The Best Tactics for Tackling Speeders
Drivers who exceed speed limits are the cause of about one-third of all crash deaths in the US. To slow them down and save lives, cities have several effective tools.
Contractors put up a new speed limit sign in Washington, DC, in 2022. Several US cities have dropped speed limits in recent years in an effort to reduce pedestrian and cyclist deaths.
Photographer: Robert Nickelsberg/Getty Images
It’s a calculation you might recall from high school physics: KE = ½ mv². In plain English: The kinetic energy of a body in motion is found by multiplying half its mass by the square of its velocity.
That simple equation carries powerful implications for street safety. Because velocity is squared, even small upticks in speed dramatically increase the force exerted when a motor vehicle is in a collision. Those walking or biking are especially vulnerable: According to research from the AAA Foundation for Traffic Safety, the odds that a pedestrian dies a crash are one in two if the striking vehicle is moving at 31 miles per hour but only one in four if it travels at 23 mph.