New evidence suggests that cars with antilock braking systems no longer are disproportionately involved in certain types of fatal crashes. However, antilocks still aren't producing reductions in overall fatal crash risk. These findings come from the latest Institute study of antilock brakes, which updates a 1996 analysis (see "Antilock brakes increase fatal single-vehicle crashes," Dec. 7, 1996).
Fatal crash risk was calculated for a set of antilock-equipped vehicles by comparing their crash experience with that of otherwise identical vehicles without antilocks from preceding years. The new data, which cover calendar years 1996-98, indicate positive changes. As before, vehicles with antilock brakes were less likely than cars with standard brakes to be in crashes fatal to the occupants of other vehicles. At the same time, the vehicles with antilocks no longer were found to be overinvolved in crashes fatal to their own occupants. Particularly important is the reduction in single-vehicle, run-off-the-road crashes.
The poor early experience of cars with antilocks never has been explained, so the changes suggested by the more recent data are puzzling. If the improvements in fatal crash risk are lasting, they could reflect positive changes in driver behavior. Experience, or perhaps exposure to information about the real-world effects of antilocks, might have helped drivers learn how to use these brakes properly. Some motorists may have learned not to overcompensate with riskier driving. But there's no clear evidence yet that this has happened. Even with the recent findings, the real-world advantages of antilock brakes are unproven. Over the long term, vehicles with such brakes have fared no better in overall fatal crash experience than vehicles without antilocks.
"Despite their impressive performance on the test track, there still is no evidence that antilock brakes are producing overall safety benefits," says Institute president Brian O'Neill.