Antilock Braking Systems
What this domain tests
Antilock Braking Systems asks how ABS changes your braking technique, what the dash lamp means, and what ABS does not do. Most misses come from drivers applying old pumping habits.
Core rules
- ABS keeps the wheels from locking so you can steer while braking hard.
- The ABS lamp should light briefly at start-up and then go out. If it stays on, ABS is disabled but the base brakes still work; report it and drive normally.
- Apply firm, continuous pressure and hold it. You may feel the pedal pulse or vibrate and hear noise; that is the system working, so keep pressing.
- Do not pump the brakes.
- ABS may lengthen stopping distance on gravel, snow, or loose surfaces. It maintains steering control; it does not shorten stops.
- Test the brakes at low speed at the start of a trip.
Worked example
A car stops short on a wet road. The driver presses the brake pedal hard and holds it. The pedal pulses and the bus slows while the driver steers around the car. Releasing pressure when the pedal pulsed would have cost steering control.
Traps that cost marks
- Pumping the brake pedal out of habit.
- Lifting off the pedal when it vibrates.
- Treating the ABS lamp as a reason to stop immediately rather than a defect to report.
- Assuming ABS will always shorten stopping distance.