RAC Cars News


Understanding ABS

By raccars Published

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Unless you are driving a very old car, the chances are that the vehicle you are driving has ABS or anti-lock brakes. Originally introduced on aircraft in the 1930s, ABS was first made available for cars in the 1970s. Higher end cars began to fit ABS as standard in the 1980s and it became a compulsory feature on any new car sold within the EU since 2004.

What ABS does and how it works

Ideally you will rarely call upon the services of your anti-lock braking system, but it's reassuring to know it's there all the same. ABS is there to prevent your car's wheels from locking up if you brake hard, which can send the car into a skid. If you brake too hard, particularly on a slippery or wet surface, the force of braking can overpower the grip of your tyres on the road, making them skid across the road surface instead of gripping and turning as they should. This can make it difficult or even impossible to steer and regain control of the car.

Professional racers use a technique called cadence braking to overcome this problem, which means pumping the brake pedal repeatedly. The pumping action engages and releases the brakes quickly to slow the car while maintaining a grip on the road and allowing the driver to steer. Anti-lock brakes mimic this action but operate at a much higher speed.

Each wheel is monitored by an electronic sensor system which applies and releases the brake on individual wheels as necessary if it detects that a wheel is locking up. ABS performs about 15 braking applications per second, far quicker than a human being.

Does my ABS work?

Pressing your brake under normal driving conditions shouldn't cause the ABS to engage, so you may concerned that your ABS isn't working properly. However a dashboard warning light should illuminate if there is any problem with the ABS. If your ABS warning light appears, take your car to the garage to investigate the problem as a matter of urgency. An ABS warning light is an automatic MOT failure issue.

You can test the ABS yourself if you want, since heavy braking should cause it to activate. When the ABS is engaged you should be able to feel a slight pulsing sensation from the brake pedal as the brakes engage and release quickly. This may feel a little odd but shows that your ABS is working as it should, so just keep your foot on the brake and allow the system to do its job.

With the advent of increasingly sophisticated automotive technology such as electronic stability control and autonomous braking, it's easy to forget the contribution that ABS has made to road safety over the years. It's impossible to estimate how many lives have been saved by ABS in the 40 years since it became a mainstream technology.

What to do if you don't have ABS

If you own an older car which does not have ABS, you may be concerned that you could lose control of your car in an emergency stop situation. However it's worth remembering how ABS and cadence braking work because you can use the same techniques yourself.

If you are forced to brake suddenly, and particularly if you feel your car wheels start to lock up and lose traction, you can pump your brakes to release the lock. Pump firmly but in a smooth, controlled manner and at a rapid but not frantic pace. Your car should slow down with the braking but allow you to maintain control and continue to steer.

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