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 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.
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 walks through next.
References
- Legal / regulatory 23 CFR 655.603, MUTCD as the national standard for traffic control devices, state adoption options.
- 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.
- Legal / regulatory U.S. EPA, About Green Infrastructure, stormwater management and Clean Water Act compliance context.
- Precedent-based NACTO, About page, coalition structure and mission.
- Precedent-based AASHTO, About page, state DOT membership, standards-setting role, and non-federal legal status.
- Precedent-based ITE, About ITE, professional membership association structure and mission.
- Precedent-based Strong Towns, About page, mission and organizational structure.
- Precedent-based Congress for the New Urbanism, Who We Are, mission and Charter of the New Urbanism.
- Precedent-based Vision Zero Network, About page, mission and safe-systems approach.
- Precedent-based Project for Public Spaces, About page, placemaking history and mission since 1975.
- Precedent-based Smart Growth America, National Complete Streets Coalition program page, mission and policy adoption count.
- Precedent-based Create Streets, Our Story page, founding, mission, and policy influence including the Building Better, Building Beautiful Commission.
- Precedent-based CROW Platform, official site, role in developing Dutch infrastructure design guidance.
- Precedent-based SWOV Institute for Road Safety Research, official site.
- Precedent-based ITDP, About Us page, mission and history.