CDL Combination Vehicles TestDriving Combination Vehicles SafelyEasy
A commercial driver is operating a combination vehicle on a level road. The driver needs to make an emergency stop. The vehicle is equipped with an Anti-lock Braking System (ABS). What is the correct technique for emergency braking with ABS?
- APump the brakes rapidly to prevent wheel lock-up.
- BRelease the brake pedal if you feel the ABS activating, then reapply.
- CApply brakes gently, then increase pressure gradually.
- DApply full, firm pressure to the brake pedal and hold it down until the vehicle stops.
Show answer & explanationAnswer & explanation
Correct answer: D. Apply full, firm pressure to the brake pedal and hold it down until the vehicle stops.
For vehicles equipped with ABS, the correct emergency braking technique is to apply firm, steady pressure to the brake pedal and hold it down. ABS 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 the correct technique for non-ABS systems to prevent lock-up, but it defeats the purpose of ABS.
- B. Releasing the brake pedal negates the ABS function and extends stopping distance. You should hold the pedal down firmly.
- C. Gentle, gradual braking is for normal stops, not emergencies where maximum braking force is needed immediately.
ABS Emergency Braking
With ABS, apply full, firm pressure to the brake pedal and hold it down during an emergency stop. The system will prevent wheel lock-up.
- ABS prevents wheel lock-up.
- Firm, continuous pedal pressure is key.
- Allows steering control during braking.
Memory trick: ABS: Always Brake Solid.