Enhanced safety belt reminders are a proven way to raise belt use, especially among drivers who typically don't use belts. Now a new Institute study concludes that enhanced belt reminders are saving lives. The main finding is a 2 percent reduction in driver fatality risk.
Since 1975, all new cars sold in the United States have been required to display a warning light and sound an audible signal for 4-8 seconds after the ignition starts if the driver belt isn't fastened. Beginning in 2000, many automakers voluntarily enhanced their belt reminders with visual and audible alerts that persist for longer than 8 seconds. About 90 percent of 2009 models have these enhanced belt reminders for drivers.
Institute studies of systems in Fords and Hondas have shown them to be effective in raising driver belt use by 5-6 percentage points (see "Automakers are adding more persistent reminders to buckle up," March 27, 2004, and "Belt reminders in Hondas are persuading motorists to buckle up," June 13, 2006).
A larger study by the National Highway Traffic Safety Administration (NHTSA) found that enhanced reminders raise driver and front passenger belt use by about 3 percentage points compared with vehicles without them (see "Reminders are effective in persuading holdouts to buckle their safety belts," June 9, 2008).
Institute researchers compared 2000-07 driver fatality rates per vehicle registration per year for vehicles with and without enhanced belt reminders. Driver fatality rates were 6 percent lower for vehicles with enhanced reminders compared with those without them. After adjusting for age differences of the vehicles being compared, the estimated effect of enhanced belt reminders on driver fatality risk was a 2 percent reduction.
The reduction is small and doesn't meet the traditional definition of statistical reliability, notes Anne McCartt, Institute senior vice president for research. But it is in line with expectations given NHTSA's estimate that enhanced reminders boost belt use by 3 percentage points. Of the 21,647 driver deaths in the U.S. during 2007, McCartt says, "only 3,442 were in vehicles with enhanced belt reminders. So the reduction in risk translates to about 70 fewer deaths. More lives will be saved as enhanced belt reminders become more widely available."