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Road diets: designing a safer street

Reconfigure traffic lanes and cars will slow down.

Carlos Waters/Vox

Transportation officials across the country agree: Several minor traffic corridors in America are overbuilt and unnecessarily unsafe. So they’ve started to adopt European-inspired designs that change how drivers, cyclists, and pedestrians use the road in order to reduce speeding and encourage safety for everyone. It’s called a “road diet.”

A road diet usually will reduce the amount of space devoted to cars along a given corridor. An engineer then might use the space left from a lane reduction to, for example, add bike lanes, widen sidewalks, or add buffer zones.

Highway Safety Information System

There are many ways to reconfigure a road, but the vast majority of road diets in the US convert four-lane roads into three-lane roads. And a handful of studies show that four-to-three-lane road diets can reduce crashes and improve the overall quality of traffic flow.

Watch the video above to find out how it’s done and how engineers evaluate which roads will work better when put on a diet.