Which Underage Drinking Law Components in the States Are Associated with Reductions in Underage Drinking Driver Fatal Crashes?

Introduction: The public generally assumes that the Minimum Legal Drinking Age of 21 (MDLA-21) is embodied in a single law, and therefore, all states have the same law. Actually, the MLDA-21 state laws consist of multiple provisions that support the core MLDA-21 laws and comprise a family of policies directed at controlling underage drinking. Underage drinking statutes vary considerably from state to state, and no state has all components advocated by the federal government. Thus, the current U.S. effort to control underage drinking involves a variable package of policies, many of which have not been evaluated for their effectiveness.

Methods: The effective dates for 16 of the MLDA-21 law components were documented. These include possession, consumption, purchase, use and lose, zero tolerance (ZT), graduated driver licensing (GDL) laws with night restrictions, keg registration laws, social host laws, the use of fake identification (ID), retailer support for fake ID, transfer/production of fake identification laws, furnishing/selling, state control of alcohol, age for on-premise sellers/servers, age for off-premise sellers/servers, and responsible beverage service (RBS) training. We used a pre-post design to evaluate the influence on drinking-and-driving fatal crashes of eight of the underage drinking law components. The Fatality Analysis Reporting System (FARS) data set was used to assess the ratio of underage drinking to nondrinking drivers involved in fatal crashes. The data were analyzed using structural equation modeling (SEM).

Results: Five of the eight underage drinking law components were associated with significant decreases in the FARS ratio of underage drinking to nondrinking drivers in fatal crashes. Significant decreases were associated with the implementation of possession and purchase laws, the ZT law, and the use and lose law. The law providing retailer support for fake ID (e.g. a distinctive drivers’ license for those under age 21; electronic fake ID detector machines) was also significant. The GDL law and social host law did not emerge as significantly related to the underage fatal crash ratio. Contrary to expectations, keg registration was associated with a significant increase in the fatal crash ratio.

Conclusions: We estimated that the two core underage drinking laws (purchase and possession) and the ZT law are currently saving 732 lives per year controlling for other exposure factors. If all states adopted use and lose laws, an additional 165 lives could be saved annually.