Antilock Brakes

Antilock BrakesAnti-lock brakes (ABS) have gone from being a novelty to being present on most vehicles today. Have you read and understood the section of your vehicle owner's manual on this vital safety system? Contrary to popular belief, ABS does not always mean shorter stopping distances.

Threshold Braking

Your brakes do their best to stop your vehicle just before it's wheels stop turning. This is called threshold braking and it takes practice and skill. In an emergency, it also takes a cool head to not simply apply as much pressure as possible to the brake pedal, lock up your wheels and hope to skid to a safe stop.

The trouble is, skidding is not as good as braking and it takes away your ability to steer. This is why we learned to pump the brakes back in the days before ABS. Press the brake to initiate threshold braking and back off if the wheels skid, then press again to get back to the threshold.

Stomp & Steer

Today, a new braking technique must be learned. Simply put, it is Stomp and Steer. When an emergency stopping situation occurs, stomp the pedal to the floor and keep it there. Steer out of the way of danger.

Noise and vibration may be felt through the brake pedal. This is normal, so don't be tempted to let up or pump the pedal. Keep it pressed to the floor and the system will do proper threshold braking for you.

A Worthwhile Trade Off

In a straight line stop on wet or dry pavement, ABS will result in shorter stopping distances than conventional braking systems when used properly. On icy, snow covered and gravel roads your stopping distance will be increased. The trade off is worthwhile because instead of becoming a projectile, the driver can attempt to steer out of danger while slowing at the same time.

Wagner does warn that under some circumstances ABS can still lock up on icy roads.

Steering while attempting to stop on wet and dry pavement will also result in increased stopping distances. The reason for this is that there is only so much traction available between your tires and the pavement. In a straight line stop, all this friction is available for braking. When you steer, the friction forces must be divided between steering and braking which means less braking is done.

Try It - With Care

Curious? Find an open slippery area with no traffic and at slow speeds, give it a try. You will find out what to expect and be a more confident driver when an emergency does occur.

Not a Replacement for Safe Driving

ABS will not overcome driver error. Being aware of road and traffic conditions, moderating your speed when required and establishing a safe following distance is still mandatory for safe driving.

ABS has been mandatory on passenger vehicles under the vehicle construction standards almost everywhere in the world for many years now. As a veteran driving instructor and safety professional myself for many decades I can tell you that in the real world the vast majority of drivers are simply not capable of executing emergency manoeuvres in an optimum manner.

High performance execution requires application of optimum technique for the circumstances without hesitation. Frankly, most drivers are totally surprised by an emergency situation and don’t have the time or the skill to do this. In my experience with several thousand students in both novice and advanced training over the years it has proven to take a great deal of repetition and practice to achieve anything close to the vehicle’s capabilities. The majority of drivers are simply not competent at emergency performance.

ABS simply takes this out of the equation and does the work for them. NO, it isn’t perfect, as you have outlined, but in the real world with the average driver it’s a heck of an improvement.

In all but controlled conditions with expert drivers, ABS leads to shorter stopping distances (let's face it, most of us don't practice regularly) the only exception I've seen is snow, sand and loose gravel, where the tyres build up a dam a aggregate in front of the tyre. And as you noted, ABS is the only option that still allows you to steer. I'm not even sure pumping the brakes actually worked (certainly not as well as practicing threshold braking on a regular basis)

So a curious phenomena I read about when ABS was not the norm, and was only an option on high end-cars: contrary to what you might have expected, insurance company stats did not show much of a decrease in accidents for ABS-equipped vehicles. As best they could figure, drivers were engaged in risk compensation, driving more aggresively and following more closely because they imagined they were protected by their new "magic" brakes. So they were in fact offsetting any protection the new technology offered.

My take away? Use the benefits of ABS, but drive as conservatively and defensively as if you didn't have ABS.

Really, really glad you've covered the ABS stuff. I spent years working with riding instructors who thought they were being really helpful advising new riders against buying a bike with ABS, blithely ignoring the extremely compelling data on it's lifesaving capacity. Even more significant than in the auto world.

So anyways, well done you. Amazing how this stuff just keeps needing to be said.

I was really surprised the first time I encountered ABS brakes. It was a rental car, and I didn't even know it had ABS, but when I was going down a steepish snow-covered hill, and applied the brakes, all of a sudden the pedal started bucking, and loud noises like springs came from the font end.

But the car stopped before I could even get worried.


I can see no reason whatsoever not to have them.