Monthly Archives: August 2007

Connectivity Part 7: Crash Safety

This is part 7 of a series. See also IntroductionHistorical BackgroundLatter Half of the 20th CenturyNeighborhood WalkingNeighborhood CrimeVehicle Miles and Traffic

High-connectivity thoroughfare patterns are the foundation of walkable neighborhoods and districts. While that fact was self-evident for most of human history, it was lost or ignored by land development and transportation professionals in the post-WWII era. Today, even as the numerous benefits of high connectivity are becoming increasingly recognized, the auto-centric standards of yesteryear remain firmly dominant, particularly in the field of traffic engineering.

Traffic engineering standards discourage small blocks and frequent intersections because of safety concerns. Many jurisdictions have codified those standards into their planning regulations for suburban construction, with the result that most new development consists of isolated pods depending from highway-size arterials. It is a profoundly auto-oriented pattern that is hostile to pedestrians and bicyclists. It creates the typical suburban landscape of separated, isolated pockets instead of the continuous fabric of streets and blocks that is characteristic of efficient, walkable towns and cities.

Are the safety objections against high connectivity grounded in reality? Several investigations suggest that the position promulgated by mainstream traffic engineering standards can be legitimately questioned. Because this is a new and somewhat revolutionary avenue of thought, formal statistical support is just beginning to be compiled. The initial round of studies has found that livable, walkable neighborhoods with well-connected streets are no less safe, and in some respects are safer, than the standard suburban template.

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