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 20 multiple-choice questions, and applicants will need to correctly answer a minimum of 16 questions to pass. Applicants should answer at a rate of about one question per minute. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question
Passing Score

15. If you must cross traffic while driving a combination vehicle, you should:

Explanation
Combination vehicles require more space on the road than other vehicles. When entering or crossing traffic while driving a combination vehicle, it is especially important that there is a large enonugh gap in traffic to safely do so.

16. If a trailer begins to jackknife, the driver:

Explanation
If a trailer begins to jackknife, you should release the brakes and allow the trailer wheels to regain traction with the road. Do not apply the trailer hand brake to attempt to straighten out the rig because the application of brakes is what caused the wheels to lock in the first place.

17. A trailer that is too high:

Explanation
Before coupling together a tractor and a trailer, you should make sure the trailer is at the proper height. If the trailer is too low, the trailer nose may be damaged. If the trailer is too high, it may not be able to couple correctly.

18. 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.

19. If the emergency air line loses pressure:

Explanation
The tractor protection valve keeps air in the trailer's braking system should the trailer break away or develop a leak. A loss of air pressure in the emergency line will cause the tractor protection valve to open and the emergency trailer brakes to activate.

20. Keeping cargo centered on a rig can:

Explanation
A rollover is more likely if cargo is unevenly loaded in a rig. To help prevent a dangerous rollover, it is important to keep a load as centered on the rig as possible.
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