<P> In gravel , sand and deep snow , ABS tends to increase braking distances . On these surfaces , locked wheels dig in and stop the vehicle more quickly . ABS prevents this from occurring . Some ABS calibrations reduce this problem by slowing the cycling time , thus letting the wheels repeatedly briefly lock and unlock . Some vehicle manufacturers provide an `` off - road '' button to turn ABS function off . The primary benefit of ABS on such surfaces is to increase the ability of the driver to maintain control of the car rather than go into a skid , though loss of control remains more likely on soft surfaces such as gravel or on slippery surfaces such as snow or ice . On a very slippery surface such as sheet ice or gravel , it is possible to lock multiple wheels at once , and this can defeat ABS ( which relies on comparing all four wheels , and detecting individual wheels skidding ) . Availability of ABS relieves most drivers from learning threshold braking . </P>
<P> In gravel , sand and deep snow , ABS tends to increase braking distances . On these surfaces , locked wheels dig in and stop the vehicle more quickly . ABS prevents this from occurring . Some ABS calibrations reduce this problem by slowing the cycling time , thus letting the wheels repeatedly briefly lock and unlock . Some vehicle manufacturers provide an `` off - road '' button to turn ABS function off . The primary benefit of ABS on such surfaces is to increase the ability of the driver to maintain control of the car rather than go into a skid , though loss of control remains more likely on soft surfaces such as gravel or on slippery surfaces such as snow or ice . On a very slippery surface such as sheet ice or gravel , it is possible to lock multiple wheels at once , and this can defeat ABS ( which relies on comparing all four wheels , and detecting individual wheels skidding ) . Availability of ABS relieves most drivers from learning threshold braking . </P>
when does anti lock brakes not prevent skidding
when does anti lock brakes not prevent skidding
On a very slippery surface such as sheet ice or gravel
On a very slippery surface such as sheet ice or gravel