Variation in U.S. traffic safety policy environments and motor vehicle fatalities 1980–2010

ObjectiveTo examine the impact of variation in state laws governing traffic safety on motor vehicle fatalities.Study designRepeated cross sectional time series design.MethodsFixed effects regression models estimate the relationship between state motor vehicle fatality rates and the strength of the state law environment for 50 states, 1980–2010. The strength of the state policy environment is measured by calculating the proportion of a set of 27 evidence-based laws in place each year. The effect of alcohol consumption on motor vehicle fatalities is estimated using a subset of alcohol laws as instrumental variables.ResultsOnce other risk factors are controlled in statistical models, states with stronger regulation of safer driving and driver/passenger protections had significantly lower motor vehicle fatality rates for all ages. Alcohol consumption was strongly associated with higher MVC death rates, as were state unemployment rates.ConclusionsEncouraging laggard states to adopt the full range of available laws could significantly reduce preventable traffic-related deaths in the U.S. – especially those among younger individuals. Estimating the relationship between different policy environments and health outcomes can quantify the result of policy gaps.