The impact of laws on driving under the influence of alcohol: A comparison across adolescents and younger adults, and older adults in Chile

Abstract

This research examines the effects of a) reducing the legally allowable alcohol levels in drivers and b) increasing the severity of punishments for drivers involved in drunk driving accidents on events, injuries, and deaths caused by driving under the influence of alcohol (DUI). The study advances prior research by using policy evaluation methods to estimate its causal effect and estimate its impact separately for younger people and older adults. Data were obtained from a database of all traffic accidents associated with alcohol consumption compiled by Chile's transport authority. Exploiting the implementation of a law introduced in March 2012 that reduced the maximum allowed concentration of alcohol in drivers and increased punishments, the study used a difference-in-differences approach that compared changes in the monthly rate of accidents before and after the policy, comparing rates of accidents during the evening (treatment group) to those during daytime (control group). Furthermore, a regression discontinuity design was implemented to examine the causal effect of reducing the permissible blood alcohol concentration (BAC) and implementing harsher punishment in two different age groups, controlling for gender and the type of area of the events (urban and rural areas). The results showed that the law effectively reduced the rate of accidents and injuries in both younger (between 15 to 25 years of age) and older groups (from 26 years of age and older). A three-way interaction test showed that the effect was slightly larger on the younger group. This study provides evidence that deterrent policies can effectively reduce risk behaviors and reduce accidental deaths associated with drunk driving.