Some state laws note that a child should be at least 57 inches tall before they switch from a child passenger restraint system to a seat belt alone. However, this height standard, derived in 1993, may be outdated, since both child sizes and the vehicle fleet have changed over the years, according to results of a recent study, Belt fit for children in vehicle seats with and without belt-positioning boosters, published in Traffic Injury Prevention. Westat staff were coauthors of the article. They worked with colleagues from the Centers for Disease Control and Prevention (CDC) and the University of Michigan Transportation Research Institute (UMTRI) to perform this research.
Westat developed measurement methods and collected data on 100+ 6- to 12-year-olds in sedan, SUV, and minivan settings. The research used a more diverse population sample and advanced 3D measurement tools to shed new light on the issue. The findings suggest that using the 57-inch height recommendation to transition a child from a booster seat to the seat belt only is not sufficient. Decisions about whether a child needs to use a booster seat should be made every time a child is placed in a new vehicle.
This research more fully informs policymakers since automotive crashes are a leading cause of child deaths in the U.S. Restraining children in rear seats reduces the risk of fatal injury by 75% for children up to age 3, and almost 50% for children ages between 4 and 8. Child safety advocates recommend that after children outgrow their forward-facing car seats, they be transitioned to a belt-positioning booster seat until the vehicle seat belt fits properly without it.