Debunking the Cul-de-Sac

The safest cities in America were all incorporated before 1930, when streets were grids. “What intuitively made sense to us a hundred years ago can be justified and measured in foreclosure rates, vehicle miles traveled, and traffic fatalities.” Cul-de-sacs, it turns out, are inefficient and dangerous.

The FHA never put it quite this way, but what we were really doing was building communities for cars, not people. Earlier neighborhoods were literally built on a scale for the human body, with architectural embellishments at eye level and blocks and sidewalks designed for foot travel. The human measuring stick hasn’t changed much over the last 200 years, and so, in theory, that model should still apply.

the safest cities had an element in common: They were all incorporated before 1930. Something about the way they were designed made them safer. The key wasn’t necessarily that large numbers of bikers produced safer cities, but that the design elements of cities that encouraged people to bike in places like Davis were the same ones that were yielding fewer traffic fatalities.

A lot of people feel that they want to live in a cul-de-sac, they feel like it’s a safer place to be,” Marshall says. “The reality is yes, you’re safer – if you never leave your cul-de-sac. But if you actually move around town like a normal person, your town as a whole is much more dangerous.

This is the opposite of what traffic engineers (and home buyers) have thought for decades. And it’s just the beginning of what we’re now starting to understand about the relative advantages of going back to the way we designed communities a century ago.

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