Home › CDL Practice Tests › Air Brakes Questions › Question 195
Why should you never shift to neutral or coast down a grade to save fuel?
- A.Coasting is illegal only at night
- B.Neutral makes the air compressor stop on every vehicle
- C.The brakes work better when the engine is disconnected
- D.Coasting removes engine braking, lets speed build quickly, and leaves the service brakes to absorb all the energy and overheat
Correct answer
D. Coasting removes engine braking, lets speed build quickly, and leaves the service brakes to absorb all the energy and overheat
Why
With the drivetrain disconnected there is no engine resistance helping to hold speed back. The truck gains speed silently and the driver discovers the loss of control only when the overheated brakes are asked to do everything.
Manual topic: Air Brakes - Downgrade Braking · From the Air Brakes practice bank (AB-195).