Seatbelt Use Following Stricter Drunk Driving Regulations

We explore seatbelt use following blood alcohol content (BAC) threshold changes from 0.10 to 0.08, which is a potential behavioral response among drivers that may affect the number of lives saved. Specifically, we hypothesize that drunk drivers may adjust their seatbelt use in light of BAC threshold changes in cases where local seatbelt laws are primarily enforced. In particular, drivers may anticipate an increased likelihood of detection of their inebriation if they are pulled over for an alternative infraction, e.g. failure to wear a seatbelt.  Hence, they avoid such interaction with law enforcement by increasing their compliance with seatbelts laws following a drinking episode. We present evidence from the Fatality Analysis Reporting System and the Behavioral Risk Factor Surveillance System that show increased seatbelt use among intoxicated drivers and binge drinkers following the enactment of stricter BAC thresholds in states where seatbelt laws are primarily enforced. This suggests that inebriated drivers who fear being pulled over in states with primarily enforced seatbelt legislation may use their seatbelts more judiciously to avoid being identified as a drunk driver by law enforcement.  In our final analysis, we again appeal to the FARS, this time to establish that the stricter thresholds and primary enforcement of seatbelt laws indeed interact to save lives. Results are consistent with this expectation, as the interactive effect of stricter drunk driving laws and primary seatbelt laws does reduce fatal traffic accidents among nighttime drivers and is also shown to be more effective than either law passed in isolation.