Pennsylvania CDL Combination Vehicles Practice Test

The Pennsylvania 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 (Pennsylvania does not publish its own number).

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 Pennsylvania 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.

Pennsylvania CDL permit facts

What	What Pennsylvania says	Source
Combination Vehicles pass mark	At least 80%. This is the federal minimum (49 CFR 383.135); Pennsylvania does not publish its own number.	Official page
CLP fee (photo fee, one permit)	$15.50 photo fee, plus $6.00 for each endorsement or restriction removal (no fee for the school bus endorsement). Add $5 for each additional commercial permit on the fee chart.	Official page
CLP validity	The permit is valid for one year from the date the Knowledge Test Authorization (KTA) is issued.	Official page
Test languages	PennDOT offers knowledge tests in multiple languages, in written and audio format. The hazmat knowledge test is English only. The test language list is not published on the pages checked.	Official page

20 question Combination Vehicles practice test

1. Before releasing the fifth wheel, how do you ease pressure on the locking jaws?
1. A. Pull forward gently with the trailer brakes released
2. B. Back up gently, then set the parking brakes while the tractor pushes against the kingpin
3. C. Release the parking brakes and idle in neutral
4. D. Raise the landing gear fully
Show answer
Answer: B. Back up gently, then set the parking brakes while the tractor pushes against the kingpin
This helps you release the fifth wheel locking lever.
From the official CDL manual, section 6.4.2.
2. 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.
3. After you push in the air supply knob to supply air to the trailer, what do you do first?
1. A. Wait until the air pressure is normal
2. B. Back under the trailer at once
3. C. Lock the trailer brakes
4. D. Raise the landing gear
Show answer
Answer: A. Wait until the air pressure is normal
The manual says to wait until the air pressure is normal.
From the official CDL manual, section 6.4.1.
4. To check that air flows to all trailers, what do you do after air pressure reaches normal?
1. A. Pull out the red trailer air supply knob
2. B. Apply the tractor parking brake only
3. C. Drain all the tractor air tanks
4. D. Push in the red trailer air supply knob
Show answer
Answer: D. Push in the red trailer air supply knob
This supplies air to the emergency (supply) lines.
From the official CDL manual, section 6.5.2.
5. In Step 8 of coupling, how do you supply air to the trailer brake system?
1. A. Pull out the "air supply" knob
2. B. Press the brake pedal once and hold
3. C. Push in the "air supply" knob
4. D. Open the shut-off valve at the rear of the trailer
Show answer
Answer: C. Push in the "air supply" knob
Pushing in the "air supply" knob supplies air to the trailer brake system.
From the official CDL manual, section 6.4.1.
6. When you pull the fifth wheel release handle, what is an important safety step?
1. A. Stand directly behind the trailer landing gear
2. B. Keep the engine running at high idle
3. C. Keep your legs and feet clear of the rear tractor wheels
4. D. Release the tractor parking brake first
Show answer
Answer: C. Keep your legs and feet clear of the rear tractor wheels
The vehicle could move and injure you.
From the official CDL manual, section 6.4.2.
7. 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.
8. 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.
9. You are checking that air flows to all trailers. How do you hold the vehicle in place?
1. A. Use the tractor parking brake and/or chock the wheels
2. B. Use the trailer hand valve only
3. C. Keep your foot on the clutch
Show answer
Answer: A. Use the tractor parking brake and/or chock the wheels
Use the tractor parking brake and/or chock the wheels to hold the vehicle.
From the official CDL manual, section 6.5.2.
10. 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.
11. At the rear of the last trailer, you open the emergency line shut-off valve and hear air escaping. What does this show?
1. A. The emergency line has a major leak
2. B. The trailer brakes are applied
3. C. The entire system is charged
4. D. The shut-off valves are closed
Show answer
Answer: C. The entire system is charged
Air at the back of the last trailer shows air reaches the whole rig.
From the official CDL manual, section 6.5.2.
12. 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.
13. 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.
14. You find the coupling is not right. What should you do?
1. A. Drive carefully to the nearest shop
2. B. Drive slowly and avoid turns
3. C. Add grease and continue the trip
4. D. Do not drive it; get it fixed
Show answer
Answer: D. Do not drive it; get it fixed
A bad coupling can let the trailer come loose.
From the official CDL manual, section 6.4.1.
15. You back a trailer. How does the steering wheel move, compared with backing a car or straight truck?
1. A. The same way as a car
2. B. You do not need to turn it at all
3. C. You turn it the opposite way
4. D. Only the trailer wheels are turned
Show answer
Answer: C. You turn it the opposite way
When backing a trailer, you turn the steering wheel in the opposite direction.
From the official CDL manual, section 6.1.7.
16. The trailer is empty. How far do you lower the landing gear?
1. A. Until it lifts the trailer off the fifth wheel
2. B. Only halfway down
3. C. Until it makes firm contact with the ground
4. D. Until the tractor tires lift
Show answer
Answer: C. Until it makes firm contact with the ground
For an empty trailer, lower the landing gear until it makes firm contact with the ground.
From the official CDL manual, section 6.4.2.
17. What is the trailer hand valve meant to be used for?
1. A. Slowing the rig on downgrades
2. B. Testing the trailer brakes
3. C. Straightening the rig in a skid
4. D. Parking the rig overnight
Show answer
Answer: B. Testing the trailer brakes
The hand valve is for testing the trailer brakes only.
From the official CDL manual, section 6.2.1.
18. 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.
19. 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.
20. You drive a tractor-trailer with ABS. How should you brake?
1. A. The same way you always have
2. B. Pump the brake pedal quickly
3. C. Brake lightly so ABS takes over
4. D. Use only the trailer hand valve
Show answer
Answer: A. The same way you always have
Use only the braking force needed to stop safely and stay in control.
From the official CDL manual, section 6.3.2.

Pennsylvania CDL Combination Vehicles questions

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

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

Is the Pennsylvania 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. Pennsylvania uses its own handbook: https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf

How much does a CDL permit cost in Pennsylvania?

CLP fee (photo fee, one permit): $15.50 photo fee, plus $6.00 for each endorsement or restriction removal (no fee for the school bus endorsement). Add $5 for each additional commercial permit on the fee chart..

What languages is the Pennsylvania CDL knowledge test offered in?

PennDOT offers knowledge tests in multiple languages, in written and audio format. The hazmat knowledge test is English only. The test language list is not published on the pages checked.

Sources

https://www.ecfr.gov/current/title-49/section-383.135
https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-form/dl-31cd.pdf
https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-fact-sheets/fs-cdl.pdf
https://www.pa.gov/content/dam/copapwp-pagov/en/penndot/documents/public/dvspubsforms/bdl/bdl-manuals/commercial-drivers-manual/pub223.pdf
Manual sections used in this test: 6.1.2; 6.1.3; 6.1.7; 6.2.1; 6.2.5; 6.2.6; 6.3.2; 6.4.1; 6.4.2; 6.4.3; 6.5.2

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