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CDL General Knowledge Test

Basic control: practice questions

Our CDL General Knowledge bank has 18 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.

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Question 1

When should you turn off the retarder?

  1. When going downhill on dry roads
  2. On dry highways
  3. On wet, icy or snow-covered roads, where it can cause the drive wheels to skid
  4. Never
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C. On wet, icy or snow-covered roads, where it can cause the drive wheels to skid — Retarders apply braking power to the drive wheels only.

Question 2

What should you do before leaving a truck unattended?

  1. Park on a downgrade with the engine running and the brakes released
  2. Set the parking brake and, if needed, chock the wheels
  3. Leave it in neutral
  4. Leave the engine running
Show the answer

B. Set the parking brake and, if needed, chock the wheels — Never leave the vehicle where it could roll.

Question 3

What can happen if you take a curve too fast in a vehicle with a high center of gravity?

  1. It can roll over
  2. Nothing
  3. It gets better traction
  4. It will stop automatically
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A. It can roll over — Trucks can roll over at the posted speed for cars.

Question 4

What is 'double clutching'?

  1. Releasing the clutch in neutral to match engine and gear speeds while shifting
  2. Shifting without the clutch
  3. Using two clutches at once
  4. Pressing the clutch pedal twice quickly before turning the key to start the engine
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A. Releasing the clutch in neutral to match engine and gear speeds while shifting — Double clutching is used in many non-synchronised transmissions.

Question 5

When you start the vehicle moving from a stop, how can you prevent rolling back?

  1. Turn off the engine
  2. Release the brake quickly and accelerate hard
  3. Start in high gear
  4. Partially engage the clutch before taking your foot off the brake (or use the parking brake as needed)
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D. Partially engage the clutch before taking your foot off the brake (or use the parking brake as needed) — Rolling back can cause a crash.

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