CDL Practice Test

CDL Mountain Driving Practice Questions

Mountain Driving makes up 1 of every 50 questions on a Tigertest CDL practice test. Here are 10 of the 30 questions on it, each with the answer and the reason.

Updated 2026-11-10 by the Tigertest team. Covers the CDL general knowledge exam. 80% to pass on the real test.

1. 1. When going down a steep grade, you should?

   • A.Pump the brakes continuously to keep them cool
   • B.Select a low gear before starting the descent
   • C.Use only the brakes to control speed
   • D.Shift to neutral and coast to save the engine

   Answer: B. Selecting a low gear before the descent provides engine braking and reduces reliance on service brakes, preventing brake fade.

2. 2. What causes brake fade on long downgrades?

   • A.Incorrect tire pressure
   • B.Poor fuel quality or water in the fuel
   • C.Low transmission fluid
   • D.Excessive heat from overuse

   Answer: D. Brake fade occurs when brakes overheat from excessive use on long downgrades, reducing their stopping power significantly.

3. 3. The best way to prevent brake fade is to?

   • A.Use engine braking and proper gear selection
   • B.Ride the brakes continuously to maintain constant pressure
   • C.Apply brakes harder to compensate for reduced effectiveness
   • D.Pump the brakes rapidly in short bursts continuously

   Answer: A. Engine braking through proper gear selection reduces heat buildup in service brakes, preventing dangerous brake fade.

4. 4. What should you do if your brakes fail on a downgrade?

   • A.Pump the brakes harder
   • B.Turn off the engine immediately
   • C.Use an escape ramp if available
   • D.Downshift to a lower gear

   Answer: C. Escape ramps are specifically designed to safely stop runaway vehicles when brakes fail on mountain grades.

5. 5. When climbing a steep grade, you should?

   • A.Use cruise control for consistent speed
   • B.Turn off the air conditioning
   • C.Downshift if the engine starts to lug
   • D.Maintain the highest gear possible

   Answer: C. Downshifting when the engine lugs prevents stalling and maintains power for climbing steep grades safely.

6. 6. Escape ramps are built to?

   • A.Stop runaway vehicles safely
   • B.Provide rest areas for drivers
   • C.Allow vehicles to turn around
   • D.Help with steep upgrade climbs

   Answer: A. Escape ramps use gravel, sand, or uphill grades to safely stop vehicles that have lost braking ability on downgrades.

7. 7. What gear should you use when going down a steep grade?

   • A.One gear higher than you used for climbing the grade
   • B.The highest gear available for maximum fuel efficiency
   • C.Neutral gear position for fuel efficiency and reduced wear
   • D.A gear lower than you would use to climb the grade

   Answer: D. The old rule was to go down in the same gear you used to climb. Modern trucks have low-friction parts and streamlined shapes, so the current CDL manual says you may need a lower gear going down to get enough engine braking.

8. 8. Mountain driving requires extra attention to?

   • A.Passenger comfort levels during steep grade navigation
   • B.Engine temperature and brake condition
   • C.Fuel consumption rates and efficiency during grade climbing
   • D.Radio reception quality and communication with dispatch centers

   Answer: B. Mountain driving puts extra stress on engines and brakes, requiring frequent monitoring to prevent overheating and failure.

9. 9. If your engine overheats going up a grade, you should?

   • A.Turn on the heater to cool the engine
   • B.Stop and let the engine cool down
   • C.Pour cold water on the radiator
   • D.Continue driving to reach the top

   Answer: B. Continuing to drive with an overheated engine can cause severe damage; stopping and cooling is the safe approach.

10. 10. Why do loaded vehicles have more trouble on grades than empty ones?

    • A.They have less traction between tires and road surface
    • B.Their brake systems work better creating more resistance
    • C.They require less power to maintain speed on grades
    • D.Gravity affects them more due to weight

    Answer: D. Heavier loads increase the gravitational force pulling vehicles downhill and require more power to climb uphill grades.