A basic skid prevention technique that involves pumping the brakes as they begin to lock-up.

It is considered now to be a cause of instability and if used in an ABS equipped car, it can be dangerous and prevent maximum braking from being  achieved.

The only braking technique that you may have hear of is Cadence Braking. This dates back to the 1930's and was the prescribed technique of improving the braking ability of vehicles when skidding occurs. It also helped to offset the problem of the inefficiency of early brake systems and the fading that occurred if prolonged braking took place.

The technique involved "pumping" the brake pedal to constantly release and re-apply the brakes rapidly , thus preventing long skids - but unfortunately at the cost of increasing braking distances. This technique rapidly became outdated as braking systems improved and then more recently ABS and other electronic aids were introduced. Unfortunately, many drivers still insist on using cadence braking or do so by re­flex, with devastating consequences .

Imagine first what occurs when ABS operates on a modern car:- 

• The Driver applies the brakes hard or on a wet surface
• The ABS sensors detect that one or more wheels are  locking-up
• The ABS releases one or all brakes momentarily, then re-applies them for the driver.
• The vehicle remains under control and so can be steered to avoid danger but it may take longer to stop in a straight line.

This indicates the one thing that most people are not aware of - ABS is a control device and not a braking device.  The ignorance factor here stems from the showroom where most salesmen have never even experienced ABS in anger and do not grasp the significance of the equipment.  Furthermore, they do not see it as anything more than a means to sell vehicles - otherwise training would be offered to all purchasers.

Now you need to consider the reaction of most drivers to the ABS as they first feel it operating. The most common reactions are as follows:-

• Panic - The driver feels a severe juddering through the brake pedal and thinks that the wheels are falling off. Consequently he releases the brakes and careers into the object he was hoping to avoid. This is the most common reaction in drivers experiencing ABS for the first time and so causes the most common problem in road accidents - the rear-end shunt.
• Fear - The driver is concerned at the strange sensations he is feeling and freezes on the controls. This means that although the option to avoid the other vehicle or hazard was available, the driver failed to take that option and hit the hazard under full control. Little can be done to overcome this without practice and the knowledge that the ABS may operate under emergency braking. Only af­ter one or two attempts , the ABS becomes a useful tool.
• Habit - This is the worst scenario. Drivers who have many years experience of driving, but little or none of ABS operation, find themselves tempted to use Cadence Braking in an emergency. This is dangerous. The rhythmic pumping of the brake pedal will coincide with the operation of the ABS and the result is the driver releasing pressure as the ABS tries to restore braking. This can result in violent undulations in the vehicle's movement, known as porpoising in Driver Training circles. The result is no control or braking!

It is now obvious that the need for training is becoming essential. The problem then arises that depend­ing on what level of training is offered, drivers may have a number of reactions when braking in an emergency. Many will concentrate on minimising their braking distance, some will concentrate on steer­ing round the hazard and the remainder will still wonder why the ABS isn't working - due to the fact that one in ten systems currently in use do  not  work correctly or will fail when used due to poor mainte­nance.