A Nifty Device to Stop Cars From Driving Too Close to Bikes

June 29th 2015

City Lab

Sarah Goodyear

Maybe your state is one of the more than two dozen around the U.S. with what is known as a three-foot passing law—a provision that requires drivers to give people on bikes at least that much clearance when passing them on the road. (Pennsylvania calls for a more generous four feet.) But are these laws enforceable? Or are they just an empty promise of safety?

One police officer in Chattanooga, Tennessee, wanted to find a way to give the law in his jurisdiction some meaning. Officer Robert Simmons, who has been with the city’s department for 12 years and on full-time bike patrol for seven, came up with an idea for a device that can measure and record the distance between a bike and a car.

“I thought, I wish there was a data-driven way, like a radar gun,” says Simmons. “This is what I want to build; this is what we need to prove it in court.”

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