Vermont Combination Vehicles CDL Practice Test
Below are 25 exam-style questions for the Vermont Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Vermont Department 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 Failure to grease
- B Backing too fast
- C Coupling with the trailer too high
- D All of the above
- A Sends supply air to the trailer reservoirs and controls the trailer emergency brakes
- B Drains the wet tank
- C Carries electrical signals
- D Operates the parking brake only
- A Engine damage
- B Tire wear only
- C The trailer to come uncoupled
- D Rust on the cab
- A May actually take longer to stop because brakes are designed for the loaded weight
- B Stops in the same distance
- C Stops only with parking brake
- D Stops faster than when loaded
- A Only at the destination
- B Before, during, and after coupling
- C Every 3 hours
- D Only at the start of the day
- A The trailer wheels lock briefly
- B The brakes are released gently
- C The drive wheels lock and the trailer pushes the tractor sideways
- D You are driving slowly
- A Connect the lines back to the tractor
- B Move the tractor far away immediately without checking
- C Disable the trailer parking brake
- D Check that the trailer is stable on its landing gear
- A Roll over before sliding
- B Spin out
- C Lose engine power
- D Stop suddenly
- A Electrical connectors
- B Manual transmission shifters
- C Brake adjustment levers
- D Coupling devices for connecting tractor air lines to the trailer
- A Release fifth wheel first, then connect lines
- B Pull tractor away first, then disconnect lines
- C Lower landing gear, disconnect lines, release fifth wheel, pull tractor away
- D No specific order is required
- A Connect only air; electrical is optional
- B Connect air emergency line first, then service line, then electrical (or per company policy) — verify with brake check
- C Connect electrical first, then air
- D Connect any line first; order doesn't matter
- A Disconnect the air supply
- B Release the brakes to allow the trailer wheels to roll again, then steer
- C Accelerate
- D Apply the trailer hand valve harder
- A The tractor brakes lock up
- B The fifth wheel breaks
- C The trailer brakes lock up
- D A wheel bearing fails
- A All of the above
- B They have a higher rollover risk
- C They are heavier and longer
- D They take more skill to back, couple, and uncouple
- A Honk the horn
- B Lower the trailer landing gear and chock the trailer wheels
- C Disconnect the electrical line first
- D Drain the air tanks
- A Last
- B Loaded last
- C First (closest to the tractor)
- D Either position is fine
- A Need a mechanic to find
- B Show up only at high speed
- C Are caused by low fuel
- D Can be detected during pre-trip inspection by visual and pressure checks
- A Tug the trailer with the trailer parking brakes set
- B Honk the horn
- C Look at the locking jaws only
- D Listen for a click
- A Be open
- B Be loose
- C Be missing
- D Be closed around the shank of the kingpin (not on the head)
- A Back without using mirrors
- B Always back to the right
- C Back as fast as practical
- D Back to the left whenever possible because you can see better
- A Cross in a low gear without shifting
- B Honk and accelerate
- C Stop on the tracks if traffic ahead slows
- D Shift in the middle of the track
- A Whatever height it happens to be
- B A height where the tractor will lift the trailer slightly when backing under
- C A height that requires the tractor to drop down to fit
- D Maximum legal height
- A Electrical power for trailer lights and ABS
- B Air for the brakes
- C Hydraulic fluid
- D Fuel
- A Loose lug nuts only
- B Engine oil leaks
- C Cargo placement
- D Cuts, abrasions, and worn seals
- A Engine wear
- B Air leakage in the supply line, low pressure, or a brake-balance issue
- C Cargo placement
- D Driver fatigue
Study tips for the Vermont Combination Vehicles exam
The Combination Vehicles portion of the Vermont CDL exam is graded out of the bank of questions the Vermont Department 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 Vermont 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 Vermont 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 Vermont Department 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 Vermont 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 Vermont 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 Vermont Department of Motor Vehicles office.
Already comfortable with this endorsement? Drill another: VT General Knowledge · VT Air Brakes · VT Hazardous Materials · VT Passenger · VT School Bus · VT Tank Vehicle · VT Doubles / Triples
New to the CDL process in Vermont? Read How to apply for a CDL in Vermont for the document checklist and step-by-step timeline.