20 Tests

CDL Combination Vehicles Practice Test Online | Idaho 2021

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

Train for FREE online with our Idaho 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 ID 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 . In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when air pressure drops to a level between:

In vehicles equipped with an automatic tractor protection valve, the valve will pop out if air pressure drops to a level between 20 and 45 psi. When the valve pops out, the protection valve will close, stopping the flow of air.

2 . Combination vehicles:

Driving combination vehicles requires more skill than driving single commercial vehicles. Combinations are generally longer, generally heavier, and are more vulnerable to rollover.

3 . When connecting a converter dolly to a second trailer, the trailer height should be ____ the center of the fifth wheel.

When connecting a converter dolly to a second or third trailer, the trailer height should correct. It should be slightly lower than the center of the fifth wheel.

4 . Rearward amplification refers to:

Vehicles with trailers are vulnerable to rollover due to the "crack-the-whip" effect, which is caused by rearward amplification.

5 . Trailers built before ____ are not required to have spring brakes.

Trailers built before 1975 are not required to have spring brakes. When parking a trailer without spring brakes, be sure to use wheel chocks to prevent the trailer from rolling.

6 . How much space should be between the upper and lower fifth wheel?

Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

7 . The service air line is often controlled by the foot brake and is attached to the ____ valves.

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

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