Effects of mandating seatbelt use: a series of surveys on compliance in Michigan.

Although proper use of automobile seatbelts reduces risk of serious injury or death in traffic crashes by 30 to 50 percent, seatbelt use remains low. Recently, several States have passed laws requiring the use of seatbelts. Michigan implemented such a law July 1, 1985. Direct-observation surveys of a probability sample of motorists throughout the State were conducted before the law was passed, after passage but before implementation, immediately after the law took effect, and 5 months after implementation. The results showed a significant increase in the use of restraints from 19.8 percent before the law was passed to 58.4 percent immediately after it took effect. A restraint use survey conducted in December 1985, 5 months after implementation, measured the use of restraints at 43.0 percent. Despite that decline, belt use was 117 percent higher than the 19.8 percent measured before passage of the law mandating the use of seatbelts.