If the sensors become contaminated with any metallic dust, it is not always picked up by the internal ABS controller therefore they will fail to detect any wheel slip.
On high traction surfaces, wet or dry, ABS equipped vehicles are able to attain braking distance better than those vehicles without. In most conditions, in typical states of alertness, ABS will reduce the majority of drivers chances of crashing. With an alert skilled driver who isn’t using ABS, with the use of techniques like cadence braking (technique used to stop the vehicle more quickly on a slippery surface) or threshold braking (the driver adjusts the control of the brake system in an attempt to maximize the braking force of the vehicle), the driver should be able to match or even improve on the performance of a typical driver that has an ABS equipped vehicle.
If you are a non-expert driver and using an ABS equipped vehicle, if you are in a full braking emergency, you would need to press the brake pedal as firmly as possible and then, where necessary, to steer around any obstructions. In these kind of situations, the ABS will reduce the chances of a skid and any loss of control.
Related Braking Terms:
Anti Lock Braking System
Anti Lock Car Brakes