Effect of booster seat laws on appropriate restraint use by children 4 to 7 years old involved in crashes.

OBJECTIVE To quantify the independent contribution of recently enacted booster seat laws on appropriate restraint use by child passengers in motor vehicles. DESIGN Longitudinal study of children involved in crashes with data collected via insurance claims records and a validated telephone survey. SETTING Sixteen states and Washington, DC, from December 1, 1998, through December 31, 2004. PARTICIPANTS Probability sample of 5198 vehicles in crashes involving 6102 children aged 4 to 7 years, representing 78 159 vehicles and 91 752 children. MAIN EXPOSURES Booster seat law provisions, child age, state, and secular trends. MAIN OUTCOME MEASURE Reported appropriate restraint use for this age group, including forward-facing child safety seats, belt-positioning booster seats, and combination seats. RESULTS Children aged 4 to 7 years in states with booster seat laws were 39% more likely to be reported as appropriately restrained than were children in other states (prevalence ratio [PR], 1.39; 95% confidence interval [CI], 1.14-1.70). Children aged 4 to 5 years were 23% more likely (PR,1.23; 95% CI, 0.80-1.42) and children 6 to 7 years twice as likely (PR, 2.09; 95% CI, 1.46-2.99) to be reported as appropriately restrained. For children aged 6 to 7 years, when compared with no law, laws through age 7 years were most effective (PR, 3.71; 95% CI, 2.49-5.42), followed by laws through age 4 or 5 years (PR, 1.43; 95% CI, 0.89-2.24). CONCLUSION Given the higher current use of age-appropriate restraints among children 4 to 5 years compared with older children, future upgrades to child restraint laws should include children through at least age 7 years to maximize the number of children properly restrained for their age.