20 Tests

CDL Combination Vehicles Practice Test Online | Maryland 2021

Train for FREE online with our Maryland 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 MD combination license in 2021, practice as much as.. Read More

Train for FREE online with our Maryland 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 MD 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 . Glad hands are:

Pleased drivers. On trailers with air brakes, glad hands are coupling devices used to connect the air lines of the tractor to those of the trailer.

2 . When driving while pulling trailers, you should:

You should always steer gently and smoothly while pulling a trailer. Making sudden steering moves could cause the trailer to tip over.

3 . 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.

4 . What can the “crack-the-whip” effect do?

Make trucks decelerate. The "crack-the-whip" effect can cause a trailer to turn over during a lane change. To avoid this phenomenon, drivers should make lane changes at slow, safe speeds.

5 . After connecting the air lines to the trailer while coupling, you should:

Connect the electrical cord. Correctly following the steps to couple and uncouple trailers is vital to safely operating a combination vehicle. After connecting the air lines to the trailer while coupling, you should supply air to the trailer.

6 . Driving a combination vehicle ____ than driving a single vehicle.

Is safer in inclement weather Driving a combination vehicle usually requires more skill than driving a single vehicle. Combination vehicles are generally longer and heavier than single commercial vehicles.

7 . What is a tractor protection 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.

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