Arizona Combination Vehicles CDL Practice Test
Below are 25 exam-style questions for the Arizona Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Arizona Department of Transportation MVD. 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 By pushing in the red trailer-air-supply valve
- B By pulling out the red trailer-air-supply valve
- C By the trailer hand valve
- D By setting the red trailer-air-supply valve
- A Air for the brakes
- B Fuel
- C Hydraulic fluid
- D Electrical power for trailer lights and ABS
- A Disable the trailer parking brake
- B Check that the trailer is stable on its landing gear
- C Move the tractor far away immediately without checking
- D Connect the lines back to the tractor
- A Raise the gear partway
- B Use blocks instead
- C Lower the landing gear all the way until firmly on the ground, then a few extra cranks
- D Leave the gear up
- A Be closed around the shank of the kingpin (not on the head)
- B Be open
- C Be loose
- D Be missing
- A Coupling devices for connecting tractor air lines to the trailer
- B Manual transmission shifters
- C Brake adjustment levers
- D Electrical connectors
- A The tractor service brakes only
- B The trailer service brakes only
- C The parking brake
- D Both tractor and trailer brakes simultaneously
- A Reduced visibility along the trailer
- B Trailer sway in crosswinds
- C Off-tracking on right turns
- D All of the above
- A Properly chocked
- B Empty
- C Loaded
- D Too high — it can damage the kingpin or skip over the fifth wheel
- A Engine failure
- B Driving too fast for conditions and/or too closely
- C Worn out tires
- D Cargo movement
- A Stop on the tracks if traffic ahead slows
- B Shift in the middle of the track
- C Honk and accelerate
- D Cross in a low gear without shifting
- A Air leakage in the supply line, low pressure, or a brake-balance issue
- B Engine wear
- C Cargo placement
- D Driver fatigue
- A Rust on the cab
- B Tire wear only
- C The trailer to come uncoupled
- D Engine damage
- A Cuts, abrasions, and worn seals
- B Cargo placement
- C Loose lug nuts only
- D Engine oil leaks
- A Be removed
- B Be locked at half-height
- C Be in the low position when traveling
- D Be in the stowed (high) position when traveling
- A Back at full speed
- B Use only mirrors
- C Have the dispatcher in the cab
- D GOAL — Get Out And Look — and walk around the trailer first
- A You are driving slowly
- B The brakes are released gently
- C The trailer wheels lock briefly
- D The drive wheels lock and the trailer pushes the tractor sideways
- A Carries electrical signals
- B Operates the parking brake only
- C Drains the wet tank
- D Sends supply air to the trailer reservoirs and controls the trailer emergency brakes
- A Trailer wheels lock more often than drive wheels in panic stops
- B Drive wheels never lock
- C Brake balance is irrelevant
- D ABS prevents jackknife in all cases
- A Loose or missing fifth-wheel mounting bolts
- B Misalignment between tractor and trailer
- C Cracks in the kingpin
- D All of the above
- A Steering becomes easier
- B Stopping distances increase and the trailer can swing
- C No effect on safety
- D Stopping distances are normal
- A Release fifth wheel first, then connect lines
- B No specific order is required
- C Pull tractor away first, then disconnect lines
- D Lower landing gear, disconnect lines, release fifth wheel, pull tractor away
- A Sends supply air to the trailer reservoirs
- B Sends air pressure to apply trailer service brakes
- C Carries electrical power
- D Drains the trailer reservoir
- A All of the above
- B They are heavier and longer
- C They have a higher rollover risk
- D They take more skill to back, couple, and uncouple
- A A height where the tractor will lift the trailer slightly when backing under
- B Maximum legal height
- C A height that requires the tractor to drop down to fit
- D Whatever height it happens to be
Study tips for the Arizona Combination Vehicles exam
The Combination Vehicles portion of the Arizona CDL exam is graded out of the bank of questions the Arizona Department of Transportation MVD draws from each year. While the exact bank is not published, every question is sourced from the Combination Vehicles chapter of the Arizona 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 Arizona 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 Arizona Department of Transportation MVD 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 Arizona 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 Arizona 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 Arizona Department of Transportation MVD office.
Already comfortable with this endorsement? Drill another: AZ General Knowledge · AZ Air Brakes · AZ Hazardous Materials · AZ Passenger · AZ School Bus · AZ Tank Vehicle · AZ Doubles / Triples
New to the CDL process in Arizona? Read How to apply for a CDL in Arizona for the document checklist and step-by-step timeline.