Skip to Content
Streetsblog USA home
Log In
Boston

Study: Lowering the Speed Limit … Works To Reduce Speeding

9:28 AM EDT on August 29, 2018

Photo: IIHS

Here's some encouraging news for cities trying to reduce speeding: New research from the Insurance Institute for Highway Safety shows that lowering posted speed limits appears to be effective at reducing driver speeds.

The IIHS study compared speeds before and after Boston lowered its speed limit from 30 mph to 25 mph in January, 2017 — and the results were clear: "Vehicles exceeding 25 mph, 30 mph, and 35 mph all declined at sites in Boston, with the largest reduction in proportions of vehicles exceeding 35 mph," wrote the study authors Wen Hu and Jessica Cicchino.

In fact, the odds of a Boston driver exceeding 35 miles per hour after the speed limit change decreased 29 percent and that a driver would exceed 30 mph declined 8.5 percent (the study offered "odds" because it tracked speeds at specific sites rather than following the same drivers before and after the change).

The study did not examine the impacts on crashes, but prior research shows that slower speeds reduce collisions, said Hu and Cicchino.

IIHS President David Harkey said in a statement that the study should encourage other cities to adopt lower speed limits to reverse the dramatic increases in pedestrian fatalities that have occurred over the last five years. Cities like Seattle, Portland and New York that have lowered their speed limits in recent years.

Two Boston City Council members — Ed Flynn and Frank Baker — have proposed lowering speed limits in the Hub even further, to 20 miles per hour.

Stay in touch

Sign up for our free newsletter

More from Streetsblog USA

Distracted Off-Duty Cop Jumped Curb and Killed Chicago Woman On Sidewalk

It's infuriating that a person who was entrusted to help keep the public safe was reckless enough to take her eyes off the road while driving to pick up a phone, with tragic consequences.

December 8, 2023

Friday’s Headlines Include Transit

An International Association of Public Transport study found that many countries are neglecting transit in their plans to combat climate change.

December 8, 2023

Calif. Using“Auxiliary Lane” Freeway Widening Loophole for Non-Aux Lane Projects

Beyond just using harmful loopholes legally, Metro and Caltrans deceptively bypass environmental regulations in order to keep on widening freeways.

December 8, 2023

Talking Headways Podcast: Sausage Making and the ADA

"It is fundamentally inappropriate to keep charging disabled people twice as much," our guest Ron Brooks says.

December 7, 2023

The Real Reason Assaults Against Transit Workers Are On The Rise

Hint: it's not just because service has been slashed.

December 7, 2023
See all posts