Statement of Purpose Motor vehicle crashes are the leading cause of death for adolescents. In 2019, 45% of the teen drivers who died in a motor vehicle crash were unbuckled. The purpose of this study is to examine the association between types of state seat belt legislation and seat belt use among U.S. high school students.

Methods/Approach This study used 2019 state Youth Risk Behavior Survey (YRBS) data. The main outcome was seat belt use when riding in a car driven by someone else (always versus not always). The exposure of interest, seat belt law type, was classified using enforcement type and seating position into three dichotomous variables based on the age and the residing state of the participant: primary vs. secondary enforcement; all seats vs. front seat only; and adult vs. child seat law. Prevalence ratios were estimated using modified Poisson regression with robust variance estimates, adjusting for sex, race/ethnicity, grade, and state graduated driver licensing passenger restriction laws.

Results The prevalence of always wearing a seat belt ranged from 40.8% (Louisiana) to 68.5% (Maine). After adjustment, among teens who are covered by enforcement on all seats, the prevalence of seat belt use for those following secondary enforcement is 13% lower than primary enforcement.

Conclusion This study provides state-level estimates of seat belt use among U.S. teens by state seat belt law in 2019. The findings suggest that primary enforcement of seat belt laws may be more effective on seat belt wearing behavior than secondary enforcement laws.

Significance Stricter legislation regarding the enforcement of seat belt laws, along with youth-targeting evidence-based, comprehensive educational campaigns and service-learning programs about seat belt use, should be considered to promote seat belt wearing and prevent crash fatalities for youth in all states.