Effects of the 65-mph Speed Limit on Rural Interstate Fatalities in New Mexico

As a result of federal legislation passed in April 1987, New Mexico was the first state to resume a 65-mph speed limit on rural Interstate highways. We compared the rates of fatal crashes before and after the speed limit change. The rate of fatal crashes in the 1 year after the speed limit was increased was 2.9 per 100 million vehicle-miles traveled, compared with a predicted rate of 1.5 per 100 million vehicle-miles based on the trend of the 5 previous years. When fatal crashes that occurred after the speed limit change were compared with fatal crashes in the 5 previous years, there was no difference in the mean age and sex of the at-fault drivers, mean age and sex of the victims, seat belt use by the victims, or alcohol involvement of the crashes. The increase in fatal crashes can be attributed to an increase in fatal single-vehicle crashes. Vehicles on rural Interstates are traveling at greater rates of speed and a larger proportion of vehicles are exceeding the 65-mph speed limit. The benefits associated with the 65-mph speed limit should be weighed against the increased loss of lives.

(JAMA. 1989;262:2243-2245)