Automobile-dependency as a barrier to vision zero, evidence from the states in the USA.

With a traffic fatality rate of 10.6 per 100,000 as of 2013-more than triple that in the UK, the Netherlands, and Sweden-the United States has the worst traffic safety performance of all developed countries. Statewide variations are even more pronounced. North Dakota registers more than twice the national average and five times the rate of Massachusetts. We used panel models and annual data from 1997 to 2013 to capture the effect of seven separate sets of factors that influence traffic safety: exposure, travel behavior, socioeconomics, macroeconomics, safety policies, and mitigating factors such as health care. The results of our panel models and supplementary analysis of state effects show that two variables - Vehicle Miles Traveled and Vehicles per Capita-have the strongest impact on traffic fatality rates. This is closely followed by Infant Mortality Rates, the proxy that we used to represent the quality of health care. Policy levers such as Graduated Driver's Licenses (GDL) have improved safety, but to a limited extent. We also found that states with higher urban density and more walking are associated with lower traffic fatality rates. Taken as a whole, our findings suggest that if additional progress is to be made in reducing traffic fatalities, emphasis needs to move beyond simply focusing on policies such as GDL and seat belt laws, which have already been adopted by almost all jurisdictions across the United States. We need to also consider factors that focus on the type of urban form that we are creating to ensure that we are fostering environments that encourage multi-modal transportation such as walking to reduce the VMT and Vehicles per Capita, the two strongest predictors of traffic fatalities.