North Carolina CDL Combination Practice Test (NC) 2

5 out of 5 (64 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Prepare for your North Carolina CDL combination test with our NC CDL combination practice test. This NC driving test practice includes 20 multiple-choice questions designed to cover essential topics such as inspection procedures, safe driving practices, and air brake systems. You need to answer at least 16 questions correctly to pass, giving you the confidence you need to ace the actual test. This North Carolina combination CDL practice test is perfect for understanding critical areas, including the risks of jackknifing. Knowing how to handle your vehicle to prevent the trailer from swinging out of alignment with the tractor through smooth braking and careful handling is crucial for safe driving. At the end of each combination vehicle test, you'll receive a detailed summary of your performance. This summary highlights the questions you missed and provides the correct answers, ensuring you learn from your mistakes and improve your knowledge. Unlike other tests, our NC CDL combination practice test is not timed. This means you can take your time to carefully work through each question, ensuring you understand the material thoroughly before moving on. Our combination CDL test questions are crafted and reviewed by professional driving instructors with decades of teaching experience. These experts have helped thousands of drivers obtain their licenses, ensuring that each question is accurate and relevant. The varied questions in this NC permit test cover a range of scenarios and conditions you might encounter on North Carolina roads, from the winding mountain routes in the Appalachians to the coastal highways near the Outer Banks. This NC combination CDL practice test provides a balanced approach to preparing for your permit test, allowing you to focus on the areas where you need the most practice. By the time you complete this NC permit test, you will be well-prepared to handle any challenge that comes your way on the road. Take advantage of this valuable resource to ensure you are ready for your North Carolina CDL combination test.
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Sample North Carolina Combination Test Questions

Question 1

In a tractor-semitrailer fifth-wheel coupling, what is the kingpin?

  1. A. The trailer pin captured by the fifth-wheel locking jaws
  2. B. The fitting that connects the service and emergency air lines
  3. C. The pin that secures a wheel to its axle
  4. D. The handle used to raise the landing gear

Correct answer: A. – The trailer pin captured by the fifth-wheel locking jaws

The kingpin is the trailer coupling pin that enters the tractor’s fifth wheel. When coupling is correct, the locking jaws close around the shank of the kingpin rather than its head. The driver must inspect the kingpin, jaws, locking lever, safety latch, and fifth-wheel gap before operating the combination.

Source: North Carolina Commercial Driver License Manual — § 6.4.1, “Step 10. Back Under Trailer” and “Step 13. Inspect Coupling”

Question 2

Before driving a coupled tractor-semitrailer, how should the landing gear be positioned?

  1. A. One-third raised, with the crank secured
  2. B. Halfway raised, with the crank secured
  3. C. Raised enough to clear level pavement
  4. D. Fully raised, with the crank secured

Correct answer: D. – Fully raised, with the crank secured

Raise the landing gear completely before moving the combination vehicle and secure the crank handle. Landing gear left partly down can catch on railroad crossings or other objects. After raising it, also verify that the tractor frame and tires have enough clearance from the landing gear and trailer during turns.

Source: North Carolina Commercial Driver License Manual — § 6.4.1, “Step 15. Raise Front Trailer Supports (Landing Gear)”

Question 3

Which statement is correct about an air-braked trailer built before 1975?

  1. A. It may not have spring brakes
  2. B. It must have an antilock braking system
  3. C. It must use a special electrical glad hand
  4. D. It cannot have emergency brakes

Correct answer: A. – It may not have spring brakes

Trailers and converter dollies built before 1975 were not required to have spring brakes. If an older trailer lacks them, its emergency brakes operate from air stored in the trailer tank, and it has no separate parking brake. Those emergency brakes can release after the stored air leaks away, making wheel chocks important when the trailer is parked.

Source: North Carolina Commercial Driver License Manual — § 6.2.8, “Trailer Service, Parking and Emergency Brakes”

Question 4

What are the two functions of a combination vehicle’s emergency air line?

  1. A. It supplies electricity and operates the trailer lights
  2. B. It controls the tractor service brakes and steering
  3. C. It supplies the trailer air tanks and controls the trailer emergency brakes
  4. D. It drains moisture from the trailer air tanks

Correct answer: C. – It supplies the trailer air tanks and controls the trailer emergency brakes

The North Carolina manual identifies two purposes for the emergency, or supply, line. It carries air from the tractor to fill the trailer air tanks, and it controls the trailer emergency brakes. A loss of pressure in this line causes the trailer emergency brakes to apply and also causes the tractor protection valve to close.

Source: North Carolina Commercial Driver License Manual — § 6.2.4, “Trailer Air-lines”

Question 5

If a trailer breaks away and tears apart the air lines, what should occur in addition to the trailer emergency brakes applying?

  1. A. The tractor immediately loses all stored air
  2. B. The tractor protection valve closes
  3. C. The tractor protection valve opens fully
  4. D. The trailer air-supply control remains open

Correct answer: B. – The tractor protection valve closes

A breakaway causes pressure loss in the trailer emergency line, applying the trailer emergency brakes. That pressure loss also closes the tractor protection valve, and the trailer air-supply control normally pops out. Closing the valve prevents air from continuing to escape from the tractor through the separated trailer lines.

Source: North Carolina Commercial Driver License Manual — § 6.2.2, “Tractor Protection Valve”, North Carolina Commercial Driver License Manual — § 6.2.4, “Trailer Air-lines”

Question 6

Why must trailer air lines be properly supported during and after coupling?

  1. A. To keep them from being crushed or caught while providing enough slack for turns
  2. B. To increase the tractor’s fuel economy
  3. C. To prevent wear on the trailer tires
  4. D. To reduce the trailer’s overall height

Correct answer: A. – To keep them from being crushed or caught while providing enough slack for turns

During coupling, air lines should be supported where they will not be crushed or caught as the tractor backs under the trailer. Before driving, verify that the lines are undamaged, properly connected, and secured with enough slack for turns. They must not drag against or contact moving tractor or trailer parts.

Source: North Carolina Commercial Driver License Manual — § 6.4.1, “Step 7. Connect Air-lines to Trailer” and “Step 14. Connect the Electrical Cord and Check Air-lines”

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