Caution Needed With Anti-Lock

Motorists should remain cautious when driving in poor whether conditions

18 June 2013

ABS (anti-lock) brakes cannot work miracles and drivers should remain cautious when driving in poor weather conditions. This is the message from the Automobile Association of South Africa (AA) as the Cape Winter gets into full swing. It's commonly (and incorrectly) believed that the main purpose of ABS brakes is to give shorter stopping distances so drivers are often surprised when they crash despite ABS braking being applied.

The primary purpose of ABS was actually to ensure steering control under braking. In vehicles without ABS, drivers confronted with obstacles frequently lock the front wheels up after applying the brakes sharply in an instinctive panic reaction to a situation where there is not enough space to stop. They then attempt to steer round the obstacle. However, steering control is lost when a vehicle's front wheels lock under braking; and when drivers realise that the steering isn't working, they tend to 'freeze' on the controls until the moment of impact, with the brakes fully applied and the steering turned.

Correcting this situation requires specialised training, which is not available to many drivers and the only alternative is an automated system to prevent wheel lockup under braking. ABS systems on vehicles became widespread from the early 1980s and have prevented countless crashes by enabling drivers to apply full braking while steering round obstacles.

The misunderstandings around ABS resulted in drivers exceeding its capabilities. Motorists need to remember that if they were simply driving too fast, ABS would not save them as it cannot change the laws of physics. Likewise, some people believe that it's not necessary to keep a two-second following distance in a vehicle with ABS. That's also incorrect. One still needs time and space to make the best of the control benefits ABS offers.

ABS brakes can also not prevent or cure aquaplaning. Aquaplaning happens when a vehicle's tyres can't disperse the water on the road surface and start skimming across the surface of the water. This is caused by inadequate tread depth on one's tyres, or excessive speed for conditions. ABS can neither prevent it, nor correct it.

The AA advises motorists to drive at moderate speeds, observe the road surface carefully and brake well in time. ABS should be treated as what it was designed to be: a control aid for genuine emergencies, not a safety net for careless driving.

Automobile Association of South Africa (AA)
011 799 1180

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