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 Texas Commercial Motor Vehicle Drivers Handbook. 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

8. In a double or triple combination:

Cargo weight must be evenly distributed between all trailers.

The heaviest trailer should be positioned directly behind the cab.

The heaviest trailer should be positioned in the rear.

The weight of the trailers does not matter.

When positioning trailers in a combination, the most heavily-loaded trailer should be the closest to the tractor. The lightest trailer should be positioned in the rear.

9. 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.

10. The best way to recognize that your trailer has begun to skid is by:

Seeing other drivers' faces.

Seeing it in your mirrors.

Feeling it.

Listening to the radio.

The earliest and best way to recognize the beginnings of a trailer skid is by seeing the trailer veer off-course in your mirrors.

11. 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.

12. 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.

13. When backing a trailer, how should you turn the steering wheel?

Turn the top of the steering wheel in the direction you want the trailer to go.

Turn the top of the steering wheel in the direction opposite of where you want the trailer to go.

It doesn’t matter.

It depends on where the trailer is being backed.

When backing with a trailer, turn the top of the steering wheel in the direction opposite of where you want to go. Once the trailer begins turning, you should then switch the direction of the steering wheel to follow the trailer.

14. After finishing a pre-trip inspection, you should:

Close the service line valve.

Remove the service line valve.

Leave the emergency line valve open.

Leave the rear shut-off valves open.

Before a trip, you should ensure that air reaches all air brakes on all trailers by opening up the rear emergency line and service line shut-off valves to listen for escaping air. Close both shut-off valves before beginning to drive.

Grade This Section