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MN · GK (Class A) Endorsement

Minnesota Combination Vehicles CDL Practice Test

Below are 25 exam-style questions for the Minnesota Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Minnesota Driver and Vehicle Services. 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
When you cross a railroad track in a combination vehicle, the safest practice is:
  • A Stop on the tracks if traffic ahead slows
  • B Honk and accelerate
  • C Cross in a low gear without shifting
  • D Shift in the middle of the track
Correct answer: C
Cross in a low gear without shifting; never stop on the tracks; never shift in the middle.
Question 2 of 25
A tractor jackknife happens when:
  • A The fifth wheel disengages
  • B The drive wheels lose traction and the tractor begins to slide
  • C The tractor parking brake fails
  • D The trailer is too heavy
Correct answer: B
A drive-wheel skid causes the tractor to swing into the trailer at an angle.
Question 3 of 25
Which is true about coupling order to a trailer?
  • 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
Correct answer: B
Specific orders vary by carrier, but the principle is to charge the trailer brakes before moving and to verify with a brake check.
Question 4 of 25
When backing a tractor-trailer, you should:
  • A Back to the left whenever possible because you can see better
  • B Always back to the right
  • C Back without using mirrors
  • D Back as fast as practical
Correct answer: A
Backing to the driver's side gives the best view of the trailer. Always GOAL — Get Out And Look — before and during.
Question 5 of 25
The crank handle on the landing gear should:
  • A Be in the stowed (high) position when traveling
  • B Be in the low position when traveling
  • C Be locked at half-height
  • D Be removed
Correct answer: A
Stow the crank up so it doesn't catch on something while traveling.
Question 6 of 25
A combination vehicle has a higher rollover risk because:
  • A It is shorter than a straight truck
  • B It uses air brakes
  • C Its center of gravity is high
  • D Its tires are wider
Correct answer: C
Loaded trailers have high centers of gravity; rollover happens at speeds the driver thinks are safe.
Question 7 of 25
During a brake check before moving, you should look for:
  • A Steering wander only
  • B Pulling, sticking, or unusual feel as you apply the brakes
  • C Smoke from the cab
  • D Engine knocking
Correct answer: B
Low-speed brake test identifies pulling, sticking, or weakness so you don't discover it on the highway.
Question 8 of 25
When a tractor pulls a trailer with brakes that are out of balance:
  • A No effect on safety
  • B Stopping distances are normal
  • C Stopping distances increase and the trailer can swing
  • D Steering becomes easier
Correct answer: C
Brake imbalance makes the rig pull, lengthens stopping distance, and increases the chance of trailer swing.
Question 9 of 25
Off-tracking means:
  • A Loss of traction
  • B The trailer wheels follow a tighter arc than the tractor wheels in a turn
  • C Driving off the road
  • D Sliding sideways
Correct answer: B
In a right turn, the trailer wheels cut the corner. To compensate, the tractor must swing wider.
Question 10 of 25
The "emergency" line (supply line) on a tractor-trailer:
  • A Drains the wet tank
  • B Sends supply air to the trailer reservoirs and controls the trailer emergency brakes
  • C Operates the parking brake only
  • D Carries electrical signals
Correct answer: B
Loss of pressure on the emergency line causes the trailer's emergency brake to apply automatically.
Question 11 of 25
Glad hands are:
  • A Brake adjustment levers
  • B Manual transmission shifters
  • C Coupling devices for connecting tractor air lines to the trailer
  • D Electrical connectors
Correct answer: C
Glad hands have rubber seals and a metal coupler that joins the tractor and trailer air lines.
Question 12 of 25
The trailer landing gear (dolly legs) should be:
  • A Fully raised before driving
  • B Always halfway extended
  • C Lowered to the ground while driving
  • D Disconnected before driving
Correct answer: A
Landing gear must be fully raised and the crank handle secured before moving the trailer.
Question 13 of 25
The proper sequence for uncoupling is generally:
  • 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
Correct answer: B
Lower the landing gear, chock the wheels, disconnect air and electrical lines and stow them, release the fifth wheel, then slowly pull the tractor forward.
Question 14 of 25
If you are pulling two trailers, the heavier trailer should be:
  • A Loaded last
  • B First (closest to the tractor)
  • C Last
  • D Either position is fine
Correct answer: B
Heavier trailer first reduces the rear-trailer crack-the-whip effect.
Question 15 of 25
The trailer hand valve should NOT be used to:
  • A Apply trailer brakes momentarily
  • B Test the trailer brakes
  • 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).
Question 16 of 25
A safe combination-vehicle following distance is at least:
  • A Two car lengths
  • B A vehicle length
  • 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 17 of 25
When backing into a dock, you should:
  • A GOAL — Get Out And Look — and walk around the trailer first
  • B Have the dispatcher in the cab
  • C Back at full speed
  • D Use only mirrors
Correct answer: A
A walk-around catches obstacles, people, and overhead clearance issues before you back.
Question 18 of 25
When you drive a combination vehicle, watch for:
  • A Reduced visibility along the trailer
  • B All of the above
  • C Off-tracking on right turns
  • D Trailer sway in crosswinds
Correct answer: B
All three are routine combination-vehicle considerations.
Question 19 of 25
After coupling, the locking jaws should:
  • A Be loose
  • B Be closed around the shank of the kingpin (not on the head)
  • C Be open
  • D Be missing
Correct answer: B
Visual check: jaws around the shank, not the head. A flashlight helps.
Question 20 of 25
Trailer air supply valves on tractors are typically:
  • A Triangular, green, marked SERVICE
  • B Round, blue, marked TRACTOR
  • C Octagonal, red, marked TRAILER AIR SUPPLY
  • D Square, white, marked CHARGE
Correct answer: C
The trailer air-supply valve is the red, octagonal knob — a federal standard.
Question 21 of 25
Which is true about combination braking?
  • A Brake balance is irrelevant
  • B Trailer wheels lock more often than drive wheels in panic stops
  • C Drive wheels never lock
  • D ABS prevents jackknife in all cases
Correct answer: B
Empty trailer wheels lock easily and contribute to jackknife and trailer-swing risks.
Question 22 of 25
Trailer ABS uses:
  • A A separate compressor
  • B Hydraulic brakes
  • C Sensors at each wheel that release brake pressure when wheel lockup is detected
  • D Hand valves
Correct answer: C
Wheel-speed sensors trigger valves to release pressure when lockup is detected.
Question 23 of 25
When you turn a combination vehicle right at an intersection, you should:
  • A Swing wide to the right first to avoid hitting the curb
  • B Swing left then right
  • C Stop in the middle of the turn
  • 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 24 of 25
The seven-pin connector on a tractor-trailer carries:
  • A Air for the brakes
  • B Hydraulic fluid
  • C Electrical power for trailer lights and ABS
  • D Fuel
Correct answer: C
The seven-pin (or older five-pin) is electrical, supplying lights, brake-light signal, and ABS.
Question 25 of 25
You should inspect a combination vehicle for:
  • A Cracks in the kingpin
  • B Loose or missing fifth-wheel mounting bolts
  • C Misalignment between tractor and trailer
  • D All of the above
Correct answer: D
All three are pre-trip combination-vehicle items.

Study tips for the Minnesota Combination Vehicles exam

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

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

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