Implications of the 65-MPH Speed Limit for Traffic Safety

This study evaluates the impact of the 65-mph speed limit on traffic safety. Using data for the years 1981 to 1995 for all 50 states, a pooled time series analysis is conducted. Separate models are estimated for state fatality rates on four categories of roads: rural interstate highways, rural noninterstate roads, all roads except for rural interstate highways, and all roads. It is reported that the 65-mph speed limit increased fatality rates on rural interstate highways but was correlated with a reduction in state fatality rates on the three other categories of roads.