FREE CDL Combination Vehicles Practice Test Online | Oregon 2024 Page 2 of 3
Train for FREE online with our Oregon 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 OR 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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8 . The trailer hand valve should not be used while you are driving because:
Never use the trailer hand valve while operating your vehicle. Using the trailer hand valve while driving can cause your trailer to skid.
9 . The trailer hand valve should be used:
On slippery surfaces.
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. Using it while a vehicle is in motion could cause a skid.
10 . Look into the back of the fifth wheel:
While inspecting a coupling, you should go under the trailer and look into the back of the fifth wheel. Ensure that the fifth wheel jaws are secured around the shank of the kingpin.
11 . 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.
12 . 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.
13 . Operating a combination vehicle usually requires ____ operating a single vehicle.
Exactly the same level of skill as
Combination vehicles require more skill to drive than single vehicles. Combination vehicles are usually longer and heavier, and are more vulnerable to rollovers.
14 . Look for matching colors when coupling glad hands. Service lines are often:
Blue.
