Why Have Traffic Fatalities Dropped in the US

A comprehensive analysis of state-level data from 1984 to 2011 provides evidence on the sources of recent US traffic fatality reductions and the effectiveness of various policies. The largest reductions in fatalities are generally associated with decreases in household median income, a proxy for economic activity. Changes in the road network, mainly increasing the number of lanes on arterial and collector roads has increased fatalities. Graduated licensing policies, mobile communication device laws, safety-belt laws and motorcycle helmet requirements are all associated with reductions in fatalities. In particular, between 2006 and 2012, the further implementation of graduated licensing and mobile communication device laws in additional states accounts for substantial reductions in nationwide fatalities. Other control factors include a proxy for medical technology, population and demographic changes, and various other proxies that are related to economic activity, with mixed effects on fatality reduction.