CDL Combination Vehicles TestCombination Vehicle Air BrakesEasy
When driving a combination vehicle, you encounter a situation requiring an emergency stop. Your vehicle is equipped with anti-lock braking systems (ABS). What is the recommended braking technique when driving an ABS-equipped combination vehicle in an emergency?
- APump the brakes rapidly to prevent wheel lock-up.
- BApply light, intermittent pressure to the brake pedal.
- CApply firm, steady pressure to the brake pedal and hold it down.
- DEngage the parking brake briefly to initiate ABS.
Show answer & explanationAnswer & explanation
Correct answer: C. Apply firm, steady pressure to the brake pedal and hold it down.
With ABS, the system automatically pumps the brakes much faster and more effectively than a human driver can. Applying firm, steady pressure allows the ABS to do its job, preventing wheel lock-up and maintaining steering control.
Why the other options are wrong
- A. Pumping the brakes is the correct technique for non-ABS vehicles but counteracts the function of ABS.
- B. Light, intermittent pressure will not provide maximum braking force in an emergency and will not fully engage the ABS.
- D. Engaging the parking brake while moving is extremely dangerous and can cause a skid or loss of control, and it does not initiate ABS.
ABS Emergency Braking
For vehicles with ABS, apply firm, steady pressure to the brake pedal during an emergency stop. Let the ABS system do the work.
- Don't pump the brakes
- Maintain steering control
- ABS prevents wheel lock-up
Memory trick: For ABS, 'Stomp and Stay' to save the day!