If the light remains on, or comes on during normal operation, there is a problem with the system. Drivers should then brake as they normally would without ABS, i.e. pumping the brakes. Experienced truck drivers maintain a moderate degree of steering control by pumping conventional brakes. Stopping distance is nearly the same for pumped brakes as it is when the brakes are locked. However, with locked brakes the driver has little, if any, control over vehicle direction.
ABS pumps the brakes automatically during emergency stop.
It prevents wheel lock and allows the driver to maintain a higher degree of control. Drivers, therefore, have more steering control. ABS pumps the brakes much faster than a human can pump conventional brakes, and is thus more effective in maintaining control. Also, it works on individual wheels so they all slow at the same rate. In spite of the fact that ABS does not change vehicle-stopping distance, the driver might still be able to avoid an accident by steering clear of it.