Higher Speed Limits or Fewer Deaths? The Choice Is Yours, Study Shows

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During the past quarter of a century, speed limits on highways have steadily gone up, and most motorists have applauded. However, the tradeoff is a big one, according to the Insurance Institute for Highway Safety: Higher speed limits have come with a corresponding rise in motor vehicle deaths.

Related: Speediest and Slowest States: Where Does Yours Rank?

According to the agency’s new study, rising speed limits over the past 25 years have cost nearly 37,000 lives and more than 1,900 people in 2017 alone.

“We can reduce this toll through effective, high-visibility enforcement and traffic engineering measures. Reasonable speed limits also have a crucial role to play, as our new study demonstrates,” IIHS President David Harkey said in a statement.

Higher Legal Limits Yield Higher Illegal Speeds

Speed limits are set by individual states. Currently, 41 states have maximum speed limits of 70 mph or higher; six states have 80-mph limits, and drivers in Texas can legally drive 85 mph on some roads. Those in favor of raising the limits argue that the new number brings the law in line with reality since most drivers exceed the limit anyway. IIHS counters that this creates even more danger because once the limit is raised, drivers will then go even faster.

According to Charles Farmer, IIHS vice president for research and statistical services, a 5-mph increase in the maximum speed limit is associated with an 8 percent increase in the fatality rate on interstates and freeways. Of the 37,133 people who died on U.S. roads in 2017, he estimates that 1,934 — or 5 percent — would still be alive if speed limits hadn’t changed since 1993.

Cost-Benefit Breakdown of Speeding

For the study, Farmer looked at changes in the maximum speed limit in every state from 1993 to 2017 and compared that data with annual traffic fatalities per mile traveled, taking into account factors that affect fatality rates like changes in unemployment, the number of young drivers and the seat belt usage rate.

“Driving 70 instead of 65 saves a driver at best 6.5 minutes on a 100-mile trip,” Farmer said in a statement. “Before raising speed limits, state lawmakers should consider whether that potential time savings is worth the additional risk to lives.”

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News Editor Jennifer Geiger joined the automotive industry in 2003, much to the delight of her Corvette-obsessed dad. Jennifer is an expert reviewer, certified car-seat technician and mom of three. She wears a lot of hats — many of them while driving a minivan. Email Jennifer Geiger

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