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

1. Large combination vehicles take the longest amount of time to stop:

When fully loaded.

When partially loaded.

When empty.

When mostly loaded.

Large combination vehicles take longer to stop when they are empty than when they are loaded. The decreased weight causes a vehicle's wheels to have decreased traction on the surface of the road.

2. If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can:

Check for wheel speed sensors coming from the back of the brakes.

Look for a red light on the front right corner of the converter dolly.

Pump the air brakes to activate the ABS.

Assume the vehicle has ABS.

If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can check under the trailer for wheel speed sensors coming from the back of the brakes.

3. Look for matching colors when coupling glad hands. Service lines are often:

Green.

Orange.

Red.

Blue.

When coupling glad hands, make sure to couple together matching glad hands. To help drivers avoid mistakes, color coding is sometimes used. Service lines are often coded with the color blue and emergency lines are often coded with the color red.

4. To help prevent rollovers, you should:

Accelerate quickly after stopping.

Drive slowly around turns.

Keep the load near the back of the trailer.

Keep the load on one side of the trailer.

To lower the risk of a rollover, load your cargo as closely to the ground as possible. To further reduce this risk, take curves and corners slowly.

5. After coupling, there should be ____ between the upper and lower fifth wheel.

No space

Very little space

A lot of space

Three inches of space

Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

6. If unsure if a trailer is equipped with ABS, you can:

Check under the trailer for wheel speed sensors coming from the back of the brakes.

Try driving on a slippery surface and see if ABS kicks in.

Assume it does have ABS.

Remove a tire and look for the ABS sensor on the axle.

Trailers and converter dollies built on or after March 1, 1998 are required to have Anti-Lock Braking Systems (ABS). This will be indicated by the presence of a yellow malfunction lamp. You can determine if older trailers have ABS by checking under the trailers for ECU and wheel speed sensor wires coming from the back of the brakes.

7. After connecting the air lines to the trailer while coupling, you should:

Supply air to the trailer.

Chock the wheels.

Inspect the fifth wheel.

Connect the electrical cord.

Correctly following the steps to couple and uncouple trailers is vital to safely operating a combination vehicle. After connecting the air lines to the trailer while coupling, you should supply air to the trailer.

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