Combination #2
Combination Vehicles Practice Test | Oregon 2025 #2
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 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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1 . What does the tractor protection valve do?
Ensures oil adequately lubricates the engine
The tractor protection valve keeps air in the tractor or truck braking system, should the trailer break away or develop a bad leak.
2 . When you are pulling a trailer, the air supply control lever should be in its ____ position.
Tractor protection controls in older vehicles may be operated by levers instead of knobs. If an air supply control is set in its "normal" position, it is properly set for you to pull a trailer.
3 . When driving a vehicle equipped with an Anti-Lock Braking System (ABS), brakes should be applied:
When driving a vehicle with ABS, you should brake in the same manner as you would in a vehicle without ABS.
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 . Keeping cargo centered on a rig can:
A rollover is more likely if cargo is unevenly loaded in a rig. To help prevent a dangerous rollover, it is important to keep a load as centered on the rig as possible.
6 . In a sudden turn, the ____ trailer is the most likely to turn over.
First
When making a turn, be sure to steer gently and smoothly. Making a quick turn while pulling trailers is dangerous and can increase the risk of the last trailer rolling over.
7 . In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when:
Air pressure is above 45 psi.
