Mississippi CDL Combination Practice Test (MS) 2

5 out of 5 (37 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Prepare for your Commercial Driver's License (CDL) with our Mississippi combination CDL practice test. This second practice test on our site is an excellent tool for those looking to sharpen their skills and knowledge. With 20 carefully crafted multiple-choice questions, you'll dive deep into essential topics such as inspection procedures, safe driving practices, air brake systems, and more. To pass, you need to answer at least 16 questions correctly. Our Mississippi drivers license practice test offers a format similar to the actual written permit test, featuring multiple-choice and true or false questions. This familiarizes you with the test-taking process, allowing you to practice eliminating incorrect answers and choosing the correct ones with confidence. Real-life driving scenarios are included to help you not only prepare for the written test but also to become a safer driver on the road. This is particularly important when navigating diverse Mississippi driving conditions, from the bustling urban areas of Jackson to the winding rural roads of the Delta and the coastal routes near Biloxi. One of the standout features of our CDL combination test is the inclusion of study aids designed to help you study more effectively. If you encounter a challenging question, you can request a hint to guide you toward the right answer. If you answer a question incorrectly, a detailed explanation will appear, helping you understand the correct answer and the reasoning behind it. The MS combination CDL practice test covers key areas such as the risks of jackknifing, where the trailer swings out of alignment with the tractor. Learning to avoid this dangerous situation through smooth braking and careful handling is vital for safe driving. By practicing these scenarios, you'll be better prepared to handle your vehicle safely and confidently. Get ready to tackle the Mississippi practice permit test with ease. Whether you are dealing with the unpredictable weather conditions in the northern parts of the state or the busy highways connecting Gulfport and Hattiesburg, our combination vehicle test will equip you with the knowledge and skills you need. Start today and ensure you're well-prepared for your permit test.
FREE CDL Practice Test App
Pass your Mississippi CDL Combination Vehicles test with the NextDoorDriving app. Real questions and answers—100% free and ad-free.
Download on the App Store

Sample Mississippi Combination Test Questions

Question 1

After coupling, you discover that the trailer’s service and supply air lines are crossed. What must you do?

  1. A Increase engine speed to force air into both lines
  2. B Continue if the trailer wheels can turn
  3. C Operate only with the tractor brakes
  4. D Reconnect the lines correctly and test the trailer brakes before driving

Correct answer: D – Reconnect the lines correctly and test the trailer brakes before driving

Crossed lines send supply air into the service line instead of charging the trailer tanks. Spring brakes may not release; on an older trailer without spring brakes, the vehicle might move even though the trailer brakes do not work. Connect the proper glad hands together and verify trailer-brake operation before driving.

Source: Mississippi Commercial Driver’s License Manual (March 2025) — § 6.2.5, “Hose Couplers (Glad Hands)”

Question 2

What visible feature normally identifies ABS equipment on a trailer?

  1. A A red warning lamp on the trailer’s right side
  2. B A yellow lamp inside the tractor cab only
  3. C A yellow ABS malfunction lamp on the trailer’s left side
  4. D A blue label attached to each spring brake

Correct answer: C – A yellow ABS malfunction lamp on the trailer’s left side

The Mississippi CDL manual states that trailers equipped with ABS have a yellow malfunction lamp on the left side, at either the front or rear corner. On older trailers, the lamp may not provide a definite answer. In that case, look underneath for the electronic control unit and wheel-speed-sensor wires leading from the brakes.

Source: Mississippi Commercial Driver’s License Manual (March 2025) — § 6.3.1, “Trailers Required to Have ABS”

Question 3

With normal air pressure and the parking brakes released, how should trailer service brakes be tested?

  1. A Move forward slowly and apply the trailer brakes with the hand control
  2. B Pull out the trailer air-supply control and try to move forward
  3. C Turn off the engine and repeatedly press the foot brake
  4. D Move forward without applying any brake control

Correct answer: A – Move forward slowly and apply the trailer brakes with the hand control

Move the combination forward slowly and apply the trailer brakes with the hand control, if equipped. You should feel the trailer brakes engage, showing that they are connected and working. Pulling out the trailer air-supply control tests the trailer emergency brakes, not the service brakes.

Source: Mississippi Commercial Driver’s License Manual (March 2025) — § 6.5.2, “Combination Vehicle Brake Check”

Question 4

How should you test a tractor-semitrailer coupling for security?

  1. A Pull forward sharply in a high gear
  2. B Rock the trailer from side to side
  3. C Pull gently forward in low gear against the locked trailer brakes, then inspect the coupling
  4. D Rely on the sound of the fifth wheel closing

Correct answer: C – Pull gently forward in low gear against the locked trailer brakes, then inspect the coupling

After the kingpin locks into the fifth wheel, raise the landing gear slightly off the ground. With the trailer brakes still locked, pull the tractor gently forward to confirm that the trailer remains attached. Secure the vehicle afterward and visually inspect the jaws, locking lever, safety latch, and the contact between the fifth-wheel surfaces.

Source: Mississippi Commercial Driver’s License Manual (March 2025) — § 6.4.1, “Coupling Tractor-Semitrailers”

Question 5

Which condition must be verified for trailer air lines and glad hands during a combination-vehicle inspection?

  1. A The connections are loose enough to rotate freely
  2. B The glad hands are properly connected, there are no leaks, and the lines are undamaged
  3. C Any damaged area has been covered with tape
  4. D The service and supply couplers can be interchanged

Correct answer: B – The glad hands are properly connected, there are no leaks, and the lines are undamaged

Inspect that the air lines are properly attached to the glad hands, secured with enough slack for turns, and free of leaks. All lines must also be free from damage. Glad-hand seals prevent air from escaping, so the couplers and seals should be clean before they are connected.

Source: Mississippi Commercial Driver’s License Manual (March 2025) — § 6.5.1, “Additional Things to Check during a Walk-around Inspection”, Mississippi Commercial Driver’s License Manual (March 2025) — § 6.2.5, “Hose Couplers (Glad Hands)”

Question 6

Which valve helps reduce the delay in applying a trailer’s air brakes?

  1. A Quick-release valve
  2. B Relay valve
  3. C Front-wheel limiting valve
  4. D Tractor-protection valve

Correct answer: B – Relay valve

The service air line carries the braking signal to relay valves on the trailer. Those valves direct air from the trailer tanks to the brakes, allowing the trailer brakes to apply more quickly than they would if application air had to travel directly from the tractor. The tractor-protection valve serves a different purpose by protecting the tractor’s air supply.

Source: Mississippi Commercial Driver’s License Manual (March 2025) — § 6.2.4, “Trailer Air-lines”

More Mississippi CDL Practice Tests
Other CDL Endorsements