Home › CDL Practice Tests › General Knowledge Questions › Question 88
What is the primary way to control speed on a long downgrade?
- A.The braking effect of the engine in a low gear, with the service brakes used in short applications
- B.Riding the service brakes the whole way
- C.Coasting in neutral
- D.Using the trailer brakes alone
Correct answer
A. The braking effect of the engine in a low gear, with the service brakes used in short applications
Why
Engine braking does not heat up or wear out, so it is the foundation of downhill speed control. The service brakes become a supplement for trimming speed, which keeps them cool and ready.
Manual topic: Safe Driving - Mountain Driving · From the General Knowledge practice bank (GK-088).