When ABS is activated, the driver feels the brake pedal pulsate gently. The all-wheel drive automobiles of the BMW X Series possess a system which shortens their braking distance: on steep, poor road surfaces and at low speeds, this system permits one or both of the front wheels to be blocked. The resulting wedge effect on the wheels means the vehicle can come to a halt quicker. A special regulatory algorithm ensures that the driver can continue to steer the automobile in this situation as well.