North Texas, where I live, is covered in ice today. It seems that once or twice a year we get icy road conditions and the same thing always happens... body shops and mechanics make a fortune. Over the last few years I have observed a disturbing trend...more and more I hear people say, "The ABS didn't work!!!!"
Just to try and get the word out, I thought I would take a minute to explain WHY the ABS system on your car doesn't work on ice.
1- ABS works by monitoring the speed of the wheels and comparing their speeds to each other and the expected wheel speed. When the computer senses a wheel is about to lock up it blocks any additional brake pressure from being applied to the wheel. If the wheel continues to slow down or stops the ABS relieves ALL of the brake pressure to the wheel. When the wheel speeds back up the ABS re-applies brake pressure to the wheel. This functions similarly to pumping the brake pedal only the ABS can do it way faster that you can. The purpose is to allow the driver to apply the brakes in wet weather and steer around a problem in the road... instead of sliding off the road, or into an object in the road, when the wheels lock up. ABS is designed for WET weather.
2- Ice is more than just WET weather. Wet ice is the slipperiest substance known to man...per an old Slick-50 ad from the 90's. When the ABS re-applies the brake pressure the wheel INSTANTLY locks up on ice because there is NO FRICTION between the wet tire and the wet ice. So even with ABS you have no traction.
ABS may possibly be the most misunderstood safety equipment on the passenger vehicle today. It works great in the rain...but NOTHIN will save you on ICE except good common sense...and most experienced race car drivers can stop faster on dry pavement WITHOUT ABS by using a technique called threshold braking.
So be careful out there...slow down...think way ahead...concentrate...and turn off the cell phone.