Combination Vehicles Practice Test | Mississippi 2025 #1

Train for FREE online with our Mississippi 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 MS 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 . Trailers with low underneath clearance can present challenges when driving over:

Bridges.

Railroad tracks.

Overpasses.

Railroad-highway crossings may be difficult to cross when pulling a trailer with a low underneath clearance. In particular, both low-slung units and single-axle tractors pulling long trailers are especially challenging to drive over raised crossings.

2 . What is the Johnson bar?

A hand valve that works the trailer brakes

A valve that indicates the fuel level

A valve that measures the amount of liquid in the air brake system

A valve that allows for the release of excess pressure in the braking system

The trailer hand valve, also called the trolley valve or Johnson bar, is used to work the trailer brakes. It should be used only to test the brakes.

3 . If the trailer begins to skid, it is best to:

Release the brakes.

Accelerate.

Quickly turn the steering wheel one way, then the other.

Brake.

If your trailer begins to skid, you should release the brakes to help regain traction. Once the wheels grip the road again, the trailer will begin to straighten out and follow the path of the tractor.

4 . Pushing in the trailer air supply control will:

Supply the trailer with air.

Deactivate the air brakes.

Prevent the vehicle from skidding.

Push in the trailer air supply control to supply the trailer with air. Pull out the trailer air supply control to turn off the air supply and activate the emergency brakes.

5 . If you are backing and the trailer begins to drift off-course, the driver should:

Return the steering wheel to the 12 o’clock position.

Turn the top of the steering wheel in the direction of the drift.

Turn the top of the steering wheel in the direction opposite of the drift.

If your trailer begins to drift while you are backing, you should correct the drift immediately by turning the top of the steering wheel in the direction of the drift.

6 . When backing up while coupling a trailer, the tractor should be positioned:

Directly in front of the trailer.

Directly next to the trailer.

Parallel with the trailer.

When backing up to couple a trailer, you should position the tractor directly in front of the trailer. Trying to couple while backing at an angle could cause the trailer to move and the landing gear to break.

7 . The emergency air line:

Is controlled by the foot brake.

Is connected to the relay valves.

Supplies air to the trailer air tanks.

Prevents skids.

The emergency air line (also known as the supply line) has two functions. The first is to supply air to the trailer air tanks on a combination vehicle, and the second is to control the emergency brakes.

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2025 Mississippi | Frequently Asked Questions

To secure a CDL Doubles/Triples endorsement in Mississippi, you must already possess a Commercial Driver's License (CDL). You'll need to pass a written knowledge test on handling large trucks with more than one trailer. Study the Mississippi CDL handbook, especially the section on doubles and triples. After passing the test, the endorsement will be added to your CDL.

To obtain a CDL Doubles/Triples license, you must already have a Commercial Driver's License (CDL). You'll need to pass a written knowledge test focused on handling large trucks with multiple trailers. This includes understanding coupling and uncoupling, inspecting doubles and triples, and crucial driving skills. Preparation via the state's CDL manual is highly recommended before taking the test.

While Mississippi does not specifically require specialized training for a CDL Doubles/Triples endorsement, it is highly recommended. The endorsement test covers topics like coupling and uncoupling, inspecting doubles and triples, and pulling double/triple trailers. Studying the CDL handbook and gaining practical experience can significantly improve your chances of passing the test.

Yes, to obtain a CDL Doubles/Triples endorsement, you must pass a specific written knowledge test. This test covers topics such as coupling and uncoupling, inspecting doubles and triples, and important driving skills. It's important to study the CDL handbook, particularly the section on doubles and triples, before taking the test.

The CDL Doubles/Triples endorsement test is a written examination, so no specific driving maneuvers are required. However, the test does assess your understanding of key skills such as coupling and uncoupling trailers, inspecting doubles and triples, and managing the substantial driving differences that come with operating these larger vehicles.

No, it's not permissible. Operating double or triple trailers requires a valid CDL Doubles/Triples endorsement in Mississippi, as well as in all other states. This endorsement ensures that the driver has the necessary knowledge and skills to safely operate these larger, more complex vehicles. Driving without the appropriate endorsement can result in fines and penalties.

Yes, you can append the CDL Doubles/Triples endorsement to your existing Commercial Driver's License. You don't need to initiate a new application for a CDL. However, you will need to pass the Doubles/Triples endorsement knowledge test to add this endorsement to your current CDL.

Yes, there are limitations for drivers holding a CDL Doubles/Triples endorsement. While this endorsement allows you to operate double and triple trailers, it doesn't permit the operation of other commercial vehicles like buses or tank trucks. Also, federal regulations limit the total length of these combinations to 81 feet. All drivers must abide by these and all other relevant rules and regulations.

The maximum weight for a double/triple trailer in Mississippi, with a CDL Doubles/Triples endorsement, is 80,000 pounds. The maximum length for a double trailer is 81 feet. However, the specific weight and length can vary depending on the combination of trailers. It's crucial to comply with these limits to ensure safety and avoid penalties.

Yes, when driving double/triple trailers, drivers must follow specific safety guidelines, including maintaining a safe following distance, avoiding sudden stops or lane changes, and inspecting the coupling devices and cargo regularly. Additionally, drivers must adhere to federal and state regulations regarding hours of service, vehicle weight and length limits, and hazardous materials transport.