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."
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 A baseline source is never called wrong, outdated, or flawed, since the disagreement is about evidence, not authority.
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.
| Who | Kevin, an enthusiast and researcher/compiler, explicitly not a credentialed engineer or planner. The citation system substitutes for personal authority. |
| 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. |
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 STR-UMS-014.
See the guide introduction for the full mechanics of reading a pattern, and the Brand Guide for how the system is written and designed.