Combination

All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Commercial Driver License.. Read More

All applicants who are applying for a Class A CDL should be prepared to take the Combination test. This test covers information found in Section 6 of the Commercial Driver License Manual. Section 6 provides the information needed to safely operate tractor-trailers, doubles, triples, and straight trucks with trailers. The test is made up of 30 multiple-choice questions, and applicants will need to correctly answer a minimum of 24 questions to pass. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question
Passing Score

9. A trailer will be most likely to swing around when:

Explanation
An empty trailer will require a longer stopping distance than a loaded trailer. Additionally, a trailer is most likely to swing out and strike other vehicles when it is lightly loaded or empty.

10. The trailer hand valve should be used:

Explanation
The trailer hand valve (also referred to as the "trolley valve" or "Johnson bar") works the trailer brakes and should be used only when testing them. Using the trailer hand valve while driving could result in a skid.

11. When coupling, you should:

Explanation
When coupling air brake hoses, you should make sure the proper pairs of gland hands are connected. They are sometimes color-coded to help drivers avoid mistakes. Typically, blue is used for service lines and red is used for emergency lines.

12. A combination vehicle has:

Explanation
Combination vehicles have two air lines: a service line and an emergency line.

13. When backing up your tractor while coupling it to a trailer, the trailer brakes should be:

Explanation
Correctly following the steps to couple and uncouple trailers is vital to safely operating a combination vehicle. Before backing your tractor under the trailer while coupling, make sure your trailer brakes are locked.

14. When driving with trailers, you should:

Explanation
To reduce the risk of tipping over when driving with a trailer, you should steer gently and smoothly. Avoid making sudden movements.

15. Pull out the trailer air supply control to test:

Explanation
Be sure to test the trailer emergency brakes before beginning a trip. After ensuring that the trailer rolls freely, you can test the emergency brakes by pulling out the trailer air supply control, or placing it in the "emergency" position. Pull forward slightly with the tractor and make sure the trailer does not move.

16. If your vehicle gets stuck on railroad tracks, you should:

Explanation
If your vehicle gets stuck on railroad tracks for any reason, you should immediately exit the vehicle and walk away from the tracks. Contact the proper emergency authorities.
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