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Lowering your speed by just 5 mph could make the roads safer

A speed limit study done in Seattle illustrates how a small decline in speed limits can make a big impact on road safety.
Posted at 8:38 PM, Mar 28, 2023

A new study out of Seattle illustrates how much safer roads would be if cities lowered speed limits.

The independent non-profit organization Insurance Institute for Highway Safety, or IIHS, conducted the study, which found lowering speed limits by 5 to 10 miles per hour reduced the likelihood that a crash would cause injuries by a fifth. 

"That is a significant reduction in the number of people who are getting hurt when there's a crash," said Cathy Chase, president of Advocates for Highway and Auto Safety.

While crashes still happened when Seattle downgraded their speed limits, accidents weren't as fatal or dangerous compared to high speeding vehicles.

Chase said a higher speed would have resulted in more fatalities due to three factors related to the dangers of speeding, including less reaction time for the driver, a vehicle taking longer to stop and a higher amount of energy if a crash happens.

The National Highway Traffic Safety Administration, or the NHTSA, estimates about 43,000 people died in motor vehicle crashes in the U.S., and Advocates for Highway and Auto Safety says nearly 12,000 of them died in speeding-related crashes in 2021.

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"Everyone tracks what kinds of fatalities are happening on the roadway, and a large portion come from distracted driving and belted impaired and speed," said Meredith Mitts, with the American Automobile Association, or AAA. "If people would just slow down and follow the speed limit and not raise speed limits, even at the government level, then we would see a reduction in those crashes."

Despite what Mitt and other traffic safety advocates say, at least nine states are looking into increasing speed limits.

"We should be going the opposite way and following the results of the study and reducing speed limits" Chase said.

Besides speed limits, Chase pointed to other ways states and local communities can slow down.

"They can be improving their infrastructures in terms of installing speed humps, having road diets so that roads are more difficult to navigate so that people slow down, and speed reduction zones," she said.

The bottom line is: Experts say exceeding the speed limit, even an extra 5 mph, isn't worth it.

"If you're driving 70 mph instead of 65 mph, that saves maybe six, six-and-a-half minutes on a 100-mile trip," Mitt said. "Realistically, that's not how far people are driving."