Effects of a mandatory safety belt law on hospital admissions.

Although the effectiveness of automobile safety belts in reducing risk of serious injury in traffic crashes is well documented, safety belt use in many U.S. jurisdictions remains low. Michigan's mandatory safety belt law for front-seat occupants, implemented in July 1985, is one of 34 similar laws in the United States intended to increase belt use and reduce crash-related injuries. Using time-series intervention analyses of data from 14 hospitals throughout the state, we found a 19% reduction in the rate of admitted patients for all automobile occupant injuries and a 20% reduction in the rate of admitted patients with extremity injuries following implementation of the safety belt law. The utility of hospital data for the evaluation of interventions like the safety belt law reinforce the importance of consistently recording E-codes for all injury patients.