Study Links 20 Years of Speed Limit Increases to 33,000 Traffic Deaths

CARS.COM — A recent study says rising speed limits on U.S. highways over the past two decades have resulted in an entire year’s worth of additional traffic fatalities that otherwise might not have occurred. The Insurance Institute for Highway Safety’s study examined state-by-state speed limit increases since the National Maximum Speed Limit’s repeal in 1995 and data from the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System.

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The study, which covers 41 states from 1993 to 2013, concluded that 33,000 additional deaths occurred in the 20 years following the elimination of the national speed limit that at the time of its repeal set top speeds of 55 to 65 mph, depending on the type of road. In 2013 alone, IIHS stated, 1,900 additional deaths effectively canceled out the number of lives saved by frontal airbags. Although the number of traffic deaths actually declined during the study period, IIHS noted, the figure would have been even lower at reduced speeds.

Calculating the number of deaths per billion miles traveled, researchers estimate that each 5 mph increase in the maximum speed limit results in a 4 percent spike in fatalities. That figure doubles to 8 percent on interstate highways and freeways.

“Proponents of raising the speed limit often argue that such increases simply bring the law in line with reality, since drivers exceed the limit,” IIHS stated. “Once the limit is raised, however, drivers go even faster.”

And in some places, that means people could be moving pretty fast. Six states now have 80 mph limits on some roads, with Texas laying claim to the highest in the nation: 85 mph. The study doesn’t cover the past three years, during which five more states joined Texas and Utah with at least a 75 mph limit, while several others raised theirs to 70 mph from 65 mph.