North Carolina CDL Combination Practice Test

The North Carolina CDL Combination Vehicles test is a multiple-choice knowledge test you take for your commercial learner's permit. North Carolina Division of Motor Vehicles (NCDMV), part of NCDOT says you need 80% to pass (source).

Last updated Oct 15, 2026. FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC.

By Scott Wilder, Editor

Last reviewed against the North Carolina CDL manual on October 15, 2026

Scott Wilder on X | scottwilderhq.com

FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC. It offers free exam-style practice tests built from the official CDL manual. FirstTry CDL is not affiliated with any DMV, FMCSA or government agency. Practice questions are exam-style questions built from the official CDL manual, not actual test questions.

North Carolina CDL permit facts

What	What North Carolina says	Source
Combination Vehicles pass mark	80%	Official page
CLP fee	$25.50 (listed as Learner's Permit in the manual fee list)	Official page
CLP validity	180 days. It can be renewed once, also for 180 days.	Official page
Test languages	The CDL pages do not name the languages for CDL tests and give no English-only rule. For regular license tests NCDMV says tests are offered in different languages and oral tests are available on request, and you can ask for an ASL or language interpreter online.	Official page

20 question Combination Vehicles practice test

1. You connect the air and electrical lines. What must you make sure of?
1. A. They are as long as possible
2. B. They are painted the same color
3. C. They are hidden under the trailer
4. D. They will not hit any moving parts
Show answer
Answer: D. They will not hit any moving parts
The lines must not hit any moving parts of the vehicle.
From the official CDL manual, section 6.4.1.
2. Why should you never back under a trailer at an angle?
1. A. You might push the trailer sideways and break the landing gear
2. B. The kingpin cannot lock at an angle
3. C. The glad hands will cross
4. D. The trailer brakes will lock up
Show answer
Answer: A. You might push the trailer sideways and break the landing gear
Line up directly in front of the trailer before backing under.
From the official CDL manual, section 6.4.1.
3. What should you do before you start to back a trailer?
1. A. Get out and walk around the vehicle to check your path and clearances
2. B. Ask a passenger to wave you in without leaving the cab
3. C. Check only the mirror on the driver's side
4. D. Begin backing slowly and check clearances as you go
Show answer
Answer: A. Get out and walk around the vehicle to check your path and clearances
Checking the path, sides and overhead clearance helps avoid hits.
From the official CDL manual, section 6.1.7.
4. Which control tests the trailer brakes, and which controls them in normal driving?
1. A. The foot pedal tests them; the hand valve controls them in driving
2. B. The hand valve tests them; the foot pedal controls them in driving
3. C. The hand valve both tests and controls them
4. D. The air supply knob tests them; the parking valve controls them
Show answer
Answer: B. The hand valve tests them; the foot pedal controls them in driving
The foot pedal applies the service brakes at all wheels.
From the official CDL manual, section 6.5.2.
5. What can happen if you do not lock the pintle hook latch correctly?
1. A. Only a small noise
2. B. The trailer and vehicle can separate
3. C. The brake lights stay on
4. D. The tires wear faster
Show answer
Answer: B. The trailer and vehicle can separate
The trailer and vehicle can separate, which can cause death or serious injury.
From the official CDL manual, section 6.4.3.
6. When you connect the air-lines, which line goes to the trailer emergency glad hand?
1. A. The tractor service air-line
2. B. The tractor parking line
3. C. The electrical cord
4. D. The tractor emergency air-line
Show answer
Answer: D. The tractor emergency air-line
The tractor emergency air-line connects to the trailer emergency glad hand, after you check the seals.
From the official CDL manual, section 6.4.1.
7. A lightly loaded combination locks its wheels in a hard stop. What can happen?
1. A. The trailer can swing out and the tractor can jackknife
2. B. The trailer will straighten out on its own
3. C. The tractor protection valve will open
4. D. The cargo will shift forward and help traction
Show answer
Answer: A. The trailer can swing out and the tractor can jackknife
With poor traction, a trailer can swing out and a tractor can jackknife very quickly.
From the official CDL manual, section 6.1.3.
8. Which event can make the emergency line lose air pressure?
1. A. Pressing the foot brake lightly
2. B. A trailer breaking loose and tearing the emergency hose
3. C. Pushing in the trailer air supply control
Show answer
Answer: B. A trailer breaking loose and tearing the emergency hose
A trailer that breaks loose can tear the emergency hose and let the air out.
From the official CDL manual, section 6.2.4.
9. According to the manual, what makes rollovers happen?
1. A. Turning too fast
2. B. Driving too far from the shoulder
3. C. Using the foot brake too early
4. D. Having a full fuel tank
Show answer
Answer: A. Turning too fast
Rollovers happen when you turn too fast, so slow down for corners and ramps.
From the official CDL manual, section 6.1.1.
10. How do you join two glad hand couplers?
1. A. Push them straight together until they click
2. B. Twist them together while pulling the hoses apart
3. C. Slide one coupler over the other and tighten it with a wrench
4. D. Press the seals together with the couplers at 90 degrees, then turn the hose-side glad hand
Show answer
Answer: D. Press the seals together with the couplers at 90 degrees, then turn the hose-side glad hand
This presses the seals and locks the couplers.
From the official CDL manual, section 6.2.5.
11. You are parking a trailer that has no spring brakes. What should you use to keep it from moving?
1. A. The trailer hand valve
2. B. The trailer air supply control pushed in
3. C. The tractor's service brake pedal
4. D. Wheel chocks
Show answer
Answer: D. Wheel chocks
Without spring brakes, chocks are what hold the trailer in place.
From the official CDL manual, section 6.2.1.
12. Engine off, you test the tractor protection valve. How do you lower the air pressure in the tanks?
1. A. Open the drain valves on the trailer
2. B. Step on and off the brake pedal several times
3. C. Pull the trailer hand valve once
Show answer
Answer: B. Step on and off the brake pedal several times
With the engine off, step on and off the brake pedal several times to reduce the air pressure.
From the official CDL manual, section 6.5.2.
13. Triples have a rearward amplification of 3.5. How easily can the last trailer roll, compared with a five-axle tractor?
1. A. 1.5 times as easily
2. B. 3.5 times as easily
3. C. 2 times as easily
4. D. 10 times as easily
Show answer
Answer: B. 3.5 times as easily
The manual says the last trailer of triples can roll 3.5 times as easily as a five-axle tractor.
From the official CDL manual, section 6.1.2.
14. What does the trailer air supply control look like on newer vehicles?
1. A. A red eight-sided knob
2. B. A blue round knob
3. C. A yellow diamond-shaped knob
4. D. A black T-handle
Show answer
Answer: A. A red eight-sided knob
The manual describes it as a red eight-sided knob.
From the official CDL manual, section 6.2.3.
15. An older vehicle has a lever for the tractor protection valve. Which position is used to pull a trailer?
1. A. The "normal" position
2. B. The "emergency" position
3. C. A middle position between the two
Show answer
Answer: A. The "normal" position
The normal position is for pulling a trailer, and emergency shuts the air off.
From the official CDL manual, section 6.2.3.
16. Which cab control opens and shuts the tractor protection valve?
1. A. The trailer hand valve
2. B. The brake pedal
3. C. The low air warning signal
4. D. The trailer air supply control valve
Show answer
Answer: D. The trailer air supply control valve
The trailer air supply control valve lets you open and shut the tractor protection valve.
From the official CDL manual, section 6.2.2.
17. Where is the yellow ABS malfunction lamp found on a trailer?
1. A. On the right side, near the landing gear
2. B. On the nose of the trailer, near the glad hands
3. C. Inside the tractor cab only
4. D. On the left side, at the front or rear corner
Show answer
Answer: D. On the left side, at the front or rear corner
The manual places the lamp on the left side of the trailer, front or rear corner.
From the official CDL manual, section 6.3.1.
18. When must you control your speed in a combination vehicle?
1. A. Whether fully loaded or empty
2. B. Only when fully loaded
3. C. Only when empty
Show answer
Answer: A. Whether fully loaded or empty
The manual says to control speed whether the rig is fully loaded or empty.
From the official CDL manual, section 6.1.3.
19. In a rig with several trailers, whose rear wheels off-track the most in a turn?
1. A. The last trailer
2. B. The tractor's rear wheels
3. C. The first trailer's rear wheels
4. D. All units off-track by the same amount
Show answer
Answer: A. The last trailer
The rear wheels of the last trailer off-track the most.
From the official CDL manual, section 6.1.6.
20. How does looking far down the road help you in a combination vehicle?
1. A. It lets you follow other vehicles closer
2. B. It lets you take curves faster
3. C. It helps you avoid surprises and sudden lane changes
Show answer
Answer: C. It helps you avoid surprises and sudden lane changes
Seeing far ahead keeps you from being surprised and having to change lanes suddenly.
From the official CDL manual, section 6.1.2.

North Carolina CDL Combination Vehicles questions

What score do you need to pass the North Carolina CDL Combination Vehicles test?

North Carolina says you need 80% to pass the Combination Vehicles test.

Is the North Carolina CDL Combination Vehicles test the same as other states?

The Combination Vehicles test is built on the same federal knowledge standards in every state, so the topics match the CDL manual. North Carolina uses its own handbook: https://www.ncdot.gov/dmv/license-id/driver-licenses/new-drivers/Documents/commercial-driver-manual.pdf

How much does a CDL permit cost in North Carolina?

CLP fee: $25.50 (listed as Learner's Permit in the manual fee list).

What languages is the North Carolina CDL knowledge test offered in?

The CDL pages do not name the languages for CDL tests and give no English-only rule. For regular license tests NCDMV says tests are offered in different languages and oral tests are available on request, and you can ask for an ASL or language interpreter online.

Sources

https://www.ncdot.gov/dmv/license-id/driver-licenses/new-drivers/Documents/commercial-driver-manual.pdf
https://www.ncdot.gov/dmv/license-id/driver-licenses/commercial/Pages/default.aspx
https://www.ncdot.gov/dmv/license-id/driver-licenses/new-drivers/Pages/driver-license-tests.aspx
Manual sections used in this test: 6.1.1; 6.1.2; 6.1.3; 6.1.6; 6.1.7; 6.2.1; 6.2.2; 6.2.3; 6.2.4; 6.2.5; 6.3.1; 6.4.1; 6.4.3; 6.5.2

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