20 Tests

CDL Combination Vehicles Practice Test Online | Mississippi 2021

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 2021, practice as much as.. Read More

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 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.

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1 . Trailers with low underneath clearance can present challenges when driving over:

Railroad-highway crossings may be difficult to cross when pulling a trailer with a low underneath clearance. In particular, both low-slung units and single-axle tractors pulling long trailers are especially challenging to drive over raised crossings.

2 . What is the Johnson bar?

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

3 . If the trailer begins to skid, it is best to:

Brake. If your trailer begins to skid, you should release the brakes to help regain traction. Once the wheels grip the road again, the trailer will begin to straighten out and follow the path of the tractor.

4 . Pushing in the trailer air supply control will:

Push in the trailer air supply control to supply the trailer with air. Pull out the trailer air supply control to turn off the air supply and activate the emergency brakes.

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

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.

6 . When backing up while coupling a trailer, the tractor should be positioned:

When backing up to couple a trailer, you should position the tractor directly in front of the trailer. Trying to couple while backing at an angle could cause the trailer to move and the landing gear to break.

7 . The emergency air line:

Prevents skids. The emergency air line (also known as the supply line) has two functions. The first is to supply air to the trailer air tanks on a combination vehicle, and the second is to control the emergency brakes.

Wait, before you go

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