Florida CDL Combination Vehicles Practice Test

The Florida CDL Combination Vehicles test is a multiple-choice knowledge test you take for your commercial learner's permit. You need at least 80% to pass. That's the federal minimum in 49 CFR 383.135 (Florida does not publish its own number).

Last updated Oct 14, 2026. FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC.

By Scott Wilder, Editor

Last reviewed against the Florida CDL manual on October 14, 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.

Florida CDL permit facts

What	What Florida says	Source
Combination Vehicles pass mark	At least 80%. This is the federal minimum (49 CFR 383.135); Florida does not publish its own number.	Official page
Test languages	All Florida knowledge and skills tests, including CLP and CDL tests, are given only in English since February 6, 2026. Interpreters and translation are not allowed.	Official page

20 question Combination Vehicles practice test

1. Which color code is commonly used for the service line and the emergency line?
1. A. Blue for service, red for emergency
2. B. Red for service, blue for emergency
3. C. Yellow for service, red for emergency
4. D. Blue for both lines, with metal tags to tell them apart
Show answer
Answer: A. Blue for service, red for emergency
The manual says red marks the emergency line and blue marks the service line.
From the official CDL manual, section 6.2.4.
2. Besides colors, what can help you join the correct glad hands?
1. A. Hoses of different lengths
2. B. Different rubber seal shapes
3. C. Metal tags stamped "service" and "emergency"
Show answer
Answer: C. Metal tags stamped "service" and "emergency"
Metal tags marked service and emergency help you avoid mixing up the lines.
From the official CDL manual, section 6.2.5.
3. What should you check about the electrical cord between the tractor and trailer?
1. A. It is hanging loose for easy movement
2. B. It is firmly plugged in and secured
3. C. It is wrapped tightly around the air lines
Show answer
Answer: B. It is firmly plugged in and secured
The electrical cord must be firmly plugged in and secured.
From the official CDL manual, section 6.5.1.
4. What can happen if the tractor protection valve does not work right?
1. A. A hose or trailer brake leak could drain all the tractor's air and put the emergency brakes on
2. B. The trailer brakes will not apply, but nothing else changes
3. C. The trailer spring brakes will not release, and nothing else
4. D. The trailer will rise off the fifth wheel
Show answer
Answer: A. A hose or trailer brake leak could drain all the tractor's air and put the emergency brakes on
This can cause a possible loss of control.
From the official CDL manual, section 6.5.2.
5. You cross the service and emergency air-lines. What happens to the trailer spring brakes?
1. A. They do not release, because air does not charge the trailer tanks
2. B. They release normally
3. C. They release only after the engine is shut off
Show answer
Answer: A. They do not release, because air does not charge the trailer tanks
Supply air goes to the service line, so the tanks are not charged and the spring brakes stay on.
From the official CDL manual, section 6.2.5.
6. 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.
7. Why should the tractor be lined up with the trailer when you uncouple?
1. A. It saves fuel
2. B. Pulling out at an angle can damage the landing gear
3. C. It keeps the air-lines cool
4. D. It makes the brakes lock
Show answer
Answer: B. Pulling out at an angle can damage the landing gear
Pulling out at an angle can damage the landing gear.
From the official CDL manual, section 6.4.2.
8. Your trailer air tanks have automatic drains. What should you still do?
1. A. Nothing, they never need a check
2. B. Open the drains to make sure the moisture is out
3. C. Close all the shut-off valves
Show answer
Answer: B. Open the drains to make sure the moisture is out
Automatic drains keep out most moisture, but you should still open the drains to check.
From the official CDL manual, section 6.2.6.
9. When does ABS activate?
1. A. Every time you touch the brake pedal
2. B. Only when wheels are about to lock up
3. C. Only at speeds above 40 mph
4. D. Only when the trailer is empty
Show answer
Answer: B. Only when wheels are about to lock up
ABS adds to your normal brakes and acts only at impending lockup.
From the official CDL manual, section 6.3.2.
10. Which vehicle will off-track more in a turn?
1. A. A shorter vehicle
2. B. A longer vehicle
3. C. Both off-track the same amount
Show answer
Answer: B. A longer vehicle
The manual says longer vehicles off-track more.
From the official CDL manual, section 6.1.6.
11. How can you tell a pintle hook latch is correctly locked?
1. A. The lock handle is flush with the top of the latch
2. B. The lock handle points straight down
3. C. The latch is in its most upright position
4. D. The drawbar eye is above the horn
Show answer
Answer: A. The lock handle is flush with the top of the latch
When locked correctly, the lock handle is flush with the top of the latch.
From the official CDL manual, section 6.4.3.
12. Your rig gets stuck on a railroad crossing. What should you do first?
1. A. Stay in the cab and call for help by radio
2. B. Get out of the vehicle and away from the tracks
3. C. Try to rock the rig loose with the clutch
4. D. Walk toward the train to warn the engineer
Show answer
Answer: B. Get out of the vehicle and away from the tracks
The manual says to get out of the vehicle and away from the tracks.
From the official CDL manual, section 6.1.4.
13. You do not hear air escaping from both lines at the rear. What should you check?
1. A. That the trailer wheels are chocked
2. B. That the shut-off valves on the trailers and dollies are open
3. C. That the landing gear is raised
4. D. That the trailer tires are fully inflated
Show answer
Answer: B. That the shut-off valves on the trailers and dollies are open
Closed valves block the air from reaching the back.
From the official CDL manual, section 6.5.2.
14. 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.
15. 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.
16. On a sliding fifth wheel, what should you check about the locking pins?
1. A. They are all removed to let it slide
2. B. All are present and locked in place
3. C. Some may be missing if the others are tight
Show answer
Answer: B. All are present and locked in place
All locking pins must be present and locked in place.
From the official CDL manual, section 6.5.1.
17. Your trailer has power-operated landing gear. What should you check for?
1. A. Extra grease on the legs
2. B. Rust on the crank handle
3. C. Air or hydraulic leaks
Show answer
Answer: C. Air or hydraulic leaks
Power-operated landing gear should have no air or hydraulic leaks.
From the official CDL manual, section 6.5.1.
18. What tends to happen when the wheels of a trailer lock up?
1. A. The trailer lifts off the road
2. B. The trailer follows the tractor straight
3. C. The trailer tends to swing around
Show answer
Answer: C. The trailer tends to swing around
Locked trailer wheels make the trailer swing around, which is a trailer jackknife.
From the official CDL manual, section 6.1.5.
19. Your trailer has ABS but the tractor does not, and the tractor starts to jackknife. What should you do?
1. A. Brake harder, since the trailer has ABS
2. B. Pull out the trailer air supply knob
3. C. Let up on the brakes, if you can do so safely, until you regain control
4. D. Use only the trailer hand valve
Show answer
Answer: C. Let up on the brakes, if you can do so safely, until you regain control
ABS on the trailer does not stop a tractor jackknife; ease off the brakes.
From the official CDL manual, section 6.3.2.
20. What does the tractor protection valve do?
1. A. Keeps the trailer wheels from locking up
2. B. Sends more air to the trailer in a hard stop
3. C. Keeps air in the tractor brake system if the trailer breaks away or leaks badly
4. D. Drains water from the trailer air tanks
Show answer
Answer: C. Keeps air in the tractor brake system if the trailer breaks away or leaks badly
This valve protects the tractor's air supply from a trailer problem.
From the official CDL manual, section 6.2.2.

Florida CDL Combination Vehicles questions

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

You need at least 80% to pass. That is the federal minimum in 49 CFR 383.135. Florida does not publish its own number.

Is the Florida 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. Florida uses its own handbook: https://www.flhsmv.gov/pdf/handbooks/englishcdlhandbook.pdf

What languages is the Florida CDL knowledge test offered in?

All Florida knowledge and skills tests, including CLP and CDL tests, are given only in English since February 6, 2026. Interpreters and translation are not allowed.

Sources

https://www.ecfr.gov/current/title-49/section-383.135
https://www.flhsmv.gov/2026/01/30/flhsmv-announces-driver-license-exams-to-be-administered-in-english-only/
https://www.flhsmv.gov/pdf/handbooks/englishcdlhandbook.pdf
Manual sections used in this test: 6.1.3; 6.1.4; 6.1.5; 6.1.6; 6.2.2; 6.2.4; 6.2.5; 6.2.6; 6.3.2; 6.4.2; 6.4.3; 6.5.1; 6.5.2

Combination Vehicles practice test in nearby states