Combination Vehicles Practice Test | Oklahoma 2025 #2

Train for FREE online with our Oklahoma 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 OK 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 . Older trailers are not equipped with spring brakes. This means that if the air supply for a vehicle's air braking system leaks away:

The trailer will stop normally.

The trailer will not have brakes.

The trailer will speed up.

Older trailers do not have spring brakes. This means that if the air supply in an older trailer's air tank has leaked away, there will be no working brakes connected to the trailer and its wheels will turn freely.

2 . If a load is placed on one side of a trailer, the trailer:

May lean during turns.

May add extra support during turns.

May be easier to steer during turns.

Positioning the weight of a load on one side of a trailer may cause the trailer to lean to that side, increasing the risk of a rollover during turns and lane changes.

3 . Fully-loaded rigs:

Usually are very responsive to steering.

Are more likely to roll over than empty rigs.

Can stop quickly.

Fully-loaded rigs are more vulnerable to rolling over than empty rigs because the weight of the cargo gives the vehicles higher centers of gravity.

4 . During a trip, landing gear should be:

Completely raised.

Completely lowered.

Skimming the pavement.

Landing gear, or trailer supports, should always be completely raised before a vehicle is driven. Landing gear that is not entirely raised could catch on railroad tracks or other hazards on the roadway.

5 . What does an Anti-Lock Braking System (ABS) do?

It allows a vehicle's wheels to lock up.

It prevents a vehicle's wheels from locking up.

It makes turning a vehicle easier.

An Anti-Lock Braking System (ABS) helps prevent wheel lockup during hard braking. If ABS detects impending lockup, it reduces braking pressure to a safe level.

6 . When driving while pulling trailers, you should:

Make sudden turns with the steering wheel.

Avoid making sudden moves.

Push the accelerator to the floor when starting from a stop.

You should always steer gently and smoothly while pulling a trailer. Making sudden steering moves could cause the trailer to tip over.

7 . If the emergency air line loses pressure:

The service brakes will activate.

The tractor protection valve will close.

The rear trailer will detach from the combination.

The tractor protection valve keeps air in the trailer's braking system should the trailer break away or develop a leak. A loss of air pressure in the emergency line will cause the tractor protection valve to open and the emergency trailer brakes to activate.

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2025 Oklahoma | Frequently Asked Questions

To acquire a CDL Hazmat endorsement in Oklahoma, you must first have a valid Oklahoma CDL. Then, pass the Hazmat knowledge test at a Department of Public Safety testing facility. After passing the test, submit a fingerprint-based background check and complete TSA security threat assessment. Once approved, your endorsement will be added to your CDL.

To obtain a CDL Hazmat license, you must have a valid Commercial Driver's License (CDL). You must be at least 21 years old and a U.S. citizen or have legal status in the U.S. You need to pass the Hazmat knowledge test and complete a Transportation Security Administration (TSA) background check, including fingerprinting.

When applying for a CDL Hazmat endorsement, you'll need to provide proof of U.S. citizenship or legal status (like a passport or birth certificate), your current Commercial Driver's License (CDL), and proof of Oklahoma residency. You'll also need to bring your TSA background check results and the proof that you've passed the Hazmat Knowledge Test.

Yes, there is a dedicated written test for the CDL Hazmat endorsement. It's called the Hazmat Knowledge Test and is required by the Federal Motor Carrier Safety Administration. This test covers topics like loading and unloading hazardous materials, bulk packaging marking, driving and parking rules, and emergency response procedures.

The written test for the CDL Hazmat endorsement covers topics such as identifying hazardous materials, understanding shipping papers, using placards and labels, loading and unloading hazardous materials, driving and parking rules, emergency procedures, and understanding the risks of different types of hazardous materials.

Yes, acquiring a CDL Hazmat endorsement involves extra charges. In addition to the standard CDL license fee, there is a separate fee for the Hazmat endorsement. This covers the cost of the knowledge test and background check. The exact amount can vary, so it's advisable to check with the Oklahoma Department of Public Safety for current fees.

Yes, obtaining a CDL Hazmat endorsement requires a federal background check and security clearance. This includes fingerprinting and checks for criminal history. The Transportation Security Administration (TSA) conducts this process to ensure that hazardous materials are transported safely and securely across the nation's highways.

Yes, specialized training is required for the CDL Hazmat endorsement. Applicants must pass a written test covering hazardous materials regulations and safety procedures. Also, they must undergo a federal background check and fingerprinting. The endorsement will only be added to your CDL after successful completion of these requirements.

No, you cannot transport hazardous materials without a valid CDL Hazmat endorsement. This endorsement is required by federal law for drivers who operate vehicles carrying hazardous materials. Driving without this endorsement can lead to serious penalties, including fines and suspension of your commercial driver's license.

Yes, you can add the CDL Hazmat endorsement to your current CDL license. You don't need to apply for a new CDL. However, you must pass a written knowledge test on hazardous materials regulations and safety protocols, and complete a TSA background check before the endorsement is added to your license.