Tips and Advice

What are anti-lock brakes (ABS)?

Anti-lock brakes (ABS) have been required by law for more than a decade, so how do they work?

Anti-lock brakes (ABS) are one of the single biggest contributors to road safety, perhaps second only to seatbelts. They were made compulsory in 2004 but have been fitted to some cars since as long ago as the 1960s.

Why is ABS so important?

A car’s only contact with the road is four small areas of rubber tyre. If one or all of these so-called ‘contact patches’ loses grip, the car starts to skid and the driver risks losing control. Many things can cause this but often heavy braking is the main culprit.

The safest cars to buy this year

In an emergency, an inexperienced driver will instinctively stamp on the brake pedal causing the car to skid, go out of control and take longer to stop. It’s to counter these effects that ABS was invented.

The system automatically takes over to prevent the wheels locking under heavy braking, which helps to restore effective braking while enabling the driver to steer because only wheels that are turning can be steered. The result is that the driver can simultaneously slow down and steer, thereby maintaining control of the car and avoiding an accident.

How does ABS work?

An ABS system uses sensors to monitor the turning speed of each wheel. If, as the driver brakes, the system senses that one or more wheels is suddenly slowing down and about to lock, risking a skid, it automatically releases the brake so the wheel can continue to turn, before re-applying it to slow it down. It performs this operation up to 15 times a second (an action you can feel as a pulse through the brake pedal) to help maintain or restore effective braking and steering control.

How can I tell if my ABS is working?

When it’s operating, you’ll probably feel it as a pulsing sensation through the brake pedal but as systems become more sophisticated so they are becoming less noticeable. In normal driving you’ll rarely provoke it into action. It’s more on wet, slippery roads that ABS has to intervene. If there’s a problem with the system, a warning light on the car’s dashboard will alert you.

If ABS does activate while you are driving, this light may also flash briefly to warn you that the tyres lost grip and the system triggered, but it will extinguish as soon as traction is regained. If the ABS light stays on at any time, this could signify there's an issue, so you’ll need to get the car checked at a garage.

As more and more safety technology is fitted to modern cars, it’s possible to forget the incredible improvement in safety brought about by ABS and hard to estimate the number of lives it has saved.

Want to know more about car safety systems? Read our guide to Autonomous Emergency Braking (AEB).

Most Popular

Top 10 best cheap-to-run cars 2022
Toyota Prius front 3/4 cornering
Best cars
17 Jan 2022

Top 10 best cheap-to-run cars 2022

UK road tax 2022: VED tax rates and bands explained
2021 Road Tax explained
Car tax
20 Jan 2022

UK road tax 2022: VED tax rates and bands explained

Top 10 best economical 4x4s, SUVs and crossovers 2022
Peugeot 3008 SUV front cornering
Best cars
6 Jan 2022

Top 10 best economical 4x4s, SUVs and crossovers 2022

Tips & advice

View All
Car dashboard warning lights: the complete guide
Car dashboard symbols and meanings
Tips and advice
10 Aug 2021

Car dashboard warning lights: the complete guide

Electric car charging stations: a complete guide
Electric car charging station
Tips and advice
5 Nov 2021

Electric car charging stations: a complete guide

PCP vs HP – which type of car finance is right for you?
PCP vs HP
Car buying
21 Jan 2022

PCP vs HP – which type of car finance is right for you?

Average speed cameras: how do they work?
Average speed cameras: how do they work?
Tips and advice
23 Jul 2021

Average speed cameras: how do they work?

Best cars

View All
Top 10 best car interiors 2022
Peugeot 208 hatchback
Best cars
25 Jun 2021

Top 10 best car interiors 2022

Top 10 best electric cars 2022
Ioniq 5
Best cars
19 Jan 2022

Top 10 best electric cars 2022

Top 10 best cheap-to-run cars 2022
Toyota Prius front 3/4 cornering
Best cars
17 Jan 2022

Top 10 best cheap-to-run cars 2022

The UK's top 10 fastest hot hatchbacks 2022
Audi RS 3 driving - front view
Hot hatches
21 Jan 2022

The UK's top 10 fastest hot hatchbacks 2022