Speed limits may not be saving lives

A new article publishing in the latest issue of Review of Policy Research examines the evolution and devolution of speed limit laws and their effects on fatality rates. The author did not find a significant increase in fatalities per miles driven after speed limit laws ceased to be national and states could, and some did, increase their highway limit to more than fifty-five miles per hour. “Automobile safety features and enforcement emerge as important factors in increasing highway safety; speed limits are far less important,” author Robert O. Yowell explains.

Although speed limits bring to mind the notion of public safety, they were formed in the 1970s to combat a gasoline shortage. In the 1980s the focus shifted to public safety while some speed limit regulation devolved back to states; the maximum speed on rural interstates could be raised to 65 mph. In 1995 and involving some controversy, Congress returned all speed limit authority back to the states. Analysis of the highway deaths per mile driven after the 1974 nationalization of the maximum highway speed indicates an initial greater decline in deaths than had been the trend, but the long-term decreasing trend reemerged following the shock. Dr. Yowell’s research finds others reasons besides speed for the long-term trend of increased highway safety. (From 1968 to 1991, the fatality rate per 100 million declined by 63.2%.) Technical progress in car manufacturing, increased use of seat belts by drivers and passengers, an increase in the minimum legal drinking age, and the general maintenance of roads all affect this rate.