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. When connecting a converter dolly to a second or third trailer, the trailer height should be:

Slightly higher than the center of the fifth wheel.

Level with the center of the fifth wheel.

Slightly lower than the center of the fifth wheel.

Next to the center of the fifth wheel.

When connecting a converter dolly to a second or third trailer, the trailer height should be correct. It should be slightly lower than the center of the fifth wheel.

2. Before a drive, ensure that air flows to all trailers by:

Opening the rear shut-off valves and listening for escaping air.

Closing the rear shut-off valves and listening for escaping air.

Disconnecting air supply lines and listening for escaping air.

Rolling each trailer down a hill and testing the brakes.

Before a trip, ensure that air in the air brake system reaches all trailers. Do this by waiting for air pressure to build, then sending air to both the emergency and service lines and opening the shut-off valves on the rear of the last trailer. If air escapes from the shut-off valves in the rear of the combination, the air is being supplied to the entire vehicle.

3. What is another name for the service line?

Control line

Exchange line

Surplus line

Parallel line

The service line, also called the control line or signal line, carries air to the trailer brakes and is controlled by the foot brake or trailer hand brake.

4. An Anti-Lock Braking System (ABS):

Allows wheels to lock up.

Prevents wheels from locking up.

Makes it easier to turn a large vehicle.

Assists with the operation of brake lights.

The function of an Anti-Lock Braking System (ABS) is to prevent a vehicle's wheels from locking up during hard braking.

5. Having ABS on only one axle:

Does not change braking in any way.

Is not possible.

Will allow the driver additional control over their vehicle when braking.

Will cause extra strain on the other axles.

Having an Anti-Lock Braking System (ABS) on only the trailer, or even on just one axle, will still provide a driver with additional control over the trailer when braking.

6. The trailer hand valve:

Should always be used for parking.

Should only be used for parking on a downhill.

Should never be used for parking.

Should only be used when transporting cargo.

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.

7. Rollovers happen when:

A truck driver is driving too fast.

The driver of a vehicle in front of a truck is moving to slowly.

A truck driver is driving too slowly.

ABS is working effectively.

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.

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