Anti Lock Braking System often referred as ABS has emerged as one of the major safety measures that is integrated in the manufacture of modern vehicles. ABS was invented to help a driver control a vehicle under heavy braking by preventing the wheels from locking up, when driving your vehicle at speeds up to 70 mph is important allowing you to brake and stop safely without skidding.
Anti-lock brakes help drivers have better control of a vehicle in some road conditions where hard braking may be necessary. In vehicles without anti-lock brake systems, drivers who encounter slippery conditions have to pump their brakes to make sure they do not spin out of control because of locked up wheels. Anti-lock braking systems coordinate wheel activity with a sensor on each wheel that regulates brake pressure as necessary, so that all wheels are operating in a similar speed range.
Advantages of Anti-Lock Brakes
ABS is designed to be useful whenever a driver slams on the brakes and swerves, particularly when road conditions are slippery or wet. In these conditions, a vehicle is more likely to slide or skid if the wheels lock. ABS would benefit drivers in a variety of fairly common situations, such as stopping on ice or slippery road conditions which makes wheel lock more likely when you must brake to stop.
How does ABS work?
Not all ABS setups are the same. Some prevent wheel lock on all four wheels, while others prevent only the rear wheels from locking. However, all ABS work by monitoring wheel speed and then, if a potential wheel lock is detected, rapidly applying and releasing the brake to the problematic wheel. ABS functions by effectively “pumping the brake”, using a technique that was taught to drivers before the development of ABS to prevent wheels from locking. The difference is that ABS setups are able to sense potential wheel lock and address the problem faster and with more efficiency than drivers. All ABS are comprised of three major components:
• Wheel speed sensors that monitor wheel rotation speed;
• Hydraulic units that pump the brakes, and;
• An electronic control unit (ECU) that receives information from the wheel speed sensors
In modern ABS setups, the ECU and the hydraulic units are attached together so that while they have different functions, they are physically one unit. The ECU continually checks for signs of rapid wheel-speed deceleration, an indicator that a wheel is about to lock. If a wheel is about to lock, the ECU directs the hydraulic unit to pump the brake to that wheel until it resumes normal rotation.
How effective is ABS at reducing crashes?
The primary purpose of ABS is to allow drivers to have directional control over their vehicle after heavy braking. In support of the effectiveness of ABS, it has been associated with:
• A 35% decrease in frontal collisions on wet roads, and;
• A 9% decrease in frontal impacts on dry roads.
A decrease in frontal collisions suggests that ABS allows drivers to steer to avoid a collision.
In addition, under controlled test conditions 58% of drivers without ABS strayed from their intended path after braking while only 24% of drivers with ABS did the same.
Stopping distance
One misconception about ABS is that its purpose is to help reduce stopping distance. However, a reduction in stopping distance is not guaranteed and is only a secondary benefit of ABS.
Steering too aggressively can still have severe consequences. On a vehicle without ABS, if a panicking driver steers the wheel sharply out of instinct to avoid a collision, nothing results from this action, as steering control is lost when the wheels lock up. However, the addition of ABS means that those same exaggerated steering commands will have an effect, and could lead to other dangerous situations like road departure, collisions, or rollovers. Drivers with ABS should continue to steer as calmly as possible.
As previously stated, the main advantage with ABS is the increased control over the steering. In situations such as when a small obstacle appears in the road or attempting to remain in the same lane when braking – this can be invaluable. However, care should always be taken to avoid any rash steering manoeuvres that would increase the severity of the collision.
Although ABS ensures that the minimum stopping distance is achieved, it is still important to drive at a safe speed for the conditions and leave a gap of at least 2 seconds between yourself and the vehicle in front in order to reduce the chances of needing to make use of the ABS.