27th September 2013

Blog: Antilock Braking Systems

ABS, Antilock Braking Systems, have been with us for a while now, with virtually every new car today having this system fitted as standard.

They work by preventing any of the four wheels on a car locking up and skidding whilst under the influence of braking. Cars without ABS can lock a wheel or all wheels if surface grip reduces dramatically, or they reflex brake and stomp suddenly on the brake pedal. The normal reaction by drivers is to then ease off the brake pedal, target fix and possibly collide with that which caused them to brake in the first place.


Target fixing is where drivers focus on a place or object in their line of vision, the outcome invariably one where they drive towards that place or object. The solution is to always look to where you want to go, your route of escape!!

What happens your car when you brake hard?

First thing to realise when you brake hard, is that all the weight of the car, including passengers and luggage, wants to continue straight on. The suspension dips severely and the tryes are forced down into the road surface. Tyre wear and inflation, road irregularities and road camber, (the fall of the road), will all individually or in combination, then influence how the car feels at the steering.

What happens you when you break hard?

Tension – You invariably will feel your body tensing, your legs going forward and bracing – your arms will tense on the steering wheel – your eyes focus on the cause of your action – you push yourself back into the seat – you may brace for an impending collision.

What you should do?

Simple as it may sound – PRACTICE!! Waiting until the demand comes on you to brake to the max is foolish. It is much better to practice your braking in a controlled area, so as you know how the car feels under the load of full braking and importantly, how you feel when you have to brake to where you find the limit of adhesion. This will equip you with the knowledge of how both the car and you react. Practicing your braking, again in a controlled area, beginning at 50kph and up 10kph increments to 100kph – three times at each until you are comfortable with how you and your car perform. On gently –Firm up – Off Gently.

ABS – What it does

During heavy braking or when braking on a low-grip surface, snow, ice, loose sand/gravel, the wheels can stop turning, but the speed still remains in the car and it is still moving forward. When the wheels are ‘locked’ the cars direction cannot be changed, the stopping distance is increased and the possibility of a total loss of control is a distinct possibility.

On a car without an Antilock Braking System, the driver must release pressure from the brake pedal to gain directional control. Obviously once they release the pressure the car may gain pace plus your need to bring it to a halt still exists. This calls for the driver to rapidly re-apply the brakes hard again, release them and re-apply as quickly as they can for as long as it takes to bring the car to a halt. This action is called Cadence Braking and should only be applied to cars without ABS.

ABS works by electronically monitoring the rotation of each wheel under the influence of braking. When the system detects that a wheel has stopped rotating, it causes the brake on that wheel to release to allow rotation to continue. It does this about 10 to 20 times per second depending on the system – way more than the human action can achieve.

Once ABS has been activated you may feel the brake pedal pulsing under your foot and hear a grating noise coming from the brakes. This is normal, so don’t panic and don’t release foot pressure off the brake pedal.

A key benefit of ABS is that it allows the driver to STEER away from that which caused them to brake. Look for your route of escape, don’t Target Fix and steer. Remember - Do not pump the brakes on an ABS equipped car.

Know if your car has ABS by checking the owner’s manual. When you turn on the car’s ignition the ABS light will appear and go off once the system self-checks.

ABS is a standard feature of all new cars. Knowing that it is there for when we need it provides a great cushion of safety. Knowing how it works and how our car and we behave when it is activated is priceless. PRACTICE!!!

By Tony Toner, BeepBeep.ie Motoring Correspondent.

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