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 State of Delaware 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

1. When backing up while coupling a trailer, the tractor should be positioned:

Directly in front of the trailer.

Directly next to the trailer.

Parallel with the trailer.

When backing up to couple a trailer, you should position the tractor directly in front of the trailer. Trying to couple while backing at an angle could cause the trailer to move and the landing gear to break.

2. The ____ trailer is the most likely to turn over if a driver takes a turn too quickly.

Front

Last

Middle

When making a turn, be sure to steer gently and smoothly. Making a quick turn while pulling trailers is dangerous and can increase the risk of the last trailer rolling over.

3. A shut-off valve:

Is located on the front of a trailer.

Is located on the instrument panel.

Prevents air from escaping an air brake system.

Should always be open.

Shut-off valves are used in air supply lines to control the passage of air from one trailer to another. The rear shut-off valve should always be closed to prevent air from leaving the braking system.

4. Using the trailer hand brake while experiencing a trailer jackknife will:

Stop the skid.

Straighten the trailer.

Increase traction.

Continue the skid.

If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.

5. If oil and water build up in your vehicle's air tanks, the brakes:

May not work correctly.

May feel squishy.

Will squeal loudly when used.

Will be extremely sensitive.

Air tanks should be drained daily to remove water and oil buildup. An excess of oil and water in the air tanks can interfere with proper brake function.

6. Proper coupling technique:

Is the same on all vehicles.

Is essential to the safe operation of a vehicle.

Includes ensuring that the fifth wheel plate is not greased.

Can be learned over time.

Knowing proper coupling and uncoupling technique is fundamental to the safe operation of combination vehicles. Improper coupling can be very dangerous.

7. When testing ____, you should apply your vehicle's brakes with the hand control while moving the vehicle forward slowly.

The Anti-Lock Braking System

The emergency braking system

The trailer service brakes

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.

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