Foundation Study Shows: Safe To Raise Freeway Speed Limits

March 1999

According to a study just completed by the National Motorists Association Foundation (NMAF), higher speed limits are not affecting highway safety. The study of recent federal fatality rate data found states that raised freeway speed limits had a significant safety improvement, slightly better than the nation as a whole.

In 1995, the National Maximum Speed Limit was repealed, allowing each state to establish its own speed limits. During 1996, 33 states did just that. The Foundation study examined data from 1995, the last full year before limits were raised in these states, and 1997, the first full year after speed limits were raised. States that raised limits enjoyed a slightly greater fatality rate reduction of (5.00%), almost identical to the experience of the nation as a whole.

Comparing the group of limit-raising states and the group of unchanged states, the study demonstrated that fatality rates dropped in both groups, essentially equally. Raising speed limits did not affect overall safety. The study examined fatality rates on all roads in each state, so that the expected usage shifts from less-safe undivided highways to safer and faster freeways were accounted for, helping to explain the favorable safety results associated with higher freeway limits.

Project leader, NMAF Senior Analyst Bennet K. Langlotz, described the findings as consistent with past studies on speed limit effects. “When evaluating the states that raised limits after 1995 against those that retained their lower speed limits, we find that both groups enjoyed essentially the same 5% reduction in fatality rates.”

National Motorists Association President, Jim Baxter commented on the results: “This study confirms what traffic engineers have known all along – driving is safest when speed limits reflect the speeds that most people naturally drive. Now that we are in our fourth year with higher limits, the myth that ‘speed kills’ is the only casualty,” noted Baxter.

While the National Highway Traffic Safety Administration (NHTSA) and others warned in 1995 that raising limits would kill 6400 more people each year, the national fatality rate has dropped to all-time record lows in each subsequent year. “Insurance industry profits may be down because there are fewer speeding ticket victims to penalize with higher premiums, but safety has not been compromised,” said Baxter.

When asked about a recently-released report published by an insurance industry trade group that claimed substantial increases in highway fatalities as a result of higher speed limits, Langlotz responded, “That was a poorly constructed study that seemed to pick and choose the data they wanted to look at. It excluded data from 17 states, raising suspicions of selective inclusion. Why include Vermont but not New Hampshire, Kentucky but not Tennessee? In addition to confusing calendar years with fiscal years, the insurance industry conclusions were impossible contradictions of known results and government statistics.”

A complete copy of the six-page NMAF study is available through the National Motorists Association.