
Tom Vanderbilt, author of Traffic: Why We Drive the Way We Do (and What It Says About Us), on the insanity of intentionally engineering so many streets - including residential ones - to the standards of “safe” 30-40 mph driving:
Among the major issues, the newspaper reported:
The panel recommended that roads in urban areas be designed for speed limits of 30 to 40 mph, saying anything slower would be unrealistic and difficult for police to enforce. The panel also said trees should be planted farther from curbs on roads with 40 mph speed limits because of the danger they pose to motorists who hit them.
What strikes me in discussions like these is the weird disconnect between design and driver behavior. One of the reasons it can so often be difficult to enforce lower speed limits is that these limits are posted on roads that are intensely over-engineered. The supposed “fix,” as suggested above, is to assume that drivers are going to drive at a certain speed, and so to then rearrange the entire landscape — removing trees, etc. — to allow them to do so “safely.”
Of course, on the road “designed” for speed limits of 30 to 40 mph, they will inevitably drive faster. But then, of course, if someone crashes and kills a pedestrian or another driver, it’s an “accident,” it’s down to driver behavior; if they smash into a tree, it’s deemed poor traffic safety engineering. As the work of Eric Dumbaugh has found, looking at streets like the one above, at Stetson University in Florida, often the worst safety performance comes on the roads that are deemed “safe” by traffic engineers, while the best can come on tree-lined streets like the one above (which had no crashes and speeds below 30 mph during the five years he looked at it).
We consistently get urban speeds wrong in the U.S. In Germany, the land where speed is supposedly worshipped, the speed-limit free sections of the autobahn are contrasted by a mandatory, heavily enforced 30 KPH (that’s 18 mph, folks) limit in residential areas.
When I look at the super-wide, treeless, high-speed roads in your typical modern subdivision and contrast them with the narrow, tree-lined, slow streets in a traditional neighborhood setting, I find it curious that we’ve somehow come to the conclusion that it’s A-OK for drivers to careen through our neighborhoods at 30-40 miles per hour (or more), even in heavily residential areas. A return to traditional neighborhood design must include a return to streets designed to slow car traffic.








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