The effects of the new 65 mile-per-hour speed limit on rural highway fatalities: a state-by-state analysis

Abstract

This paper examines the effects of the new 65 mile-per-hour (mph) speed limit on U.S. rural highway fatality counts. Separate analyses are conducted for each of the 40 states that had adopted the new (higher) limit by mid-1988. Using monthly Fatal Accident Reporting System (FARS) data from January 1976 through November 1988, time-series regression equations--including policy variables, seasonal variables, and surrogate exposure variables--are estimated for each state. The results suggest that the new laws have increased fatalities on both rural interstate and rural noninterstate highways in most states, but also that these effects differ substantially across the states. For rural interstate fatalities the estimates suggest a median (among the 40 states) effect of the increased speed limit of roughly 15% more fatalities; the median estimates for rural noninterstates suggest a 5% increase in fatalities due to the increased speed limits. Estimates such as those reported here should be revised as more information becomes available.