CDL Combination Vehicles TestDriving Combination Vehicles SafelyMedium
A commercial driver is operating a combination vehicle and is forced to drive through a deep puddle. What is the immediate action the driver should take after exiting the puddle to ensure brake effectiveness?
- ADrive at a high speed for a few miles to air dry the brakes.
- BStop the vehicle immediately and wait for the brakes to air dry naturally.
- CLightly apply the brakes for a short distance to heat and dry them.
- DEngage the parking brake to dry the drums.
Show answer & explanationAnswer & explanation
Correct answer: C. Lightly apply the brakes for a short distance to heat and dry them.
Driving through deep water can wet the brakes, reducing their effectiveness. Lightly applying the brakes while driving slowly will generate friction, heat, and dry the brake components, restoring full braking power.
Why the other options are wrong
- A. Driving at high speeds with potentially wet brakes is unsafe; the goal is to dry them safely, not air dry them by speed.
- B. Stopping completely might allow the brakes to rust or remain wet, and won't actively dry them as effectively as light application.
- D. Engaging the parking brake while moving is extremely dangerous and can cause a skid or loss of control.
Wet Brake Drying
After driving through water, lightly apply the brakes while driving slowly to create friction and heat, drying the brake components.
- Water reduces brake effectiveness.
- Light application generates heat to evaporate water.
- Restores full braking power.
Memory trick: Puddle's splash, brakes feel trash? Light touch, don't crash!