Combination #2
Combination Vehicles Practice Test | Tennessee 2025 #2 Page 3 of 3
Train for FREE online with our Tennessee 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 TN 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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15 . If the emergency air line loses pressure:
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.
16 . Rearward amplification refers to:
Vehicles with trailers are vulnerable to rollover due to the "crack-the-whip" effect, which is caused by rearward amplification.
17 . When a vehicle goes around a corner, the rear wheels:
When any vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking. The degree of off-tracking will be greater on long vehicles than on short vehicles.
18 . A loss of air pressure in the emergency line will cause:
The suspension springs to extend.
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.
19 . If you use the trailer hand brake while your trailer is skidding, it will:
If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.
20 . A tractor protection valve is:
A device that allows the battery to recharge efficiently.
On combination vehicles with air brakes, the tractor protection valve keeps air in the tractor or truck brake system, should the trailer develop a bad leak or break away from the tractor.
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2025 Tennessee | Frequently Asked Questions
To secure a CDL Doubles/Triples endorsement in Tennessee, you must already have a Commercial Driver’s License (CDL). You will need to pass the Doubles/Triples Knowledge test. Study the relevant section in the TN CDL manual before taking the test. Once you pass, the endorsement will be added to your CDL.
To obtain a CDL Doubles/Triples license, you must have a valid Commercial Driver’s License (CDL). You'll also need to pass the Doubles/Triples Knowledge test. This test covers the specific skills and knowledge needed to safely operate such vehicles. Studying the relevant sections of your state's CDL manual will help you prepare for this test.
While you don't necessarily need specialized experience or training to get a CDL Doubles/Triples endorsement, it's highly recommended. You must pass the Doubles/Triples Knowledge test, so studying the relevant sections of your state's CDL manual is crucial. Some choose to attend a CDL training school for hands-on experience before taking the test.
Yes, to acquire a CDL Doubles/Triples endorsement, you must pass the Doubles/Triples Knowledge test. This test evaluates your knowledge of safely operating double and triple trailers, coupling and uncoupling, inspecting doubles and triples, and more. It's crucial to study the relevant sections of your state's CDL manual thoroughly before taking the test.
The CDL Doubles/Triples endorsement test is primarily a written exam, focusing on your knowledge rather than specific driving maneuvers. It covers areas such as coupling and uncoupling, inspecting doubles and triples, and the specifics of managing these larger vehicles. However, it's beneficial to practice driving these larger vehicles for real-world application of these principles.
No, it is not permissible to operate double/triple trailers without a valid CDL Doubles/Triples endorsement in Tennessee. The state requires drivers to obtain this endorsement to ensure they have the necessary knowledge and skills to safely operate such vehicles. Violating this requirement can result in penalties and potential suspension of driving privileges.
You can add the CDL Doubles/Triples endorsement to your existing commercial driver's license. You don't need to initiate a new application for a separate license. However, you must pass the Doubles/Triples Knowledge test to get this endorsement. It's important to check with your local DMV for specific state requirements and procedures.
Yes, there are limitations. A CDL Doubles/Triples endorsement only permits you to drive vehicles with more than one trailer. However, it doesn't allow you to operate other special vehicle types like buses or tank vehicles unless you have the specific endorsements for those. Also, all federal and state regulations regarding hours of service, vehicle maintenance, and load securement must still be followed.
In Tennessee, the maximum legal weight for a vehicle including double/triple trailers is 80,000 pounds. The maximum length for each semi-trailer is 28 feet 6 inches, and for each full trailer it's 28 feet. However, these restrictions can vary depending on road types and specific routes. Always check local regulations to ensure compliance.
Yes, drivers with a CDL Doubles/Triples endorsement must adhere to specific safety regulations. These include performing routine vehicle inspections, following appropriate coupling and uncoupling procedures, and maintaining safe following distances. They must also understand the high rollover risk associated with these vehicles and the effects of speed and curves on stability. Compliance with these guidelines helps ensure road safety.
