Direct observation of child restraint use was combined with interviews and mail questionnaires to measure prevalence of various child restraint practices and factors related to use of child safety seats and seat belts for children under the age of four. Trained observers assessed multiple dimensions of child restraint practices for a sample of motorists entering fast-food parking lots in Michigan. On-site interviews and follow-up questionnaires measured sociodemographic, attitudinal, belief, and behavioral characteristics related to restraint use. Ninety-two percent of infants under age 1 and 55% of children age 1 to 3 were traveling in a child safety seat. Public support for the mandatory child restraint law was very high--9 out of 10 believed it should be strictly enforced. Child restraint use was lower than average among motorists who: (1) had low family incomes, (2) were not currently married, (3) were of nonwhite ethnic backgrounds, and (4) were over the age of 40. A shift in social norms appears to have occurred in recent years, such that restraint of young children traveling in cars is now socially expected behavior. Recommendations include: (1) continuing educational efforts to increase knowledge of mandatory child restraint use laws, and (2) increased enforcement of mandatory child restraint use laws.