Tilt your sheet of cardboard to form an inclined plane for the toy car to roll down. Hold the toy car by pressing down on the roof with your fingertip and then release - no surprises yet! With all wheels rotating freely, the car rolls as expected. To simulate heavy braking without ABS, push a small blob of Blu-Tack or plasticine into the rear wheel arches to lock both back wheels.
This will prevent the wheels from rolling and cause them to skid down the inclined plane. Ask the class to predict how the car will behave when it rolls down the inclined plane with both rear wheels locked.
Will it roll down forwards or backwards? With the rear wheels locked, the car immediately starts to rotate as it slides down the inclined plane. This demonstrates that rolling wheels have more friction with the road than a locked wheel. ABS brakes prevent wheels from locking and therefore provide better control for the driver.
This experiment demonstrates that a skidding locked wheel experiences less friction with the road than a rotating wheel. The toy car spins and continues down the inclined plane backwards because the locked, rear wheels have less traction than the freely rotating front wheels. A real car with one or both rear wheels locked and skidding will start rotating the same way and, without driver intervention, may slide and spin out of control.
An even more dangerous situation arises if both front wheels become fully locked. In four-wheel ABS equipped vehicles, pumping the brake turns the system on and off. ABS pumps the brakes for you automatically, at a much faster rate, and allows better steering control.
Four-wheel ABS enables drivers to steer in emergency braking situations, but the system itself does not steer. Always "brake and steer" when using four-wheel anti-lock brakes. With ABS, all you have to do is "brake and steer". With four-wheel ABS, push the brake pedal while steering normally and keep your foot firmly on the brake pedal until the car comes to a complete stop.
Don't take your foot off the brake pedal or pump the brakes, because that will disengage the anti-lock system. Remember that you can steer while you are braking with four-wheel anti-lock brake systems. Steer clear of hazards while keeping your foot firmly on the brake pedal.
Be aware that your vehicle will not turn as quickly on a slippery road as it would on dry pavement. Anti-lock brakes cannot compensate for driving faster, more aggressively, or maintaining unsafe following distances. They cannot guarantee recovery from a spin or skid prior to an emergency braking situation. Avoid extreme steering maneuvers while your anti-lock brake system is engaged.
Anti-lock brake systems can stop more quickly than conventional brakes on wet paved surfaces and on icy or packed snow-covered roads. Stopping distances can be longer on loose gravel or freshly fallen snow, although drivers won't experience the lock-up of the wheels usually associated with conventional hard braking. Therefore, drivers will still have the ability to steer around objects in front of them—such as another car.
Know that there is a difference between four-wheel and rear-wheel ABS. Four-wheel ABS prevents wheel lock on all four wheels giving the driver improved control over steering.
Drivers of four-wheel ABS cars should step firmly on the brake in an emergency stopping situation and keep their foot on the pedal. In light trucks that are equipped with rear-wheel ABS, however, the front wheels can still lock up the same as with conventional brakes. If that happens, the driver should ease up on the brake pedal with just enough pressure to allow the front wheels to roll again so the driver can steer. Read your owner's manual for more details on the complete operation and benefits of ABS.
The antilock brake system is speed sensitive, and will not activate at very slow speeds. It is easier to activate the ABS on a wet and slippery road surface. The antilock system should prevent the wheels from skidding. Pulsation may be felt in the brake pedal and you may hear a clicking sound. Avoid pumping the brake, even if the pedal is pulsating. What are the correct brakes for your car?
View BrakeBook. Summertime in the Southern Hemisphere coincides with the festive season and end-of-year travels. To that end, various safety systems constantly monitor the performance and surroundings of a vehicle. Simply put, active safety systems avoid or mitigate an accident pre-impact — so before it happens or contact is made. Road safety: what progress has been made? Active safety systems: what are they and how do they work?
Passive safety systems: what are they and how do they work? Why should we focus on active safety in the future? How can automated and connected vehicles improve road safety? What role do road users and infrastructure play in improving safety?
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