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 have one hour to correctly answer a minimum of 16 questions. The Combination test is not a replacement for the Double/Triple endorsement test.

Number of Question 20

Passing Score 16

1. Bobtail tractors are ____ to stop than tractors attached to full semitrailers.

Quicker

Easier

More difficult

Bobtail tractors are tractors that are not attached to any semitrailers. When operating a bobtail, you should be aware that stopping can be difficult and that it will take a longer distance to come to a complete stop than a tractor attached to a loaded semitrailer.

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

The parking brake.

The trailer emergency brakes.

The trailer service brakes.

The landing gear.

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.

3. When glad hands are coupled, the seals should be pressed together at a ____ angle.

50-degree

180-degree

90-degree

When coupling, be sure to couple the proper glad hands. When glad hands are connected, the seals should be pressed together at a 90-degree angle.

4. Before backing your tractor under the trailer, make sure your trailer brakes are:

Disengaged.

Locked.

Deactivated.

Dry.

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.

5. If a trailer begins to skid, the driver should:

Lock the brakes.

Release the brakes.

Steer in the opposite direction.

Accelerate.

If your trailer starts to skid while you are braking, you should release the brakes and allow them to begin to regain traction. Once its wheels have regained their grip on the road, the trailer will begin to straighten out and follow the tractor.

6. While inspecting a coupling, you should go under the trailer and:

Detach the jaws from around the kingpin.

Make sure the locking lever is in the "emergency" position.

Remove the safety latch.

Look into the back of the fifth wheel.

While inspecting a coupling, you should go under the trailer and look into the back of the fifth wheel. Ensure that the fifth wheel jaws are secured around the shank of the kingpin.

7. A combination vehicle has:

One air line.

Two air lines.

Three air lines.

Four air lines.

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

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