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.

Number of Question 20

Passing Score 16

Number of Tests 20

1 . What does the tractor protection valve do?

Protects the tractor from being stolen

Protects the tractor from exceeding a set speed

Keeps air in the braking system, should the trailer break away or develop a leak

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.

Emergency

Supply

Normal

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:

In the same way as they would be in a vehicle without ABS.

As the vehicle is placed in neutral.

With the hand brake.

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:

The amount of noise projected to the rear of a vehicle.

The cause of the "crack-the-whip" effect.

The number of trailers that can be pulled by a tractor.

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:

Help you drive faster.

Prevent a rollover.

Make turns more dangerous.

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.

Front

Last

Middle

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 drops to a level between 20 and 45 psi.

You are experiencing a trailer jackknife.

Wheels have regained traction after a skid.

Air pressure is above 45 psi.

In vehicles equipped with an automatic tractor protection valve, the valve will pop out if air pressure drops to a level between 20 and 45 psi. When the valve pops out, the protection valve will close, stopping the flow of air.

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2025 Oregon | Frequently Asked Questions

To acquire a CDL Hazmat endorsement in Oregon, you need to pass a written test. First, you must apply at a DMV office, provide proof of U.S. citizenship or lawful permanent residency, and pass the Hazmat knowledge test. After passing the test, you'll need to undergo a federal TSA background check. Once cleared, your new endorsement will be added to your CDL.

To obtain a CDL Hazmat license, you must have a Commercial Driver's License (CDL). You should also be at least 21 years old, a U.S. citizen or have lawful permanent residency. You must pass the Hazmat knowledge test and a Transportation Security Administration (TSA) background check. Lastly, you should have a clean driving record and no disqualifying criminal offenses.

When applying for a CDL Hazmat endorsement, you need to provide proof of U.S. citizenship or lawful permanent residency. This could be a passport, birth certificate, or Permanent Resident Card. You also need your current valid Commercial Driver's License (CDL). Finally, you must complete and pass the TSA background check, and the Hazmat knowledge test results are required.

Yes, there is a dedicated written test for the CDL Hazmat endorsement. The test covers topics like loading and unloading hazardous materials, bulk packaging marking, driving and parking rules, and emergency response procedures. This knowledge test is required in addition to the general CDL written test. You must pass this test to receive your Hazmat endorsement.

The written test for the CDL Hazmat endorsement covers various subjects related to hazardous materials. These include understanding hazard classifications, proper loading and unloading procedures, use of placards and labels, transport rules and regulations, emergency response procedures, and the handling and transport of specific types of hazardous materials.

Yes, there are extra charges associated with acquiring a CDL Hazmat endorsement. These fees cover the written test, fingerprinting, and a background check. The exact cost can vary based on the state you're in, but in Oregon, the total fee is typically around $100. It's advisable to check the exact costs with your local DMV office.

Yes, to obtain a CDL Hazmat endorsement, you must pass a Transportation Security Administration (TSA) background check. This includes a review of your criminal, immigration, and FBI terrorist watch list status. The purpose is to ensure you are not a security risk and can safely transport hazardous materials.

Yes, specialized training or certification is mandatory for the CDL Hazmat endorsement. Applicants must pass a written knowledge test on hazardous materials regulations and safety procedures. Additionally, they must undergo a Transportation Security Administration (TSA) background check. The training ensures drivers can safely handle and transport hazardous materials.

No, you cannot legally transport hazardous materials without a valid CDL Hazmat endorsement in Oregon or any other state. The endorsement ensures that drivers have the necessary training and knowledge to handle and transport hazardous materials safely. Violating this regulation can lead to severe penalties, including fines and suspension of your CDL.

Yes, you can add a CDL Hazmat endorsement to your existing CDL license. You don't need to apply for a new CDL. However, you must pass the Hazmat knowledge test, undergo a TSA background check, and pay the required fees. The endorsement is then added to your existing CDL upon approval.