Project Summary The goal of this project is to assess how changes in local alcohol policy and enforcement are associated with excessive alcohol use and alcohol-impaired driving. We will use a longitudinal design with local-level policies and outcome data tracked over a 15-year period, and enforcement of alcohol policies measured at two time points. We propose to conduct a 5-year longitudinal study to address the following specific aims: (1) assess the longitudinal associations of individual local alcohol policies with excessive alcohol use and alcohol-impaired driving; (2) assess the longitudinal association of combinations of local alcohol policies with excessive alcohol use and alcohol-impaired driving; and (3) assess the longitudinal association of alcohol enforcement at the local level with excessive alcohol use and alcohol-impaired driving and assess how enforcement influences associations between alcohol policies and outcomes (effect modification/interaction). The proposal addresses recommendations from several national-level institutions, provides a tool for future research studies, and will inform policymakers' decisions about effective strategies to prevent and reduce health and social harms that result from excessive drinking and impaired driving.