To reduce the risk of tipping over when driving with a trailer, you should steer gently and smoothly. Avoid making sudden movements.

Accelerate by pushing the accelerator to the floor.

Never use the trailer hand valve while parking because doing so may release the air pressure from the braking system, releasing the brakes that are holding the vehicle in place. Instead, use the parking brake or wheel chocks.

Should never be used for parking.

Should always be used for parking.

Should only be used for parking on a downgrade.

Should never be used for parking.

The trailer hand valve, also called the trolley valve or Johnson bar, is used to work the trailer brakes. It should be used only to test the brakes.

A hand valve that works the trailer brakes

A valve that indicates the fuel level

A valve that measures the amount of liquid in the air brake system

A valve that allows for the release of excess pressure in the braking system

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.

Listening for air at the rear shut-off valve.

Checking for moving air inside of each trailer.

Listening for air at the rear shut-off valve.

Feeling for air at the front shut-off valve.

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.

A valve to keep air in the brake system should there be a bad leak

A valve that prevents a truck from being stolen

A valve that prevents the driver from driving too fast

If your trailer begins to drift while you are backing, you should correct the drift immediately by turning the top of the steering wheel in the direction of the drift.

Turn the top of the steering wheel in the direction of the drift.

Return the steering wheel to the 12 o’clock position.

Turn the top of the steering wheel in the direction of the drift.

Turn the top of the steering wheel in the direction opposite of the drift.

Combination Vehicles Practice Test | Mississippi 2024 #2

Train for FREE online with our Mississippi 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 MS combination license in 2024, 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

Combination Vehicles Practice Test | Mississippi 2024 #2

1 . When driving with trailers, you should:

2 . The trailer hand valve:

3 . What is the Johnson bar?

4 . Before a trip, you can make sure air flows to all trailers by:

5 . What is a tractor protection valve?

6 . After completing a pre-trip inspection, you should ensure that the:

7 . If you are backing and the trailer begins to drift off-course, the driver should:

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