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Montana Combination Vehicles CDL Practice Test

Below are 25 exam-style questions for the Montana Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Montana Motor Vehicle Division. 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.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.
Question 1 of 25
Trailer air supply valves on tractors are typically:
  • A Round, blue, marked TRACTOR
  • B Square, white, marked CHARGE
  • C Octagonal, red, marked TRAILER AIR SUPPLY
  • D Triangular, green, marked SERVICE
Correct answer: C
The trailer air-supply valve is the red, octagonal knob — a federal standard.
Question 2 of 25
The proper test of a good fifth-wheel coupling is:
  • 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
Correct answer: A
After coupling and locking, gently pull forward against the locked trailer brakes to confirm engagement.
Question 3 of 25
Combination vehicles are usually harder to drive than single CMVs because:
  • A They take more skill to back, couple, and uncouple
  • B They are heavier and longer
  • C All of the above
  • D They have a higher rollover risk
Correct answer: C
All three factors apply. The Combination Vehicles section of the federal manual emphasizes the higher skill needed.
Question 4 of 25
After coupling, the locking jaws should:
  • A Be closed around the shank of the kingpin (not on the head)
  • B Be loose
  • C Be missing
  • D Be open
Correct answer: A
Visual check: jaws around the shank, not the head. A flashlight helps.
Question 5 of 25
The fifth-wheel locking lever should be:
  • A Tied with rope
  • B Locked and the safety latch in place after coupling
  • C Released and visible after coupling
  • D Removed before driving
Correct answer: B
After backing under, the locking jaws must close around the kingpin and the safety latch must be in place.
Question 6 of 25
The "emergency" line (supply line) on a tractor-trailer:
  • A Operates the parking brake only
  • B Drains the wet tank
  • C Carries electrical signals
  • D Sends supply air to the trailer reservoirs and controls the trailer emergency brakes
Correct answer: D
Loss of pressure on the emergency line causes the trailer's emergency brake to apply automatically.
Question 7 of 25
Tracking refers to:
  • A The fuel mileage
  • B The trailer following the same path as the tractor in a straight line
  • C Cargo placement
  • D Lane positioning at intersections
Correct answer: B
Tracking is how well the trailer follows the tractor; misalignment can indicate suspension or tire problems.
Question 8 of 25
If you cross the air lines (service to emergency and vice versa) when coupling:
  • A You will notice immediately because trailer brakes will not work properly
  • B Nothing will happen
  • C The trailer brakes will be locked on
  • D The horn will sound
Correct answer: A
Crossed glad hands often produce no air flow to brake chambers and incorrect brake operation; you should notice on the brake test.
Question 9 of 25
A safe combination-vehicle following distance is at least:
  • A A vehicle length
  • B Two car lengths
  • C One second per 10 feet of vehicle length below 40 mph, plus one extra second above 40 mph
  • D No specific rule
Correct answer: C
A 60-ft combination needs at least 6 seconds under 40 mph, 7 seconds above 40 mph.
Question 10 of 25
When uncoupling, after the tractor is clear, you should:
  • A Check that the trailer is stable on its landing gear
  • B Disable the trailer parking brake
  • C Connect the lines back to the tractor
  • D Move the tractor far away immediately without checking
Correct answer: A
Verify the trailer is sitting solidly before leaving the area.
Question 11 of 25
Which of the following can damage a fifth wheel?
  • A Coupling with the trailer too high
  • B All of the above
  • C Failure to grease
  • D Backing too fast
Correct answer: B
All three: high trailer skips the jaws, fast backing impacts hardware, and lack of lubrication accelerates wear.
Question 12 of 25
When you turn a combination vehicle right at an intersection, you should:
  • 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
Correct answer: D
Hugging the right side of the turn lane prevents another vehicle from squeezing in next to you and getting clipped by the trailer.
Question 13 of 25
When coupling a tractor to a semitrailer, the trailer should be at:
  • A A height where the tractor will lift the trailer slightly when backing under
  • B Whatever height it happens to be
  • C Maximum legal height
  • D A height that requires the tractor to drop down to fit
Correct answer: A
The trailer should be slightly lower than the fifth wheel so backing in lifts the trailer.
Question 14 of 25
Why should you not jackknife to get out of a tight spot?
  • A It is illegal in some states
  • B It is the standard procedure
  • C It is fine if you are careful
  • D It can damage the cab and the trailer (cab corner crush)
Correct answer: D
Bending the tractor too sharply against the trailer can cause body damage and disconnect the lines.
Question 15 of 25
When you drive a combination vehicle, watch for:
  • A Trailer sway in crosswinds
  • B Off-tracking on right turns
  • C Reduced visibility along the trailer
  • D All of the above
Correct answer: D
All three are routine combination-vehicle considerations.
Question 16 of 25
The trailer hand valve operates:
  • A The trailer service brakes only
  • B Both tractor and trailer brakes simultaneously
  • C The tractor service brakes only
  • D The parking brake
Correct answer: A
The hand valve applies only the trailer service brakes. It is for testing — not for parking or routine use.
Question 17 of 25
Glad hands are:
  • A Coupling devices for connecting tractor air lines to the trailer
  • B Brake adjustment levers
  • C Electrical connectors
  • D Manual transmission shifters
Correct answer: A
Glad hands have rubber seals and a metal coupler that joins the tractor and trailer air lines.
Question 18 of 25
A skid is most likely to result in a jackknife if:
  • A The drive wheels lock and the trailer pushes the tractor sideways
  • B The trailer wheels lock briefly
  • C You are driving slowly
  • D The brakes are released gently
Correct answer: A
Drive-wheel lockup is the classic jackknife cause.
Question 19 of 25
Before pulling the kingpin release lever to uncouple, you must:
  • 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
Correct answer: B
Always lower the landing gear and chock the trailer so it cannot move once you pull out from under it.
Question 20 of 25
A combination vehicle with empty trailers:
  • A Stops in the same distance
  • B May actually take longer to stop because brakes are designed for the loaded weight
  • C Stops only with parking brake
  • D Stops faster than when loaded
Correct answer: B
Empty trailers can lock up easily and skid, which counterintuitively increases stopping distance.
Question 21 of 25
Trailer wheels with worn brake linings:
  • A Only need attention every 5 years
  • B Are normal until the lining is gone
  • C Should be replaced when worn beyond manufacturer specs
  • D Make the truck quieter
Correct answer: C
Worn linings are an out-of-service item; replace per manufacturer/federal limits.
Question 22 of 25
When you cross a railroad track in a combination vehicle, the safest practice is:
  • A Stop on the tracks if traffic ahead slows
  • B Shift in the middle of the track
  • C Cross in a low gear without shifting
  • D Honk and accelerate
Correct answer: C
Cross in a low gear without shifting; never stop on the tracks; never shift in the middle.
Question 23 of 25
After connecting the air lines, before pulling the tractor away, you must:
  • A Drain the wet tank
  • B Drive away immediately
  • C Charge the trailer brakes by setting the trailer air supply control
  • D Pump the brakes 10 times
Correct answer: C
After connecting, charge the trailer system and verify brake operation.
Question 24 of 25
A worn or damaged fifth wheel can cause:
  • A Rust on the cab
  • B The trailer to come uncoupled
  • C Tire wear only
  • D Engine damage
Correct answer: B
Worn locking jaws or a cracked structure can fail and release the trailer in motion.
Question 25 of 25
The trailer hand valve should NOT be used to:
  • A Test the trailer brakes
  • B Apply trailer brakes momentarily
  • C Both for parking and to prevent jackknife
  • D Hold the vehicle when parking
Correct answer: C
Don't use it to park (it can leak off) or to prevent a jackknife (it locks the trailer wheels and worsens the skid).

Study tips for the Montana Combination Vehicles exam

The Combination Vehicles portion of the Montana CDL exam is graded out of the bank of questions the Montana Motor Vehicle Division draws from each year. While the exact bank is not published, every question is sourced from the Combination Vehicles chapter of the Montana 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 Montana 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 Montana Motor Vehicle Division 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 Montana 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 Montana 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 Montana Motor Vehicle Division office.

Already comfortable with this endorsement? Drill another: MT General Knowledge · MT Air Brakes · MT Hazardous Materials · MT Passenger · MT School Bus · MT Tank Vehicle · MT Doubles / Triples

New to the CDL process in Montana? Read How to apply for a CDL in Montana for the document checklist and step-by-step timeline.