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.. 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's 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. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question
Passing Score

8. To test the trailer service brakes, you should:

Explanation
To test the trailer service brakes, you should first ensure that the braking system has a normal air pressure level, then release the parking brake. You should then move the vehicle forward slowly and apply the brakes with the hand control. If the trailer service brakes are working properly, you will feel the brakes activate.

9. The best way to recognize that your trailer has begun to skid is by:

Explanation
The earliest and best way to recognize the beginnings of a trailer skid is by seeing the trailer veer off-course in your mirrors.

10. Compared to other commercial motor vehicles, combination vehicles need more space on the road because they are longer and they:

Explanation
Combination vehicles need more space on the road than other commercial vehicles because they are longer and need more space to turn and stop. It is especially important to properly manage space when you are operating a combination vehicle.

11. Rollovers happen when:

Explanation
Rollovers happen when a vehicle is driven too fast. To reduce the risk of rollover, make sure the weight of cargo is loaded low to the ground, and that you take turns and curves slowly.

12. One function of the emergency air line is to:

Explanation
The emergency air line (also known as the supply line) has two functions. The first is to supply air to the trailer air tanks, and the second is to control the emergency brakes on combination vehicles.

13. The trailer hand valve:

Explanation
The trailer hand valve should not be used for parking. This could cause all of the air to leak out of the braking system, resulting in the brakes releasing. Instead, use the parking brake.

14. Trailers manufactured after ____ must be equipped with Anti-Lock Braking Systems (ABS).

Explanation
Trailers and converter dollies manufactured on or after March 1, 1998 are required to have Anti-Lock Braking Systems (ABS).
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