Home › CDL Practice Tests › Air Brakes Questions › Question 178
What is the most important decision to make before starting down a long, steep grade?
- A.Select a gear (and speed) low enough that engine braking does most of the work for the whole descent
- B.Choose the highest gear so the vehicle descends quickly
- C.Plan to ride the service brakes lightly the entire way
- D.Decide which escape ramp looks easiest to use
Correct answer
A. Select a gear (and speed) low enough that engine braking does most of the work for the whole descent
Why
Once speed builds on a grade, downshifting can become difficult or impossible and the service brakes must do punishing extra work. Choosing the right gear at the top keeps speed in the range where occasional brake use can control it.
Manual topic: Air Brakes - Downgrade Braking · From the Air Brakes practice bank (AB-178).