An analysis of the relationships between accidents and the 55-mph speed limit on the Arizona highway system. Prepared for the 55th Annual Meeting of the Transportation Research Board TRB, Washington, D.C., January 1976.

Research was conducted to determine what causal relationship, if any, exist between the reduced number of Arizona traffic accidents and traffic fatalities in 1974 and the 55 mph speed limit imposed at the beginning of 1974. It can be concluded that the accident reduction experienced on the studied sections, affected by the 55 mph speed limit, accounted for virtually the entire state-wide reduction in fatal accidents.