Drivers are less likely to go fast when city speed limits are lowered. It may seem counter intuitive, but new research has found that drivers in Boston slowed down when speed limits were lowered as little as 5 mph.

Those are the results of new research by the Insurance Institute for Highway Safety, a nonprofit financed by the insurance industry.

“Even on lower speed roads, speeding can have deadly consequences, especially for pedestrians and bicyclists,” Gordon Fox, president of 2Pass Defensive Driving School. “Some cities are lowering speed limits to reduce the risks for these vulnerable road users, who are increasingly dying in crashes.”

The Insurance Institute for Highway Safety study focused on Boston, which lowered the default speed limit on city streets from 30 mph to 25 mph beginning January 9, 2017, and publicized the change via advertisements, social media and traditional media outlets. The city’s move came after the Massachusetts legislature in 2016 amended state law to allow cities and towns to lower speed limits from 30 mph to 25 mph on municipal roads in densely populated areas or business districts. Unless otherwise posted, the speed limit on all City of Boston roadways is 25 mph, same as in Arizona.

Insurance Institute for Highway Safety researchers looked at vehicle speeds in Boston before and after the lower limit took effect and compared them to control sites in Providence, Rhode Island, where the speed limit remained the same. The study sites in both Boston and Providence included arterials, collectors and local roads. All sites were similar in that they had no more than one lane per direction and were located away from intersections on relatively flat, straight road segments and at least a half-mile away from any school or speed feedback sign. There was no posted speed limit sign at any of the sites.

Researchers evaluated changes in the odds of vehicles exceeding 25 mph, 30 mph and 35 mph associated with the new speed limit.

Significant reductions in the odds of vehicles in Boston exceeding 25 mph, 30 mph and 35 mph associated with the reduced speed limit, and the decline was biggest for the odds of vehicles exceeding 35 mph,

There was a 29.3 percent decline in the odds of speeding for vehicles traveling faster than 35 mph. The odds of speeding fell by 8.5 percent for vehicles going faster than 30 mph and 2.9 percent for vehicles exceeding 25 mph.

The study didn’t examine how lowering the speed limit affected crashes in Boston. That’s a next step,