Home › CDL Practice Tests › Air Brakes Questions › Question 194
Which practice best preserves service brakes for an emergency on a long grade?
- A.Use the trailer hand valve continuously so tractor brakes stay cool
- B.Ride the service brakes and save the engine brake for emergencies
- C.Use the engine and retarder to control most speed, and use the service brakes in planned snub applications only as needed
- D.Turn the engine off and coast to save fuel
Correct answer
C. Use the engine and retarder to control most speed, and use the service brakes in planned snub applications only as needed
Why
Foundation brakes are the only system that can make a full emergency stop, so their heat capacity should not be spent on routine speed holding. Engine braking does the steady work while snub applications trim speed when it creeps up.
Manual topic: Air Brakes - Downgrade Braking · From the Air Brakes practice bank (AB-194).