What Are Anti-lock Brakes
Bradley Jando | Thursday 2nd January 2020 11:20am
Introduced as a common safety feature in cars by Ford and Chrysler in the 1970s, the concept of anti-lock brakes was inspired by the anti-skid system used in aircrafts and developed by Dunlop in the 1950s. The aviation industry benefited from this feature as it improved aircraft stopping distances during landing through the use of hydraulics, reduced damage to tyres and helped to prevent brakes locking on ice and other unstable surfaces, which had been a common cause of accidents.
By developing a similar safety measure for road vehicles, anti-lock brake systems (ABS) soon became a key component of modern car safety. Indeed, today, all new cars that are sold in Europe must be fitted with ABS.
What do anti-lock brakes do?
Anti-lock braking systems allow wheels to keep a good grip on the road, working with your standard brakes to bring you to a safe and steady stop. Without ABS, wheels could lock up and drag along the road instead of continuing to spin when you brake suddenly, resulting in little to no traction. It is almost impossible to steer when this happens, feeling similar to driving on ice or coasting around a corner. As you might imagine, this can be dangerous, as your wheels don’t have a steady grip on the road.
The primary aim of an ABS is to ensure stability in any situation. Each wheel has a sensor attached to it that can detect when the breaks are about to lock up. When this happens, the wheel stops moving. As a response to this action, the ABS will release the brake for a short moment and then apply the correct braking pressure for each wheel repeatedly, providing just the right amount of pressure for the car to come to a stop while keeping the tyres rolling and in contact with the road’s surface.
When are anti-lock brakes most effective?
Contrary to popular belief, ABS doesn’t significantly reduce your vehicle’s stopping distance. In fact, it may even increase it, particularly on wet or icy roads. Without anti-lock brakes, your vehicle could come to a stop faster, however, you would have less control. With an ABS, your vehicle can stop in a safer manner, but it may take a little longer.
The ABS will kick in whenever you brake promptly to come to a stop, but it may not come into effect every time if it senses that it doesn’t need to. They are least effective on loose dirt, mud, snow or any other slippery surfaces. However, on loose surfaces, such as dirt tracks, the tyres are able to naturally dig in and stick to the surface much better. That’s why, in some off-road vehicles, there is an option to turn the ABS off, potentially enhancing the performance.
When will anti-lock brakes take effect?
You may occasionally feel your anti-lock brakes working when you apply the brakes. It usually feels like a pulsing in the brake pedal that you’ll be able to sense through your foot. This will be especially noticeable when you perform an emergency brake. In this case, the pulsing feeling might be quite violent, but you should continue to press on the brake, allowing the ABS to do its job.
If you’re attempting to force your ABS into action, it would be advisable to avoid repeatedly tapping the brake pedal. In older cars, this technique was used to make the brakes unlock, but with modern cars, ABS will do this job for you. If anything, pumping the brakes could even take you longer to stop.
In the event of a fault developing with your car’s ABS or if it is simply not working, you will be alerted via an orange warning light on your dashboard. The cause of a fault to the ABS could be a blockage in the release valves or damage to the sensors. It’s rare for an ABS to become damaged, as they’re built for reliability and durability.
However, if the warning light is glowing on your dashboard, you should get your car checked immediately. Putting this off could put your own safety, as well as that of other road users, at risk as the ABS is unlikely to step in when it’s required.
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