Mountain driving and downgrades for the CDL
Section 2.16 of the CDL handbook covers mountain driving: choosing a safe speed and braking on long downgrades. It is tested on the General Knowledge test.
Key facts
| Part of | the General Knowledge test (80% to pass) | DL-7C p. iv |
|---|---|---|
| Handbook section | §2.16 Mountain driving | DL-7C p. 2-32 |
| Questions in CDL Mile's bank | 8 | CDL Mile, checked against DL-7C |
Key rules
- § 2.16.2p. 2-33
Newer trucks are built with low-friction parts and sleek shapes to save fuel, so less drag holds them back on the way down. They may need a lower gear to descend than to climb.
Select the Right Gear before Starting Down the Grade
- § 2.16.2p. 2-33
Forcing an automatic into a lower gear at high speed can damage the transmission and can also cost you all engine braking. Pick your low gear before the grade.
Select the Right Gear before Starting Down the Grade
Try two questions
General Knowledge · Mountain driving
Why can brakes that are out of adjustment lead to brake fade on a long downgrade?
Tap an answer to see the explanation and the handbook page.
General Knowledge · Mountain driving
At the top of a grade you pass a sign reading 'Maximum Safe Speed 35.' Your truck is lightly loaded and the road is dry. What should you do?
Tap an answer to see the explanation and the handbook page.
More General Knowledge topics
Sources
Texas Commercial Motor Vehicle Drivers Handbook (DL-7C), revised March 2026, Texas Department of Public Safety. Page references are to its printed page numbers. CDL Mile is independent and not affiliated with Texas DPS.
Updated for the March 2026 Texas CDL handbook (DL-7C). Last checked November 4, 2026.
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