Combination #1
Combination Vehicles Practice Test | Texas 2025 #1 Page 2 of 3
Train for FREE online with our Texas 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 TX 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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8 . Air pressure in the ____ air line is controlled by either the foot brake or trailer hand brake.
Auxiliary
Air pressure in the service air line is controlled by either the foot brake or trailer hand brake. The service air line is also known as the control line or signal line. This line is connected to relay valves, which allow the trailer brakes to be applied more quickly than would otherwise be possible.
9 . If a trailer's spring brakes do not release when you push the tractor air supply control, you should:
Drive normally without checking anything.
It is important that all of your vehicle's equipment is in proper working condition before you begin a trip. If a trailer's spring brakes do not release when you push in the tractor air supply control, you should make sure the air line connections are properly attached and sealed.
10 . If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can:
Assume the vehicle has ABS.
If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can check under the trailer for wheel speed sensors coming from the back of the brakes.
11 . To test the trailer service brakes, you should:
Move the vehicle forward slowly and apply the brakes with the hand control.
To test the trailer service brakes, you should first ensure that the braking system has a normal air pressure level, then release the parking brake. You should then move the vehicle forward slowly and apply the brakes with the hand control. If the trailer service brakes are working properly, you will feel the brakes activate.
12 . If oil and water build up in your vehicle's air tanks, the brakes:
Will be extremely sensitive.
Air tanks should be drained daily to remove water and oil buildup. An excess of oil and water in the air tanks can interfere with proper brake function.
13 . To help prevent rollovers, you should:
Keep the load on one side of the trailer.
To lower the risk of a rollover, load your cargo as closely to the ground as possible. To further reduce this risk, take curves and corners slowly.
14 . A lightly-loaded combination vehicle will stop more slowly than a fully-loaded vehicle because:
The suspension springs only operate when a trailer reaches a minimum weight.
An empty combination vehicle will come to a complete stop more slowly than a fully-loaded vehicle. The stiff suspension springs and strong brakes will have lower traction on a light trailer than they would if the vehicle carried more weight.
2025 Texas | Frequently Asked Questions
To acquire a CDL Hazmat endorsement in Texas, you must first have a Commercial Driver's License (CDL). Then, pass the Hazardous Materials Endorsement Knowledge Test at a Texas Department of Public Safety office. After passing, you'll need to undergo a TSA background check. Once cleared, the endorsement will be added to your CDL.
To obtain a CDL Hazmat license, you must first hold a valid Commercial Driver's License (CDL). You must be at least 21 years old and have a clean driving record. You'll also need to pass the Hazardous Materials Endorsement Knowledge Test and undergo a TSA background check. Good vision and physical health are also prerequisites.
When applying for a CDL Hazmat endorsement, you will need your current CDL, proof of U.S. citizenship or legal status (like a birth certificate or green card), and proof of identity and Texas residency. You'll also need your Social Security card and a completed Application for Texas Driver License or Identification Card. Lastly, you'll need to pass a TSA background check.
Yes, there is a dedicated written test for the CDL Hazmat endorsement. Called the Hazardous Materials Endorsement Knowledge Test, it covers topics like loading and unloading hazardous materials, bulk packaging marking, driving and parking rules, and emergency response procedures. This test must be passed to obtain the Hazmat endorsement.
The written test for the CDL Hazmat endorsement covers a range of subjects related to hazardous materials. These include recognizing hazardous materials, safe loading and unloading procedures, proper use of placards and labels, emergency response procedures, driving and parking rules for hazardous materials, and understanding the associated risks and regulations.
Yes, acquiring a CDL Hazmat endorsement comes with additional charges. These include a fingerprinting fee for the required TSA background check, and an endorsement fee. The exact costs can vary, so it's recommended to check with your local Department of Motor Vehicles (DMV) or similar agency for the most accurate information.
Yes, obtaining a CDL Hazmat endorsement requires a background check and security clearance. The Transportation Security Administration (TSA) conducts the check, which includes fingerprinting and a review of criminal, immigration, and terrorism records. This process is necessary to ensure the safety and security of hazardous materials transportation.
Yes, specialized training is required for the CDL Hazmat endorsement. Applicants must pass a written test, and in some cases, a driving test with a vehicle that carries hazardous materials. Once passed, this endorsement is added to your Commercial Driver's License (CDL). Regular renewal of this certification is also required.
No, you cannot legally transport hazardous materials without a valid Commercial Driver's License (CDL) with a Hazardous Materials (Hazmat) endorsement in the United States. This requirement ensures that drivers have the necessary training and knowledge to handle such materials safely, protecting public safety and the environment.
Yes, you can add the CDL Hazmat endorsement to your current CDL. 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. Once completed, the endorsement will be added to your existing CDL.