The Effect of Mandatory Seat Belt Laws on Seat Belt Use by Socioeconomic Position


  • Sam Harper,

  • Erin C. Strumpf,

  • Scott Burris,

  • George Davey Smith,

  • John Lynch


We investigated the differential effect of mandatory seat belt laws on seat belt use among socioeconomic subgroups. We identified the differential effect of legislation across higher versus lower education individuals using a difference-in-differences model based on state variations in the timing of the passage of laws. We find strong effects of mandatory seat belt laws for all education groups, but the effect is stronger for those with fewer years of education. In addition, we find that the differential effect by education is larger for mandatory seat belt laws with primary rather than secondary enforcement. Our results imply that existing socioeconomic differences in seat belt use would be further mitigated if all states upgraded to primary enforcement.