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 Nevada 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 Nevada 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. A loss of air pressure in the emergency line will cause:

The suspension springs to extend.

The tractor protection valve to open.

The rear trailer to detach from the combination.

The emergency brakes to activate.

The emergency air line controls the emergency brakes on a combination vehicle. A loss of air pressure in the emergency line will cause the emergency trailer brakes to activate.

2. Combination vehicles:

Are usually shorter than single commercial vehicles.

Usually require less skill to drive than single commercial vehicles.

Usually require more skill to drive than single commercial vehicles.

Driving combination vehicles requires more skill than driving single commercial vehicles. Combinations are generally longer, generally heavier, and are more vulnerable to rollover.

3. 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.

4. When coupling a trailer:

Make sure to couple matching glad hands.

Any glad hand can be connected to any other glad hand.

It is best to leave one glad hand unattached.

Only one set of glad hands should be connected.

When coupling, make sure you couple matching glad hands. They are often color-coded to help drivers avoid mistakes. Typically, blue is used for service lines and red is used for emergency lines.

5. When backing a trailer, you must first turn the steering wheel:

In the direction you want the trailer to go.

In the direction opposite of where you want the trailer to go.

To the left.

When backing a vehicle without a trailer, a driver must turn the vehicle in the direction that they want to go. However, when backing with a trailer, the driver must begin by turning in the opposite direction. Once the trailer starts to turn, they should turn the wheel in the other direction to follow the trailer.

6. 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.

7. If a trailer begins to jackknife, you should not:

Release the brakes.

Apply the trailer hand brake.

Allow the wheels to grip the road.

Allow the trailer to straighten out.

If a trailer begins to jackknife, you should release the brakes and allow the trailer wheels to regain traction with the road. Do not apply the trailer hand brake to attempt to straighten out the rig because it will only prolong the skid. The application of brakes is what caused the wheels to lock in the first place.

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