Which of these is the safest speed for descending a long, steep grade?
Correct. Choose a speed and gear that lets the brakes work intermittently without continuous pressure. Posted truck-grade signs help.
CDL Practice Question #133
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.