North Carolina Combination Vehicles CDL Practice Test
Below are 25 exam-style questions for the North Carolina Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the North Carolina Division of Motor Vehicles. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.
- A Small trailer movement
- B Loss of brake pressure
- C No effect
- D Large trailer angle changes; small inputs are key
- A Keep the cab close to the curb and swing the front out so following cars cannot squeeze beside you on the right
- B Stop in the middle of the turn
- C Swing wide to the right first to avoid hitting the curb
- D Swing left then right
- A A wheel bearing fails
- B The tractor brakes lock up
- C The trailer brakes lock up
- D The fifth wheel breaks
- A Drain the wet tank
- B Pump the brakes 10 times
- C Drive away immediately
- D Charge the trailer brakes by setting the trailer air supply control
- A Rust on the cab
- B Tire wear only
- C The trailer to come uncoupled
- D Engine damage
- A Electrical connectors
- B Brake adjustment levers
- C Manual transmission shifters
- D Coupling devices for connecting tractor air lines to the trailer
- A No off-tracking
- B Off-tracking — the trailer wheels follow a tighter arc than the tractor
- C Brake fade
- D Wheel damage
- A Spin out
- B Roll over before sliding
- C Stop suddenly
- D Lose engine power
- A Always back to the right
- B Back as fast as practical
- C Back to the left whenever possible because you can see better
- D Back without using mirrors
- A Use the shoulder
- B Stay in the right lane and swing the front of the tractor wide enough to clear the curb without inviting cars to pass on the right
- C Stop traffic by signaling left
- D Turn from the left lane
- A Lane positioning at intersections
- B The trailer following the same path as the tractor in a straight line
- C Cargo placement
- D The fuel mileage
- A Properly chocked
- B Empty
- C Too high — it can damage the kingpin or skip over the fifth wheel
- D Loaded
- A Coupling with the trailer too high
- B Failure to grease
- C Backing too fast
- D All of the above
- A Air leakage in the supply line, low pressure, or a brake-balance issue
- B Engine wear
- C Cargo placement
- D Driver fatigue
- A Leave the engine running with the brakes off
- B Use the trailer hand valve
- C Set both tractor and trailer parking brakes
- D Set only the tractor parking brake
- A Nothing will happen
- B You will notice immediately because trailer brakes will not work properly
- C The horn will sound
- D The trailer brakes will be locked on
- A Be loose
- B Be open
- C Be closed around the shank of the kingpin (not on the head)
- D Be missing
- A Released and visible after coupling
- B Removed before driving
- C Locked and the safety latch in place after coupling
- D Tied with rope
- A A height where the tractor will lift the trailer slightly when backing under
- B Maximum legal height
- C Whatever height it happens to be
- D A height that requires the tractor to drop down to fit
- A Pull tractor away first, then disconnect lines
- B Lower landing gear, disconnect lines, release fifth wheel, pull tractor away
- C No specific order is required
- D Release fifth wheel first, then connect lines
- A Always halfway extended
- B Lowered to the ground while driving
- C Disconnected before driving
- D Fully raised before driving
- A They take more skill to back, couple, and uncouple
- B They have a higher rollover risk
- C They are heavier and longer
- D All of the above
- A No effect on safety
- B Stopping distances are normal
- C Steering becomes easier
- D Stopping distances increase and the trailer can swing
- A Steering wander only
- B Smoke from the cab
- C Pulling, sticking, or unusual feel as you apply the brakes
- D Engine knocking
- A Sends air pressure to apply trailer service brakes
- B Carries electrical power
- C Drains the trailer reservoir
- D Sends supply air to the trailer reservoirs
Study tips for the North Carolina Combination Vehicles exam
The Combination Vehicles portion of the North Carolina CDL exam is graded out of the bank of questions the North Carolina Division of Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the Combination Vehicles chapter of the North Carolina CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.
Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official North Carolina handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.
Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about Combination Vehicles.
Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The North Carolina Division of Motor Vehicles will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.
Finally, keep your General Knowledge fundamentals sharp even when you're focused on the Combination Vehicles exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh North Carolina General Knowledge practice test before scheduling the real exam.
Next steps
Missed more than four questions? Re-read the Combination Vehicles study guide and the matching chapter in the official North Carolina CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local North Carolina Division of Motor Vehicles office.
Already comfortable with this endorsement? Drill another: NC General Knowledge · NC Air Brakes · NC Hazardous Materials · NC Passenger · NC School Bus · NC Tank Vehicle · NC Doubles / Triples
New to the CDL process in North Carolina? Read How to apply for a CDL in North Carolina for the document checklist and step-by-step timeline.