What is ABS (anti-lock braking system)?

  • What does ABS do?
  • How does ABS work?
  • What was the first car with ABS?

An anti-lock braking system (usually shortened to ABS) has been mandatory on all production cars since 2004. It’s an essential piece of safety technology that has saved countless lives over the years.

What does ABS do? 

In an emergency stop in a car without ABS, the brakes can lock up, meaning that the wheels can stop turning and start skidding along the road surface. This gives the driver very little control and almost no steering ability to avoid any obstacles in their path. 

In a vehicle with ABS, the system prevents the brakes from locking, allowing the wheels to keep turning and enabling the driver to maintain control and also to take evasive action, steering around any obstacles.

How does ABS work?

At its simplest, ABS uses sensors in the wheel hubs to relay information back to a controller. If a sensor detects rapid deceleration in the speed of the wheel, the controller, using a series of valves, will release pressure from the braking system before rapidly applying and releasing it again until the car comes to a stop. This pulsing allows just enough wheel slippage to prevent the brakes locking and to avoid a skid, while maximising the available grip, thus allowing the driver to maintain steering control. Some systems can apply and release the brakes up to 15 times per second and drivers in an emergency stop will often feel a judder coming up through the pedal as the ABS system works.

What was the first car to use ABS?

The first production car to use ABS was the British Jensen FF back in 1966. Rather than an electronic set-up such as those seen on cars today, it used the Dunlop Maxaret mechanical system that had been developed for aircraft. With just 320 FF models built by the time production ended in 1971, ABS’s effectiveness was slow to be realised by the general public, even after Chrysler introduced the more modern, electronic Sure-Brake system for its 1971 Imperial. While other manufacturers also introduced such systems, as an expensive optional extra it wasn’t popular among car buyers.

Public acceptance of ABS increased through the 1980s and 1990s and, by the turn of the millennium, it was a common feature on the majority of new cars.

What systems in a car use ABS? 

Electronic Stability Control (ESC) helps prevents skids, for example if it detects the vehicle’s back-end sliding (oversteer) or if the front wheels struggle to steer as a car makes a turn (understeer). If the ESC system detects that kind of slippage, it will use the ABS system to apply braking to the appropriate wheel and reduce engine power to prevent a dangerous skid. 

Autonomous emergency braking (AEB) can use technology such as cameras, sensors, GPS, lasers and radar to detect a vehicle’s proximity to an object in front. If it detects that the driver is failing to take action to avoid the object, the AEB system will automatically apply the anti-lock brakes to try to prevent an accident. AEB is a common feature on many new cars. 

What does the ABS warning light mean? 

The ABS warning light on the dashboard indicates a malfunction in a vehicle’s ABS system. Because ABS is such a critical safety element, it’s highly advisable to get the problem professionally checked as soon as possible.

Looking for more jargon-busting motoring meanings? Head over to our Parkers Car Glossary page and take a look at our other definitions