Anti-lock braking system

From ArticleWorld

An anti-lock braking system (or ABS) is a safety feature on vehicles that keeps the wheels from locking during emergency braking. This system allows the driver to ‘’slam on the brakes’’ without fear of skidding or losing control of the vehicle, this has the effect of shortening the braking distance.


A German company called Bosch began developing an electronic anti-lock braking system in the 1930s. The system was originally developed for aircraft and modern versions of this system are still in use on aircraft today. The first automotive use of the anti-lock braking system came in the 1960s when a mechanical anti-lock braking system was used on the Jensen FF and the Ferguson P99 racing cars. Later in 1978, Mercedes-Benz began to use the anti-lock braking system on limousines and some truck models. The first production car to offer an anti-lock braking system as standard equipment was the Ford Granada in 1985.


The typical anti-lock braking system is composed of four-wheel speed sensors (one on each wheel), two to four hydraulic valves in the brake circuit and an anti-lock brake controller (or CAB). The controller (CAB) continually monitors the rotation of each wheel, when it detects one or more wheels rotating much slower than the others, it adjusts the valves to decrease braking pressure on those wheels. This often causes a pulsating feeling in the brake pedal, which is normal. Anti-lock braking systems have been shown to shorten braking distances and reduce the chances of a collision. Some road conditions such as snow or gravel may actually produce larger stopping distances because the wheels do not lock and ‘’dig in’’ to the road surface.