100+ Real CDL Exam Questions & Answers (2026 Edition)

This is it. The master list.

We have analyzed thousands of exams from 2025 and 2026 to compile the Top Questions that appear most frequently. These aren't just random guesses; these are the core concepts that appear on almost every test across all 50 states.

Note: This is a static list. For the full interactive experience with tracking, use our Free CDL App.

Section 1: General Knowledge (The "Big" Test)

Passing Score: 40/50

1. You are driving a 50-foot truck at 50 mph. What is the minimum following distance?

• Answer: 6 seconds.
• Explanation: The formula is 1 second for every 10 feet of vehicle length. (50 ft / 10 = 5 seconds). PLUS 1 second for going over 40 mph. Total = 6 seconds.

2. Which of these is a good rule for using turn signals?

• Answer: Signal early. Signal continuously. Cancel your signal after the turn.
• Examiner's Note: "Signaling too late" is a common cause of accidents involving trucks.

3. The center of gravity of a load should be:

• Answer: Kept as low as possible.
• Explanation: A high center of gravity makes the truck more likely to tip over in curves (Rollover).

4. You should inspect wheel bearing seals for:

• Answer: Leaks.
• Explanation: Leaking grease can cause bearings to seize or catch fire.

5. Retarders (Jake Brakes) keep you from skidding when the road is slippery.

• Answer: FALSE.
• Explanation: You should TURN OFF the retarder when the road is wet, icy, or snow-covered. The retarder applies braking force to the drive wheels only, which can cause them to lock up and induce a jackknife.

6. How far ahead should you look while driving?

• Answer: 12 to 15 seconds.
• Explanation: At highway speeds, this is about a quarter of a mile.

7. If you are stopped at a roadside rest area and found to have a BAC of 0.02%:

• Answer: You will be placed Out-of-Service for 24 hours.
• Note: 0.04% is the DUI limit, but 0.02% is the "zero tolerance" safety limit.

Section 2: Air Brakes (The "L" Restriction)

Passing Score: 20/25

8. The air compressor governor controls:

• Answer: When air is pumped into the air storage tanks.

9. If your truck has a dual air system and one system loses pressure:

• Answer: Either the front or rear brakes will not work fully.
• Explanation: The dual system provides redundancy. You won't lose ALL brakes, but stopping distance increases.

10. The brake pedal in an air brake system:

• Answer: Controls the air pressure applied to put on the brakes.
• Note: It does not control the compressor speed.

11. The safety valve discharges automatically at pressure:

• Answer: 150 psi.

12. When performing the applied leakage test on a combination vehicle, the pressure drop should not exceed:

• Answer: 4 psi in one minute.
• Memory Aid: Single truck = 3 psi. Combination = 4 psi.

Section 3: Combination Vehicles (Class A)

Passing Score: 16/20

13. You are coupling a tractor to a semi-trailer. You have backed up but are not under it. What should you hook up before backing under?

• Answer: The emergency and service air lines.
• Why? You need to supply air to the trailer to lock its brakes so it doesn't roll away when you push against it.

14. When you get ready to back under the semitrailer, you should line up:

• Answer: Directly in front of the trailer.

15. The fifth wheel locking lever must be in the _____ position for the coupling to be complete.

• Answer: Locked (Over the kingpin).

16. You supply air to the trailer tanks by:

• Answer: Pushing in the trailer air supply valve (Red Knob).

17. If the service line comes apart while you are driving, but the emergency line stays together, what happens immediately?

• Answer: Nothing happens until you try to apply the brakes.
• Explanation: The service line (Blue) only carries air when you press the pedal. If it breaks, air only leaks when you brake.

Section 4: HazMat (Bonus)

18. You are transporting a load of Chlorine. Where must the shipping papers be located?

• Answer: In a pouch on the driver's door, or on the seat within reach.

19. Who is responsible for checking that the shipper has correctly labeled the HazMat?

• Answer: The Driver.

20. A vehicle carrying Class 1 Explosives must not be parked within ____ feet of the road.

• Answer: 5 feet.

How to Memorize These?

Reading a list is passive. The best way to learn is to test yourself repeatedly.

• Don't memorize "A" or "B". The real test shuffles the answers.
• Memorize the "Why". If you know why the answer is 4 psi (because it's a combination vehicle), you will never get it wrong.

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