In Praise of the Speed Hump

In a piece in Bloomberg, David Zipper expounds on the virtues of the humble speed hump, a simple-to-install, cost-effective, and (mostly) popular traffic control device that has proven to be one of the most effective way to slow dangerous traffic and improve road safety.

As Zipper explains, “Safety interventions like road diets, bike lanes and automatic red light cameras often trigger fierce opposition from neighbors and business owners; speed humps, on the other hand, tend to be wildly popular among those who live nearby.”

Speed humps are defined by the National Association of City Transportation Officials (NACTO) as “traffic calming devices between 3 and 4 inches tall and 12 to 14 feet wide, with a “ramp length” of 3 to 6 feet and a slope between 1:10 and 1:25.” This differentiates them from speed bumps, which are taller and usually located in parking lots. Speed humps typically cost roughly $5,000 to install, a much lower cost than many other traffic interventions.

Research shows that speed humps, particularly in a series, are effective at slowing down drivers. “ In Arlington, Virginia, the installation of speed humps led to a 43% reduction in drivers exceeding 20 miles per hour. A 2020 study of South Korea found that speed humps slowed vehicle speeds by 18.4% to 24%.” While they can’t be installed in all situations, speed humps can be a key part of an effective traffic calming strategy.