Curtailing alcohol-related traffic fatalities is especially important for policymakers since research indicates that a considerable share of these deaths and their associated consequences are preventable. I exploit time and geographic variation in the adoption of zero-tolerance laws in a difference-in-differences design. Using county-level data, I find no sizeable reductions in fatalities or injury counts after the adoption of such laws. I also test for heterogeneity across age groups, finding no significant differences. I propose and evaluate the persistence of drinking behavior and alcohol-related hospitalizations as mechanisms for the null effects, finding no significant changes in several measures of alcohol consumption
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