20 Tests

CDL Combination Vehicles Practice Test Online | South Carolina 2021

Train for FREE online with our South Carolina 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 SC combination license in 2021, practice as much as.. Read More

Train for FREE online with our South Carolina 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 SC 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 . The trailer hand valve:

Should only be used when transporting cargo. The trailer hand valve should not be used for parking. This could cause all of the air to leak out of the braking system, resulting in the brakes releasing. Instead, use the parking brake.

2 . If your trailer beings to drift off course while you are backing, you should:

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

3 . When coupling a trailer:

Only one set of glad hands should be connected. 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.

4 . In a double or triple combination, the ____ trailer should be directly behind the cab.

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.

5 . An air supply control in its "emergency" position will:

Accelerate the vehicle. Tractor protection controls in older vehicles may be operated by levers instead of knobs. If an air supply control is set in its "emergency" position, the air supply will be stopped and the trailer emergency brakes will be applied.

6 . Look for matching colors when coupling glad hands. Service lines are often:

Blue. When coupling glad hands, make sure to couple together matching glad hands. To help drivers avoid mistakes, color coding is sometimes used. Service lines are often coded with the color blue and emergency lines are often coded with the color red.

7 . In a combination rig, it is best to make:

Slow, planned stops. When driving a combination vehicle, it is important to brake well in advance and look far ahead of your vehicle to avoid the need for sudden stops. Making habits of these actions will help you prevent your trailer from jackknifing.

Wait, before you go

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