Almost every car in the market today is equipped with ABS or Antilock braking system.  In this article, I’ll try to explain in brevity how ABS works and keeps us safe on icy roads.  It is not easy, even for an experienced driver, to bring a car to safe halt on a really slippery road.  Without ABS, the tires continue skidding relative to the road and steering the wheel in such situations never helps. ABS prevents the wheels of the car from locking or skidding, while braking.  This gives the driver two advantages: he can stop faster, and he will able to steer the vehicle to safety while he stops.

    The ABS needs four components for the functioning of its system, which are the speed sensors, the valves, the pump and the controller. The speed sensors supply the system with the velocity of the car.  These are linked to the wheels of the car, or the differentials.

    A series of valves are connected to each braking system equipped with ABS.  The function of each valve is to regulate and ensure even pressure distribution to the braking systems.  There are three valves in each system for this purpose.

    The pressure pump serves as a backup to compensate for the pressure which is released by any of the above valves. When the valve releases the pressure in a braking system, the pump works to get the pressure back up.
    All three components above are monitored by a fourth component, a computer in the car.  It monitors the speed of the car and also pressure variations in each braking line.

    The computer controller is always on the lookout for abnormal decelerations the wheel will be experiencing.  Normally, the car would take some time to come to a halt while travelling at 60 miles per hour.  But in some cases, the wheel can lock and it stops spinning at that very moment.  It is this type of deceleration that the computer controller is watching out for.  The controller is programmed to realize that such immediate deceleration is not practically possible, and hence it lowers the pressure to that particular braking system until it senses acceleration and then it increases the pressure until it senses the deceleration again.  The system is designed so that it senses such abnormalities in speed quickly, just before the wheels start to lock up.  As a result, the tires slow down at the same rate as the car does.  This in turn produces maximum braking power also.

    There are different versions of ABS which differ depending on the car manufacturer.  One of the features of ABS is that it turns off automatically if the speed of the vehicle goes below 12 miles per hour.

    The ABS is a very effective system if used the way it is intended to be.  Equipping your car with ABS does not mean that it is safe to drive aggressively thereafter.  It should also be kept in mind that ABS has demerits of its own like increased braking distance on icy surfaces, etc.