Anti-lock Braking System (ABS)

Anti-lock braking system (ABS) /an-tee-lock bray-king sis-tuhm/ noun (countable)

An anti-lock braking system is an active safety system in a motor vehicle that prevents the wheels from locking up during heavy braking, allowing the driver to maintain steering control. This was the first electronic nanny to be widely fitted to cars, the first piece of silicon to prove it had faster reflexes than a human, no matter how talented they claimed to be. It stops you from skidding helplessly into a ditch by pulsing the brakes with the superhuman speed of a panicked woodpecker. For decades, the British considered the ability to brake on the edge of a skid a key driving skill. ABS rendered this hard-won expertise obsolete overnight, replacing a nuanced art form with the reassuring, if slightly insulting, judder of a pedal that refuses to let you make a fool of yourself.

The Full Story of the Anti-lock Braking System

The concept of anti-lock brakes was not invented for the car, but for the aeroplane. In the post-war years, engineers were faced with the problem of very fast, very heavy jet aircraft trying to land on wet British runways without pirouetting into a field. The solution was the Dunlop Maxaret system, a brilliant piece of mechanical engineering that could detect a locked wheel and release the brake pressure, preventing a skid. It was fitted to bombers like the Avro Vulcan, and it worked.

For years, the technology remained firmly in the sky. The 1966 Jensen FF, already stuffed with advanced all-wheel-drive technology, was fitted with an adapted Dunlop Maxaret-inspired anti-lock braking system. As the first production car to feature ABS, the FF was a piece of pioneering technology, a fact for which it received almost no commercial reward or lasting recognition from the wider market.

The real breakthrough came in the 1970s when the Germans, specifically Bosch, perfected an electronic version of the system. Gone was the complex clockwork of the Maxaret, replaced by wheel speed sensors and a microprocessor. This new system could monitor all four wheels independently and react with a speed and precision no mechanical setup could match. It made its debut on the 1978 Mercedes-Benz S-Class, and from that moment, the fate of the locked-up wheel was sealed.

In Britain, the reaction from driving purists was one of deep suspicion. Motoring magazines of the era were filled with debates about whether a proper racing driver could stop faster without this newfangled electronic interference. On a perfectly dry racetrack, the answer was sometimes yes. On a damp B-road with a patch of diesel in the middle of a corner, the answer was a resounding no.

Ultimately, safety trumped purism. The technology’s undeniable benefit in preventing accidents meant it quickly trickled down from luxury German saloons to everyday family cars. Ford was instrumental in this process, making ABS a widely available option on humble cars like the Escort and Fiesta throughout the 1980s and 90s before it gradually became a standard feature. What was once a costly option for the well-heeled became a fundamental safety feature for everyone. More than that, the wheel speed sensors at the heart of the ABS became the foundation for almost every other electronic safety system that followed, from traction control to stability control. It was the gateway drug for the modern, computer-controlled car.

For The Record

Does ABS actually help you stop faster?

Not always. On a dry, consistent surface, a highly skilled driver might stop in a fractionally shorter distance without it. Its real benefit is on mixed or slippery surfaces and, most importantly, it allows the driver to steer while braking heavily, which is usually far more useful for avoiding an accident than stopping a metre shorter.

Why does the brake pedal judder when ABS is active?

The juddering or pulsing feeling is the system rapidly applying and releasing brake pressure to the affected wheel. You are feeling the hydraulic pump and valves working at high speed. The correct response is to keep your foot firmly on the pedal and let the system do its work, a sensation which feels deeply unnatural to those who learned to drive without it.

Can you retrofit ABS to a classic car?

While technically possible, it is an extremely complex and expensive job that involves fitting wheel speed sensors, a hydraulic control unit, an electronic brain, and a great deal of bespoke plumbing. It is almost never a practical or cost-effective modification.

Is cadence or threshold braking a useful skill anymore?

Cadence braking - pumping the brake pedal to avoid locking the wheels - was essential before ABS. Today, ABS does it faster and better, so the technique is obsolete.

Threshold braking is different: it means holding the brakes at the exact point just before the wheels lock. Done perfectly, it can stop a car shorter than ABS. But it takes racing-driver precision, and almost nobody can do it reliably in an emergency.

So unless you’re a racing driver, in a modern car the right move is simple: press the brake as hard as you can, let ABS do its job, and steer around the obstacle.

Was the Jensen FF's ABS the same as a modern system?

No. It used the Dunlop Maxaret system, which was entirely mechanical, relying on a small flywheel and a set of valves to detect and release a lock-up. It was a brilliant piece of clockwork engineering but less sophisticated and much slower-acting than the electronic systems that followed.