The State of Michigan implemented a mandatory child restraint law in April, 1982, with the goal of reducing crash-induced injuries to young children. The law required that children under the age of four be restrained by an approved child restraint device or adult seat belt when traveling in passenger cars and light trucks. Most states have passed similar child restraint laws, and several studies have found increased restraint use after the laws took effect. However, significant reductions in childhood injuries have not been demonstrated in the limited research to date.

All reported traffic crashes in the State of Michigan from January, 1978 through December 1982 were examined using Box-Jenkins time-series analysis methods. Recent general downward trends in motor vehicle casualties were controlled when assessing the specific effects of the child restraint law. The monthly frequency of motor vehicle occupant injuries was analyzed for children the focus of the new law as well as multiple comparison age groups.

Results revealed substantial increases in restraint use and substantial decreases in the frequency of injuries among crash-involved children. The final time-series models revealed the following effects directly associated with the child restraint law. Restraint use increased from 12 to 36% and injuries decreased 17% among children age one through three. Infants under age one experienced a 50% reduction in injuries.

The findings demonstrate that significant reductions in crash-related injuries can be achieved through implementation of laws mandating use of restraints by motor vehicle occupants.