Some of the early ABS systems are easily fooled but newer systems are more
sophisticated. The good ones will sense the speed at each wheel and will
relieve pressure on that brake until the wheel begins to spin again then add
pressure until it starts to lock and again release. They do this from
several to many times each second. So they keep the wheel near its point of
lock up regardless of pedal pressure so that the stopping distance will be
as short as the available traction will allow. One of the problems that has
also occurred is related to driver training with the system. A police
officer was killed (If I remember correctly in a Caprice) due to improper
training on ABS system use. The pedal will sort of vibrate as the ABS
system cycles between adding and relieving pressure from each brake. This
PD had trained it's drivers with the old "pump the brakes" bit which,
especially with an ABS system only increases the stopping distances. When
the driver felt the pedal vibrating under his foot he interpreted the
problem as wheel lock and released (began to pump) the pedal ultimately
causing him to enter a corner too fast and lose control.
The pedal does feel weird when the ABS engages and that can be
disconcerting.
Brian
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I have heard some horror stories about the ABS Brakes. They do not stop a
car on ice or sand or Gravel. Any loose soil that allows it to slip and the
brakes release. Pat
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