Combination #2
Combination Vehicles Practice Test | District Of Columbia 2025 #2 Page 2 of 3
Train for FREE online with our District Of Columbia 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 DC combination license in 2025, 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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8 . When a combination vehicle goes around a corner:
It is acceptable for street signs to be knocked over if they are too close to the road.
When a vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking. This effect is especially pronounced on vehicles with trailers.
9 . Rollovers happen when:
ABS is working effectively.
Rollovers happen when a vehicle is driven too fast. To reduce the risk of rollover, make sure the weight of cargo is loaded low to the ground, and that you take turns and curves slowly.
10 . Failure to keep the fifth wheel plate properly greased could:
Affect the lights.
Failure to keep the fifth wheel plate properly lubricated can create friction between the tractor and trailer, causing steering problems.
11 . Push in the trailer air supply control to:
Supply the trailer with air.
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.
12 . 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.
13 . Having ABS on only one axle:
Will cause extra strain on the other axles.
Having an Anti-Lock Braking System (ABS) on only the trailer, or even on just one axle, will still provide a driver with additional control over the trailer when braking.
14 . When glad hands are coupled, the seals should be pressed together at an angle of:
90 degrees.
