Expanding child restraint laws to cover children through ages 7 or 8 reduces crash injuries among booster-age kids, increases the use of age-appropriate restraints, and lifts the number of children seated in back, where it's safest for them to ride. These are the main findings of a new Institute analysis of the effectiveness of booster seat laws.
Using a booster is important for kids who have outgrown internal-harness child restraints and aren't big enough for safety belts. Children ages 4-8 in boosters are 45 percent less likely to sustain injuries in crashes than kids restrained by belts alone (see "Kids should use rear-facing seats at least until 2," Aug. 18, 2011, and "Boosters offer better protection than safety belts alone in a crash," Dec. 22, 2009).
The problem is that many children, especially older ones, graduate too soon to safety belts even though they would benefit from a booster. That's partly because many states don't require boosters for older grade schoolers. In 29 states and Washington, D.C., the laws apply to children 7 and younger, with exceptions for size. Wyoming and Tennessee cover kids 8 and younger.
"With this study we wanted to see if extending booster requirements to older kids would make a difference in terms of restraint use and rates of injuries in crashes," explains Anne McCartt, the Institute's senior vice president for research. "What we found was that 5 states with stricter laws are seeing measurable benefits."
Researchers analyzed state crash data to compare population-based injury rates, restraint use, and seating position among 4-8 year-olds before and after 5 states expanded laws to require child restraints or boosters at least until age 7. Researchers focused on kids affected by the changes, so if 4 year-olds were already covered, for example, they were excluded. Missouri, North Carolina, Pennsylvania, and Wisconsin expanded laws to require child restraints or boosters through age 7, and Wyoming extended coverage through age 8. Researchers adjusted effectiveness estimates using a comparison group of 9-12 year-olds who weren't required to use boosters.
Previous studies have found that booster seat laws increase booster use and reduce injury risk among children. These studies have primarily included states with laws that cover younger children, usually 5-6 year-olds.
"What's new about the Institute's analysis is that it is the first study to look at law changes affecting older booster-age kids, using data for all crashes involving injuries," McCartt says.
Expanded child restraint laws were associated with a 5 percent reduction in the rate of children with injuries of any severity in crashes and a 17 percent reduction in the rate of kids with fatal and incapacitating injuries. Plus, children covered by the laws were nearly 3 times more likely to be in age-appropriate restraints (boosters or child restraints) after the states amended their laws.
Another positive benefit is that parents are more likely to put children in the back seat, even if the laws don't prohibit booster-age kids from sitting in front. Research shows that children younger than 13 involved in crashes are at greater risk of injury in the front.
In the Institute study, 6 percent more booster-age kids were seated in the back after the restraint laws were expanded. Only Wyoming stipulates that kids in boosters must be in an available back seat.
"States with laws requiring boosters or internal-harness child restraints for younger children should consider revising them to ensure that older children receive the best crash protection, too," McCartt says. "It sends the message to parents that their school-age sons and daughters still need safeguarding."
Children who are using improperly fitted belts are at risk of a host of crash injuries known as "seat belt syndrome." These include hip and abdominal contusions, pelvic fractures, cervical and lumbar spine injuries, and internal organ injuries. Boosters help by elevating a child into position and guiding the belts for better protection.
During 2009, only 55 percent of 4-7 year-olds were observed in an appropriate restraint, a National Highway Traffic Safety Administration survey found. Of these, 41 percent were in boosters and 14 percent were in child restraints. Thirty-two percent of children this age were seen using belts, and 13 percent weren't restrained at all.