Car Industry

IIHS claims raising speed limits cost 33,000 lives over two decades

Following that logic to its extreme conclusion, the group would prefer we never move at all.

© Alan Schein Photography/Corbis

Thanks to federalism, our speed-limit laws are a patchwork of varying limits. We haven't had a national speed limit law since the '90s.

Insurance Institute for Highway Safety

A high speed limit is a nice thing to have. You shave a few seconds or minutes off your commute and you get to explore parts of the speedometer that are illegal in other areas. Yet, rising speed limits aren't all fun and games. In fact, the Insurance Institute for Highway Safety considers them downright deadly.

Since the National Maximum Speed Law was fully repealed in 1995, speed limits have steadily crept upward, with some regions rocking 80- or 85-mph limits at the moment. The IIHS study took a look at the effects of all speed limit increases between 1993 and 2013 in 41 states -- 9 states (plus Washington, D.C.) were excluded because low figures were producing aberrant data points.

Framing it in the context of deaths per billion miles traveled, broken down by state and road type, the IIHS study found that every 5-mph bump in the limit led to a 4 percent increase in fatalities. On highways alone, that increase jumped to 8 percent. Comparing that to control data (where no speed limits were raised), the study finds that raising speed limits cost us about 33,000 lives over that 20-year period.

Even though the data stops at 2013, speed limits have risen since then, along with the potential consequences. "Since 2013, speeds have only become more extreme, and the trend shows no sign of abating," said Charles Farmer, IIHS' vice president of research, in a statement. "We hope state lawmakers will keep in mind the deadly consequences of higher speeds when they consider raising limits."

That said, fatalities are still on the way down. In 1993, there were 40,868 deaths on roadways. In 2013, that number dropped to 32,035. IIHS posits that the number could have been as low as 30,129, a difference of 1,906 fatalities.


This chart tracks the difference between actual road fatalities and what that number might have been if speed limits didn't go up.

Insurance Institute for Highway Safety