Combination #2
Combination Vehicles Practice Test | South Dakota 2025 #2 Page 3 of 3
Train for FREE online with our South Dakota 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 SD 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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15 . Using the trailer hand brake while experiencing a trailer jackknife will:
Continue the skid.
If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.
16 . 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.
17 . When should the trailer hand valve be used?
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.
18 . The trailer hand valve:
Never use the trailer hand valve while parking because doing so may release the air pressure from the braking system, releasing the brakes that are holding the vehicle in place. Instead, use the parking brake or wheel chocks.
19 . When backing up to couple a trailer, you should position the tractor:
At a 60-degree angle in front of the trailer.
When backing up to couple a trailer, you should position the tractor directly in front of the trailer. Trying to couple while backing at an angle could cause the trailer to move and the landing gear to break.
20 . If your trailer begins to drift off course while you are backing, you should:
Return the steering wheel to the 12 o’clock position.
