Updated estimates of the effectiveness of child safety seats, 1996-2005

Background

Child restraint effectiveness has been estimated using a variety of data sources and methods. Commonly cited estimates of the effectiveness of restraints in preventing death come from data more than 15 years old. This study provide updated, detailed estimates of child restraint effectiveness.

Methods

We estimated the effectiveness of child restraints in preventing death among children age 3 or younger and examined modification by collision and vehicle factors. A matched cohort study was conducted using data from the Fatality Analysis Reporting System for years 1996-2005. Death risk ratios were estimated with a conditional Poisson regression analysis that included bootstrapping, multiple imputation, and a sensitivity analysis of misclassification bias.

Results

The estimated death risk ratios comparing child safety seats to no restraint were 0.27 (95% CI 0.21-0.34) for infants, 0.24 (0.19-0.30) for children age 1, 0.40 (0.32-0.51) for age 2, and 0.41 (0.33-0.52) for age 3. Safety seat effectiveness appeared to be greater during rollover collisions, in rural environments, and in light trucks. Restraint effectiveness did not vary meaningfully over the 10-year study period.

Conclusions

Child safety seats are highly effective in preventing death during severe traffic collisions, while seat belts appear to be moderately effective. The seat belt risk ratios may be sensitive to misclassification bias. This study did not examine the effects of child restraints on the reduction non-fatal injury severity. Practitioners should continue to encourage parents to use child safety seats in favor of seat belts and should provide information on the proper selection of safety seats.