New Jersey Combination Vehicles CDL Practice Test
Below are 25 exam-style questions for the New Jersey Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the New Jersey Motor Vehicle Commission. 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 You will notice immediately because trailer brakes will not work properly
- B The horn will sound
- C The trailer brakes will be locked on
- D Nothing will happen
- A Engine failure
- B Cargo movement
- C Worn out tires
- D Driving too fast for conditions and/or too closely
- A Stop in the middle of the turn
- B Swing left then right
- C Swing wide to the right first to avoid hitting the curb
- D Keep the cab close to the curb and swing the front out so following cars cannot squeeze beside you on the right
- A The drive wheels lose traction and the tractor begins to slide
- B The tractor parking brake fails
- C The fifth wheel disengages
- D The trailer is too heavy
- A A height that requires the tractor to drop down to fit
- B A height where the tractor will lift the trailer slightly when backing under
- C Maximum legal height
- D Whatever height it happens to be
- A All of the above
- B Coupling with the trailer too high
- C Backing too fast
- D Failure to grease
- A Roll over before sliding
- B Lose engine power
- C Spin out
- D Stop suddenly
- A No specific rule
- B One second per 10 feet of vehicle length below 40 mph, plus one extra second above 40 mph
- C Two car lengths
- D A vehicle length
- A Large trailer angle changes; small inputs are key
- B No effect
- C Small trailer movement
- D Loss of brake pressure
- A Listen for a click
- B Honk the horn
- C Tug the trailer with the trailer parking brakes set
- D Look at the locking jaws only
- A By pushing in the red trailer-air-supply valve
- B By pulling out the red trailer-air-supply valve
- C By setting the red trailer-air-supply valve
- D By the trailer hand valve
- A Connect only air; electrical is optional
- B Connect electrical first, then air
- C Connect air emergency line first, then service line, then electrical (or per company policy) — verify with brake check
- D Connect any line first; order doesn't matter
- A Drive away immediately
- B Drain the wet tank
- C Charge the trailer brakes by setting the trailer air supply control
- D Pump the brakes 10 times
- A Hydraulic brakes
- B Hand valves
- C A separate compressor
- D Sensors at each wheel that release brake pressure when wheel lockup is detected
- A Disable the trailer parking brake
- B Move the tractor far away immediately without checking
- C Connect the lines back to the tractor
- D Check that the trailer is stable on its landing gear
- A Engine knocking
- B Steering wander only
- C Pulling, sticking, or unusual feel as you apply the brakes
- D Smoke from the cab
- A The tractor service brakes only
- B The parking brake
- C Both tractor and trailer brakes simultaneously
- D The trailer service brakes only
- A Both for parking and to prevent jackknife
- B Test the trailer brakes
- C Hold the vehicle when parking
- D Apply trailer brakes momentarily
- A The brakes are released gently
- B You are driving slowly
- C The drive wheels lock and the trailer pushes the tractor sideways
- D The trailer wheels lock briefly
- A Cracks in the kingpin
- B All of the above
- C Loose or missing fifth-wheel mounting bolts
- D Misalignment between tractor and trailer
- A It is fine if you are careful
- B It is illegal in some states
- C It can damage the cab and the trailer (cab corner crush)
- D It is the standard procedure
- A Last
- B First (closest to the tractor)
- C Either position is fine
- D Loaded last
- A Always halfway extended
- B Lowered to the ground while driving
- C Disconnected before driving
- D Fully raised before driving
- A Cargo placement
- B Engine wear
- C Driver fatigue
- D Air leakage in the supply line, low pressure, or a brake-balance issue
- A Use blocks instead
- B Lower the landing gear all the way until firmly on the ground, then a few extra cranks
- C Leave the gear up
- D Raise the gear partway
Study tips for the New Jersey Combination Vehicles exam
The Combination Vehicles portion of the New Jersey CDL exam is graded out of the bank of questions the New Jersey Motor Vehicle Commission draws from each year. While the exact bank is not published, every question is sourced from the Combination Vehicles chapter of the New Jersey 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 New Jersey 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 New Jersey Motor Vehicle Commission 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 New Jersey 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 New Jersey 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 New Jersey Motor Vehicle Commission office.
Already comfortable with this endorsement? Drill another: NJ General Knowledge · NJ Air Brakes · NJ Hazardous Materials · NJ Passenger · NJ School Bus · NJ Tank Vehicle · NJ Doubles / Triples
New to the CDL process in New Jersey? Read How to apply for a CDL in New Jersey for the document checklist and step-by-step timeline.