Antilock braking systems ensure you can stop safely

By Barry Lake

ANTILOCK braking systems and its acronym, ABS, have become common-place expressions in the world of motoring. Here is what ABS is and what it can do for you.

It can happen to any one of us at any time: someone else is crashing right in front of us and we have to try to take avoiding action.

If you're healthy, alert and not affected by drugs, alcohol or tiredness, you will instinctively and rapidly take your right foot off the accelerator pedal and begin to press the brake pedal.

At the same time, you will try to steer the car away from whatever it is that you don't want to hit.

Assuming you find an "escape route", you are now reliant upon your car's brakes and tires to enable you to steer a path around the cars ahead.

It is very likely, however, that in your rush to get onto that brake pedal as quickly as you could, you have pushed it down way too hard.

This, in a car without ABS, will lock the wheels -- stop them from rotating. Now you will have lost much of your braking capacity and all of your car's steering capability.

When a car's tire is rolling along a roadway the relationship between the patch of tire tread that is touching the road, and the roadway itself, is relatively static.

This is what gives the tire the "grip" it requires to steer the car and to slow the car when the brakes are applied.

Once you have stopped the tire from rotating, it is just a patch of rubber sliding along the road.

It has very little grip and no directional capability in this situation and you can turn that steering wheel all you like but the car will simply travel straight ahead.

It is best to apply pressure to the brake pedal quickly but progressively to avoid wheel lockup.

If they do lock, then it is essential to ease off that brake pedal until the wheels begin rolling again so that braking and steering grip are restored.

Unfortunately, we are not born with these skills. It requires practice.

Taking courses in car control with the better advanced driving schools on a regular basis can enable almost anyone to develop skills to a degree that could save them in such an emergency road situation.

But, because people don't take regular driving courses to develop emergency avoidance skills, and because most people "slam on the brakes" in an emergency, antilock braking systems -- ABS -- were invented.

What ABS does for you is that, when you apply the brakes too hard and the wheels stop turning, the computer-controlled system unlocks them for you -- for just a fraction of a second.

When the wheels begin to rotate again, then the ABS reapplies the brakes. And it will repeat this action many times per second, if necessary, to find the right balance between giving you maximum braking for the situation while at the same time preventing wheel lockup.

The ABS does this through opening and closing electronically operated valves in the car's brake hydraulic system and each wheel can be controlled independently.

With an ABS-equipped car you can press as hard as you like on that brake pedal and the brakes will not lock.

You will still be able to steer the car and thus, hopefully, avoid whatever it is that you don't want to hit.

Some statistics have shown that drivers of ABS-equipped cars continue to have as many accidents as those that are not so equipped.

I believe this is because people buying ABS-equipped cars are being misinformed and also are not being educated on how to use the system.

First, drivers are told that ABS will save them from having accidents. They then become more aggressive in their driving, particularly driving closer to the car ahead.

By driving too close, they reduce their available reaction time and block their view of what is happening up ahead.

They don't see dangerous situations developing and they can not see potential escape routes.

Second, these drivers are not taught how to use the system, nor given the opportunity to experience what it feels like when it begins working.

When the ABS activates, the switching on and off of the hydraulic pressure, causes the brake pedal to pulsate under the driver's foot.

Experiments have shown that drivers who have never experienced ABS in action, will often think there has been a malfunction of some kind and instinctively lift their foot off the brake pedal, therefore losing all braking effort.

And, in their temporary confusion, they do not take avoiding action.

ABS is not perfect. For example, it can increase stopping distances on loose gravel surfaces. But for most people in most circumstances, it can be a lifesaver.

It does not, however, relieve the driver of his or her responsibility in controlling the car and avoiding accidents.

I recommend ABS as a worthwhile safety feature for motorists, but I also strongly suggest that all motorists -- whether or not they have ABS on their car -- should take regular car control courses so they can practice emergency avoidance techniques in a safe environment and become used to the sensations that arise in such situations.

The opportunity should then also be available, for those who drive different cars from time to time, to learn how to brake in a way that is suitable for both ABS-equipped and non-ABS cars; in this case the ABS is not always automatically activated in every emergency braking situation.

Those who drive various cars will not then have to try to remember, in that instant the emergency arises, whether or not they have ABS in the car they are driving.