The Effectiveness of Enhanced Seat Belt Reminder Systems: Observational Field Data Collection Methodology and Findings

Abstract

Enhanced seat belt reminder systems (ESBRs) provide a more conspicuous warning to fasten seat belts than the Federal Motor Vehicle Safety Standard (FMVSS) currently requires. The effect of ESBRs on driver and front passenger seat belt use was examined in a field observational study of seat belt use of unalerted front seat occupants in nearly 40,000 passenger vehicles in eight States with and without primary seat belt laws. License tag numbers were matched to State motor vehicle registration records to determine Vehicle Identification Number (VIN), manufacturer, model, and year. ESBR features (e.g., sound, icon, text, duration, cycle, etc.) were determined by matching make, model, and year to a features database compiled by NHTSA and Westat. A propensity analysis was conducted using stepwise logistic regression models to estimate the probability of seatbelt use while controlling for the influence of key vehicle, occupant and geographic location factors. ESBRs were found to increase front occupant seat belt use by 3-4 percentage points compared to vehicles without ESBRs. Significant positive effects of ESBRs were more often found among the lowest belt use propensity groups. ESBR features were found individually and in combinations to have significant effects on driver seat belt use. The findings suggest that ESBRs may be most effective in converting belt use resistors if they incorporate the features found to have positive effects among lowest belt use propensity groups.