CDL General Knowledge TestAir Brakes (if applicable)Hard
A driver is performing an emergency stop in a commercial vehicle equipped with ABS air brakes on a slippery road. What is the most appropriate braking technique to maintain control?
- APump the brake pedal rapidly to prevent wheel lock-up.
- BApply light, intermittent pressure to the brake pedal.
- CDisengage the clutch and coast to a stop.
- DApply firm, steady pressure to the brake pedal until the vehicle stops.
Show answer & explanationAnswer & explanation
Correct answer: D. Apply firm, steady pressure to the brake pedal until the vehicle stops.
With ABS (Anti-lock Braking System), the correct technique for an emergency stop, even on slippery surfaces, is to apply firm, steady pressure to the brake pedal. The ABS system will automatically modulate the brake pressure to prevent wheel lock-up, allowing the driver to maintain steering control.
Why the other options are wrong
- A. Pumping the brakes is for non-ABS systems. With ABS, this interferes with its operation.
- B. Light, intermittent pressure is insufficient for an emergency stop and does not fully engage ABS.
- C. Disengaging the clutch and coasting removes engine braking and is not an effective emergency stop technique.
ABS Emergency Braking
For emergency stops with ABS, apply firm, steady pressure to the brake pedal. ABS will prevent wheel lock-up and allow steering.
- Do not pump the brakes with ABS.
- Maintain firm, steady pedal pressure.
- ABS helps maintain steering control.
- Expect pulsation or noise from pedal.
Memory trick: ABS is your friend, firm and steady to the end.