Traffic fatalities are the second largest contributor to years of life lost before age 75 and are the leading cause of death among youth aged 15-24 years. Alcohol involvement in these crashes has remained relatively steady despite overall declines in traffic fatality rates. Public policies (laws, regulations, penalties) concerning alcohol and car safety have contributed to these declines, but there is enormous variation in policies among states. To date, little scholarship has systematically investigated the impact of such a diverse regulatory environment on health outcomes. This study uses variation across states from 1980-2010 as a natural experiment to examine the relationship between the evolution of state policies concerning alcohol and motor vehicle safety on changes in traffic fatalities and injuries, and the role of alcohol in these outcomes. Data come from the Alcohol Policy Information System, linked to other available datasets and supplemented by original legal research. The study proposes to develop a comprehensive database on state alcohol and traffic safety policies; identify patterns in state law adoption; assess factors associated with health policy adoption and diffusion; and quantify the impact of multiple state health policies on traffic fatalities and injuries over time. The study is consistent with and contributes to NIAAA's priorities for assessing the alcohol policy environment. This grant was funded by the National Institute on Alcohol Abuse and Alcoholism.