--- title: "Stroad (Commercial Arterial)" url: "https://commonwaysystem.org/patterns/arterials/stroad/" id: "ART-STD-05" description: "An Arterial anti-pattern, Avoid status, mixing on-street parking or direct property access with through traffic. This page exists to help identify and replace it." updated: "2026-09-26" --- # 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)