A National Highway Traffic Safety Administration study found that ABS increased stopping distance on loose gravel roads by what percent?

The correct answer indicates that Anti-lock Braking Systems (ABS) can actually increase stopping distances on loose gravel roads by about 27.2%. This outcome can be attributed to the functioning of ABS, which prevents the wheels from locking up during hard braking. While ABS is highly beneficial on paved surfaces, where it helps maintain steering control and reduces stopping distances, on loose surfaces like gravel, the mechanism of ABS may not be as effective. The system can inhibit the natural braking that occurs when tires lock up, which can lead to longer stopping distances due to the reduced traction and the lower coefficient of friction on loose surfaces.

Understanding this metric helps drivers recognize that while advanced braking technologies such as ABS improve safety in many driving conditions, they may have limitations in certain scenarios, like driving on gravel. This knowledge emphasizes the importance of adjusting driving techniques in different environments to ensure safety, particularly when stopping or navigating on unstable surfaces.