Continuous use of the brakes on a long downgrade can cause:
Correct. Holding the brakes overheats them and causes brake fade — drums expand and brake compounds lose effectiveness, reducing braking force.
CDL Practice Question #122
Category: Air Brakes
Why this question matters
This question is one of 71 in our Air Brakes bank. The reasoning above comes directly from the AAMVA CDL Manual, the source document used by every U.S. state DMV. Memorizing the underlying rule — not just the letter answer — is what separates passing on the first attempt from a return trip and another fee.