BACKGROUND AND AIMS: Alcohol-impaired driving contributes to over 10,000 fatalities in the United States each year. The research estimated the unique effect of enforcement intensity on reductions in alcohol-impaired fatal crashes.
DESIGN: We collected data from 30 states (including the District of Columbia) that experienced the greatest changes in alcohol-impaired fatal crashes from 1996 to 2006. Mixed-model regression was used to examine the extent to which year-over-year changes in the intensity of impaired driving enforcement predicted year-over-year reductions of drivers killed in alcohol-involved fatal crashes. SETTING: Data from 30 states were obtained online. PARTICIPANTS: Aggregate state-level data from a total of 279 state-year combinations were analyzed. MEASURES: Our dependent measure was the ratio of drivers involved in fatal crashes with BACs ≥ .08 g/dl over drivers involved in fatal crashes with BACs = .00 g/dl. Per capita driving under the influence (DUI) arrests and traffic enforcement funding were the primary predictors. Covariates were estimated vehicle miles traveled (VMT); the proportional distributions of gender and racial/ethnic; geographic distribution; the proportion of drivers aged 21 to 34 years; median family income; and education level.
FINDINGS: Analysis revealed that DUI arrests per capita uniquely and significantly predicted reductions in the ratio of fatal crashes (β = -.753, t (238) = 2.1, p < .05) after controlling the covariates. Exploratory analysis suggests the increase in arrest rates was associated with stronger reductions in urban versus rural settings.
CONCLUSIONS: Drunk driving enforcement intensity uniquely contributes to reductions in alcohol-impaired crash fatalities after controlling for other factors.