When braking in an older car that has regular brakes, the wheels can lock causing you to lose steering control of the car. More modern cars, however, have an anti-lock braking system (ABS). With ABS, the wheels do not lock when braking, which means that you can continue to steer even when braking hard. ABS also reduces the risk of skidding and can often shorten the car's braking distance.
However, the car's braking distance will not always be shorter with ABS. On gravel, ice and snow, the braking distance may even be longer. The biggest advantage of ABS is that it helps you maintain steering control of the car, not that the braking distance becomes shorter.
ABS operates by automatically reducing the braking force on wheels that are about to lock. When there is no longer any risk of the wheel locking up, the system increases the braking force again. This process is repeated several times per second, which helps you maintain steering control of the car.
When the system is active, the brake pedal vibrates and pulses and make a certain sound. This is normal, and means that the system is working as it should.