Effectiveness of Safety Belt Warning and Interlock Systems

NHTSA - Behavioral Safety Researchhttps://doi.org/10.21949/15248601973PDFResearch PaperCohen, Joel B. (Joel Benjamin)Brown, A. SuzanneNational Analysts (Firm)United States. National Highway Traffic Safety AdministrationUnited States. National Highway Traffic Safety AdministrationUnited StatesManual safety beltsAudible warning devices in vehiclesIgnition seat belt interlocksImpact studiesInterviewingDOT-HS-800-859NTIS-PB220169DOT-HS-200-2-451Final reportRental cars in Fayetteville, N.C., were equipped with four seat belt and warning systems: (Phase I) detachable shoulder and lap belt, no warning system; (Phase II) detachable shoulder and lap belt, warning system (January 1, 1972 standard); (Phase III) non-detachable shoulder and lap belt with inertia reel on shoulder belt, warning and logic system; and (Phase IV) non-detachable shoulder and lap belt with inertia reel on shoulder belt, warning, logic, and starter/interlock system (August 15, 1973 standard). Counters were installed in the cars to measure the respondents' use of seat belts while driving the rental car. Interviews were conducted with rental car drivers to determine drivers' attitudes toward the four systems. A significant increase in measured use of seat belts was seen from Phase I to Phases II, III and IV, however, there was no significant difference in the measured usage rates of respondents in the last three phases. Respondents claimed use of shoulder belts was significantly higher in Phases III and IV compared to the first two phases. Drivers in Phases I and II voiced more favorable attitudes toward the seat belt and warning systems than did respondents in Phases III and IV. /Abstract from report summary page/129