Instructions

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

Number of Question 20

Passing Score 16

8. What happens when the wheels of a trailer lock up?

The trailer will often continue to move in a straight line.

The trailer may disengage.

The trailer may swing around.

Steering will become easier.

A trailer may swing out and strike other vehicles if its wheels lock up. This is especially likely with lightly-loaded trailers.

9. During a trip, which shut-off valves should be open?

All shut-off valves should be open.

The rear shut-off valves should be open.

All shut-off valves should be in the open position, except the rear shut-off valves.

No shut-off valves should be open.

When starting a trip, be sure that all shut-off valves are in the open position, except for the last valves on the rear trailer. It is important that air reaches the brakes on all trailers and that the air is not able to escape from the back of the vehicle.

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

Sit in the cab and call for help.

Exit the cab and walk away from the tracks.

Motion for another driver to push your vehicle.

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.

11. If color-coded, which color is used to identify service lines?

White

Yellow

Blue

Air lines are sometimes color-coded to help drivers avoid mistakes when coupling glad hands. Typically, blue is used for service lines and red is used for emergency lines.

12. When lightly loaded, combination vehicles:

Should not be driven.

Have reduced braking capabilities.

Will not rollover.

Should be loaded with most of the weight in the rear of the trailer.

When a combination vehicle is lightly loaded, it may have poor traction. It is very easy for wheels to lock up on lightly-loaded vehicles when they are being stopped.

13. Combination vehicles need extra space on the road because they:

Drive more slowly than other commercial motor vehicles.

Are heavier than other commercial motor vehicles.

Need more space to turn and stop than other commercial motor vehicles.

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.

14. The service air line is attached to the:

Relay valves.

Supply line.

Emergency air line.

Steering wheel.

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

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