Anti-lock Braking System (ABS)

An anti-lock braking system (ABS) is a system on vehicles which prevents the wheels from locking whilst braking. The purpose of this is to allow the driver to maintain steering control under heavy braking and in most situations, to shorten braking distances (by allowing the driver to hit the brake fully without the fear of skidding or loss of control). Disadvantages of the system include increased braking distances under certain conditions and the creation of a "false sense of security" among drivers who do not understand the operation and limitations of ABS.

History

Anti-lock braking systems were first developed for aircraft. An early system was Dunlops Maxaret system, introduced in the 1950s and still in use on some aircraft models. This was a fully mechanical system. It saw limited automobile use in the 1960s in the Ferguson P99 racing car, the Jensen FF and the experimental all wheel drive Ford Zodiac, but saw no further use; the system proved expensive and, in automobile use, somewhat unreliable. However, a limited form of anti-lock braking, utilizing a valve which could adjust front to rear brake force distribution when a wheel locked, was fitted to the 1964 Austin 1800. The first car (worldwide) to have ABS fitted as standard (across the entire range) was the Ford Granada Mk 3 (of 1985).

The American firm Kelsey Hayes (now part of TRW Automotive), developed the first electronic ABS system in the late sixties and introduced on the 1970 Lincoln Town Car. It was a rear wheel system, as was General Motors Cadillac version of anti-lock brakes called Track Master, which was introduced in 1970 on the Eldorado coupe and made an option for the entire line in the following year.

The first true electronic 4-wheel multi-channel ABS was co-developed by Chrysler and Bendix for the 1971 Imperial. Called "Sure Brake", it was available for several years and had a satisfactory performance and reliability record. The German firm Bosch had been developing anti-lock braking technology since the 1930s, but the first production cars using Boschs electronic system became available in 1978. They first appeared in trucks and the Mercedes-Benz S-Class. Interestingly, M-B has recently advertised that it had 4-wheel ABS first, when, in reality, they were beaten by seven years - by a company they now own: Chrysler. BMW started using ABS at the time, making the technology standard on all vehicles in 1986. ABS Systems were later introdu