Effects of booster seat laws on injury risk among children in crashes

Belt-positioning booster seats have been shown to reduce injury risk among child passengers aged 4 to 8 in motor vehicle crashes. To encourage the use of booster seats, many states have enacted laws that require the use of either a child restraint with internal harness or a belt-positioning booster seat, but the specific age range covered by the laws varies by state. Previous studies have found evidence that booster seat laws are effective in reducing injury risk among children, but these studies primarily have included states with younger age requirements (e.g., ages 4-6) for booster seats. The objective of the present study was to examine the effectiveness of booster seat laws in several states that cover children through age 7 or 8.

Police-reported crash data from 5 states--Missouri, North Carolina, Pennsylvania, Wisconsin, and Wyoming--were used to compare population-based injury rates, restraint use, and seating position among children before and after booster seat laws. The pre-law period was comprised of the 2 calendar years prior to the year of enactment of the booster seat law, and the post-law period was comprised of the 2 calendar years after the year of the effective start of the booster seat law. Effectiveness estimates were adjusted using a comparison group of children aged 9 to 12 in the same states who were not covered by the booster seat laws.

Among children in crashes who were affected by law changes in the 5 study states, the per capita rate of children using child safety seats (either a harnessed child restraint or booster seat) increased nearly 3 times, and the per capita rate of children riding in rear seats increased 6 percent after the booster seat laws were implemented. Booster seat laws were associated with a 5 percent reduction in the per capita rate of children who sustained injuries of any severity and a 17 percent reduction in the per capita rate of children who sustained fatal or incapacitating injuries.

Results provide evidence that booster seat laws are effective in increasing the use of child safety seats, increasing the placement of children in rear seats, and reducing injuries, especially severe injuries, among children covered by the laws.