Michigan CDL Combination Vehicles Practice Test

The Michigan CDL Combination Vehicles test is a multiple-choice knowledge test you take for your commercial learner's permit. Michigan Department of State (Secretary of State offices) says you need 80% to pass (source).

Last updated Oct 18, 2026. FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC.

By Scott Wilder, Editor

Last reviewed against the Michigan CDL manual on October 18, 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.

Michigan CDL permit facts

What	What Michigan says	Source
Combination Vehicles pass mark	80%	Official page
Combination Vehicles test questions	20	Official page
CLP holding period	Drive with a CLP for at least 14 days before the skills test	Official page
Knowledge test retest wait	If you fail a knowledge test, you must wait one day to retake it. There is a one day wait before any later retest too	Official page
Test languages	Michigan's CDL pages do not state the languages for CDL knowledge tests. See notes.	Official page

20 question Combination Vehicles practice test

1. Which trailers are not required to have spring brakes?
1. A. Trailers built before 1998
2. B. All trailers shorter than 40 feet
3. C. Only trailers carrying hazardous materials
4. D. Converter dollies and trailers built before 1975
Show answer
Answer: D. Converter dollies and trailers built before 1975
The manual says these are not required to have spring brakes.
From the official CDL manual, section 6.2.8.
2. At what speed do you add one extra second to your following distance in a combination vehicle?
1. A. Over 25 mph
2. B. Over 55 mph
3. C. Over 30 mph on wet roads only
4. D. Over 40 mph
Show answer
Answer: D. Over 40 mph
The manual adds one second when going over 40 mph.
From the official CDL manual, section 6.1.2.
3. Before coupling, how should the jaws of the fifth wheel be?
1. A. Closed
2. B. Locked on a shank
3. C. Greased and closed
4. D. Open
Show answer
Answer: D. Open
The manual says the fifth wheel jaws must be open for coupling.
From the official CDL manual, section 6.4.1.
4. Before you uncouple, what must you check about the parking area?
1. A. That it is painted with lines
2. B. That it is close to the road
3. C. That the surface can support the weight of the trailer
4. D. That it is level with the road
Show answer
Answer: C. That the surface can support the weight of the trailer
The parking surface must support the weight of the trailer.
From the official CDL manual, section 6.4.2.
5. What is the main benefit of ABS in a hard stop?
1. A. It always shortens the stopping distance
2. B. It helps you keep the vehicle under control
3. C. It lets you stop without using the brake pedal
4. D. It lets you follow closer to the vehicle ahead
Show answer
Answer: B. It helps you keep the vehicle under control
ABS keeps the wheels from locking so you can stay in control.
From the official CDL manual, section 6.3.2.
6. How often should you drain each trailer air tank?
1. A. Once a week
2. B. Every day
3. C. Once a month
4. D. Only when the brakes feel weak
Show answer
Answer: B. Every day
Draining daily keeps water and oil from building up.
From the official CDL manual, section 6.2.6.
7. 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.
8. What is a "bobtail" in trucking?
1. A. A tractor without a semitrailer
2. B. A trailer with a short body
3. C. A tractor pulling a single empty trailer
4. D. A straight truck with a dump body
Show answer
Answer: A. A tractor without a semitrailer
The manual defines bobtail tractors as tractors without semitrailers.
From the official CDL manual, section 6.1.3.
9. Which setup can get hung up on a raised railroad crossing?
1. A. A tandem-axle tractor pulling a short trailer
2. B. A single-axle tractor pulling a long trailer with landing gear set for a tandem-axle tractor
3. C. A straight truck with a single rear axle
4. D. A tractor pulling a trailer with the landing gear fully raised
Show answer
Answer: B. A single-axle tractor pulling a long trailer with landing gear set for a tandem-axle tractor
The landing gear is set low for a tandem tractor, so it can catch on a raised crossing.
From the official CDL manual, section 6.1.4.
10. 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.
11. 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.
12. What is off-tracking?
1. A. The trailer drifting out of its lane on a straight road
2. B. The rear wheels following a different path than the front wheels in a turn
3. C. The trailer skidding when brakes lock
4. D. The tractor leaning in a high-speed turn
Show answer
Answer: B. The rear wheels following a different path than the front wheels in a turn
The manual calls this off-tracking or "cheating."
From the official CDL manual, section 6.1.6.
13. After you pull the tractor partly clear of the trailer, what is the next step?
1. A. Pull clear and drive away
2. B. Raise the landing gear
3. C. Apply the parking brake and put the transmission in neutral
4. D. Chock the trailer wheels
Show answer
Answer: C. Apply the parking brake and put the transmission in neutral
Step 8 is to secure the tractor with the parking brake and neutral.
From the official CDL manual, section 6.4.2.
14. In a rig with several trailers, which shut-off valves must be closed?
1. A. All of them
2. B. The ones at the back of the first trailer
3. C. None of them
4. D. Only the ones at the back of the last trailer
Show answer
Answer: D. Only the ones at the back of the last trailer
All others must be open so air reaches every trailer.
From the official CDL manual, section 6.2.7.
15. Why should you never use the trailer hand valve to park?
1. A. All the air might leak out, unlocking the brakes
2. B. It damages the trailer relay valves
3. C. It locks the brakes so tightly they cannot be released
4. D. It closes the tractor protection valve
Show answer
Answer: A. All the air might leak out, unlocking the brakes
Without spring brakes, the leaking air would release the brakes and the trailer could roll.
From the official CDL manual, section 6.2.1.
16. When the ABS computer senses a wheel is about to lock up, what does it do?
1. A. It raises the braking pressure
2. B. It turns off the brakes on that axle for good
3. C. It reduces the braking pressure to a safe level
Show answer
Answer: C. It reduces the braking pressure to a safe level
The computer reduces the braking pressure to a safe level so you keep control.
From the official CDL manual, section 6.3.2.
17. When uncoupling, when should you chock the trailer wheels?
1. A. Only when the trailer is loaded
2. B. If the trailer has no spring brakes, or you are not sure
3. C. Never, because the landing gear holds it
4. D. Only on a downgrade
Show answer
Answer: B. If the trailer has no spring brakes, or you are not sure
Air could leak out of the tank, releasing emergency brakes.
From the official CDL manual, section 6.4.2.
18. When does a large combination vehicle take longer to stop?
1. A. When it is fully loaded
2. B. The stopping distance is the same either way
3. C. When it is empty
4. D. Only when the trailer is loaded and the tractor is empty
Show answer
Answer: C. When it is empty
An empty combination takes longer to stop than a fully loaded one.
From the official CDL manual, section 6.1.3.
19. The ABS malfunction lamp stays on. What does the manual say about your brakes?
1. A. You have no brakes and should stop at once
2. B. The brakes work only at low speed
3. C. Ignore the lamp since ABS is optional
4. D. You still have regular brakes; drive normally and get the system serviced soon
Show answer
Answer: D. You still have regular brakes; drive normally and get the system serviced soon
A malfunctioning ABS does not remove your regular brakes.
From the official CDL manual, section 6.3.2.
20. Why shut the engine off when checking for crossed air-lines after supplying air to the trailer?
1. A. To keep the compressor from overheating
2. B. To keep the trailer air tanks from overfilling
3. C. To close the tractor protection valve
4. D. So you can hear the trailer brakes apply and release
Show answer
Answer: D. So you can hear the trailer brakes apply and release
You should hear the brakes move when applied and air escape when released.
From the official CDL manual, section 6.4.1.

Michigan CDL Combination Vehicles questions

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

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

Is the Michigan 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. Michigan uses its own handbook: https://www.michigan.gov/sos/-/media/Project/Websites/sos/Resources/Forms-and-publications/CDL-Manual/cdlmanual.pdf

What languages is the Michigan CDL knowledge test offered in?

Michigan's CDL pages do not state the languages for CDL knowledge tests. See notes.

Sources

https://www.michigan.gov/sos/all-services/cdl-apply
https://www.michigan.gov/sos/-/media/Project/Websites/sos/Resources/Forms-and-publications/CDL-Manual/cdlmanual.pdf
Manual sections used in this test: 6.1.2; 6.1.3; 6.1.4; 6.1.6; 6.1.7; 6.2.1; 6.2.5; 6.2.6; 6.2.7; 6.2.8; 6.3.2; 6.4.1; 6.4.2; 6.5.2

Combination Vehicles practice test in nearby states