State alcohol control policies and alcohol-impaired driving in the United States

Background: Alcohol-impaired driving (AID) kills more than 11,000 people each year in the US and is a leading cause of injury morbidity. Despite the enactment of policies to prevent AID over the past 30 years, the proportion of crash deaths that are alcohol-related has not decreased since 1995. This coincides with a period in which several effective policies to curb excessive drinking have eroded, and both binge drinking and per capita consumption have increased.

Methods: An Alcohol Policy Scale (APS) score was created from data on 29 state-level alcohol control policies from the Alcohol Policy Information System and other data sources and weighted by their relative efficacy and degree of implementation for each U.S. state and year from 2002-2010. A scale to measure the alcohol impaired driving environment (AID-APS) was derived by restricting the APS to the 15 policies that were driving-oriented. The relationships among APS and AID-APS scores and state-level prevalence of self-reported AID from the Behavioral Risk Factor Surveillance System surveys from 2002-2010 were examined.

Results: APS scores varied substantially by state and were inversely associated with impaired-driving (r=-0.54, p<0.01, R2=0.30); AID-APS scores also varied by state and were inversely correlated with AID, although the AID-APS explained less variance between states (r=-0.36, p<0.01, R2=0.13) than the overall APS score.

Summary: States with stronger overall alcohol control environment had lower prevalence of less self-reported AID. More work is necessary to better understand the relative effect of policies targeting excessive drinking versus those targeting driving after drinking.