CDL General Knowledge TestDriving SafelyHard
You are driving a commercial vehicle and must make an emergency stop on a wet road. Which braking technique is generally recommended for vehicles without anti-lock brakes (ABS)?
- APump the brakes rapidly to prevent wheel lock-up.
- BApply steady, firm pressure just to the point of wheel lock-up, then release slightly.
- CApply full brake pressure and hold until stopped.
- DUse only the engine brake to slow down.
Show answer & explanationAnswer & explanation
Correct answer: B. Apply steady, firm pressure just to the point of wheel lock-up, then release slightly.
For vehicles without ABS, the 'controlled braking' technique is recommended. This involves applying firm pressure up to the point of wheel lock-up, then backing off slightly to regain control, and reapplying. This maximizes braking force while maintaining steering control.
Why the other options are wrong
- A. Pumping the brakes is an older technique for cars; for heavy vehicles, 'controlled braking' is more effective.
- C. Applying full pressure will likely lock the wheels, leading to a skid and loss of steering control.
- D. Engine braking alone is insufficient for an emergency stop and does not provide enough stopping power.
Emergency Braking (Non-ABS CMV)
For commercial vehicles without ABS, use controlled braking: apply firm pressure to the point of lock-up, then release slightly to prevent skidding, and reapply.
- Maximizes braking force without losing steering.
- Prevents wheel lock-up and skidding.
- Requires driver skill and practice.
Memory trick: No ABS? Press, Release, Control, then stop with a pole.