What is ABS?

Brake hard without losing control: how ABS helps you avoid crashing

BuyaCar team
May 18, 2018

ABS, or anti-lock braking system, is a technology that allows the driver to still control the car in the event of extremely hard braking.

Braking violently and suddenly can make the car skid, especially on slippery surfaces. If that happens, the wheels stop turning and lock in one position. The car slides along the road and is impossible to steer because there's no grip: you lose control of the car.

ABS prevents the car from skidding, enabling you to brake hard and steer round any obstacle in the road at the same time as braking. It also helps your car to stop in a shorter distance.

How does ABS work?

At its heart is a computer called a controller, which monitors data from sensors at each wheel. The sensors record how quickly a wheel is rotating.

The moment that the controller detects a wheel starting to skid, it releases the brakes for a split second until the wheel regains grip. It then slams the brakes on again.

As the wheel loses grip for a second time, the process is repeated and this continues at a rate of up to 15 times a second. It slows the car down quickly but maintains grip so you can steer out of trouble at the same time.

When ABS is active, there's an odd sensation from the brake pedal, and it feels as if it's vibrating. But you've got to keep your foot hard on the brake to stop in the shortest distance. When the system is in use, an ABS light will usually flash on the dashboard too.


Does my car have ABS?

Probably. ABS has been mandatory on all mass-market cars since 2004 and was commonly fitted before then. You'll see an ABS symbol warning light (see top of page) come on and then switch off when you start the car.

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