A meta-analysis of .08 BAC laws in 19 jurisdictions in the United States.

More than a dozen studies on the effectiveness of the .08 blood alcohol concentration (BAC) laws have been published; however, those studies have varied both in the statistical methods and the type of outcome measure used, so it is difficult to integrate the findings into an overall estimate of the effectiveness of the law. This study used a consistent outcome measure, drinking drivers in fatal crashes and an identical methodology time-series analysis, to analyze the introduction of the .08 law in 18 states and the District of Columbia from 1982 to 2000. Each analysis accounted for other key safety laws (administrative license suspension/revocation and safety belt laws), as well as economic conditions that might influence the effectiveness of the .08 law. This provided 19 independent evaluations in which the effectiveness (treatment effect) of the law could be measured in the same quantitative terms. The number of drinking drivers in fatal crashes declined in 16 of the 19 jurisdictions after the .08 law was adopted. Nine of the 16 reductions were statistically significant (p < .05). The effect size combined across all 19 locations showed statistically significant decline (p < .005) of 14.8% in the rate of drinking drivers in fatal crashes after the .08 laws were introduced. The reduction was greater in states that had an administrative license suspension/revocation law and implemented frequent sobriety checkpoints. This analysis suggests that 947 lives might have been saved, had all 50 states and the District of Columbia had the .08 law throughout the year 2000.