Combination #1
Combination Vehicles Practice Test | Utah 2025 #1 Page 4 of 4
Train for FREE online with our Utah 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 UT 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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24 . When glad hands are coupled, the seals should be pressed together at an angle of:
90 degrees.
When coupling, be sure to couple the proper glad hands. When glad hands are connected, the seals should be pressed together at a 90-degree angle.
25 . A driver should test the tractor protection valve by:
You should test the tractor protection valve by allowing the air supply to properly charge, turning off the engine, then releasing air from the system by pressing the brake pedal several times. The tractor protection valve should move into its emergency position when psi drops to an unsafe level.
26 . 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.
27 . 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.
28 . If a trailer begins to skid, it is best for the driver to:
If your trailer begins to skid, you should release the brakes to regain traction. The trailer will begin to straighten out once the wheels begin to grip the road again.
29 . What does the trailer air supply control look like?
It is a circular orange knob.
On newer vehicles, the trailer air supply control is an eight-sided red knob. It's used to control the tractor protection valve.
30 . After finishing a pre-trip inspection, you should:
Leave the emergency line valve open.
