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.

The tractor protection valve will close.

The service brakes will activate.

The tractor protection valve will close.

The rear trailer will detach from the combination.

A tractor protection valve keeps air in a tractor or truck air brake system should the trailer break away or develop a bad leak. The valve will close automatically if the pressure drops to an unsafe level.

Keeps air in the truck braking system if the trailer develops a leak.

Ensures that oil adequately lubricates the engine.

Protects the tractor from exceeding a set speed.

Keeps air in the truck braking system if the trailer develops a leak.

Fully-loaded rigs are more vulnerable to rolling over than empty rigs because the weight of the cargo gives the vehicles higher centers of gravity.

Are more likely to roll over than empty rigs.

Usually are very responsive to steering.

Are more likely to roll over than empty rigs.

Older trailers do not have spring brakes. This means that if the air supply in an older trailer's air tank has leaked away, there will be no working brakes connected to the trailer and its wheels will turn freely.

The trailer will not have brakes.

The trailer will stop normally.

The trailer will not have brakes.

If a parked trailer does not have spring brakes, wheel chocks should be used to prevent it from moving.

Having the vehicle parked against a wall or other vehicle.

When coupling air brake hoses, you should make sure the proper pairs of gland hands are connected. They are sometimes color-coded to help drivers avoid mistakes. Typically, blue is used for service lines and red is used for emergency lines.

Couple together the proper glad hands.

Couple glad hands with any other glad hands.

Leave one pair of glad hand loose.

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.

Make sure to couple the proper glad hands.

Glad hands can be connected to any other glad hands.

Only one set of glad hands should be connected.

Arizona Driver's Examination

Combination #2

FREE CDL Combination Vehicles Practice Test Online | Arizona 2024

Train for FREE online with our Arizona CDL combination vehicle test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a AZ combination license in 2021, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that DMV requirements for issuing a combination license may vary from state to state.

Number of Question 20

Passing Score 16

Number of Tests 20

FREE CDL Combination Vehicles Practice Test Online | Arizona 2024

1 . If the emergency air line loses pressure:

2 . The tractor protection valve:

3 . Fully-loaded rigs:

4 . Older trailers are not equipped with spring brakes. This means that if the air supply for a vehicle's air braking system leaks away:

5 . If a parked trailer does not have spring brakes, you should keep the trailer from moving by:

6 . When coupling a trailer, you should:

7 . When coupling a trailer:

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