specific pairing

## Related patterns

[Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37), [Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md) (FAC-TPL-02) (the two facilities this pattern reconciles); [Detectable Warning Surface](https://commonwaysystem.org/patterns/elements/detectable-warning-surface.md) (ELM-DWS-10), [Curb Ramp](https://commonwaysystem.org/patterns/elements/curb-ramp.md) (ELM-CRP-03) (companion accessibility elements)

## References

1.  Precedent-based [NACTO, _Urban Bikeway Design Guide_, 3rd Ed., "Boarding Islands." Width, accessibility, and detectable-warning-surface requirements at the bike lane and transit conflict this pattern resolves.](https://nacto.org/publication/urban-bikeway-design-guide/designing-bikeways-for-all-ages-and-abilities/transit-stops/boarding-islands/)

---

Source: https://commonwaysystem.org/patterns/elements/trash-recycling-receptacle/

# Trash / Recycling Receptacle

`ELM-TRR-32`

Recommended Element

Trash / Recycling Receptacle

A fixed waste and recycling container installed in the public right-of-way or an adjacent public space, providing a designated disposal point for pedestrians and street users.

## Why this pattern exists

Without a designated disposal point, litter accumulates in places people already gather or pass through; this pattern exists to document placement and servicing considerations that determine whether a receptacle actually reduces litter or becomes an overflowing problem itself.[1]

## Key considerations

-   Servicing frequency must match actual usage volume at the location; an under-serviced receptacle in a high-traffic area quickly overflows and undermines its own purpose
-   Placement near activity generators (transit stops, plazas, commercial frontages) sees more appropriate use than placement based on even spacing alone
-   Design should resist wildlife access and weather intrusion where relevant to the local context

## Related patterns

[Bench](https://commonwaysystem.org/patterns/elements/bench.md) (ELM-BCH-31), [Transit Shelter](https://commonwaysystem.org/patterns/facilities/transit-shelter.md) (FAC-TSH-01) (common companion elements and facilities)

## References

1.  Legal / regulatory [PROWAG, Section R212, "Street Furniture." General accessible placement requirements for street furniture.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/elements/tree-pit-tree-trench/

# Tree Pit / Tree Trench

`ELM-TPT-29`

Recommended Element

Tree Pit / Tree Trench

The below-grade excavated and engineered soil volume, either an individual pit or a shared linear trench connecting multiple planting locations, providing root space and often structural soil to support street tree growth beneath a sidewalk or paved surface.

## Why this pattern exists

A tree’s long-term health depends far more on below-grade soil volume and quality than on what is visible at the surface; a standard small pit surrounded by compacted pavement subgrade starves a tree’s root system, while a shared trench connecting multiple pits dramatically increases available soil volume. This pattern exists to document that structural, below-grade design distinct from the visible tree itself.

## Key considerations

-   Shared trench designs generally outperform isolated individual pits for tree health and should be preferred where feasible[1]
-   Structural soil or suspended pavement systems may be needed where a trench must also support pavement loads above it
-   Coordination with underground utilities is essential early in design, since a trench’s extent can conflict with existing utility corridors

## Related patterns

[Street Tree](https://commonwaysystem.org/patterns/elements/street-tree.md) (ELM-STT-28) (the visible element this pattern supports); [Pervious Strip](https://commonwaysystem.org/patterns/elements/pervious-strip.md) (ELM-PVS-21), [Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md) (ELM-BIO-19) (related below-grade stormwater and soil treatments)

## References

1.  Evidence-based [Lindsey, J.P. and Bassuk, N. (1991), "Specifying Soil Volumes to Meet the Water Needs of Mature Urban Street Trees and Trees in Containers," _Journal of Arboriculture_ 17(6). Direct evidentiary basis for shared trenches, pooling soil volume across pits, outperforming isolated small pits.](https://auf.isa-arbor.com/content/17/6/141)

---

Source: https://commonwaysystem.org/patterns/elements/two-stage-turn-queue-box/

# Two-Stage Turn Queue Box

`ELM-TSQ-43`

Recommended Element

Two-Stage Turn Queue Box

A designated waiting area positioned in the far corner of an intersection, allowing a cyclist making a left turn (or right turn in left-driving contexts) to cross the intersection in two separate straight-through movements rather than merging across vehicle traffic to execute a conventional turn.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Why this pattern exists

A conventional vehicle-style left turn asks a cyclist to merge across one or more lanes of traffic to reach a turn position, a maneuver that becomes increasingly stressful and dangerous as traffic volume, speed, or lane count increases; a two-stage turn queue box removes that merge entirely by breaking the turn into two straight crossings. This pattern exists to document this specific, well-established alternative to the conventional turning movement.[1]

## Key considerations

-   Box placement and orientation must align with the cyclist’s path in the second stage of the crossing, so the movement reads as intuitive rather than requiring guesswork
-   Most valuable at intersections with multi-lane approaches or higher traffic volume, where a conventional merge-and-turn movement would be most stressful
-   Signal timing at the intersection needs to accommodate the two-stage movement, since a cyclist queued in the box is waiting for the second phase of the crossing, not simply out of the way

## Related patterns

[Protected Bike Lane/Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37), [Bike Box](https://commonwaysystem.org/patterns/elements/bike-box.md) (ELM-BKB-42) (related bike-specific intersection treatments); [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) (a different intersection default this pattern complements at signalized locations specifically)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Part 9. Formalized as standard, previously FHWA Interim Approval IA-20.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/vertical-speed-control/

# Vertical Speed Control

`ELM-VSC-06`

Recommended Element

Vertical Speed Control

A raised roadway feature (speed hump, speed table, or speed cushion) that slows vehicles through vertical deflection, forcing a driver to reduce speed to avoid an uncomfortable jolt.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

## Why this pattern exists

Signage and paint alone rarely change driver speed on their own; a physical vertical deflection imposes a real cost on speeding that self-enforces without requiring active enforcement presence. This pattern exists to document the distinct forms this treatment takes and where each is appropriate, since a hump, table, and cushion serve different vehicle types and roadway contexts differently.[1]

## Key considerations

-   Form should match context: cushions allow emergency vehicles and buses to straddle them with less impact than a full-width hump or table
-   Placement and spacing should be based on desired speed and roadway geometry, not applied as a one-size-fits-all interval
-   Drainage and snowplow operations need consideration in colder climates, since a raised feature can interfere with both

## Related patterns

[Rumble Strip](https://commonwaysystem.org/patterns/elements/rumble-strip.md) (ELM-RMS-07) (a related but distinct calming treatment using texture rather than vertical deflection); relevant Local and Collector Segment patterns where speed control applies; [Neighborhood Traffic Circle / Mini-Roundabout](https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout.md) (ELM-NTC-46) (an alternative Local-to-Local calming treatment)

## References

1.  Precedent-based [Institute of Transportation Engineers, _Guidelines for the Design and Application of Speed Humps_ (updated edition).](https://ecommerce.ite.org/iCommerce/iCommerce/Orders/Item_Detail.aspx?iProductCode=RP-038A)

---

Source: https://commonwaysystem.org/patterns/elements/warning-sign/

# Warning Sign

`ELM-WNS-12`

Recommended Element

Warning Sign

A sign alerting drivers to an upcoming hazard or changed condition, such as a curve, a crossing, a narrowing roadway, or a stop ahead, advising caution without carrying the direct legal force of a regulatory sign.

## Why this pattern exists

A warning sign gives a driver advance notice of a condition they need to react to, a curve tighter than expected, a crossing they might not anticipate, filling the gap between a road’s physical design and a driver’s real-time awareness of what is coming. This pattern exists to document its distinct advisory function and placement logic, separate from a regulatory sign’s enforceable message.[1][2]

## Key considerations

-   Placement distance ahead of the hazard should give a driver adequate time to react at the roadway’s operating speed
-   Should supplement, not substitute for, a self-explaining roadway design; a warning sign at a hazard the geometry itself should have signaled is a weaker fix
-   Overuse dilutes driver attention the same way excessive regulatory signage does; each sign should correspond to a genuine, non-obvious hazard

## Related patterns

[Regulatory Sign](https://commonwaysystem.org/patterns/elements/regulatory-sign.md) (ELM-RGS-11), [Guide Sign](https://commonwaysystem.org/patterns/elements/guide-sign.md) (ELM-GDS-13) (related sign categories); [Rumble Strip](https://commonwaysystem.org/patterns/elements/rumble-strip.md) (ELM-RMS-07) (often paired ahead of a hazard this sign warns of)

## References

1.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Section 2A.03, "Classification of Signs."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
2.  Legal / regulatory [MUTCD 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 2C, "Warning Signs and Object Markers."](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/elements/wheel-stop/

# Wheel Stop

`ELM-WHS-05`

Situational / Discouraged Element

Wheel Stop

A small barrier, typically a short raised block or bumper, placed at the end of a parking space to prevent a parked vehicle from overrunning a curb, sidewalk, or space limit.

## Why this pattern exists

Vehicles routinely pull farther into a parking space than intended, and without a physical stop, this can push a vehicle’s front end over a curb and into pedestrian space, into landscaping, or into an adjacent lane. This pattern exists to document this small but common protective element, distinct from the curb itself.[1]

## Key considerations

-   Placement should account for typical vehicle overhang so the stop actually prevents encroachment rather than just marking the space’s nominal end
-   Wheel stops in a path of pedestrian travel can themselves become a tripping hazard, and should be placed and colored to avoid this
-   Not always appropriate: some contexts favor a full curb or landscaped buffer over a discrete wheel stop

## Related patterns

[Curb](https://commonwaysystem.org/patterns/elements/curb.md) (ELM-CRB-01) (the element this pattern protects); [Surface Parking Lot](https://commonwaysystem.org/patterns/facilities/surface-parking-lot.md) (FAC-SPL-04) (Facility pattern where this most commonly applies)

## References

1.  Legal / regulatory [2010 ADA Standards for Accessible Design, Section 502.7 (Advisory). Regulatory basis for using wheel stops to prevent vehicle overhang into accessible routes and access aisles.](https://www.ada.gov/assets/pdfs/2010-design-standards.pdf)

---

Source: https://commonwaysystem.org/patterns/facilities/bike-parking-corral/

# Bike Parking Corral

`FAC-BPC-08`

Recommended Facility

Bike Parking Corral

An on-street, curbside cluster of bike racks, typically installed in place of a single car parking space, providing multiple bike parking spots in the footprint one vehicle would otherwise occupy.

## Why this pattern exists

Sidewalk-mounted bike racks compete with pedestrian clear-path space and other furnishings, and demand at popular destinations often exceeds what a sidewalk can hold; converting curbside vehicle space to bike parking solves both problems at once, at a much lower space cost per bike than a car per space. This pattern exists to document that specific curbside conversion, distinct from sidewalk-mounted racks documented at the Element scale.[1][2]

## Key considerations

-   Physical protection from adjacent travel lane traffic (wheel stops, bollards, or a raised curb) should be provided, since the corral sits where a vehicle used to be
-   Placement should preserve sightlines at nearby crosswalks and driveways, not introduce a new sight-obstruction where one did not exist
-   Capacity should reflect observed or projected demand at the specific destination, not a flat citywide default

## Related patterns

[Bike Parking / Rack](https://commonwaysystem.org/patterns/elements/bike-parking-rack.md) (ELM-BPR-40) (the Element-scale fixture used within the corral); [Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md) (ELM-CBE-02) (a related on-street space conversion)

## References

1.  Precedent-based [Association of Pedestrian and Bicycle Professionals (APBP), _Bicycle Parking Guidelines_, 2nd Ed. On-street/in-lane parking siting.](https://www.apbp.org/Publications)
2.  Precedent-based [NACTO, "Bike and Scooter Parking." Corral-specific design guidance.](https://nacto.org/publication/urban-bikeway-design-guide/maintenance-and-operations/bike-and-scooter-parking/)

---

Source: https://commonwaysystem.org/patterns/facilities/bike-share-station/

# Bike-Share Station

`FAC-BSS-09`

Situational / Discouraged Facility

Bike-Share Station

A docking location for a shared-bike program, where users check out and return bikes from a fixed station, either dock-based (physical docking points) or hybrid/dockless with a designated parking zone.

## Why this pattern exists

A shared-bike system depends on station siting decisions (density, spacing, proximity to transit and destinations) that determine whether the system actually gets used; this pattern exists to document those siting and sizing considerations as their own facility type, separate from the bike parking infrastructure a station physically resembles.[1]

## Key considerations

-   Station spacing and density should reflect the service area’s trip-length expectations; stations too far apart undermine the system’s utility for short trips[2]
-   Proximity to transit stops strengthens first/last-mile connections and should be prioritized in siting
-   Rebalancing access (space for a service vehicle to reach and restock the station) needs to be planned into the site, not assumed

## Related patterns

[Secure Bike Parking / Bike Station](https://commonwaysystem.org/patterns/facilities/secure-bike-parking-bike-station.md) (FAC-SBP-10) (a related but distinct higher-security facility type); [Transit Hub/Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) (FAC-THS-03) (a common co-location site)

## References

1.  Precedent-based [NACTO, _Bike Share Station Siting Guide_. Station placement principles.](https://nacto.org/publication/bike-share-station-siting-guide/)
2.  Evidence-based [NACTO, "Walkable Station Spacing is Key to Successful, Equitable Bike Share." Approximately 28 stations per square mile, a station every 1,000 ft.](https://nacto.org/publication/walkable-station-spacing-is-key-to-successful-equitable-bike-share/)

---

Source: https://commonwaysystem.org/patterns/facilities/park-and-ride/

# Park-and-Ride

`FAC-PNR-06`

Situational / Discouraged Facility

Park-and-Ride

A parking facility, surface or structured, designed specifically for commuters to leave a personal vehicle and transfer to transit for the remainder of their trip.

## Why this pattern exists

Park-and-ride serves a distinct trip purpose (a single daily transfer at a predictable time) rather than general destination parking, which shapes its sizing, its relationship to the transit stop it serves, and its access design in ways a generic lot or garage does not need to consider. This pattern exists to document that specific use case rather than leaving it as an unstated variant of Surface Parking Lot or Parking Garage/Structure.[1]

## Key considerations

-   Walking distance and path quality between the parking area and the transit platform should be prioritized, since a poor connection undermines the facility’s entire purpose
-   Sizing should be based on realistic transit ridership projections; an oversized facility encourages unnecessary driving while an undersized one turns away potential riders
-   Peak-period arrival and departure surges concentrated around transit schedules require different circulation design than a steady-demand lot[2]

## Related patterns

[Surface Parking Lot](https://commonwaysystem.org/patterns/facilities/surface-parking-lot.md) (FAC-SPL-04), [Parking Garage/Structure](https://commonwaysystem.org/patterns/facilities/parking-garage-structure.md) (FAC-PGS-05) (the physical forms this pattern typically takes); [Transit Hub/Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) (FAC-THS-03), [Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md) (FAC-TPL-02) (the transit facility being served)

## References

1.  Precedent-based [TCRP Report 153, "Guidelines for Providing Access to Public Transportation Stations." Station access planning and mode-tradeoff analysis for sizing against ridership projections.](https://nap.nationalacademies.org/catalog/14614/guidelines-for-providing-access-to-public-transportation-stations)
2.  Evidence-based [TCRP Report 95, Chapter 3, "Park-and-Ride/Pool," Transportation Research Board. Facility classification by size (small, 200 spaces or fewer; large, more than 1,000 spaces) and peak-period demand patterns.](https://www.nationalacademies.org/read/23432/chapter/2)

---

Source: https://commonwaysystem.org/patterns/facilities/parking-garage-structure/

# Parking Garage / Structure

`FAC-PGS-05`

Situational / Discouraged Facility

Parking Garage / Structure

A multi-level parking structure, above-grade or underground, using ramp or helix circulation to move vehicles between levels.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why Amsterdam is Removing 10,000 Parking Spaces](https://www.youtube.com/watch?v=mXLqrMljdfU)

Not Just Bikes

Documents Amsterdam's on-street parking reduction through permit attrition and street redesigns, including the tradeoff of a large replacement garage inducing more driving nearby.

## Why this pattern exists

Where land value or density makes surface parking impractical, a structure trades footprint for height and circulation complexity, introducing its own set of design problems (ramp grade and turning radius, pedestrian egress from upper levels, ground-floor treatment facing the street) that a surface lot never has to solve. This pattern exists to document those structure-specific considerations separately from surface parking.

## Key considerations

-   Ground-floor frontage facing the street should avoid a blank wall; active uses or architectural treatment help the structure read as a building rather than a void
-   Pedestrian egress routes (stairs, elevators) should be direct, well-lit, and clearly wayfinding-marked from every level[2]
-   Ramp and turning geometry should be sized for the largest vehicle expected to use the facility, including service and emergency vehicles[1]

## Related patterns

[Surface Parking Lot](https://commonwaysystem.org/patterns/facilities/surface-parking-lot.md) (FAC-SPL-04) (lower-density alternative); [Park-and-Ride](https://commonwaysystem.org/patterns/facilities/park-and-ride.md) (FAC-PNR-06) (a specific use case that may take structured form)

## References

1.  Precedent-based [ULI/National Parking Association, _The Dimensions of Parking_. Ramp grade, turning radius, and structural circulation design.](https://knowledge.uli.org/en/books/2009/the-dimensions-of-parking)
2.  Legal / regulatory [2010 ADA Standards for Accessible Design / PROWAG. Accessible egress (stairs, elevators) from every level.](https://www.ada.gov/assets/pdfs/2010-design-standards.pdf)

---

Source: https://commonwaysystem.org/patterns/facilities/plaza-parklet/

# Plaza / Parklet

`FAC-PLZ-07`

Recommended Facility

Plaza / Parklet

A public gathering space reclaimed from roadway or parking space, ranging from a single parking-space-sized parklet to a full intersection-corner plaza.

## Why this pattern exists

Streets historically allocate nearly all their space to vehicle movement and storage; this pattern documents the deliberate conversion of some of that space into space for people to sit, gather, and linger, a use case with its own siting, furnishing, and drainage considerations distinct from a sidewalk widening alone.

## Key considerations

-   Site selection should account for sun exposure, adjacent building frontage activity, and pedestrian flow; a plaza with no reason to stop rarely gets used[2]
-   Drainage must be resolved deliberately, since converted roadway space was not designed to shed water toward a pedestrian-occupied surface[1]
-   Where a parklet occupies a former parking space, physical protection from adjacent traffic (bollards, curb, planters) is necessary, not optional

## Related patterns

[Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md) (ELM-CBE-02) (related Element pattern, since a plaza often anchors at a curb extension or corner); [Bench](https://commonwaysystem.org/patterns/elements/bench.md) (ELM-BCH-31), [Street Tree](https://commonwaysystem.org/patterns/elements/street-tree.md) (ELM-STT-28) (common furnishing elements)

## References

1.  Precedent-based [WSDOT Design Manual, Chapter 1238, "Parklets and Plazas." Drainage, catch-basin avoidance, and railing/planter separation from traffic.](https://wsdot.wa.gov/publications/manuals/fulltext/m22-01/1238.pdf)
2.  Precedent-based [NACTO Urban Street Design Guide, "Parklets, Pop-ups and Street Seats." Siting principles (sun exposure, adjacent frontage activity).](https://nacto.org/publication/urban-street-design-guide/interim-design-strategies/parklets/)

---

Source: https://commonwaysystem.org/patterns/facilities/secure-bike-parking-bike-station/

# Secure Bike Parking / Bike Station

`FAC-SBP-10`

Situational / Discouraged Facility

Secure Bike Parking / Bike Station

An enclosed or attended facility offering higher-security, longer-term bike parking than an open-air rack or corral, ranging from a lockable cage to a staffed bike station with additional services.

## Why this pattern exists

Commuters and long-term parkers need protection from theft and weather that an open rack cannot provide; this pattern exists to document the access control, capacity, and siting considerations specific to an enclosed facility, distinct from the simpler open-air patterns that serve short-term parking needs.[1]

## Key considerations

-   Access control method (key, fob, membership, staffed attendant) should match the expected user base and usage duration
-   Siting works best near major trip generators (transit hubs, large employers) where sustained demand justifies the higher cost per space
-   Capacity planning should account for growth in demand over time, since retrofitting an enclosed facility is more disruptive than adding open racks

## Related patterns

[Bike Parking Corral](https://commonwaysystem.org/patterns/facilities/bike-parking-corral.md) (FAC-BPC-08), [Bike Parking / Rack](https://commonwaysystem.org/patterns/elements/bike-parking-rack.md) (ELM-BPR-40) (lower-security alternatives); [Bike-Share Station](https://commonwaysystem.org/patterns/facilities/bike-share-station.md) (FAC-BSS-09), [Transit Hub/Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) (FAC-THS-03) (common co-location sites)

## References

1.  Precedent-based [Association of Pedestrian and Bicycle Professionals (APBP), _Bicycle Parking Guidelines_, 2nd Ed. Long-term/enclosed parking recommendations, access control approaches.](https://www.apbp.org/Publications)

---

Source: https://commonwaysystem.org/patterns/facilities/surface-parking-lot/

# Surface Parking Lot

`FAC-SPL-04`

Situational / Discouraged Facility

Surface Parking Lot

An at-grade, open-air parking area serving adjacent land uses, ranging from a small business lot to a large-format shared or municipal lot.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why Amsterdam is Removing 10,000 Parking Spaces](https://www.youtube.com/watch?v=mXLqrMljdfU)

Not Just Bikes

Documents Amsterdam's on-street parking reduction through permit attrition and street redesigns, including the tradeoff of a large replacement garage inducing more driving nearby.

## Why this pattern exists

Surface lots are the most common and land-intensive parking facility, and their design choices (stall layout, stormwater handling, pedestrian access, landscaping) carry outsized impact on both the immediate streetscape and the site’s runoff and heat-island footprint. This pattern exists to document the tradeoffs specific to at-grade, uncovered parking, distinct from the structural and circulation problems a parking garage presents.

## Key considerations

-   Pedestrian paths through and across the lot should be clearly delineated rather than left to informal desire lines between parked cars[2]
-   Stormwater management (permeable paving, bioswales, tree canopy) should be integrated into the lot design, not treated as an afterthought[1]
-   Lot placement relative to the building and street matters: a lot between the building and the street undermines the streetscape it fronts

## Related patterns

[Parking Garage/Structure](https://commonwaysystem.org/patterns/facilities/parking-garage-structure.md) (FAC-PGS-05) (structural alternative for higher-density sites); [Pervious Pavement](https://commonwaysystem.org/patterns/elements/pervious-pavement.md) (ELM-PVP-22), [Bioswale](https://commonwaysystem.org/patterns/elements/bioswale.md) (ELM-BIO-19) (related Element patterns for stormwater treatment); [Park-and-Ride](https://commonwaysystem.org/patterns/facilities/park-and-ride.md) (FAC-PNR-06) (a specific use case of surface parking)

## References

1.  Legal / regulatory [EPA, _Reducing Urban Heat Islands: Compendium of Strategies_, "Trees and Vegetation" and "Cool Pavements" chapters (2008; Cool Pavements chapter updated 2012). Direct source for the runoff and heat-island footprint claim above.](https://www.epa.gov/heatislands/guide-reducing-heat-islands)
2.  Precedent-based [ULI/National Parking Association, _The Dimensions of Parking_. Circulation, stall layout, and access design standards.](https://knowledge.uli.org/en/books/2009/the-dimensions-of-parking)

_"Legal / regulatory" here refers to the EPA guidance that municipal NPDES stormwater permits and heat-island mitigation programs are legally built around, not a single mandatory design spec like MUTCD or PROWAG._

---

Source: https://commonwaysystem.org/patterns/facilities/transit-hub-station/

# Transit Hub / Station

`FAC-THS-03`

Recommended Facility

Transit Hub / Station

A compound facility where multiple transit patterns (platforms, shelters, wayfinding, sometimes multiple routes or modes) converge into a single coordinated site, documenting intermodal transfer and placemaking rather than a single boarding point.

## Why this pattern exists

Once a stop grows past a single platform and shelter, it becomes its own design problem: passengers transferring between routes or modes need legible wayfinding, adequate circulation space, and often supporting amenities (restrooms, retail, bike parking) that a simple stop never requires. This pattern exists to mark that threshold and give higher-order stops their own documentation rather than treating them as an oversized version of a basic stop.[1]

## Key considerations

-   Circulation between platforms, modes, and site entrances should be direct and legible, minimizing backtracking or unclear paths
-   Passenger volume and transfer patterns should drive the mix of amenities provided, not a fixed template applied regardless of site
-   Where multiple agencies or modes share a hub, wayfinding and signage should read as one coordinated system, not stitched-together pieces

## Related patterns

[Transit Shelter](https://commonwaysystem.org/patterns/facilities/transit-shelter.md) (FAC-TSH-01), [Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md) (FAC-TPL-02) (component facilities); [Park-and-Ride](https://commonwaysystem.org/patterns/facilities/park-and-ride.md) (FAC-PNR-06) (a related but distinct compound facility oriented around auto transfer rather than multimodal transfer); [Bike-Share Station](https://commonwaysystem.org/patterns/facilities/bike-share-station.md) (FAC-BSS-09), [Secure Bike Parking/Bike Station](https://commonwaysystem.org/patterns/facilities/secure-bike-parking-bike-station.md) (FAC-SBP-10) (frequently co-located amenities)

## References

1.  Precedent-based [TCRP Report 153, "Guidelines for Providing Access to Public Transportation Stations," Transportation Research Board. Circulation, multimodal transfer, and amenity mix planning for higher-order stations.](https://nap.nationalacademies.org/catalog/14614/guidelines-for-providing-access-to-public-transportation-stations)

---

Source: https://commonwaysystem.org/patterns/facilities/transit-platform/

# Transit Platform

`FAC-TPL-02`

Recommended Facility

Transit Platform

The boarding surface at a transit stop where passengers board and alight, varying by platform height (level or low), length (accommodating one or multiple vehicles), and configuration (island platform serving two directions, or side platforms serving one direction each).

## Why this pattern exists

Boarding is where accessibility, dwell time, and safety concerns concentrate most tightly; a platform that does not match vehicle floor height or lacks adequate length creates real barriers for wheelchair users and slows every boarding cycle. This pattern exists to separate platform design, a distinct engineering and accessibility problem, from the shelter, signage, and other amenities that sit on top of it.

## Key considerations

-   Platform height should match the boarding vehicle’s floor height wherever feasible, to enable level boarding[1]
-   Island platforms require special attention to the intersection or roadway crossing needed to reach them safely
-   Length must accommodate the longest vehicle expected to serve the stop, including multi-unit or articulated vehicles

## Related patterns

[Transit Shelter](https://commonwaysystem.org/patterns/facilities/transit-shelter.md) (FAC-TSH-01) (typically paired amenity); [Transit Hub/Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) (FAC-THS-03) (compound facility); [Pedestrian Safety Island/Refuge](https://commonwaysystem.org/patterns/elements/pedestrian-safety-island-refuge.md) (ELM-PSI-09) (related Element pattern for reaching island platforms)

## References

1.  Legal / regulatory [PROWAG, Section R309.1, "Boarding and Alighting Areas," and Section R309.1.2, "Platform and Vehicle Floor Coordination." Direct basis for platform height and vehicle floor coordination, and the 8 ft x 5 ft minimum boarding area.](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/facilities/transit-shelter/

# Transit Shelter

`FAC-TSH-01`

Recommended Facility

Transit Shelter

A small- or large-format weather shelter installed at a transit stop, protecting waiting passengers from sun, rain, and wind, ranging from a simple lean-to canopy to a fully enclosed structure with seating and lighting.

## Why this pattern exists

Passenger comfort and perceived safety at a stop directly affect transit ridership; a stop with no protection from weather discourages waiting and signals that the route is not a priority investment. This pattern exists to document shelter as a distinct facility with its own siting, sizing, and structural considerations, separate from the platform it sits on and the route it serves.

## Key considerations

-   Shelter footprint must not obstruct the required clear path of travel on the adjacent sidewalk[1]
-   Sizing should scale with ridership volume at the stop, not be applied uniformly regardless of demand[2]
-   Orientation should account for prevailing wind and sun exposure specific to the site, not follow a single default facing

## Related patterns

[Transit Platform](https://commonwaysystem.org/patterns/facilities/transit-platform.md) (FAC-TPL-02) (the boarding surface it typically pairs with); [Transit Hub/Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) (FAC-THS-03) (the compound facility this becomes part of at higher-order stops)

## References

1.  Legal / regulatory [PROWAG, Section R309.2, "Transit Shelters" (federally adopted by DOT, effective January 17, 2025). Minimum clear space for mobility devices, connection to boarding areas via pedestrian access route.](https://www.access-board.gov/prowag/technical.html)
2.  Precedent-based [TCRP Report 19, "Guidelines for the Location and Design of Bus Stops," Transportation Research Board. Sizing relative to ridership volume, siting and orientation.](https://www.trb.org/Main/Blurbs/153827.aspx)

---

Source: https://commonwaysystem.org/patterns/freeways/beltway-ring-road/

# Beltway / Ring Road

`FRE-BLT-03`

Recommended Freeway

Beltway / Ring Road

A limited-access Freeway circling a metro area's outer edge, connecting radial corridors without routing through-traffic into the urban core. Out of the Commonway System's detailed design scope.[1]

Typical at: Rural Suburban

Undeveloped, Compact, and Urban are edge cases. Core is an unlikely pairing.

## Design notes

A Beltway's purpose, routing traffic around a metro area rather than through its densest core, means it realistically sits at Rural and Suburban density even in large metros, with Compact and Urban only appearing as the ring tightens around a fast-growing edge.

## Related patterns

[Default (Freeway)](https://commonwaysystem.org/patterns/freeways/default.md) (FRE-DEF-01) (the base form this extends), [Radial](https://commonwaysystem.org/patterns/network/radial.md) (NET-RAD-03) (the Network topology a Beltway completes by connecting radial corridors around, rather than through, the core)

## References

1.  Legal / regulatory [FHWA, _Highway Functional Classification Concepts, Criteria and Procedures_.](https://www.fhwa.dot.gov/planning/processes/statewide/related/hwy-functional-classification-2023.pdf)

---

Source: https://commonwaysystem.org/patterns/freeways/default/

# Default (Freeway)

`FRE-DEF-01`

Recommended Freeway

Default (Freeway)

A limited-access road with grade-separated interchanges and no direct property access. Freeway is intentionally out of the Commonway System's detailed design scope; no modal hierarchy or speed regulation applies within CS.[1]

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [You've Been Lied To About Roads For 60 Years](https://www.youtube.com/watch?v=CVq7XOXkg1U)

Global Cycling Network

Covers "junk roads," traffic-model incentives to overbuild, and the trillion-dollar cost of designing roads around growth projections that the roads themselves inflate.

Typical at: Undeveloped Rural Suburban Compact

Urban is an edge case. Core is an unlikely pairing, marked unlikely rather than edge case on purpose: a limited-access road cutting through a Core-density area is the kind of pattern the Commonway System would flag for retrofit, not treat as a realistic design target.

## Design notes

Freeway entries are listed in the Commonway System for completeness and cross-reference, not as a detailed design guide the way Local, Collector, and Arterial patterns are. CS's scope is street and road design; Freeway-scale interchange and alignment design belongs to a different discipline.

## Related patterns

[Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md) (INT-GSI-10) (the Intersection pattern governing where this pattern's design guidance resumes), [Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the Arterial pattern a Freeway interchange typically connects into)

## References

1.  Legal / regulatory [FHWA, _Highway Functional Classification Concepts, Criteria and Procedures_.](https://www.fhwa.dot.gov/planning/processes/statewide/related/hwy-functional-classification-2023.pdf)

---

Source: https://commonwaysystem.org/patterns/freeways/expressway/

# Expressway

`FRE-EXP-02`

Recommended Freeway

Expressway

A high-speed road with partial access control, some at-grade intersections remain, unlike a fully grade-separated Freeway. Out of the Commonway System's detailed design scope.[1]

Typical at: Rural Suburban Compact

Undeveloped and Urban are edge cases. Core is an unlikely pairing.

## Design notes

Expressway sits between full Freeway and Arterial in character, partial rather than complete access control, which is why its realistic density range skews slightly narrower than the full Freeway Default entry.

## Related patterns

[Default (Freeway)](https://commonwaysystem.org/patterns/freeways/default.md) (FRE-DEF-01) (the fully grade-separated form this sits just short of), [Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the Arterial-scale end of the spectrum this sits between), [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) (INT-SIG-03) (the control type governing the at-grade intersections this pattern still retains)

## References

1.  Legal / regulatory [FHWA, _Highway Functional Classification Concepts, Criteria and Procedures_.](https://www.fhwa.dot.gov/planning/processes/statewide/related/hwy-functional-classification-2023.pdf)

---

Source: https://commonwaysystem.org/patterns/freeways/freeway-transit/

# Freeway-scale Transit (Commuter / Heavy Rail)

`FRE-FTR-04`

Recommended Freeway

Freeway-scale Transit (Commuter / Heavy Rail)

Grade-separated commuter or heavy rail, moving passenger volume at Freeway scale without the limited-access roadway itself.[1]

Typical at: Suburban Compact Urban Core

Rural is an edge case. Undeveloped is an unlikely pairing.

## Design notes

This is the mirror image of the other three Freeway entries. Default, Expressway, and Beltway/Ring Road all taper off as density rises, while commuter and heavy rail exist specifically to move volume into dense cores, so this Typology becomes more typical, not less, as density increases.

## Related patterns

[Arterial Transit (BRT/LRT)](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) (ART-ATR-04) (the Arterial-scale equivalent transit pattern), [Transit Hub/Station](https://commonwaysystem.org/patterns/facilities/transit-hub-station.md) (FAC-THS-03) (the Facility pattern where riders interface with this rail scale)

## References

1.  Legal / regulatory [FTA, National Transit Database Glossary.](https://www.transit.dot.gov/ntd/national-transit-database-ntd-glossary)

---

Source: https://commonwaysystem.org/patterns/intersections/all-way-stop/

# All-Way Stop

`INT-AWS-04`

Situational / Discouraged Intersections & Crossings

All-Way Stop

An intersection where every approach carries a stop sign, with right-of-way determined by arrival order.

Typical at: Suburban Compact

Rural and Urban are edge cases. Undeveloped and Core are unlikely pairings.

## Design notes

All-Way Stop tapers off past Compact and Urban density, as intersection volumes exceed what stop control can handle safely. This is the same taper logic that applies to Stop/Yield control, just shifted one tier higher on the density range.[1]

## Related patterns

[Stop / Yield (Two-Way)](https://commonwaysystem.org/patterns/intersections/stop-yield.md) (INT-SYD-05) (explicitly named on this page as sharing the same density-taper logic, one tier lower), [Neighborhood Traffic Circle / Mini-Roundabout](https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout.md) (ELM-NTC-46) (a control type this pattern sometimes replaces at a Local intersection)

## References

1.  Legal / regulatory [Manual on Uniform Traffic Control Devices, 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Section 2B.13-2B.17.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/intersections/continuous-sidewalk/

# Continuous Sidewalk / Raised Junction

`INT-CSJ-06`

Recommended Intersections & Crossings

Continuous Sidewalk / Raised Junction

A junction where the sidewalk and bike path continue across the intersection at a consistent grade, and the roadway ramps up to meet them rather than the reverse. Dutch terminology;[1] carries an implicit yield to pedestrians and cyclists crossing.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

Aligned

### [Are Roundabouts Actually Better Than Traffic Lights?](https://www.youtube.com/watch?v=012fMI3TdRo)

Streetcraft

A real head-to-head test (Carmel, IN) backing the case for roundabouts on time, fuel efficiency, and crash severity, while being upfront about roundabouts' accessibility gap for blind pedestrians.

Aligned

### [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

Typical at: Compact Urban Core

Suburban is an edge case, thinning for the same reason as Bicycle Boulevard: a disconnected, cul-de-sac-heavy grid gives it fewer places to apply. Undeveloped and Rural are unlikely pairings.

## Design notes

This is the Commonway System's locked default treatment for Local-to-Collector intersections, giving priority to people walking and biking at the exact point where a slower Local street meets a faster Collector.

## Related patterns

[Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md) (LOC-DEF-01) (the page that names this pattern as its own locked default Local-to-Collector treatment), [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12) (explicitly named on this page as thinning for the same connectivity reason)

## References

1.  Precedent-based [CROW Platform for Transport, Infrastructure and Public Space, _Road Safety Manual_ / _Design Manual for Bicycle Traffic_.](https://www.crow.nl/Onderwerpen/verkeer-en-vervoer/)

---

Source: https://commonwaysystem.org/patterns/intersections/displaced-left-turn/

# Displaced Left-Turn (DLT)

`INT-DLT-14`

Situational / Discouraged Intersections & Crossings

Displaced Left-Turn (DLT)

An intersection where the left-turn lane is shifted to the opposing side of oncoming traffic at a signalized crossover upstream of the main intersection, letting left-turning and opposing through traffic move on concurrent phases. Also known as a continuous flow intersection.

Typical at: Suburban Compact Urban

Rural is an unlikely pairing. Core is an edge case.

## Design notes

This design resolves the same unprotected-left-turn conflict as Median U-Turn and Restricted Crossing U-Turn, but through signalized displacement rather than a median crossover, and at high-volume urban or suburban intersections rather than the higher-speed rural and suburban divided highways those two patterns typically suit. It's a faster, lower-cost alternative to a grade-separated interchange where volume is high enough that conventional protected left-turn phasing creates severe delay.[1] The additional right-of-way this pattern requires upstream of the main intersection, and its higher construction cost relative to Median U-Turn or Restricted Crossing U-Turn, keep it Situational rather than broadly Recommended.[2]

## Related patterns

[Median U-Turn](https://commonwaysystem.org/patterns/intersections/median-u-turn.md) (INT-MUT-12), [Restricted Crossing U-Turn](https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn.md) (INT-RCU-13) (the two lower-cost alternatives addressing the same underlying unprotected-left-turn problem in a different speed and volume context), [Grade-Separated Interchange](https://commonwaysystem.org/patterns/intersections/grade-separated-interchange.md) (INT-GSI-10) (the higher-cost alternative this pattern is often chosen instead of)

## Getting there: Retrofit path options

[Displaced Left-Turn (DLT) retrofit](https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit.md) (RFT-INT-04) reroutes an existing conventional intersection's left-turn movement to this geometry.

## References

1.  Evidence-based ["Unconventional Arterial Intersection Designs under Connected and Automated Vehicle Environment: A Survey," on Displaced Left-turn Intersection design and cost tradeoffs relative to grade-separated interchanges.](https://arxiv.org/abs/1811.03074)
2.  Legal / regulatory [U.S. Patent 7,135,989, "Parallel flow vehicle turn system for traffic intersections," on displaced left-turn design and right-of-way considerations.](https://patents.google.com/patent/US7135989B2/en)

---

Source: https://commonwaysystem.org/patterns/intersections/driveway-curb-cut/

# Driveway / Curb Cut

`INT-DCC-09`

Situational / Discouraged Intersections & Crossings

Driveway / Curb Cut

A break in the curb and sidewalk giving a driveway or parking entrance access to the street, a minor junction rather than a full intersection.

Typical at: Undeveloped Rural Suburban Compact Urban

Core is an edge case.

## Design notes

Driveways and curb cuts drop off at Core density, not because access needs disappear there, but because dense Core contexts typically consolidate individual curb cuts into shared alley or rear access instead, reducing how often each individual property needs its own street-facing break in the curb.[1]

## Related patterns

[Curb Cut / Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md) (ELM-CCA-04) (the Element-scale counterpart to this junction-level pattern), [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md) (LOC-ALY-02) (the Local Typology whose purpose is moving this kind of access to the rear)

## References

1.  Legal / regulatory [U.S. Access Board, Public Right-of-Way Accessibility Guidelines (PROWAG), Section R302, "Pedestrian Access Routes."](https://www.access-board.gov/prowag/technical.html)

---

Source: https://commonwaysystem.org/patterns/intersections/grade-separated-interchange/

# Grade-Separated Interchange

`INT-GSI-10`

Situational / Discouraged Intersections & Crossings

Grade-Separated Interchange

An interchange carrying conflicting movements on separate vertical levels, connected by ramps, eliminating at-grade conflict entirely. Freeway-scale only.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Roads don't have to be FAT to be FAST](https://www.youtube.com/watch?v=UV0x2hNRYnU)

Road Guy Rob

Explains the interrupted-flow/platooning physics behind signalized-arterial congestion, then covers Carmel's Keystone Parkway conversion to a limited-access road using compact elevated roundabout interchanges instead of a full diamond interchange.

Typical at: Undeveloped Rural Suburban

Compact and Urban are edge cases. Core is an unlikely pairing.

## Design notes

This is an acknowledged fallback for genuinely Freeway-scale volume or speed beyond what even a turbo-roundabout can manage, not a general-purpose alternative to the Commonway System's roundabout-first intersection philosophy. It stays confined to the density range where full Freeway-scale roads themselves are realistic.[1]

## Related patterns

[Default (Freeway)](https://commonwaysystem.org/patterns/freeways/default.md) (FRE-DEF-01) (reciprocal link to the Freeway-scale pattern this connects into), [Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md) (INT-TRB-02) (explicitly named on this page as the tier just below it), [Displaced Left-Turn](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) (INT-DLT-14) (the faster, lower-cost alternative often chosen over this pattern at high-volume urban and suburban intersections)

## References

1.  Legal / regulatory [American Association of State Highway and Transportation Officials, _A Policy on Geometric Design of Highways and Streets_.](https://store.transportation.org/Item/PublicationDetail?ID=4127)

---

Source: https://commonwaysystem.org/patterns/intersections/median-u-turn/

# Median U-Turn (MUT)

`INT-MUT-12`

Situational / Discouraged Intersections & Crossings

Median U-Turn (MUT)

An intersection where left-turn movements from both the major and minor approaches are removed from the main crossing and rerouted through a downstream median crossover, requiring a driver to travel past the intersection, make a U-turn, then complete the turn from the opposite direction.

Typical at: Rural Suburban

Compact is an edge case. Urban and Core are unlikely pairings.

## Design notes

This geometry exists to remove unprotected left turns from a major intersection entirely, rather than managing them with a longer signal phase.[1] Doing so shortens the signal cycle the main intersection needs to run and reduces the conflict points a driver has to judge in a single movement.[2] The tradeoff is a longer path for the rerouted turn and the median width needed to accommodate it, which is why this pattern is Situational rather than broadly Recommended: it solves a real problem well on a wide, higher-speed divided road, but doesn't fit a narrower cross-section or a genuinely low-speed context where Roundabout or a conventional Signal remains the better fit.

## Related patterns

[Restricted Crossing U-Turn](https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn.md) (INT-RCU-13) (the related, more restrictive geometry that also removes the minor road's direct through movement), [Displaced Left-Turn](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) (INT-DLT-14) (an alternative approach to the same unprotected-left-turn problem), [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) (INT-SIG-03) (the conventional intersection this pattern modifies rather than replaces outright)

## Getting there: Retrofit path options

[Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md) (RFT-INT-02) reroutes an existing conventional intersection's left-turn and through movements to this geometry.

## References

1.  Precedent-based [Indiana Department of Transportation, "Median U-turns."](https://www.in.gov/indot/traffic-engineering/median-u-turn/)
2.  Legal / regulatory [Federal Highway Administration, "Chapter 2. Intersections," _Handbook for Designing Roadways for the Aging Population_.](https://highways.dot.gov/safety/other/older-road-user/handbook-designing-roadways-aging-population/chapter-2-intersections)

---

Source: https://commonwaysystem.org/patterns/intersections/midblock-crossing/

# Midblock Pedestrian Crossing

`INT-MPC-08`

Recommended Intersections & Crossings

Midblock Pedestrian Crossing

A marked, and typically signalized or raised, pedestrian crossing placed mid-block rather than at a corner, serving a specific crossing demand between intersections.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings.

## Design notes

Midblock crossings supplement, rather than replace, intersection-level crossing treatment. They concentrate at higher density, where longer blocks and denser pedestrian destinations make a corner-only crossing pattern insufficient on its own.[1]

## Related patterns

[Crosswalk](https://commonwaysystem.org/patterns/elements/crosswalk.md) (ELM-CRW-08) (the Element-scale pattern this is a specific placement context for), [Pedestrian Hybrid Beacon](https://commonwaysystem.org/patterns/elements/pedestrian-hybrid-beacon.md) (ELM-PHB-18) (the Element most often used to control this crossing type at higher speeds or volumes)

## References

1.  Evidence-based [Zegeer, C. et al., "Safety Effects of Marked vs. Unmarked Crosswalks at Uncontrolled Locations," FHWA-RD-01-075 (Federal Highway Administration, 2002).](https://rosap.ntl.bts.gov/view/dot/15480/dot_15480_DS1.pdf)

---

Source: https://commonwaysystem.org/patterns/intersections/protected-intersection/

# Protected Intersection

`INT-PRI-11`

Recommended Intersections & Crossings

Protected Intersection

A Dutch-style intersection treatment using corner refuge islands and setback bicycle/pedestrian crossings to reduce conflict between turning vehicles and people walking or biking through the intersection.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural contexts are an unlikely pairing.

## Design notes

The first addition to Intersections & Crossings since the original ten. Addresses a specific, well-documented failure mode of conventional intersections, insufficient separation between turning vehicles and through bicycle/pedestrian traffic, that no other pattern in the set directly solves.[1]

Corner islands should provide genuine physical refuge, not a painted buffer alone. Crossing setback distance should give turning drivers a clear sightline and adequate reaction distance to pedestrians and cyclists.

Compatible with, and often paired with, [Roundabout](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) as the default intersection treatment.

## Turning trucks

Vehicles making a turn are involved in a disproportionate share of fatal pedestrian and cyclist crashes relative to vehicles going straight, and that risk rises sharply with vehicle size.[2][3] See [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) for the general pattern.

Where a truck route runs through this intersection, setting the bicycle stop bar back keeps a cyclist waiting at the intersection out of a turning truck's swept path. Where a bicycle signal phase exists, separating bicycle and truck turning movements in time, not just space, closes the gap a setback stop bar alone cannot.[4]

## Related patterns

-   [Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01)

## References

1.  Precedent-based [Falbo, Nick, "Protected Intersections for Bicyclists," ProtectedIntersection.com (2014).](http://www.protectedintersection.com/)
2.  Evidence-based [U.S. Government Accountability Office, _Pedestrian and Cyclist Safety: DOT Should Take Steps to Address Risks Related to Limited Driver Visibility_, GAO-26-107954 (2026).](https://www.gao.gov/products/gao-26-107954)
3.  Evidence-based [Wang, Q. et al., "Exploring the Influencing Factors and Formation of the Blind Zone of a Semitrailer Truck in a Right-Turn Collision," _Sustainability_ 14(16), 9805 (2022).](https://doi.org/10.3390/su14169805)
4.  Precedent-based [Seattle Streets Illustrated, 3.11 "Freight" (setback bike lane stop bars and bicycle signals as tools against large-truck turning movements).](https://streetsillustrated.seattle.gov/design-standards/freight/)

---

Source: https://commonwaysystem.org/patterns/intersections/railroad-grade-crossing/

# Railroad Grade Crossing

`INT-RGC-15`

Situational / Discouraged Intersections & Crossings

Railroad Grade Crossing

An at-grade crossing where any street type meets an active rail line, with its own geometry, warning devices, and low-clearance-vehicle risk distinct from any road-to-road intersection.

Typical at: Undeveloped Rural Suburban

Compact, Urban, and Core are also possible wherever an active rail line crosses a public street. The pattern is most common near industrial or agricultural rail spurs, but it is not exclusive to them.

## Design notes

This is its own pattern, not a row on another page, because it has its own geometry standard, its own required warning devices (distinct from any road-only intersection control), and its own sight-distance rules that vary by railroad company. It also applies across street types, not just [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) (COL-IND-03) or [Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) (COL-FTM-02), where an active spur is a realistic condition.

The core hazard is a "humped" or high-profile crossing that can strand a low-ground-clearance or long-wheelbase vehicle on the tracks. This is a distinct failure mode from any other intersection risk in this guidebook.[1][2]

-   **Approach grade.** The maximum approach grade should not exceed 3 inches of rail elevation at a point 30 ft from the center of the nearest rail, on both sides.[3]
-   **Warning device.** Where an existing humped crossing cannot be corrected, the MUTCD W10-5 Low Ground Clearance sign, with its W10-5P plaque, is the required warning device.[3]
-   **Sight lines.** Required sight-line distances vary by the specific railroad company operating the line, not a single national number.[3]
-   **Storage and queuing.** A crossing located near a highway intersection carries a higher collision rate in part because of the short vehicle storage area between the crossing and the intersection. Queues can form across the crossing itself.[4]
-   **Pedestrians.** Pedestrian-specific treatments are a separate design discipline from vehicle treatments: inter-track fencing, pedestrian gates, swing gates, channelization, and detectable warning surfaces.[5]

## Related patterns

[Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) (COL-IND-03) (an active rail spur is a realistic condition on industrial land), [Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) (COL-FTM-02) (rail spurs are plausible in agricultural contexts), [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) (INT-SIG-03) (a nearby signalized intersection is the storage and queuing interaction described above)

## References

1.  Legal / regulatory [Federal Highway Administration and Federal Railroad Administration, _Highway-Rail Crossing Handbook_, Third Edition.](https://railroads.dot.gov/sites/fra.dot.gov/files/2024-10/GXHandbook2019FRAFHWA.pdf)
2.  Evidence-based [Eck, R.W. and Kang, S.K., "Low-Clearance Vehicles at Rail-Highway Grade Crossings: An Overview of the Problem and Potential Solutions," _Transportation Research Record_ 1327 (1991), pp. 27 to 35.](https://onlinepubs.trb.org/Onlinepubs/trr/1991/1327/1327-005.pdf)
3.  Legal / regulatory [Florida Department of Transportation, _FDOT Design Manual_, Topic #625-000-002, Section 220 "Railroads" (humped crossing definition and MUTCD W10-5 sign requirement).](https://fdotwww.blob.core.windows.net/sitefinity/docs/default-source/roadway/fdm/2024/2024fdm220rr.pdf)
4.  Legal / regulatory [Federal Highway Administration, _Highway-Rail Crossing Handbook_, Appendix B, "Components of a Highway-Rail Grade Crossing."](https://highways.dot.gov/safety/hsip/xings/highway-rail-crossing-handbook-third-edition/b-appendix-components-highway-rail)
5.  Legal / regulatory [Federal Railroad Administration, "Engineering Design for Pedestrian Safety at Highway-Rail Grade Crossings."](https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/16553/Engineering_for_Ped_Safety_At_Crossings_final.pdf)

---

Source: https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn/

# Restricted Crossing U-Turn (RCUT)

`INT-RCU-13`

Situational / Discouraged Intersections & Crossings

Restricted Crossing U-Turn (RCUT)

An at-grade intersection design in which minor-road through and left-turn movements are removed entirely and redirected via a right turn followed by a U-turn at a designated median crossover. Also known as a J-turn or superstreet.

Typical at: Rural Suburban

Compact is an edge case. Urban and Core are unlikely pairings.

## Design notes

RCUT goes further than a Median U-Turn intersection by removing the minor road's direct crossing movement as well as its left turn, letting the main intersection serve the major road's through traffic with minimal minor-road interference.[1] This design carries particular benefit for large trucks, since a driver only has to judge a gap in one direction of traffic at a time rather than crossing the full width of a divided highway at once.[2] Like Median U-Turn, this pattern is Situational: it's a strong fit for a high-speed, four-lane-or-larger divided highway, and a poor fit anywhere lower speed or lower volume already makes a Roundabout the better default.[3]

## Related patterns

[Median U-Turn](https://commonwaysystem.org/patterns/intersections/median-u-turn.md) (INT-MUT-12) (the related, less restrictive geometry that still allows a direct minor-road through movement), [Displaced Left-Turn](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) (INT-DLT-14) (an alternative approach to the same unprotected-left-turn and through-crossing problem), [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) (INT-SIG-03) (the conventional intersection this pattern modifies rather than replaces outright)

## Getting there: Retrofit path options

[Restricted Crossing U-Turn (RCUT) retrofit](https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit.md) (RFT-INT-03) reroutes an existing conventional intersection's minor-road movements to this geometry.

## References

1.  Legal / regulatory [Texas Department of Transportation, "14.6 Restricted Crossing U-Turn Intersection (RCUT)."](https://www.txdot.gov/manuals/des/rdw/chapter-14--alternative-intersections-and-intercha/14-6-restricted-crossing-u-turn-intersection--rcut.html)
2.  Precedent-based [Wisconsin Department of Transportation, "Restricted Crossing U-Turn (RCUT) Intersections."](https://wisconsindot.gov/Pages/safety/safety-eng/rcut.aspx)
3.  Evidence-based [Kentucky Transportation Cabinet, "Reduced Conflict U-Turn," SAFERoads Solutions, before-after crash data.](https://transportation.ky.gov/saferoadsolutions/Pages/RCUT.aspx)

---

Source: https://commonwaysystem.org/patterns/intersections/roundabout/

# Roundabout (Single / Multi-Lane)

`INT-RAB-01`

Recommended Intersections & Crossings

Roundabout (Single / Multi-Lane)

A circular intersection where entering traffic yields to the circulating flow, sized single or multi-lane to the volume it carries.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Why Aren't Dangerous Drivers Punished?](https://www.youtube.com/watch?v=dHRfClVJg70)

Global Cycling Network

Traces why traffic law rarely punishes road violence proportionally, then makes the case CS already builds on: infrastructure should be designed so mistakes aren't fatal, rather than relying on punishment after the fact.

Context only

### [America Built the Wrong Roundabout (The Dutch Didn't)](https://www.youtube.com/watch?v=CKjTkXljhWc)

Safe By Design

Traces the turbo roundabout's origin and safety data, but also reports the Fietsersbond's documented cyclist/pedestrian crossing hazards at turbo roundabouts directly, worth noting since it complicates a clean "aligned" label.

Aligned

### [Are Roundabouts Actually Better Than Traffic Lights?](https://www.youtube.com/watch?v=012fMI3TdRo)

Streetcraft

A real head-to-head test (Carmel, IN) backing the case for roundabouts on time, fuel efficiency, and crash severity, while being upfront about roundabouts' accessibility gap for blind pedestrians.

Aligned

### [Roads don't have to be FAT to be FAST](https://www.youtube.com/watch?v=UV0x2hNRYnU)

Road Guy Rob

Explains the interrupted-flow/platooning physics behind signalized-arterial congestion, then covers Carmel's Keystone Parkway conversion to a limited-access road using compact elevated roundabout interchanges instead of a full diamond interchange.

Aligned

### [Let's FIX the HIGH SCHOOL (with 152 ROUNDABOUTS!)](https://www.youtube.com/watch?v=1ZUZA76L09M)

Road Guy Rob

The origin story of Carmel's roundabout program, starting with a contentious school-zone traffic-calming project, and the engineering fix (tightened entries, fatter center island) that made the design work.

Typical at: Suburban Compact Urban Core

Rural is an edge case. Undeveloped is an unlikely pairing.

## Design notes

Roundabout is the default control wherever two Collector-or-higher streets meet within the Commonway System's intersection philosophy. Traffic signals remain available but only as a documented last resort, and turbo-roundabouts take over at the highest-volume Arterial-to-Arterial junctions.[1][2]

## Freight-priority streets

When this pattern serves a freight-priority street ([Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) or any Typology carrying significant truck volume), size the inscribed circle diameter to the current NCHRP Research Report 1043 guidance for large vehicles, rather than the base passenger and bus vehicle range.[1]

The truck apron is for the occasional oversize check vehicle. The everyday design vehicle should clear the roundabout within the traveled way without off-tracking onto the apron.[3]

Two cautions apply. Designing every movement for the largest conceivable truck degrades safety for vulnerable users without a demonstrated need, so confirm actual vehicle-classification counts first.[3] And oversized intersections carry their own costs: more crash exposure, more confusion, more right-of-way, and longer pedestrian crossings.[4]

## Related patterns

[Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md) (INT-TRB-02) (the step up for higher-volume Arterial-to-Arterial junctions, per this page), [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) (INT-SIG-03) (the alternative control competing for the same higher-volume intersections, per Signal's own Design notes), [Neighborhood Traffic Circle / Mini-Roundabout](https://commonwaysystem.org/patterns/elements/neighborhood-traffic-circle-mini-roundabout.md) (ELM-NTC-46) (the much smaller, unsized analogue for a Local-to-Local intersection), [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) (COL-IND-03) (a freight-priority street whose intersection answer depends on this page's freight-street sizing note)

## Getting there: Retrofit path options

[Signal-to-roundabout conversion](https://commonwaysystem.org/retrofits/intersection/signal-to-roundabout-conversion.md) (RFT-INT-01)

## References

1.  Legal / regulatory [Transportation Research Board, _Guide for Roundabouts_, NCHRP Research Report 1043 (2023). Supersedes NCHRP Report 672.](https://www.nationalacademies.org/publications/27069)
2.  Evidence-based [Persaud, B. et al., "Safety Effect of Roundabout Conversions in the United States: Empirical Bayes Observational Before-After Study," Insurance Institute for Highway Safety (2001).](https://www.iihs.org/topics/bibliography/ref/1248)
3.  Legal / regulatory [Delaware Department of Transportation, _Design Guidance Memorandum_ (DGM) 1-26, "Roundabouts" (design vehicle versus check vehicle, and the caution against over-designing for the largest possible truck).](https://deldot.gov/Publications/manuals/dgm/pdfs/1-26_Roundabouts.pdf)
4.  Legal / regulatory [Wisconsin Department of Transportation, _Facilities Development Manual_, FDM 11-25 (costs of oversized truck-accommodating intersections).](https://wisconsindot.gov/rdwy/fdm/fd-11-25.pdf)

---

Source: https://commonwaysystem.org/patterns/intersections/signal/

# Signal

`INT-SIG-03`

Situational / Discouraged Intersections & Crossings

Signal

A signalized intersection, controlling conflicting movements with timed lights.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings.

Note

Signal remains available within the Commonway System, but only as a last resort requiring documented burden-of-proof justification, modeled on WSDOT's Roundabout First and Intersection Control Evaluation policy.[1][2] It is not banned, just never presumed. Where a roundabout or turbo-roundabout can serve the same volume, that is the default choice instead.

## Design notes

Signal's realistic density range overlaps heavily with Roundabout and Turbo-Roundabout, since all three ultimately compete for the same higher-volume intersections. The difference is which one the Commonway System treats as the presumed choice absent a documented reason otherwise.

## Turning-maneuver risk to people walking and biking

Vehicles making a turn are involved in a disproportionate share of fatal pedestrian and cyclist crashes relative to vehicles going straight, and that risk rises sharply with vehicle size.[3][4] This applies to every signal installation, not just those on freight-priority streets. [Industrial Collector](https://commonwaysystem.org/patterns/collectors/industrial-collector.md) is the acute case of it.

-   **Leading pedestrian intervals.** Give pedestrians a several-second head start into the crosswalk before the parallel vehicle phase turns green, so a turning driver has a chance to see the pedestrian before beginning the turn.[5]
-   **Curb extensions.** They shorten crossing exposure time and place waiting pedestrians directly in the turning driver's line of sight.[5] See [Curb Extension](https://commonwaysystem.org/patterns/elements/curb-extension.md).

## Related patterns

[Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) and [Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md) (INT-TRB-02) (explicitly named on this page as competing for the same higher-volume intersections); [Median U-Turn](https://commonwaysystem.org/patterns/intersections/median-u-turn.md) (INT-MUT-12), [Restricted Crossing U-Turn](https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn.md) (INT-RCU-13), and [Displaced Left-Turn](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) (INT-DLT-14) (unconventional geometries that modify rather than replace this pattern to remove unprotected left turns)

## References

1.  Legal / regulatory [Washington State Department of Transportation, _WSDOT Design Manual_, Chapter 1300, "Intersection Control Evaluation."](https://wsdot.wa.gov/publications/manuals/fulltext/m22-01/1300.pdf)
2.  Legal / regulatory [Manual on Uniform Traffic Control Devices, 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Chapter 4C.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)
3.  Evidence-based [U.S. Government Accountability Office, _Pedestrian and Cyclist Safety: DOT Should Take Steps to Address Risks Related to Limited Driver Visibility_, GAO-26-107954 (2026).](https://www.gao.gov/products/gao-26-107954)
4.  Evidence-based [Wang, Q. et al., "Exploring the Influencing Factors and Formation of the Blind Zone of a Semitrailer Truck in a Right-Turn Collision," _Sustainability_ 14(16), 9805 (2022).](https://doi.org/10.3390/su14169805)
5.  Evidence-based [Insurance Institute for Highway Safety, "Vehicles with big blind zones spell danger to pedestrians during left turns" (November 19, 2025) (leading pedestrian intervals and curb extensions as blind-zone mitigations).](https://www.iihs.org/news/detail/vehicles-with-big-blind-zones-spell-danger-to-pedestrians-during-left-turns)

---

Source: https://commonwaysystem.org/patterns/intersections/stop-yield/

# Stop / Yield (Two-Way)

`INT-SYD-05`

Situational / Discouraged Intersections & Crossings

Stop / Yield (Two-Way)

An intersection where only the minor-street approaches stop or yield, and the major street proceeds without control.

Typical at: Undeveloped Rural Suburban Compact

Urban is an edge case. Core is an unlikely pairing.

## Design notes

Two-way stop or yield control is the lowest-volume intersection treatment in the Commonway System's set, realistic across the widest density range of any control type before tapering off past Compact, the same taper logic that applies to All-Way Stop one tier higher.[1]

## Related patterns

[All-Way Stop](https://commonwaysystem.org/patterns/intersections/all-way-stop.md) (INT-AWS-04) (the reciprocal pattern, explicitly named on this page as sharing the same taper logic one tier higher)

## References

1.  Legal / regulatory [Manual on Uniform Traffic Control Devices, 11th Edition with Revision 1 (FHWA, December 2025; effective March 5, 2026), Section 2B.05 and 2B.10.](https://mutcd.fhwa.dot.gov/pdfs/11th_Editionr1/mutcd11theditionr1hl.pdf)

---

Source: https://commonwaysystem.org/patterns/intersections/turbo-roundabout/

# Turbo-Roundabout

`INT-TRB-02`

Recommended Intersections & Crossings

Turbo-Roundabout

A roundabout variant using spiral lane markings and raised lane dividers to guide multi-lane traffic without the weaving conflicts a standard multi-lane roundabout allows.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Context only

### [America Built the Wrong Roundabout (The Dutch Didn't)](https://www.youtube.com/watch?v=CKjTkXljhWc)

Safe By Design

Traces the turbo roundabout's origin and safety data, but also reports the Fietsersbond's documented cyclist/pedestrian crossing hazards at turbo roundabouts directly, worth noting since it complicates a clean "aligned" label.

Typical at: Compact Urban

Suburban and Core are edge cases. Undeveloped and Rural are unlikely pairings.

## Design notes

Reserved for higher-volume Arterial-to-Arterial junctions, where a standard roundabout's capacity is not enough but a signal is still not the preferred default. This keeps the roundabout-first philosophy intact at higher volumes rather than defaulting to a signal once traffic grows.[1]

## Related patterns

[Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01) (the base pattern this scales up from), [Signal](https://commonwaysystem.org/patterns/intersections/signal.md) (INT-SIG-03) (explicitly named on this page as the alternative not preferred even at these volumes)

## Getting there: Retrofit path options

[Signal-to-roundabout conversion](https://commonwaysystem.org/retrofits/intersection/signal-to-roundabout-conversion.md) (RFT-INT-01)

## References

1.  Evidence-based [Fortuijn, L.G.H., "Turbo Roundabouts: Design Principles and Safety Performance," _Transportation Research Record_ 2096 (2009).](https://doi.org/10.3141/2096-03)

---

Source: https://commonwaysystem.org/patterns/intersections/uncontrolled/

# Uncontrolled

`INT-UNC-07`

Situational / Discouraged Intersections & Crossings

Uncontrolled

An intersection with no stop, yield, signal, or roundabout control, right-of-way resolved informally by the drivers and other road users present.

Typical at: Undeveloped Rural

Suburban is an edge case. Compact, Urban, and Core are unlikely pairings.

## Design notes

Uncontrolled intersections are only realistic where traffic volume is low enough on every approach that informal right-of-way resolution stays safe, which narrows this pattern to the lowest end of the density range.[1] Where volume rises past that point, Stop / Yield (Two-Way) is the first applied control tier.

## Related patterns

[Stop / Yield (Two-Way)](https://commonwaysystem.org/patterns/intersections/stop-yield.md) (INT-SYD-05) (the next control tier up as volume exceeds informal right-of-way resolution, made explicit by the sentence added to this page's own Design notes)

## References

1.  Precedent-based [SWOV Institute for Road Safety Research, "Principles for a Safe Road Network."](https://swov.nl/en/fact-sheet/principles-safe-road-network)

---

Source: https://commonwaysystem.org/patterns/local-streets/alley/

# Alley

`LOC-ALY-02`

Recommended Local

Alley

A narrow Local street serving rear or side property access, service vehicles, and utility placement rather than through movement of any mode.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural contexts are unlikely to carry a purpose-built alley.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Vehicle > Freight > Pedestrian > Bicycle > Transit

Alley inverts the Local base order. The override is justified because the Typology's stated purpose is service and driveway access, not through movement, one of the closed set of triggers that permits a departure from the base order.[1]

## Design notes

Because an alley is not a through-route for people walking or biking, its narrow width and service function do not conflict with the 20 mph Local speed cap. The override applies to mode priority, not to the speed rule.

## Related patterns

[Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md) (LOC-DEF-01) (the base modal order this pattern inverts), [Curb Cut / Driveway Apron](https://commonwaysystem.org/patterns/elements/curb-cut-driveway-apron.md) (ELM-CCA-04) (the Element governing the driveway access this Typology exists to serve)

## References

1.  Precedent-based [NACTO, _Urban Street Design Guide_, "Green Alley" and "Commercial Alley."](https://nacto.org/publication/urban-street-design-guide/streets/green-alley/)

---

Source: https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard/

# Bicycle Boulevard / Neighborhood Greenway

`LOC-BBG-12`

Recommended Local

Bicycle Boulevard / Neighborhood Greenway

A Local street where traffic calming and diversion discourage through car traffic while prioritizing bicycle through-movement in the shared roadway.

Typical at: Compact Urban Core

Suburban is an edge case, thinning for the same reason as [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md): a disconnected, cul-de-sac-heavy grid gives it fewer parallel, low-traffic routes to use. Undeveloped and Rural are unlikely pairings.

## Illustration

**Type:** Paired. **Format:** Segment / cross-section (~2.8:1).

Typical condition

An ordinary Local street cross-section: unrestricted through car traffic, a cyclist taking the lane alongside car volumes, no diverters, no wayfinding.

Commonway recommendation

A modal diverter or traffic circle blocks car through-movement while a bicycle-width gap passes through; wayfinding signage marks the route; a calmed, low-volume, low-speed shared roadway.

Callouts

1.  (Physical) Modal diverter / traffic circle blocking through car movement; a bicycle-width gap allows continuous bicycle passage.
2.  (Physical) Wayfinding signage marking the route as a through bicycle connection.
3.  (Control-timing) At crossings of higher-volume streets, a signalized or protected crossing reduces bicyclist delay.[1]

No supplemental illustration needed.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

Aligned

### [More Lanes Are (Still) A Bad Thing](https://www.youtube.com/watch?v=CHZwOAIect4)

Not Just Bikes

Lays out induced demand, Braess's Paradox, and traffic evaporation with real case studies (LA 405, Houston Katy Freeway, Cheonggyecheon), then shows the Dutch one-lane-plus-transit cross-section as the actual fix.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions. A separate 85th/95th-percentile operating-speed threshold of 25 mph is used as a trigger for additional traffic calming, not as a substitute design speed.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Bicycle > Pedestrian > Transit > Vehicle > Freight

An override justified because shared-street bicycle priority is this Typology's entire reason for existing.

## Design notes

Traffic calming and diverters discourage through car traffic while retaining local access, the reverse of a Collector-scale Bike Highway / Greenway's full physical separation. NACTO's guidance sets the design threshold where the treatment works: daily motor vehicle volume at or below 3,000 and a 95th-percentile speed at or below 25 mph, with heavier calming needed above those figures.[1]

A comparison of Berkeley's bicycle boulevards to their parallel arterials found bicyclist collision rates two to eight times lower on the boulevards.[2]

## Related patterns

[Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) (COL-BHG-04) — the Collector-scale pattern this one is explicitly distinguished from on that page: physical separation there, a shared, calmed roadway here.

[Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md) (INT-CSJ-06) — the Local-to-Collector intersection default, explicitly named alongside this pattern on that page as thinning in Suburban for the same grid-connectivity reason.

[Modal Filter / Point Closure](https://commonwaysystem.org/patterns/elements/modal-filter-point-closure.md) (ELM-MFP-44) — the Element pattern most frequently paired with this one to build the diversion shown above.

## Getting there: Retrofit path options

[Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md) (RFT-CDR-05), [Modal filtering / Low Traffic Neighborhood retrofit](https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit.md) (RFT-NET-01, applies _within_ this pattern rather than transforming it into something else)

## References

1.  Precedent-based [National Association of City Transportation Officials, _Urban Bikeway Design Guide_, 3rd ed. (2025), "Bike Boulevards," in _Designing Bikeways for All Ages and Abilities_.](https://nacto.org/publication/urban-bikeway-design-guide/designing-bikeways-for-all-ages-and-abilities/bikeways-on-low-speed-low-volume-streets/bike-boulevards/)
2.  Evidence-based [Minikel, E., "Cyclist Safety on Bicycle Boulevards and Parallel Arterial Routes in Berkeley, California," _Accident Analysis & Prevention_ 45 (2012): 241–247.](https://nacto.org/wp-content/uploads/Minikel-2011.pdf)

---

Source: https://commonwaysystem.org/patterns/local-streets/cul-de-sac/

# Cul-de-sac

`LOC-CDS-03`

Situational / Discouraged Local

Cul-de-sac

A dead-end Local street with no through connection for any mode.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

Typical at: Suburban

Compact is an edge case. Undeveloped, Rural, Urban, and Core are unlikely pairings.

Caution

Cul-de-sac carries Situational status. The connectivity and walkability expectations that define Urban and Core density are close to incompatible with a dead-end street pattern, so this Typology's realistic range is narrow, peaking at Suburban.[1]

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Bicycle > Vehicle > Freight

The Local base order minus Transit, since a dead-end street rarely carries a transit route.

## Design notes

A cul-de-sac trades network connectivity for a quiet, low-through-traffic environment. That trade only holds up at lower densities, where a disconnected street grid does not yet conflict with pedestrian and bicycle route continuity.

## Related patterns

[Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01) (the connected Network topology this pattern structurally departs from, the basis of this page's cited connectivity/safety research), [Default (Standard Local Street)](https://commonwaysystem.org/patterns/local-streets/default.md) (LOC-DEF-01) (the base order this pattern drops Transit from)

## References

1.  Evidence-based [Marshall, W.E. and Garrick, N.W. (2011), "Street network types and road safety: A study of 24 California cities," _Urban Design International_ 16(2).](https://link.springer.com/article/10.1057/udi.2009.31)

---

Source: https://commonwaysystem.org/patterns/local-streets/default/

# Default (Standard Local Street)

`LOC-DEF-01`

Recommended Local

Default (Standard Local Street)

The baseline Local street. No special access pattern, event use, or dedicated mode gives it a name of its own, so it carries the base Local modal hierarchy and speed rule unmodified. Every other Local Typology is defined as a departure from this one: a Typology earns its own name only when its entire reason for existing is a specific access pattern, a specific event use, or a specific mode.

## Illustration

**Type:** Paired. **Format:** Segment / cross-section (~2.8:1).

Typical condition

Oversized suburban local cross-section: no planting buffer, a narrow or absent sidewalk, and an overly wide travel lane.

Commonway recommendation

Sidewalk 5 ft, planting/furnishing zone 5 ft (standard, not optional), shared two-way undivided travel lane 18 ft, sized to self-enforce 20 mph.[1]

Callouts

1.  (Physical) Sidewalk sized for comfortable two-way pedestrian travel.
2.  (Physical) Planting/furnishing zone buffering pedestrians from the travel lane.
3.  (Physical) Travel lane narrowed to self-enforce 20 mph.[2]

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [What is the "Correct" Speed Limit?](https://www.youtube.com/watch?v=JRbnBc-97Ps)

Not Just Bikes

Makes the physics and data case for 30 km/h (roughly 20 mph) as the safe default urban speed, the same logic behind CS's own Local street speed cap.

## Where this pattern applies

Typical at: Suburban Compact Urban Core

Rural is an edge case, not the norm. Farm and rural-residential contexts more often produce a [Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) pattern instead, since a genuinely Local-scale street needs enough nearby development to serve. Undeveloped contexts are unlikely to carry a Local street at all, for the same reason.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

20 mph hard maximum, no exceptions. This is not a target or an aspirational limit: under CS's self-enforcing roadway principle, design speed always equals posted speed, so the street's geometry itself has to make 20 mph the comfortable driving speed, not just the posted number.[1]

Modal hierarchy

Pedestrian > Bicycle > Transit > Vehicle > Freight

Modal hierarchy follows the Local base order without an override. This order follows directly from Local's access-priority role in the Functional Classification system, not from a judgment call specific to this Typology. A named Typology only reorders it when the Typology's whole purpose is a specific mode, for example [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md) (Vehicle and Freight first, since the entire point is service and driveway access) or [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (Bicycle first, since shared-street bicycle priority is the entire point).

## Relationship to other Local Typologies

This entry is the reference point, not one option among equals. Reading the other eleven Local Typologies as departures from this baseline makes the whole set easier to hold in mind:

-   **Access-pattern departures:** [Alley](https://commonwaysystem.org/patterns/local-streets/alley.md), [Cul-de-sac](https://commonwaysystem.org/patterns/local-streets/cul-de-sac.md), [Frontage / Service Road](https://commonwaysystem.org/patterns/local-streets/frontage-service-road.md)
-   **Land-use departures:** [Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md)
-   **Traffic-model departures:** [Living Street / Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md), [Yield Street](https://commonwaysystem.org/patterns/local-streets/yield-street.md)
-   **Temporary or event-based departures:** [Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md), [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md)
-   **Full-time single-mode departures:** [Pedestrian-only Street / Plaza](https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza.md), [Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md), [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md)

## Where a Local street meets a bigger street

The default intersection treatment where this pattern meets a Collector is a [Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md): the sidewalk and bike path stay uninterrupted, and the roadway ramps up to meet them rather than the reverse.

## Design notes

This entry is the standard against which every other Local Typology is defined as an override. A Typology only departs from the base modal order when its entire reason for existing is a specific mode.

## Related patterns

[Continuous Sidewalk / Raised Junction](https://commonwaysystem.org/patterns/intersections/continuous-sidewalk.md) (INT-CSJ-06) (this pattern's own default intersection treatment where it meets a Collector), [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01) (the equivalent baseline one Functional Classification up)

## References

1.  Legal / regulatory [FHWA, "Self-Enforcing Roadways: A Guidance Report," FHWA-HRT-17-098, 2018.](https://highways.dot.gov/research/publications/safety/FHWA-HRT-17-098)
2.  Precedent-based [National Association of City Transportation Officials, _Urban Street Design Guide_, "Street Design Principles: Lane Width."](https://nacto.org/publication/urban-street-design-guide/street-design-elements/lane-width/)

---

Source: https://commonwaysystem.org/patterns/local-streets/festival-street/

# Festival Street

`LOC-FES-08`

Recommended Local

Festival Street

A Local street designed to convert between full vehicle access and a pedestrian-and-bicycle-only event space, on a schedule rather than permanently.

Typical at: Urban Core

Compact is an edge case. Undeveloped, Rural, and Suburban are unlikely pairings.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Vehicle access is excluded entirely during scheduled events. Outside of events, the Local default applies: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

During events:

Pedestrian > Bicycle

Off-hours:

Pedestrian > Bicycle > Transit > Vehicle > Freight

This pattern carries two separate modal hierarchies depending on time of day, not one: full pedestrian/bicycle exclusivity during scheduled events, the Local base order the rest of the time.

## Design notes

The dual-mode design, full street for events and normal Local operation otherwise, is what distinguishes this from a permanent Pedestrian-only Street or Plaza. It requires enough event demand and foot traffic to justify the conversion, which is why it concentrates at Urban and Core density.[1]

## Related patterns

[Pedestrian-only Street / Plaza](https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza.md) (LOC-PED-09) (the permanent version of what this pattern does on a schedule), [School Street](https://commonwaysystem.org/patterns/local-streets/school-street.md) (LOC-SCH-11) (shares this pattern's schedule-based structure, per both pages' Design notes)

## References

1.  Precedent-based [Seattle Municipal Code §11.14.203, "Festival Streets."](https://streetsillustrated.seattle.gov/urban-design/public-space/festival-streets/)

---

Source: https://commonwaysystem.org/patterns/local-streets/frontage-service-road/

# Frontage / Service Road

`LOC-FSR-04`

Recommended Local

Frontage / Service Road

A Local street running alongside a higher-speed Arterial or Freeway, giving property access and slower-mode movement a lane physically separated from the through traffic next to it.

Typical at: Rural Suburban Compact Urban

Undeveloped and Core are edge cases.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions, even where this road runs alongside a higher-speed Arterial or Freeway.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Bicycle > Transit > Vehicle > Freight

Follows the Local base order. Flagged for confirmation rather than fully locked.

## Design notes

The safety rationale is separation, not speed: keeping people walking and biking off a roadway designed for faster through traffic.[1] This is the Local-scale companion to the Arterial safety rule that access needs are served by a separate road rather than mixed into through lanes.

## Related patterns

[Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) (the Arterial-scale rule this pattern serves as the Local-scale companion to), [Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md) (ART-STD-05) (the Avoid pattern that results when this separation isn't provided)

## References

1.  Legal / regulatory [AASHTO, _A Policy on Geometric Design of Highways and Streets_.](https://store.transportation.org/Item/PublicationDetail?ID=4127)

---

Source: https://commonwaysystem.org/patterns/local-streets/living-street-woonerf/

# Living Street / Woonerf

`LOC-LSW-06`

Recommended Local

Living Street / Woonerf

A Local street with no separation between the pedestrian, bicycle, and vehicle space. Vehicles are guests, moving at walking pace and yielding to people on foot or bike by design, not by signage alone.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Can we make cities car free?](https://www.youtube.com/watch?v=g9-9CxCxrVE)

City Beautiful

Covers Oslo's parking-elimination approach, Barcelona's superblocks, and Houten's ring-road-with-car-free-interior model, each a different route to the same modal-filtering goal.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions. In practice, the shared-surface design typically produces actual speeds well below this ceiling.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Bicycle > Vehicle > Transit > Freight

Vehicle ranks third as a guest in this order, not a peer road user: it moves at walking pace and yields to people on foot or bike by design.

## Design notes

NACTO's Home Zone is, strictly, an area-wide overlay rather than a distinct street type of its own, but the Commonway System folds it into this single entry rather than tracking it separately, since the on-the-ground design treatment is the same shared, no-separation street.[1]

## Related patterns

[Yield Street](https://commonwaysystem.org/patterns/local-streets/yield-street.md) (LOC-YLD-07) (the other Local pattern using street geometry itself, rather than signage, as the calming mechanism)

## Getting there: Retrofit path options

[Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md) (RFT-NET-02) applies _within_ a multi-block area; this is one of the two typical results for its interior streets.

## References

1.  Precedent-based [Ben-Joseph, E. (1995), "Changing the Residential Street Scene: Adapting the Shared Street (Woonerf) Concept to the Suburban Environment," _Journal of the American Planning Association_ 61(4).](https://www.tandfonline.com/doi/abs/10.1080/01944369508975661)

---

Source: https://commonwaysystem.org/patterns/local-streets/local-transit/

# Local Transit

`LOC-LTR-10`

Recommended Local

Local Transit

A Local street carrying a fixed transit route, most often a local bus line, where transit priority is layered onto the base pedestrian and bicycle priority rather than replacing it.

Typical at: Suburban Compact Urban Core

Undeveloped and Rural are unlikely pairings, since Local Transit assumes a rider base a low-density area typically cannot support.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions. Transit priority in the modal hierarchy below does not change the vehicle speed cap.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Transit > Pedestrian > Bicycle > Vehicle > Freight

This is an override of the Local base order, justified by the Typology's stated purpose: a designated transit route.

## Design notes

This entry is the Local-scale sibling of Collector Transit and Arterial Transit. All three follow the same override logic, moving Transit to the top of their respective base order once a route is designated, rather than treating transit priority as automatic on every street a bus happens to use.[1]

## Related patterns

[Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) (COL-CTR-05) and [Arterial Transit (BRT/LRT)](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) (ART-ATR-04) (this pattern's siblings across Functional Classification, following the same override logic per this page's own Design notes)

## Getting there: Retrofit path options

[Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md) (RFT-CDR-05), [Transit priority lane retrofit](https://commonwaysystem.org/retrofits/corridor/transit-priority-lane-retrofit.md) (RFT-CDR-06)

## References

1.  Precedent-based [NACTO, _Transit Street Design Guide_, 2016.](https://nacto.org/publication/transit-street-design-guide/)

---

Source: https://commonwaysystem.org/patterns/local-streets/main-street/

# Main Street

`LOC-MST-05`

Recommended Local

Main Street

A Local street lined with retail and commercial frontage, where pedestrian movement and lingering are treated as primary and vehicle movement is subordinate.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [South Carolina's Freeway for Bikes](https://www.youtube.com/watch?v=NxGYs8kHxw4)

Road Guy Rob

The Swamp Rabbit Trail's rail-to-trail history and its treatment as genuine transportation infrastructure, plus the Travelers Rest Main Street road diet that reallocated car lanes to parking and bike parking.

Typical at: Compact Urban

Rural, Suburban, and Core are edge cases: a small-town pattern at Rural, less common at Suburban, and tapering at Core where retail frontage folds into larger mixed-use blocks. Undeveloped is an unlikely pairing.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Transit > Bicycle > Vehicle > Freight

This ordering is a judgment call, reasoned from the Typology's purpose rather than derived cleanly from a listed override trigger, and is open for correction.

## Design notes

Main Street is the clearest case where a Local street's identity comes from its edge condition, retail frontage, rather than from a special traffic control treatment. It shares its defining density range with Stroad, the Arterial-scale pattern for commercial frontage done wrong.[1]

## Related patterns

[Stroad (Commercial Arterial)](https://commonwaysystem.org/patterns/arterials/stroad.md) (ART-STD-05) (shares this pattern's defining density range), [Downtown Thoroughfare](https://commonwaysystem.org/patterns/collectors/downtown-thoroughfare.md) (COL-DTH-07) (the Collector-scale pattern for a comparable commercial-thoroughfare hybrid)

## Getting there: Retrofit path options

[One-way to two-way conversion](https://commonwaysystem.org/retrofits/corridor/one-way-to-two-way-conversion.md) (RFT-CDR-04)

## References

1.  Precedent-based [NACTO, _Urban Street Design Guide_, "Neighborhood Main Street."](https://nacto.org/publication/urban-street-design-guide/streets/neighborhood-main-street/)

---

Source: https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza/

# Pedestrian-only Street / Plaza

`LOC-PED-09`

Situational / Discouraged Local

Pedestrian-only Street / Plaza

A Local street or plaza space that excludes vehicle traffic permanently, not on an event schedule the way a Festival Street does.

Typical at: Urban Core

Compact is an edge case. Undeveloped, Rural, and Suburban are unlikely pairings.

Caution

Pedestrian-only Street / Plaza carries Situational status. Full vehicle exclusion is only realistic where surrounding land use and network connectivity can absorb the displaced access, which concentrates this pattern at Urban and Core density.

## Modal hierarchy

Modal hierarchy

Pedestrian > Bicycle

Where permitted, Bicycle ranks second. All other modes are excluded rather than ranked; Design Speed & Speed Limits doesn't apply here, since this pattern excludes automobiles entirely.

## Design notes

Unlike Festival Street, which toggles between full and pedestrian-only operation, this Typology's exclusion of vehicles is permanent. That makes it a heavier commitment, appropriate only where the surrounding block can genuinely support it.[1]

## Related patterns

[Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md) (LOC-FES-08) (the scheduled version of this pattern's permanent vehicle exclusion), [Plaza / Parklet](https://commonwaysystem.org/patterns/facilities/plaza-parklet.md) (FAC-PLZ-07) (the Facility-scale pattern for a comparable public-space treatment)

## Getting there: Retrofit path options

[Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md) (RFT-NET-02) applies _within_ a multi-block area; this is one of the two typical results for its interior streets.

## References

1.  Precedent-based [NACTO, _Urban Street Design Guide_, "Pedestrian Streets" and "Public Plazas."](https://nacto.org/publication/urban-street-design-guide/streets/)

---

Source: https://commonwaysystem.org/patterns/local-streets/school-street/

# School Street

`LOC-SCH-11`

Recommended Local

School Street

A Local street adjacent to a school that restricts or excludes vehicle traffic during arrival and dismissal, then reverts to normal Local operation the rest of the day.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Let's FIX the HIGH SCHOOL (with 152 ROUNDABOUTS!)](https://www.youtube.com/watch?v=1ZUZA76L09M)

Road Guy Rob

The origin story of Carmel's roundabout program, starting with a contentious school-zone traffic-calming project, and the engineering fix (tightened entries, fatter center island) that made the design work.

Typical at: Compact Urban Core

Suburban is an edge case. Undeveloped and Rural are unlikely pairings, where schools are typically set back with dedicated drop-off lots rather than fronting a closable street.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Vehicle access is restricted or excluded during arrival and dismissal. Outside of active hours, the Local default applies: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

During active hours:

Pedestrian > Bicycle

Off-hours:

Pedestrian > Bicycle > Transit > Vehicle > Freight

This pattern carries two separate modal hierarchies depending on time of day, not one: full pedestrian/bicycle exclusivity during arrival and dismissal, the Local base order the rest of the time.

## Design notes

This Typology and Festival Street share the same schedule-based structure, full closure or restriction during a defined window, base operation otherwise. Both were added to the system after a NACTO gap-check identified time-restricted street patterns not otherwise covered by the core Local set.[1]

## Related patterns

[Festival Street](https://commonwaysystem.org/patterns/local-streets/festival-street.md) (LOC-FES-08) (shares this pattern's schedule-based structure, per both pages' Design notes)

## References

1.  Evidence-based [Gellatly, R. and Marner, B., "Air Quality Monitoring Study: London School Streets," 2021.](https://www.london.gov.uk/programmes-and-strategies/environment-and-climate-change/environment-publications/school-streets-air-quality-study)

---

Source: https://commonwaysystem.org/patterns/local-streets/shared-use-path/

# Shared-Use Path

`LOC-SUP-13`

Recommended Local

Shared-Use Path

An off-street path physically separated from the roadway, shared by pedestrians and bicyclists under roughly equal priority, connecting local-scale destinations.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

Typical at: Suburban Compact Urban Core

Undeveloped and Rural contexts are unlikely to carry a purpose-built shared-use path.

## Modal hierarchy

Modal hierarchy

Pedestrian = Bicycle

Pedestrian and Bicycle share top priority under this pattern's own equal-priority definition, no ranking between the two. Transit, Vehicle, and Freight do not apply off-street; Design Speed & Speed Limits doesn't apply here, since this pattern excludes automobiles entirely.

## Design notes

Width should accommodate two-way pedestrian and bicycle travel without forcing conflict, with connections back to the street network at logical, safe, visible points rather than incidental gaps.[1] Distinct from [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12), which shares an on-street roadway rather than separating off-street, and from [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) (COL-MUT-06), which is longer-distance and destination-scale rather than local-connector scale.

## Related patterns

-   [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12)
-   [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) (COL-MUT-06)

## Getting there: Retrofit path options

[Barrier-crossing / network reconnection retrofit](https://commonwaysystem.org/retrofits/network/barrier-crossing-network-reconnection-retrofit.md) (RFT-NET-03) commonly takes this form where it crosses a highway, rail line, or disconnected cul-de-sac pattern.

## References

1.  Legal / regulatory [AASHTO, _Guide for the Development of Bicycle Facilities_, 5th Edition, 2024.](https://store.transportation.org/item/collectiondetail/267)

---

Source: https://commonwaysystem.org/patterns/local-streets/yield-street/

# Yield Street

`LOC-YLD-07`

Recommended Local

Yield Street

A Local street narrow enough that two vehicles cannot pass without one yielding, using the street's width itself as a traffic-calming device.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Typical at: Suburban Compact

Rural and Urban are edge cases. Undeveloped and Core are unlikely pairings, since local street volumes at Core density typically exceed what yield control can handle safely.

## Speed and modal hierarchy

Design speed & speed limit

\[SPEED LIMIT 20\]

Follows the Local default: 20 mph hard maximum, no exceptions.

See [Design Speed & Speed Limits](https://commonwaysystem.org/guide/design-speed.md).

Modal hierarchy

Pedestrian > Bicycle > Vehicle > Transit > Freight

Marked as needing confirmation rather than fully locked.

## Design notes

This pattern only functions where traffic volume is genuinely low. It thins out toward Urban and Core, where local street volumes typically outgrow what a shared, yield-controlled width can safely absorb.[1]

## Related patterns

[Living Street / Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md) (LOC-LSW-06) (the reciprocal pattern, sharing width-as-calming-device but going further to treat vehicles as guests)

## References

1.  Precedent-based [NACTO, _Urban Street Design Guide_, "Yield Street."](https://nacto.org/publication/urban-street-design-guide/streets/yield-street/)

---

Source: https://commonwaysystem.org/patterns/network/dendritic-hierarchical/

# Dendritic / Hierarchical

`NET-DEN-02`

Situational / Discouraged Network

Dendritic / Hierarchical

A tree-like network topology where local streets feed into collectors, which feed into arterials, minimizing through-connections at lower tiers and concentrating traffic onto a smaller number of higher-order routes. Historically progressed through increasingly branch-heavy, cul-de-sac-dominated forms over the 20th century, documented as an internal four-stage spectrum: Fragmented Parallel (c. 1950), Warped Parallel (c. 1960), Loops and Lollipops (c. 1970), and Lollipops on a Stick (c. 1980).

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

## Why this pattern exists

Dendritic/Hierarchical networks reduce through-traffic on local streets by design, which is genuinely valuable for neighborhood quiet and safety, but the same branching structure that filters traffic also reduces route choice and increases circuity for everyone, including people walking and biking. This pattern documents both the topology and its historical sub-stages together, since the four named stages are not separate topologies but points along one continuous progression toward heavier branching and fewer through-connections.[1][2]

## Key considerations

-   The four historical sub-stages (Fragmented Parallel, Warped Parallel, Loops and Lollipops, Lollipops on a Stick) represent increasing degrees of branching and decreasing route choice, not four separate patterns; later stages have progressively fewer access points, intersections, and lineal feet of street per unit area
-   Pedestrian and bicycle cut-throughs at cul-de-sac heads meaningfully mitigate the circuity penalty for people not in cars, and should be a standard companion treatment rather than an afterthought
-   Independent research has found residents of tree-like/dendritic networks drive measurably more than residents of grid networks, a consideration worth weighing against the traffic-reduction benefit this pattern provides

## Related patterns

[Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01) (contrasting topology); Superblock/Cellular (a [Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01) modifier addressing a similar through-traffic concern by a different mechanism); Marshall’s D-type/Distributory

## References

1.  Precedent-based Southworth, Michael, and Eran Ben-Joseph. _Streets and the Shaping of Towns and Cities_. Rev. ed. Washington, DC: Island Press, 2003. Chapter 5, "Streets for Living," pp. 105-107. Print/ebook source, no persistent URL to monitor.
2.  Precedent-based Marshall, Stephen. _Streets and Patterns_. London: Spon Press, 2005. Chapter 4, "Pattern Type," "Developing Typologies of Pattern" (ABCD typology, D-type/Distributory), pp. 83-96. Print/ebook source, no persistent URL to monitor.

---

Source: https://commonwaysystem.org/patterns/network/grid/

# Grid

`NET-GRD-01`

Recommended Network

Grid

A network topology in which streets form a continuous, evenly spaced pattern of parallel and perpendicular routes intersecting at right angles, producing rectangular blocks and multiple direct route options between any two points.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

Aligned

### [Why do so many U.S. cities have gridded streets?](https://www.youtube.com/watch?v=KUDVP6aRS1Y)

City Beautiful

Traces how the grid became the default American street pattern, from William Penn's Philadelphia through Jefferson's Midwest land ordinances, historical background for why the Grid network topology pattern is so dominant in U.S. contexts.

## Why this pattern exists

Grid is one of the most common and longest-documented network topologies worldwide, prized for the route choice and connectivity it offers: because most intersections allow through-travel in multiple directions, traffic is not forced onto a small number of bottleneck routes the way a more hierarchical network can produce. This pattern documents that base topology before any of the modifiers (Superblock/Cellular) or contrasting topologies (Dendritic/Hierarchical, Radial, Organic/Irregular) that relate to it.[1][2]

## Key considerations

-   Connectivity and route choice are the grid’s core strength, but this also means it produces more total pavement, more blocks, and more intersections per unit area than more hierarchical alternatives
-   A grid can be paired with the Superblock/Cellular modifier to filter through-traffic from interior cells while preserving the grid’s overall connectivity for walking, cycling, and emergency access
-   Historic gridiron patterns and modern grid-based neotraditional developments both fall under this pattern, even though they differ in block size and detail

## Related patterns

[Dendritic/Hierarchical](https://commonwaysystem.org/patterns/network/dendritic-hierarchical.md) (NET-DEN-02), [Radial](https://commonwaysystem.org/patterns/network/radial.md) (NET-RAD-03), [Organic/Irregular](https://commonwaysystem.org/patterns/network/organic-irregular.md) (NET-ORG-04) (contrasting Network topologies); Superblock/Cellular (a modifier applied to this pattern, not a separate topology)

## References

1.  Precedent-based Southworth, Michael, and Eran Ben-Joseph. _Streets and the Shaping of Towns and Cities_. Rev. ed. Washington, DC: Island Press, 2003. Chapter 5, "Streets for Living," pp. 105-107. Print/ebook source, no persistent URL to monitor.
2.  Precedent-based Marshall, Stephen. _Streets and Patterns_. London: Spon Press, 2005. Chapter 4, "Pattern Type," "Developing Typologies of Pattern" (ABCD typology, B-type/Bilateral), pp. 83-96. Print/ebook source, no persistent URL to monitor.

---

Source: https://commonwaysystem.org/patterns/network/organic-irregular/

# Organic / Irregular

`NET-ORG-04`

Descriptive Network

Organic / Irregular

An unplanned, irregular network shaped incrementally over time by terrain, property lines, and historical settlement patterns rather than a deliberate overall layout, typically found in historic or pre-industrial city cores.

## Why this pattern exists

Organic/Irregular networks are a real, common existing condition, especially in historic cores worldwide, and the Patterns section’s role is descriptive documentation of what exists, not prescriptive endorsement of what to build. This pattern is documented for that reason: Commonway System does not recommend building new organic/irregular networks, but existing ones are a genuine, common reality that needs naming and description like any other topology.[1]

## Key considerations

-   Irregular orientation and angularity often produce natural traffic calming through unpredictability and reduced sightlines, an incidental but real benefit of this topology
-   Retrofitting modern accessibility and modal infrastructure into an organic network requires context-sensitive, block-by-block approaches rather than standard geometric assumptions that work on a regular grid
-   Closely corresponds to Marshall’s A-type/Altstadt, typically found at a settlement’s historic core

## Related patterns

[Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01), [Radial](https://commonwaysystem.org/patterns/network/radial.md) (NET-RAD-03), [Dendritic/Hierarchical](https://commonwaysystem.org/patterns/network/dendritic-hierarchical.md) (NET-DEN-02) (contrasting Network topologies); Marshall’s A-type/Altstadt

## References

1.  Precedent-based Marshall, Stephen. _Streets and Patterns_. London: Spon Press, 2005. Chapter 4, "Pattern Type," "Developing Typologies of Pattern" (ABCD typology, A-type/Altstadt), pp. 83-96. Print/ebook source, no persistent URL to monitor.

---

Source: https://commonwaysystem.org/patterns/network/radial/

# Radial

`NET-RAD-03`

Situational / Discouraged Network

Radial

A network topology in which routes converge toward and radiate outward from a central point, frequently supplemented by circumferential (ring) routes connecting the radial spokes at varying distances from the center.

## Why this pattern exists

Radial networks arose historically and organically around a defined city center, and remain genuinely efficient for travel oriented toward that center; but the same convergence that makes downtown travel efficient also concentrates traffic at the center and underserves travel between non-downtown points. This pattern documents the topology and its common hybrid forms.[1]

## Key considerations

-   Distinguish pure Radial from Radial-Circumferential (radial routes connected by one or more ring roads) and Radial-Grid (a radial system superimposed on an underlying grid); each has different tradeoffs
-   Route convergence near the center requires deliberate capacity and intersection design, since multiple high-volume routes meeting at or near one point is a well-documented source of congestion
-   As travel patterns shift away from single-downtown-focused trips toward more distributed origin-destination pairs, a purely radial system increasingly underserves the majority of trips

## Related patterns

[Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01), [Dendritic/Hierarchical](https://commonwaysystem.org/patterns/network/dendritic-hierarchical.md) (NET-DEN-02), [Organic/Irregular](https://commonwaysystem.org/patterns/network/organic-irregular.md) (NET-ORG-04) (contrasting Network topologies)

## References

1.  Precedent-based Levinson, Herbert S., and Kenneth R. Roberts. "System Configurations in Urban Transportation Planning." _Highway Research Record_, no. 64 (1965): pp. 71-83. Available at: [https://onlinepubs.trb.org/Onlinepubs/hrr/1965/64/64-002.pdf](https://onlinepubs.trb.org/Onlinepubs/hrr/1965/64/64-002.pdf)

---

Source: https://commonwaysystem.org/references/

# Reference

Every pattern page in this guidebook carries two kinds of backup: numbered citations at the bottom of the page, which back specific claims, and this section, which holds the fuller technical detail sitting beneath a pattern's plain-language description.

## What lives here

A pattern page tells you what a Street Typology is and when to use it. This section holds the layer beneath that: exact dimensions, formulas, design criteria, and specification tables, the detail a reader needs when they're actually drawing or building something, not just deciding what to build.

This is different from a page's References list. References back a specific claim with a source. This section expands on the claim itself with the numbers and criteria a citation alone doesn't carry.

## How it's organized

Reference entries follow the same Pattern ID used throughout the guidebook. A pattern's expanded technical detail, where it exists, sits at the same ID under this section.

## Where this stands today

This section is new. It's being built out pattern by pattern, and most patterns don't have an entry here yet. Where no entry exists, the pattern page itself is still the complete, current guidance, this section only adds detail beyond what's already there.

---

Source: https://commonwaysystem.org/retrofits/

# Retrofit Strategy Index

Every Retrofit Strategy currently in the Commonway System, grouped by scale: Network, Corridor, and Intersection. See [How to read a retrofit strategy](https://commonwaysystem.org/guide/how-to-read-a-retrofit-strategy.md) for what each part of a Retrofit Strategy entry covers and how it relates to the Pattern catalog.

A Pattern describes what a street should be. A Retrofit Strategy describes how to move an existing street toward one. This index lists the strategies; [Patterns](https://commonwaysystem.org/patterns.md) has the destinations.

## Network level strategies

Network strategies change how an area functions as a whole, typically by restricting motor vehicle through-traffic without changing any single street's underlying topology classification.

1

### [Modal filtering / Low Traffic Neighborhood retrofit](https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit.md)

`RFT-NET-01`

2

### [Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md)

`RFT-NET-02`

3

### [Barrier-crossing / network reconnection retrofit](https://commonwaysystem.org/retrofits/network/barrier-crossing-network-reconnection-retrofit.md)

`RFT-NET-03`

## Corridor level strategies

Corridor strategies change a single street segment's cross-section: lane count, lane width, curb use, or surface. Most can move through the construction spectrum starting from paint and temporary materials.

1

### [Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md)

`RFT-CDR-01`

2

### [Five-plus lane reallocation](https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation.md)

`RFT-CDR-02`

3

### [Lane diet](https://commonwaysystem.org/retrofits/corridor/lane-diet.md)

`RFT-CDR-03`

4

### [One-way to two-way conversion](https://commonwaysystem.org/retrofits/corridor/one-way-to-two-way-conversion.md)

`RFT-CDR-04`

5

### [Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md)

`RFT-CDR-05`

6

### [Transit priority lane retrofit](https://commonwaysystem.org/retrofits/corridor/transit-priority-lane-retrofit.md)

`RFT-CDR-06`

7

### [Protected bike lane retrofit via lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md)

`RFT-CDR-07`

8

### [Protected bike lane retrofit via lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md)

`RFT-CDR-08`

9

### [Protected bike lane retrofit via parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md)

`RFT-CDR-09`

10

### [Depaving / pavement-to-gravel conversion](https://commonwaysystem.org/retrofits/corridor/depaving-pavement-to-gravel.md)

`RFT-CDR-10`

11

### [2+1 road with cable median barrier](https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier.md)

`RFT-CDR-11`

## Intersection level strategies

Intersection strategies change how a single intersection controls conflicting movements. Several of these require real construction from the outset and can't be meaningfully piloted with temporary materials.

1

### [Signal-to-roundabout conversion](https://commonwaysystem.org/retrofits/intersection/signal-to-roundabout-conversion.md)

`RFT-INT-01`

2

### [Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md)

`RFT-INT-02`

3

### [Restricted Crossing U-Turn (RCUT) retrofit](https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit.md)

`RFT-INT-03`

4

### [Displaced Left-Turn (DLT) retrofit](https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit.md)

`RFT-INT-04`

---

Source: https://commonwaysystem.org/retrofits/corridor/depaving-pavement-to-gravel/

# Depaving / pavement-to-gravel conversion

`RFT-CDR-10` Corridor

Depaving / pavement-to-gravel conversion

Converts a paved roadway to a gravel or unpaved surface, typically on a low-volume rural or exurban road, reducing both construction cost and vehicle speed.

## Overview

This is the outlier among Corridor retrofit strategies: its primary driver is usually cost and maintenance burden rather than safety countermeasure evidence, though it carries real traffic-calming and financial benefits on the right road. A paved rural road that sees very low traffic volume can cost more to maintain as pavement than it would as gravel, and a gravel surface naturally discourages high speeds.

## Where this leads: Target patterns

[Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) (COL-FTM-02)

## Applicability and thresholds

Applicable to low-volume rural or exurban roads where paving costs exceed the practical benefit of a paved surface for the traffic actually using it. Not applicable to any corridor carrying meaningful through-traffic volume, transit service, or bicycle commuting demand, all of which benefit materially from a paved surface.

## Evidence and effectiveness

Minnesota's GreenStep Cities program lists retention of a gravel road, or conversion of a paved road to gravel, as a traffic-calming and financial best practice for appropriate low-volume roads.[1]

## Getting it built

This strategy sits differently on the construction spectrum than most others in this catalog: it moves toward less permanent infrastructure rather than more, and doesn't have a meaningful demonstration or pilot stage in the usual sense. The decision is typically made and executed directly, based on cost analysis rather than iterative testing. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Usually a county or rural township public works decision, based on maintenance budget analysis rather than a formal safety or capacity process. See [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

None currently cataloged.

## References

1.  Precedent-based [Minnesota Pollution Control Agency, GreenStep Cities, "Implement Traffic Calming Policy/Measures," best practice action referencing gravel road retention and conversion.](https://greenstep.pca.state.mn.us/best_practice_action/implement-traffic-calming-policymeasures-including-lane-conversions-road-diets)

---

Source: https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation/

# Five-plus lane reallocation

`RFT-CDR-02` Corridor

Five-plus lane reallocation

Reduces the through-lane count on a roadway of five or more lanes, applying road diet principles at a larger scale than the standard four-to-three conversion.

## Overview

Wider roadways, five lanes and up, carry enough volume and turning complexity that a straightforward four-to-three conversion doesn't apply directly. This strategy still removes excess through capacity and adds or widens a center turn lane, but requires more careful traffic analysis and often a phased approach, since five-lane-and-larger corridors typically carry higher volumes and more conflicting turning movements than the classic road diet case.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

## Where this leads: Target patterns

[Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01), [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (ART-BLV-02)

## Applicability and thresholds

Evaluated specifically for roadways with five or more lanes in NCHRP-adjacent research, distinct from the four-to-three case. Sight-distance and conflict-point improvements follow the same underlying mechanism as a standard road diet, but volume thresholds run higher given the additional capacity these corridors typically carry.

## Evidence and effectiveness

Research on five-lane-and-larger road diet projects documents conflict-point reduction and improved sight distance for turning drivers, using the same two-stage reasoning as smaller road diets: fewer lanes to scan, and a dedicated turn lane separating through and turning movements.[1]

## Getting it built

Can move through the construction spectrum, though the larger scope, more lanes, more signal coordination, more turning-movement analysis, makes a formal pilot or quick-build stage more valuable here than on a simple four-to-three conversion. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is worth considering where the corridor's intersections will also see a change in turn-lane configuration. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Typically a city or county transportation department decision, though the larger scope and often-higher-classification roadway makes state DOT coordination more likely than with a simple four-to-three road diet. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) (RFT-CDR-01) (the smaller-scale equivalent this strategy extends)

## References

1.  Evidence-based ["An Evaluation of 'Road Diet' Projects on Five Lane and Larger Roadways," transportation research summary distributed via NACTO.](https://nacto.org/wp-content/uploads/An-Evaluation-of-Road-Diet-Projects-on-Five-Lane-and-Larger-Roadways.pdf)
2.  Legal / regulatory [Federal Highway Administration, "Road Diets (Roadway Reconfiguration)," Proven Safety Countermeasures, FHWA-SA-12-013.](https://highways.dot.gov/safety/proven-safety-countermeasures/road-diets-roadway-reconfiguration)

---

Source: https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet/

# Four-to-three lane road diet

`RFT-CDR-01` Corridor

Four-to-three lane road diet

Converts an existing four-lane undivided roadway (two through lanes each direction) into three lanes: one through lane each direction plus a center two-way left-turn lane, reclaiming the freed width for other uses.

## Overview

This is the classic road diet. A road built with more through capacity than its traffic actually needs gets restriped, sometimes with minimal construction, to remove one lane of excess capacity and separate through traffic from left-turning traffic, which today shares a lane and creates rear-end and sideswipe conflicts. The reclaimed width typically becomes a bike lane, wider sidewalk, on-street parking, or landscaping.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [This is the key to safer streets](https://www.youtube.com/watch?v=xsSp8gxzfjo)

Streetcraft

A full traffic-calming toolkit walkthrough, plastic mini-roundabouts, curb extensions, chicanes, the speed bump/hump/cushion/table family, and a Cincinnati road-diet case study with dramatic before/after crash data.

## Where this leads: Target patterns

[Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01), [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01), [Downtown Thoroughfare](https://commonwaysystem.org/patterns/collectors/downtown-thoroughfare.md) (COL-DTH-07)

## Applicability and thresholds

Most effective below roughly 19,000 vehicles per day; can succeed up to about 23,000 to 25,000 with careful signal coordination, though more extensive redesign is typically needed above the lower threshold. Corridors with closely spaced signals need timing coordination to avoid queuing impacts at adjacent intersections.

## Evidence and effectiveness

FHWA reports an overall crash reduction of 19 to 47 percent for four-to-three lane road diets, driven by separating through and turning movements and reducing the speed variance between lanes that a four-lane cross-section otherwise creates.[1][2]

## Getting it built

Can move through the full construction spectrum. A road diet is frequently implemented as a low-cost restriping project, sometimes opportunistically bundled with routine repaving, making it one of the more common demonstration- and pilot-stage strategies before becoming permanent. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is not typically required unless the road diet is paired with a change in intersection control along the corridor. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Usually a city or county public works or transportation department decision, often achievable without new legislation since it can be executed as a maintenance restriping project. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

[Five-plus lane reallocation](https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation.md) (RFT-CDR-02) (the equivalent approach for wider roadways), [Lane diet](https://commonwaysystem.org/retrofits/corridor/lane-diet.md) (RFT-CDR-03) (a lighter-touch alternative that narrows lanes without removing one)

## References

1.  Legal / regulatory [Federal Highway Administration, "Road Diets (Roadway Reconfiguration)," Proven Safety Countermeasures, FHWA-SA-12-013.](https://highways.dot.gov/safety/proven-safety-countermeasures/road-diets-roadway-reconfiguration)
2.  Evidence-based [Federal Highway Administration, Highway Safety Information System, "Evaluation of Lane Reduction 'Road Diet' Measures and Their Effects on Crashes and Injuries," 2010.](https://highways.dot.gov/research/publications/safety/hsis/FHWA-HRT-10-053)
3.  Precedent-based [NACTO Urban Street Design Guide, "Neighborhood Main Street."](https://nacto.org/publication/urban-street-design-guide/streets/neighborhood-main-street/)

---

Source: https://commonwaysystem.org/retrofits/corridor/lane-diet/

# Lane diet

`RFT-CDR-03` Corridor

Lane diet

Narrows existing travel lane widths without removing a lane, reclaiming the width difference for a bike lane, wider sidewalk, or buffer.

## Overview

Where a road diet removes a whole lane, a lane diet keeps the same lane count but makes each lane narrower, typically down to 10 or 10.5 feet from a wider original width. This is a lighter-touch alternative, useful where traffic volume doesn't support removing a lane but the existing lanes are wider than necessary for safe operation.

## Where this leads: Target patterns

[Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01), [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01)

## Applicability and thresholds

Appropriate on corridors where lane count must stay the same, due to volume or a jurisdiction's unwillingness to remove a lane, but where existing lanes exceed the width actually needed for safe operation at the corridor's design speed.

## Evidence and effectiveness

A Canadian Institute of Transportation study presented in 2015 found side-impact and turn-related crash rates lowest where average lane widths fall between 10 and 10.5 feet, challenging the assumption that wider lanes are inherently safer.[1]

## Getting it built

Can move through the construction spectrum easily, since restriping to a narrower lane width is typically a paint-only change, well suited to a demonstration or pilot stage before permanent striping. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

No formal decision process is typically required, since lane count is unchanged.

## Who can move this

Usually a city or county public works decision, achievable through routine restriping without new legislation. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) (RFT-CDR-01) (the more aggressive alternative where lane count itself can be reduced)

## References

1.  Evidence-based [Findings presented at the Canadian Institute of Transportation Engineers annual meeting, June 2015, on lane width and side-impact/turn-related crash rates, as referenced in "Technical Guidance on Road Diets."](https://www.pps.org/article/technical-guidance-on-road-diets)

---

Source: https://commonwaysystem.org/retrofits/corridor/one-way-to-two-way-conversion/

# One-way to two-way conversion

`RFT-CDR-04` Corridor

One-way to two-way conversion

Converts a one-way street back to two-way operation, typically reducing lane width and count in the process.

## Overview

Many one-way streets were converted from an original two-way configuration in the mid 20th century, aimed at speeding vehicle throughput through downtowns. Converting back to two-way slows traffic (drivers on a one-way street tend to travel faster and pay less attention, since they only need to watch one direction) and restores each direction's visibility to passing traffic, which research links to improved business exposure.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc)

Not Just Bikes

Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift.

## Where this leads: Target patterns

[Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01), [Main Street](https://commonwaysystem.org/patterns/local-streets/main-street.md) (LOC-MST-05), [Downtown Thoroughfare](https://commonwaysystem.org/patterns/collectors/downtown-thoroughfare.md) (COL-DTH-07)

## Applicability and thresholds

Most commonly applied to downtown one-way pairs originally converted for vehicle throughput. A feasibility study is typically warranted first, since delivery access, transit routing, and turn restrictions all need re-evaluation under two-way operation.

## Evidence and effectiveness

Documented average speeds on one-way streets have measured roughly double those on comparable two-way streets in the same neighborhood.[1] Separately, Louisville, Kentucky recorded a 23 percent decline in crime and a 42 percent reduction in robberies following conversion of a one-way pair to two-way, a result researchers attribute in part to slower speeds and increased pedestrian and cyclist presence.[2][3]

## Getting it built

Two-way conversion is harder to pilot informally than a simple road diet, since it typically requires new signal phasing, new signage, and turn-restriction changes at every intersection along the corridor. A quick-build stage using temporary signage and striping is more realistic than a short demonstration. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is commonly warranted at each affected intersection, since signal phasing and turn movements change substantially. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

A city council or transportation department decision, often requiring coordination across multiple city departments (signals, signage, parking) given the corridor-wide scope of the change. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

None currently cataloged.

## References

1.  Evidence-based [Ayres Associates, "One-Way or the Other? Two-Way Traffic Conversion Requires Study."](https://www.ayresassociates.com/one-way-or-the-other-two-way-traffic-conversion-requires-study/)
2.  Precedent-based ["Student Corner: The State of the Debate: Two-Way Street Conversion," Community and Economic Development, UNC School of Government.](https://ced.sog.unc.edu/2018/12/06/the-state-of-the-debate-two-way-street-conversion/)
3.  Precedent-based [Steuteville, R., "Cities Benefit from Restoring Two-Way Traffic," Congress for the New Urbanism.](https://www.cnu.org/publicsquare/2019/07/09/cities-benefit-one-way-two-way-conversions)

---

Source: https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation/

# Parking-lane reallocation

`RFT-CDR-05` Corridor

Parking-lane reallocation

Converts an existing on-street parking lane to another use: a bike lane, a transit lane, a parklet, or public plaza space.

## Overview

A parking lane is curb space, not travel-lane space, so reallocating it changes the curb's function rather than the roadway's through capacity. This makes it a distinct retrofit strategy from a road diet or lane diet, even though it's often executed alongside one. Common outcomes include a painted or protected bike lane, a peak-hour or full-time bus lane, or a parklet occupying what was previously one or two parking spaces.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why Amsterdam is Removing 10,000 Parking Spaces](https://www.youtube.com/watch?v=mXLqrMljdfU)

Not Just Bikes

Documents Amsterdam's on-street parking reduction through permit attrition and street redesigns, including the tradeoff of a large replacement garage inducing more driving nearby.

## Where this leads: Target patterns

[Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12), [Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) (LOC-LTR-10), [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) (COL-CTR-05)

## Applicability and thresholds

Applicable wherever on-street parking exists and demand analysis shows the parking is underutilized relative to the corridor's other needs, or where the reallocated use (transit, bikes, public space) is judged a higher priority than parking supply at that location.

## Evidence and effectiveness

AASHTO identifies reconfiguring or reducing on-street parking as one of three established approaches to retrofitting bicycle facilities without widening the road, alongside reallocating travel-lane width and reducing the number of travel lanes.[1]

## Getting it built

Well suited to the early stages of the construction spectrum. A parklet or bike lane conversion is a common demonstration- or pilot-stage project, using paint, planters, and removable barriers before any permanent construction. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

No formal decision process is typically required, though negotiation with affected business owners and residents is common practice, per FHWA guidance on parking removal.

## Who can move this

Usually a city public works or planning department decision, sometimes requiring business improvement district or city council coordination where displaced parking affects adjacent businesses. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Protected bike lane retrofit via parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) (RFT-CDR-09) (a specific application of this strategy aimed at bike facilities)

## References

1.  Evidence-based [Federal Highway Administration University Course on Bicycle and Pedestrian Transportation Design, module on street reconfiguration and parking removal.](https://www.fhwa.dot.gov/publications/research/safety/pedbike/05085/chapt15.cfm)
2.  Precedent-based [PPS, "A Glossary of Road Diet Strategies," on converting parking lanes to plazas and parklets.](https://www.pps.org/article/a-glossary-of-road-diet-strategies)

---

Source: https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal/

# Protected bike lane retrofit via lane removal

`RFT-CDR-08` Corridor

Protected bike lane retrofit via lane removal

Installs a physically separated bike lane by removing an entire travel lane, the same underlying mechanism as a road diet, applied specifically to create bike facility space.

## Overview

Where narrowing lanes alone doesn't recover enough width for a genuine protected facility, removing a full travel lane does. This is effectively a road diet whose primary purpose, rather than a secondary benefit, is the bike lane it creates. AASHTO recommends this approach specifically where a corridor's traffic volume can absorb the reduced through capacity.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Where this leads: Target patterns

[Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) (COL-BHG-04), [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) with [Protected Bike Lane / Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37)

## Applicability and thresholds

Follows the same volume thresholds as a standard road diet, since removing a lane carries the same through-capacity implications regardless of what the recovered space becomes. Most viable below roughly 19,000 to 25,000 vehicles per day.

## Evidence and effectiveness

FHWA reports crash reductions of up to 29 percent on road diet conversions generally; where the recovered lane specifically becomes a protected bike lane, the same crash-reduction mechanism applies alongside the added bicycling safety benefit of physical separation from traffic.[1][2]

## Getting it built

Can move through the construction spectrum the same way a standard road diet does, restriping first, with a protected lane's physical separation elements (curbs, planters, or flexible posts) added at the quick-build stage before permanent construction. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Usually a city or county transportation department decision, following the same approval path as a standard road diet. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Protected bike lane retrofit via lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md) (RFT-CDR-07), [Protected bike lane retrofit via parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) (RFT-CDR-09) (the other two approaches to the same underlying goal, distinguished by where the recovered width comes from)

## References

1.  Evidence-based [Transportation Policy Research, Texas A&M Transportation Institute, "Bicycle Lanes." AASHTO-recommended retrofit approaches without widening the road.](https://policy.tti.tamu.edu/strategy/bicycle-lanes)
2.  Legal / regulatory [Federal Highway Administration, "Road Diets (Roadway Reconfiguration)," Proven Safety Countermeasures, FHWA-SA-12-013.](https://highways.dot.gov/safety/proven-safety-countermeasures/road-diets-roadway-reconfiguration)

---

Source: https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction/

# Protected bike lane retrofit via parking reduction

`RFT-CDR-09` Corridor

Protected bike lane retrofit via parking reduction

Installs a physically separated bike lane by removing or reconfiguring on-street parking, often placing the bike lane where parking used to be and shifting parking, if retained, to the outside of a physical buffer.

## Overview

This is the parking-specific case of Parking-Lane Reallocation, applied to bike facilities. A common configuration keeps some parking but moves it away from the curb, using the parked cars themselves as part of the physical buffer protecting the bike lane between the parking lane and the sidewalk.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Where this leads: Target patterns

[Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) (COL-BHG-04), [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01) with [Protected Bike Lane / Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37)

## Applicability and thresholds

Most applicable where on-street parking demand analysis shows capacity to reduce or relocate parking without materially harming adjacent businesses or residents, and where lane width or count changes alone don't recover sufficient space.

## Evidence and effectiveness

AASHTO identifies reconfiguring or reducing on-street parking as one of three established retrofit approaches for adding bike facilities without widening the road.[1] Removing parking near intersections specifically has documented safety benefits beyond the bike facility itself, improving sightlines between drivers and other road users.[2]

## Getting it built

Can move through the construction spectrum starting with temporary channelizers and paint at the pilot stage, since testing community and business response to the parking change before committing to permanent curb reconstruction is common and often politically necessary. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Usually a city public works or planning department decision, though parking removal frequently requires more direct business and resident engagement than lane-width or lane-count retrofits, and may need city council involvement where removal is contested. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Protected bike lane retrofit via lane-width reallocation](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation.md) (RFT-CDR-07), [Protected bike lane retrofit via lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md) (RFT-CDR-08) (the other two approaches to the same underlying goal, distinguished by where the recovered width comes from); [Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md) (RFT-CDR-05) (the general-purpose version of this same mechanism)

## References

1.  Evidence-based [Transportation Policy Research, Texas A&M Transportation Institute, "Cycle Tracks." Retrofitting protected bike lanes by reallocating parking, underutilized lanes, or excess lane width.](https://policy.tti.tamu.edu/strategy/cycle-tracks/)
2.  Evidence-based [Federal Highway Administration University Course on Bicycle and Pedestrian Transportation Design, on parking removal and safety/capacity effects.](https://www.fhwa.dot.gov/publications/research/safety/pedbike/05085/chapt15.cfm)

---

Source: https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-width-reallocation/

# Protected bike lane retrofit via lane-width reallocation

`RFT-CDR-07` Corridor

Protected bike lane retrofit via lane-width reallocation

Installs a physically separated bike lane by narrowing existing travel lanes and reallocating the recovered width, without removing a lane or on-street parking.

## Overview

This is the lightest-touch of the three protected bike lane retrofits. AASHTO's Green Book allows narrower vehicle lanes, down to 10 feet, in many contexts, and a four-lane arterial with turn lanes can often be restriped during routine maintenance to include a buffer and a physically separated bike lane without touching lane count or parking at all.[1]

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Are Streets Too Complicated Now?](https://www.youtube.com/watch?v=u1Xs5EA5_uU)

City Beautiful

Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.

Aligned

### [Dutch-style intersection design: bike-friendly](https://www.youtube.com/watch?v=yCzi1Q4xCTA)

BicycleDutch

Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.

## Where this leads: Target patterns

[Bike Highway / Greenway](https://commonwaysystem.org/patterns/collectors/bike-highway-greenway.md) (COL-BHG-04), [Default (Standard Collector)](https://commonwaysystem.org/patterns/collectors/default.md) (COL-DEF-01) with [Protected Bike Lane / Cycle Track](https://commonwaysystem.org/patterns/elements/protected-bike-lane-cycle-track.md) (ELM-PBL-37)

## Applicability and thresholds

Most applicable where existing lanes are wider than required for safe operation at the corridor's design speed, giving enough recoverable width to build a genuine physical buffer rather than a painted line alone.

## Evidence and effectiveness

FHWA identifies planned road diets and similar retrofits of higher-speed roads as prime opportunities to add separated bike lanes, since the same width analysis that supports a lane diet or road diet also identifies the space available for a buffer and protected lane.[2]

## Getting it built

Restriping-based, so it can move through the full construction spectrum starting from paint and flexible delineators at the demonstration or pilot stage, before committing to permanent curb or planter-based separation. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Usually a city or county public works decision, achievable through routine restriping maintenance in many cases. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Protected bike lane retrofit via lane removal](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-lane-removal.md) (RFT-CDR-08), [Protected bike lane retrofit via parking reduction](https://commonwaysystem.org/retrofits/corridor/protected-bike-lane-parking-reduction.md) (RFT-CDR-09) (the other two approaches to the same underlying goal, distinguished by where the recovered width comes from)

## References

1.  Legal / regulatory [AASHTO, _A Policy on Geometric Design of Highways and Streets_ (Green Book), lane width criteria.](https://store.transportation.org/Item/PublicationDetail?ID=4127)
2.  Evidence-based [Federal Highway Administration, "Separated Bike Lanes," Bicycle and Pedestrian Program.](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/separated_bike_lanes/index.cfm)

---

Source: https://commonwaysystem.org/retrofits/corridor/transit-priority-lane-retrofit/

# Transit priority lane retrofit

`RFT-CDR-06` Corridor

Transit priority lane retrofit

Converts an existing general travel lane or on-street parking lane into a lane dedicated to bus travel, curbside or center-running.

## Overview

On a bus route with frequent service and heavy congestion, buses stuck in general traffic lose the reliability advantage that makes transit competitive with driving. Dedicating a lane to buses, marked with red paint and "Bus Only" signage in most U.S. applications, removes that conflict. The lane can run curbside, offset from the curb to preserve a parking or loading lane, or along the center median on a wider corridor.[2]

## Where this leads: Target patterns

[Local Transit](https://commonwaysystem.org/patterns/local-streets/local-transit.md) (LOC-LTR-10), [Collector Transit](https://commonwaysystem.org/patterns/collectors/collector-transit.md) (COL-CTR-05), [Arterial Transit (BRT/LRT)](https://commonwaysystem.org/patterns/arterials/arterial-transit.md) (ART-ATR-04)

## Applicability and thresholds

Most applicable on corridors with frequent bus service experiencing measurable delay from mixed traffic, particularly where curb, street, or driveway conflicts are low to moderate; where conflicts are high, a curbside lane may need to shift further from the curb or run center-median instead.

## Evidence and effectiveness

Agencies implementing dedicated and business-access-and-transit lanes report improved bus speed and schedule reliability, with the effect scaling with how much of the corridor's delay was previously caused by mixed-traffic conflict rather than signal timing or stop dwell time.[1][3]

## Getting it built

Frequently piloted with temporary cones, signage, and paint before permanent installation, since testing the lane's effect on both bus reliability and general traffic before committing to red paint and enforcement infrastructure is common practice. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Typically a joint decision between the transit agency and the city or county transportation department, since the lane affects both bus operations and general traffic capacity. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Parking-lane reallocation](https://commonwaysystem.org/retrofits/corridor/parking-lane-reallocation.md) (RFT-CDR-05) (the underlying mechanism when the transit lane replaces parking rather than a travel lane)

## References

1.  Precedent-based [Nelson\\Nygaard, "Better Bus Transit Priority Toolkit," prepared for TriMet, March 2024.](https://trimet.org/betterbusprogram/pdf/better-bus-toolkit.pdf)
2.  Precedent-based [NACTO Urban Street Design Guide, "Transit Corridor," Transit Streets section.](https://nacto.org/publication/urban-street-design-guide/streets/transit-corridor/)
3.  Evidence-based [Federal Transit Administration, "Bus Lanes."](https://www.transit.dot.gov/research-innovation/bus-lanes)

---

Source: https://commonwaysystem.org/retrofits/corridor/two-plus-one-road-cable-barrier/

# 2+1 road with cable median barrier

`RFT-CDR-11` Corridor

2+1 road with cable median barrier

Converts an undivided rural two-lane road into a continuous three-lane cross section, with an alternating passing lane and a cable median barrier, built within the existing right-of-way.

## Overview

This strategy converts an existing undivided two-lane rural road into a continuous three-lane cross section. The center lane serves as a passing lane for one direction of travel, then switches to the other direction along the corridor, and a cable median barrier separates opposing traffic through the sections where the center lane is not open for passing. It is built within the existing right-of-way: no new land, and no added lanes beyond the single shared center lane.

Run-off and head-on crashes together account for the large majority of fatalities on this road type. The alternating passing lane breaks up the long straight stretches that produce driver drift, and it gives a driver stuck behind a slow vehicle a defined window to pass without crossing into the opposing lane at all. The cable barrier physically stops a drifting vehicle from crossing the centerline, converting a would-be head-on collision into a barrier strike, survivable by design rather than by chance.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [Why America Won't Copy Sweden's Cheap Highway Fix](https://www.youtube.com/watch?v=jyNEnYaBszk)

Safe By Design

Explains Sweden's 2+1 alternating-passing-lane cable-barrier retrofit and the specific AASHTO Green Book barriers (literally) that have kept the same fix from scaling in the US.

## Where this leads: Target patterns

[Rural Collector / Farm-to-Market Road](https://commonwaysystem.org/patterns/collectors/rural-collector.md) (COL-FTM-02), [Default (No Parking, No Direct Property Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01), [Scenic Highway / Byway](https://commonwaysystem.org/patterns/arterials/scenic-highway-byway.md) (ART-SCB-03)

This strategy does not change a road into a different pattern so much as change the safety properties of the same pattern when it runs at high speed. It applies within these patterns, wherever a two-lane rural road is functioning as a through-highway rather than a low-volume access road.

## Applicability and thresholds

Appropriate on rural two-lane roads where design speed, terrain, or existing posted speed exceeds roughly 45 mph. Past that point two vehicles closing head-on hit each other at roughly 90 mph or more combined, and collision energy scales with the square of closing speed, not linearly, so the safety answer changes qualitatively rather than just numerically.

It is the direct destination for the terrain and volume combinations in Rural Collector / Farm-to-Market Road's own [Speed management row](https://commonwaysystem.org/patterns/collectors/rural-collector.md#layered-guidance-across-sources) that cross that threshold: level terrain at 400 to 2,000 vehicles per day (50 mph) and above 2,000 (60 mph), and rolling terrain above 2,000 vehicles per day (50 mph). It also applies to the Rural density tier of Default (No Parking, No Direct Property Access) and to Scenic Highway / Byway, wherever a two-lane rural road is functioning as a through-highway.

## Evidence and effectiveness

Sweden's network-wide experience with 2+1 roads that have a median barrier shows fatalities down 77%, and fatal-and-serious-injury crashes down 51% on 110 km/h roads and 63% on 90 km/h roads.[1]

The barrier itself is a recognized countermeasure, with a real limit worth stating plainly: FHWA lists median barriers as a Proven Safety Countermeasure, but scopes it to divided highways with an actual median. An undivided rural road cannot simply invoke that designation, which is why states have had to write separate guidance for exactly this retrofit.[2]

The passing lane contributes on its own: Missouri DOT's research found passing-lane sections with 12 to 24% fewer crashes per mile per year than conventional two-lane sections. That is the documented network-level result; larger reductions are reported for individual cases elsewhere, but those were not independently verified here.[4]

The evidence has honest limits. Colorado DOT's feasibility study of a Swedish-style 2+1 road with barrier states that its crash reduction estimate carries real statistical uncertainty, because the underlying study had a short after-period, and it recommends a limited pilot rather than full rollout.[5]

## Getting it built

Unlike many Corridor strategies, this one cannot start from paint: the cable barrier and the three-lane cross section are permanent construction. Colorado's study recommends a limited pilot before wider deployment.[5] Kentucky's 2+1 design guidance reports construction cost savings of 50 to 90% compared with a full four-lane divided highway.[3] See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Most rural two-lane roads of this kind are state or county highways, so the decision typically sits with the state department of transportation or the county road agency, through its design guidance and engineering review. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Related retrofit strategies

[Depaving / pavement-to-gravel conversion](https://commonwaysystem.org/retrofits/corridor/depaving-pavement-to-gravel.md) (RFT-CDR-10) (the opposite response to a low-volume rural road: lowering its speed by changing the surface rather than adding a barrier)

## References

1.  Evidence-based [Anna Vadeby, Swedish National Road and Transport Research Institute (VTI), network-wide safety effects of 2+1 roads with median barrier: fatalities down 77%, fatal-and-serious-injury crashes down 51% (110 km/h roads) to 63% (90 km/h roads).](https://bransch.trafikverket.se/contentassets/6af107d0cbe94281af73a57b9761c189/16_safety_benefits_vadeby.pdf)
2.  Legal / regulatory [Federal Highway Administration, "Median Barriers," Proven Safety Countermeasures.](https://rosap.ntl.bts.gov/view/dot/49401/dot_49401_DS1.pdf)
3.  Legal / regulatory [Kentucky Transportation Cabinet, Division of Highway Design, 2+1 road design guidance (August 2013), construction cost savings of 50 to 90% versus a full four-lane divided highway.](https://scholars.uky.edu/en/projects/spr-21-605-21-roadway-design-guidance-update/)
4.  Evidence-based [Potts & Harwood, Missouri Department of Transportation, "Benefits and Design/Location Criteria for Passing Lanes" (RDT 04-008, 2004).](https://spexternal.modot.mo.gov/sites/cm/CORDT/RDT04008.pdf)
5.  Legal / regulatory [Colorado Department of Transportation, "2+1 Road with Barrier: Evaluation of the Feasibility of Deployment of Swedish 2+1 Road with Barrier in Colorado" (CDOT-2020-05, April 2020).](https://rosap.ntl.bts.gov/view/dot/88633/dot_88633_DS1.pdf)

---

Source: https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit/

# Displaced Left-Turn (DLT) retrofit

`RFT-INT-04` Intersection

Displaced Left-Turn (DLT) retrofit

Shifts the left-turn lane to the opposing side of oncoming traffic upstream of the main intersection, letting left-turning and opposing through traffic move simultaneously without a dedicated protected phase.

## Overview

Also known as a continuous flow intersection, this retrofit resolves the same unprotected-left-turn conflict that Median U-Turn and RCUT address, but through signalized displacement rather than a median crossover. A driver turning left crosses opposing traffic at a signal well before the main intersection, then proceeds through the main intersection on a green phase running concurrently with through traffic in both directions, since the crossing conflict has already been resolved upstream.

## Where this leads: Target patterns

[Displaced Left-Turn (DLT)](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) (INT-DLT-14)

## Applicability and thresholds

Requires substantial additional right-of-way width upstream of the main intersection to build the displaced left-turn crossing, which is this retrofit's primary limitation compared to Median U-Turn or RCUT.[2] Most viable at high-volume urban or suburban intersections where a grade-separated interchange isn't justified but conventional signal delay from protected left-turn phasing is severe.

## Evidence and effectiveness

DLT is documented as a faster, lower-cost alternative to a grade-separated interchange at high-volume intersections, resolving left-turn and through-movement conflicts without the cost of a flyover or underpass, though at higher construction cost and impact than Median U-Turn or RCUT.[1]

## Getting it built

Cannot be piloted informally. Widening for the displaced left-turn crossing is real, costly construction, frequently impacting adjoining properties given the additional area required. This strategy effectively starts at Permanent on the construction spectrum. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is standard practice, and given the higher cost and impact of this design relative to Median U-Turn or RCUT, is particularly important for justifying the additional expense. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Typically a state DOT or large-city capital project, given the cost and right-of-way scope involved. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

[Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md) (RFT-INT-02), [Restricted Crossing U-Turn (RCUT) retrofit](https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit.md) (RFT-INT-03) (the two lower-cost alternatives addressing the same underlying unprotected-left-turn problem)

## References

1.  Evidence-based ["Unconventional Arterial Intersection Designs under Connected and Automated Vehicle Environment: A Survey," on Displaced Left-turn Intersection design and cost tradeoffs relative to grade-separated interchanges.](https://arxiv.org/abs/1811.03074)
2.  Legal / regulatory [U.S. Patent 7,135,989, "Parallel flow vehicle turn system for traffic intersections," on displaced left-turn retrofit considerations and right-of-way impacts.](https://patents.google.com/patent/US7135989B2/en)

---

Source: https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit/

# Median U-Turn (MUT) retrofit

`RFT-INT-02` Intersection

Median U-Turn (MUT) retrofit

Reroutes left-turn and through movements from a minor approach away from the main intersection, requiring drivers to turn right first, then complete a U-turn at a median opening downstream.

## Overview

Also known as a Michigan U-turn, this retrofit removes direct and unprotected left turns from the main intersection entirely by relocating them to a signalized or unsignalized median crossover a short distance away. This reduces the conflict points at the primary intersection and shortens the left-turn phase a signal there needs to serve, in exchange for a slightly longer path for the rerouted movement.

## Where this leads: Target patterns

[Median U-Turn (MUT)](https://commonwaysystem.org/patterns/intersections/median-u-turn.md) (INT-MUT-12)

## Applicability and thresholds

Requires a wide enough median, or the ability to widen one, to accommodate the U-turn movement, sized to the corridor's design vehicle. Most commonly applied on divided arterials and highways with four or more lanes, where a conventional left turn from the minor approach would otherwise cross multiple lanes of opposing traffic at once.[2]

## Evidence and effectiveness

State DOT data (Indiana) shows a MUT-style retrofit improving traffic capacity by 20 to 50 percent at the retrofitted intersection, through more efficient signal phasing, timing, and progression with adjacent intersections, and reduces stops by a third or more.[1][3]

## Getting it built

Cannot be piloted informally. Retrofitting a standard intersection to this geometry costs from a few hundred thousand dollars to more than a million, and requires real median construction and, often, signal relocation. This strategy effectively starts at Permanent on the construction spectrum. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is standard practice, comparing this geometry against a conventional signal or other alternative intersection designs using safety and operational data. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Typically a state DOT capital project, given the scale of median reconstruction involved, though a state highway running through a small city may still be responsive to local advocacy given the safety case. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

[Restricted Crossing U-Turn (RCUT) retrofit](https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit.md) (RFT-INT-03) (a closely related median U-turn geometry that also restricts the minor-road through movement), [Displaced Left-Turn (DLT) retrofit](https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit.md) (RFT-INT-04) (an alternative approach to the same unprotected-left-turn problem)

## References

1.  Precedent-based [Indiana Department of Transportation, "Median U-turns."](https://www.in.gov/indot/traffic-engineering/median-u-turns/)
2.  Legal / regulatory [Federal Highway Administration, "Chapter 2. Intersections," _Handbook for Designing Roadways for the Aging Population_.](https://highways.dot.gov/safety/other/older-road-user/handbook-designing-roadways-aging-population/chapter-2-intersections)
3.  Evidence-based ["Evaluating the Operational Features of an Unconventional Dual-Bay U-Turn Design for Intersections."](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158914)

---

Source: https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit/

# Restricted Crossing U-Turn (RCUT) retrofit

`RFT-INT-03` Intersection

Restricted Crossing U-Turn (RCUT) retrofit

Reroutes both left-turn and through movements from the minor road, requiring drivers to turn right onto the major road first, then complete a U-turn at a designated median crossover. Also known as a J-turn or superstreet.

## Overview

RCUT goes a step further than a standard median U-turn retrofit: it removes the minor road's direct through movement across the major road entirely, not just its left turn. A driver crossing the major road from the minor approach turns right, merges, then makes a U-turn to continue in the direction they originally needed. This lets the main intersection focus entirely on major-road through movement, since it no longer needs to serve conflicting minor-road crossing traffic at all.

## Where this leads: Target patterns

[Restricted Crossing U-Turn (RCUT)](https://commonwaysystem.org/patterns/intersections/restricted-crossing-u-turn.md) (INT-RCU-13)

## Applicability and thresholds

Used primarily on high-speed, four-lane-or-larger divided highways, both signalized and unsignalized versions exist, with median width sized to the design vehicle's turning requirements.[1] Particularly beneficial where large trucks are common, since the design gives them a single direction of traffic to focus on rather than requiring a gap-judgment across the full width of opposing traffic.

## Evidence and effectiveness

FHWA reports RCUT intersections reduce fatal and injury crashes substantially compared to the conventional intersections they replace, primarily by eliminating the right-angle and left-turn crash types associated with direct crossing and turning movements at a conventional design.[3]

## Getting it built

Cannot be piloted informally. Wisconsin DOT notes RCUT designs are easily retrofitted, often without purchasing additional right-of-way, since the crossover reuses existing median width, but the crossover construction itself is still real, permanent infrastructure.[2] This strategy effectively starts at Permanent on the construction spectrum. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is standard practice for this geometry. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Typically a state DOT capital project, since RCUT is used almost exclusively on state-maintained highways rather than local streets. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md) (RFT-INT-02) (the related, less restrictive geometry that still allows a direct minor-road through movement), [Displaced Left-Turn (DLT) retrofit](https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit.md) (RFT-INT-04) (an alternative approach to the same unprotected-left-turn and through-crossing problem)

## References

1.  Legal / regulatory [Texas Department of Transportation, "14.6 Restricted Crossing U-Turn Intersection (RCUT)."](https://www.txdot.gov/manuals/des/rdw/chapter-14--alternative-intersections-and-intercha/14-6-restricted-crossing-u-turn-intersection--rcut.html)
2.  Precedent-based [Wisconsin Department of Transportation, "Restricted Crossing U-Turn (RCUT) Intersections."](https://wisconsindot.gov/Pages/safety/safety-eng/rcut.aspx)
3.  Evidence-based [Kentucky Transportation Cabinet, "Reduced Conflict U-Turn," SAFERoads Solutions, before-after crash data.](https://transportation.ky.gov/saferoadsolutions/Pages/RCUT.aspx)

---

Source: https://commonwaysystem.org/retrofits/intersection/signal-to-roundabout-conversion/

# Signal-to-roundabout conversion

`RFT-INT-01` Intersection

Signal-to-roundabout conversion

Replaces an existing signalized intersection with a roundabout, removing signal equipment and phasing entirely in favor of continuous yield-controlled circulation.

## Overview

A signal manages conflict by separating movements in time; a roundabout manages it by separating movements in space, requiring every entering vehicle to yield to circulating traffic rather than wait for a green phase. This retrofit is the most direct route between Signal and the Commonway System's own default intersection control, and is the concrete mechanism behind the System's broader roundabouts-first philosophy.

## Where this leads: Target patterns

[Roundabout (Single/Multi-Lane)](https://commonwaysystem.org/patterns/intersections/roundabout.md) (INT-RAB-01), [Turbo-Roundabout](https://commonwaysystem.org/patterns/intersections/turbo-roundabout.md) (INT-TRB-02) at the highest-volume Arterial-to-Arterial locations

## Applicability and thresholds

Applicable at nearly any signalized intersection where right-of-way exists or can be acquired for the roundabout's circular footprint. Volume alone rarely disqualifies a location, since multi-lane and turbo-roundabout designs scale to high-volume conditions, but right-of-way constraints and adjacent property impacts are the most common practical limits.[3]

## Evidence and effectiveness

FHWA reports roundabouts reduce overall crashes by 35 percent, injury crashes by 76 percent, and fatal crashes by 90 to 100 percent compared to the signals or stop signs they replace.[1] An Insurance Institute for Highway Safety empirical Bayes study of U.S. roundabout conversions found a crash modification factor of 0.801, an approximately 20 percent reduction in crashes overall.[2]

## Getting it built

Cannot be meaningfully piloted or demonstrated. A roundabout requires real construction, new pavement, curbs, and central island, to exist at all; there's no reversible, low-cost version of this conversion. This strategy effectively starts at Permanent on the construction spectrum. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is standard practice before this conversion, comparing the roundabout against retaining or upgrading the signal using the same safety and operational data. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Typically a city, county, or state DOT capital project, given the construction scope and cost. Right-of-way needs may bring in acquisition or easement tools. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

None currently cataloged.

## References

1.  Evidence-based [Federal Highway Administration, "Roundabouts," Intersection Safety.](https://highways.dot.gov/safety/proven-safety-countermeasures/roundabouts)
2.  Evidence-based [Persaud, B. et al., "Safety Effect of Roundabout Conversions in the United States: Empirical Bayes Observational Before-After Study," Insurance Institute for Highway Safety, 2001.](https://journals.sagepub.com/doi/abs/10.3141/1751-01)
3.  Legal / regulatory [Rodegerdts, L. et al., _Roundabouts: An Informational Guide_, 2nd ed., NCHRP Report 672, Transportation Research Board, 2010.](https://nap.nationalacademies.org/catalog/22914/roundabouts-an-informational-guide-second-edition)

---

Source: https://commonwaysystem.org/retrofits/network/barrier-crossing-network-reconnection-retrofit/

# Barrier-crossing / network reconnection retrofit

`RFT-NET-03` Network

Barrier-crossing / network reconnection retrofit

Adds a new pedestrian and bicycle connection, a bridge, tunnel, or path linkage, across a highway, rail line, or disconnected cul-de-sac pattern that currently severs an otherwise walkable or bikeable network.

## Overview

A network can be well-connected on paper and still function poorly for anyone not driving, if the connections that exist only work for cars. A limited-access highway, a railroad, or a subdivision built entirely from disconnected cul-de-sacs can each cut a walking or biking trip off at a distance a driver never notices, since a driver's route simply goes around. This retrofit adds the missing link directly, rather than requiring a long detour to the nearest through-street.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Reason Our Streets Switched to Cul-De-Sacs](https://www.youtube.com/watch?v=d9vDcfH03gs)

City Beautiful

Traces the postwar shift from connected grid networks to tree-shaped cul-de-sac subdivisions, then covers the same shared-use-path connector strategy CS's Network Reconnection retrofit recommends for stitching disconnected cul-de-sacs back into the surrounding network.

## Where this leads: Target patterns

Like the other two Network-scale retrofits, this doesn't necessarily change a network's overall topology classification, it applies _within_ it. A [Dendritic / Hierarchical](https://commonwaysystem.org/patterns/network/dendritic-hierarchical.md) (NET-DEN-02) network with a new cross-connection added is measurably more connected for active travel, without becoming a Grid outright. The connection itself typically takes the form of a [Shared-Use Path](https://commonwaysystem.org/patterns/local-streets/shared-use-path.md) (LOC-SUP-13) or [Multi-Use Trail / Greenway](https://commonwaysystem.org/patterns/collectors/multi-use-trail-greenway.md) (COL-MUT-06) at the Local or Collector scale.

## Applicability and thresholds

Most applicable where Level of Traffic Stress analysis or similar network connectivity research shows a barrier, a highway, rail corridor, or cul-de-sac pattern, is forcing an unreasonable detour for active travel, commonly assessed against a threshold such as a 25 percent detour penalty compared to the most direct path.[2]

## Evidence and effectiveness

Low-stress connectivity research finds cities are often divided into disconnected islands of otherwise-comfortable walking and biking conditions, separated by barriers that can only be crossed using high-stress links; adding a dedicated crossing directly addresses that fragmentation without requiring the barrier itself, the highway or rail line, to change at all.[1]

## Getting it built

A single crossing (a path connection through an existing cul-de-sac stub) can sometimes be demonstrated informally, but a genuine bridge or tunnel across a highway or rail corridor requires real capital construction and effectively starts at Permanent on the construction spectrum. The two cases differ substantially, and each specific project should be assessed on its own rather than assuming one pattern for all barrier types. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Varies significantly by barrier type. A local street reconnection is often a city or county decision; a highway or rail crossing typically requires state DOT or rail authority coordination given jurisdiction over the barrier itself. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

None currently cataloged.

## References

1.  Evidence-based [Federal Highway Administration, "Part 2: Reducing Conflicts," Multimodal Networks, Bicycle and Pedestrian Program, on cul-de-sac connectivity and barrier crossings.](https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/multimodal_networks/part02.cfm)
2.  Evidence-based [Mineta Transportation Institute, "Low-Stress Bicycling and Network Connectivity," MTI Report 11-19, Level of Traffic Stress and detour-based connectivity measures.](https://transweb.sjsu.edu/sites/default/files/1005-low-stress-bicycling-network-connectivity.pdf)

---

Source: https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit/

# Modal filtering / Low Traffic Neighborhood retrofit

`RFT-NET-01` Network

Modal filtering / Low Traffic Neighborhood retrofit

Installs a scattered set of point closures across a residential area, restricting motor vehicle through-traffic on interior streets while preserving full access for residents, deliveries, and emergency services, and full passage for pedestrians and bicyclists.

## Overview

Rather than redesigning any single street, this retrofit changes how an entire area functions by selectively blocking through-driving routes at chosen points. The area's streets remain physically unchanged except at the closures themselves; what changes is which trips are still possible by car. A driver can still reach any address inside the filtered area, but can no longer use it as a shortcut between two points outside it.

## Where this leads: Target patterns

Unlike every Corridor and Intersection strategy, this doesn't produce a different destination pattern, it applies _within_ an existing pattern or topology, changing a property (permeability) rather than replacing it. A filtered [Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01) is still a Grid. It changes the network's effective permeability within whatever topology already exists. Grid is the most common context for this retrofit, since a grid's redundant routes are what make filtering possible without stranding any address. At the Local scale, filtered streets typically read as [Bicycle Boulevard / Neighborhood Greenway](https://commonwaysystem.org/patterns/local-streets/bicycle-boulevard.md) (LOC-BBG-12), built using the [Modal Filter / Point Closure](https://commonwaysystem.org/patterns/elements/modal-filter-point-closure.md) (ELM-MFP-44) element at each closure point.

## Applicability and thresholds

Requires enough route redundancy in the underlying network that closing a through-route doesn't strand any address or eliminate emergency access; a Grid or well-connected network is far more amenable to this retrofit than a Dendritic or cul-de-sac-heavy network, where fewer alternate routes exist.

## Evidence and effectiveness

Research on London's outer-borough Low Traffic Neighbourhoods, using the People and Places Survey, documents measurable reductions in car use and increases in active travel following modal filter installation, with over 25,000 modal filters already in place across the UK before 2020.[1][2]

## Getting it built

Well suited to the early construction spectrum stages. A single filter can be demonstrated with planters, and an area-wide network of filters is commonly piloted before permanent bollards or curb reconstruction, since resident and emergency-service response to the full filtered network is easier to evaluate after living with a temporary version. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Usually a city transportation or public works department decision, often following resident petition or a council-directed neighborhood traffic study, since the area-wide scope affects many residents at once. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Superblock retrofit](https://commonwaysystem.org/retrofits/network/superblock-retrofit.md) (RFT-NET-02) (a related, more comprehensive area-wide approach that also reallocates the interior street space itself, not just its through-traffic access)

## References

1.  Evidence-based [Aldred, R. and Goodman, A., "Low Traffic Neighbourhoods, Car Use, and Active Travel: Evidence from the People and Places Survey of Outer London Active Travel Interventions," _Findings_, 2020.](https://findingspress.org/article/17128-low-traffic-neighbourhoods-car-use-and-active-travel-evidence-from-the-people-and-places-survey-of-outer-london-active-travel-interventions)
2.  Precedent-based ["Identification of Plausible Low Traffic Neighbourhoods Using Open Data," _ScienceDirect_, definitions of modal filter, permeability, and filtered permeability.](https://www.sciencedirect.com/science/article/pii/S2950105925000415)

---

Source: https://commonwaysystem.org/retrofits/network/superblock-retrofit/

# Superblock retrofit

`RFT-NET-02` Network

Superblock retrofit

Groups several existing blocks into a single traffic cell, routing through-traffic around the perimeter while reclaiming the interior streets for pedestrians, bicyclists, and local access only.

## Overview

Where modal filtering works point by point, a superblock works by treatment area: an entire multi-block zone is reorganized at once, with clearly designated perimeter streets carrying all through-traffic and interior streets rebuilt for a much lower level of vehicle priority, sometimes fully pedestrianized. Barcelona's and Vienna's programs are the most documented examples, using this as a deliberate top-down planning model rather than an incremental, street-by-street change.

## Where this leads: Target patterns

As with modal filtering, this doesn't necessarily produce a different destination pattern, it applies _within_ an existing network's topology rather than replacing it. A superblock applied within a [Grid](https://commonwaysystem.org/patterns/network/grid.md) (NET-GRD-01) leaves it a Grid. Interior streets within the superblock typically become [Living Street / Woonerf](https://commonwaysystem.org/patterns/local-streets/living-street-woonerf.md) (LOC-LSW-06) or [Pedestrian-only Street / Plaza](https://commonwaysystem.org/patterns/local-streets/pedestrian-plaza.md) (LOC-PED-09), while perimeter streets retain or gain through-traffic capacity.

## Applicability and thresholds

Requires a multi-block area with a genuine perimeter capable of absorbing the rerouted through-traffic without creating unacceptable congestion or diversion onto adjacent neighborhoods. A Grid topology is again the most amenable context, given its inherent route redundancy along the perimeter.

## Evidence and effectiveness

The superblock model is documented as reallocating street space from motorised traffic to active travel and public use at the scale of an entire neighborhood or set of residential blocks, a top-down urban planning model distinct from the more incremental, street-by-street approach of modal filtering alone.[1]

## Getting it built

Given its area-wide scope, this retrofit is rarely demonstrated at full scale in a single short pilot; a phased approach, testing perimeter rerouting and one or two interior streets before committing to the full superblock, is more typical than a citywide or neighborhood-wide launch. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

## Who can move this

Typically a city-level planning and transportation department initiative, given the scale, often requiring a dedicated area plan or district designation rather than a single project approval. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md).

## Related retrofit strategies

[Modal filtering / Low Traffic Neighborhood retrofit](https://commonwaysystem.org/retrofits/network/modal-filtering-low-traffic-neighborhood-retrofit.md) (RFT-NET-01) (a related, more incremental approach that restricts through-traffic without necessarily rebuilding the interior streets themselves)

## References

1.  Precedent-based ["Identification of Plausible Low Traffic Neighbourhoods Using Open Data," _ScienceDirect_, definition and comparison of the Superblock model against modal filtering and Low Traffic Neighbourhoods.](https://www.sciencedirect.com/science/article/pii/S2950105925000415)