Higher speed limits in the U.S. have contributed to the death of tens of thousands of people over two decades, according to an Insurance Institute for Highway Safety study.
The report examined the impact of speed limit increases in 41 states over a 20-year period starting in 1993. The increases resulted in 33,000 fatalities that would not have occurred had speed limits remained unchanged, the institute reported.
“Although fatality rates fell during the study period, they would have been much lower if not for states’ decisions to raise speed limits,” said Charles Farmer, who wrote the study. “Since 2013, speeds have only become more extreme, and the trend shows no sign of abating.”
In 2014, there were 9,262 speed-related fatalities—equivalent to 28 percent of crash deaths in the U.S. Approximately half of those fatalities occurred on roads where the speed limit was lower than 55 mph.
Driving too fast contributes to a large proportion of all traffic-related deaths, said the Governors Highway Safety Association. The organization is worried that increasing current speed limits will only make the problem worse, since most drivers treat maximum speeds as a minimum target.
“Past research has shown that as posted speed limits are raised, drivers will exceed these limits, and more fatal crashes will result,” the GHSA said.
The GHSA supports efforts to enforce existing speed limits through traditional and automated means, including using police officers to detect violations and deploying speed cameras.
Farmer, the IIHS researcher, looked at deaths per billion miles traveled by state and roadway type. He then considered factors like alcohol consumption, changes in unemployment, and the number of young drivers aged 16-24—all of which could affect the fatality rate.
Overall, Farmer found that the number of deaths climbed 4 percent with each 5 mph increase in the maximum speed limit.
“Getting somewhere 5 minutes faster is not worth a life,” said Kelly Nantel, spokesperson for the National Safety Council.
The council also is calling for stricter enforcement of speed limits, Nantel said.