Planetizen links to a New Urban News article reporting on a study which finds that cities built in California before 1950 have safer raods than those built after 1950. The authors, Wes Marshall and Norman Garrick, find that post 1950 cities:
tend to have more “dendritic” networks — branching, tree-like organizations that include many cul-de-sacs, limiting the movement of traffic through residential areas. They also don’t have as many intersections.
They suggest these “dendric” networks actually lead to greater travel speeds which in turn cause more fatalities. “Connected” grid-like streets are less likely to lead to fatal accidents because the heavier traffic leads to lower travel speeds.
Comments 2
Kenneth M. Kambara — February 5, 2009
I think there's something to limiting movement, unsafe speed, & fatalities. Looking at this list:
Safe: Santa Cruz, San Mateo, Berkeley, La Habra, and Danville. The more dangerous cities were places such as Turlock, Rialto, Victorville, Antioch, and West Sacramento.
I realize I've been in each of these cities listed. I'd be concerned about spurious correlation. Berkeley is an odd duck. It's on a grid structure, but there are lots of traffic calming and blocked streets/intersections. One thing I noticed about the unsafe cities is that they all have roads that lead into them from rural or open space areas.
ThickCulture » The Walkable City:: Toronto, Transit, & Car Culture — July 10, 2009
[...] the development of neighborhoods and community. José’s blog earlier this year notes how grids are safer than dendritic street patterns. Jane Jacobs helped to thwart a freeway project, the Spadina Expressway, which would have taken [...]