Nighttime seat belt use among front seat passengers: Does the driver's belt use matter?

Introduction and Method: We explored the relationship between nighttime seat belt use of right-front passengers and their drivers using observational data from 33,310 vehicles in east Tennessee during March 2015 – May 2017. Results: Overall, nighttime passenger seat belt use varied by 50 percentage points from 92% when drivers were belted to 42% when drivers were not belted, suggesting that part-time seat belt users can be heavily influenced by the seat belt status of their traveling companions. When stratified by vehicle type and sex, passenger seat belt use by driver seat belt status varied as much as 74 percentage points from 96% to 22%. Passenger seat belt use was typically lower when riding with unbelted same-sex drivers than when riding with unbelted drivers of the opposite sex. Conclusions and Practical Applications: This finding suggests that the role of peer influence in decision-making about seat belt use may differ depending on the sex of a vehicle driver and his or her passengers. Further research is warranted to explore this finding as well as other social and cultural influences that have not been fully examined in seat belt research.