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.. 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's 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

15. When a combination vehicle goes around a corner:

The turn should be made as tightly as possible.

The front and rear wheels move in different paths.

The rear wheels should run over the curb.

It is acceptable for street signs to be knocked over if they are too close to the road.

When a vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking. This effect is especially pronounced on vehicles with trailers.

16. 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.

17. 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.

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

The service brakes to activate.

The tractor protection valve to close.

The rear trailer to detach from the combination.

The suspension springs to extend.

The tractor protection valve keeps air in the trailer's braking system should the trailer break away or develop a leak. A loss of air pressure in the emergency line will cause the tractor protection valve to open and the emergency trailer brakes to activate.

19. Simply changing lanes can cause:

A “crack-the-whip” effect, resulting in a rollover.

A trailer to straighten out.

Confusion over which lane the driver is hoping to use.

Other drivers to reduce their speed.

Due to the "crack-the-whip" effect caused by rearward amplification, changing lanes too quickly in a combination vehicle can result in a rollover.

20. 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.

Grade This Section

See the exact questions that will be on the 2024 Pennsylvania DMV exam.

99.2% of people who use the cheat sheet pass the FIRST TIME

Click Here
Full Cheat Sheet Unlock Your Exclusive Cheat Sheet!