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UT · GK (Class A) Endorsement

Utah Combination Vehicles CDL Practice Test

Below are 25 exam-style questions for the Utah Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Utah Driver License 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
The "service" line on a tractor-trailer:
  • 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
Correct answer: B
The service line carries braking-pressure changes from the foot valve to the trailer brakes.
Question 2 of 25
A combination vehicle with empty trailers:
  • A Stops faster than when loaded
  • B Stops only with parking brake
  • C Stops in the same distance
  • D May actually take longer to stop because brakes are designed for the loaded weight
Correct answer: D
Empty trailers can lock up easily and skid, which counterintuitively increases stopping distance.
Question 3 of 25
When coupling a tractor to a semitrailer, the trailer should be at:
  • 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
Correct answer: B
The trailer should be slightly lower than the fifth wheel so backing in lifts the trailer.
Question 4 of 25
If you are pulling two trailers, the heavier trailer should be:
  • A Either position is fine
  • B First (closest to the tractor)
  • C Loaded last
  • D Last
Correct answer: B
Heavier trailer first reduces the rear-trailer crack-the-whip effect.
Question 5 of 25
The seven-pin connector on a tractor-trailer carries:
  • A Air for the brakes
  • B Fuel
  • C Electrical power for trailer lights and ABS
  • D Hydraulic fluid
Correct answer: C
The seven-pin (or older five-pin) is electrical, supplying lights, brake-light signal, and ABS.
Question 6 of 25
Trailer air supply valves on tractors are typically:
  • A Square, white, marked CHARGE
  • B Triangular, green, marked SERVICE
  • C Round, blue, marked TRACTOR
  • D Octagonal, red, marked TRAILER AIR SUPPLY
Correct answer: D
The trailer air-supply valve is the red, octagonal knob — a federal standard.
Question 7 of 25
When inspecting the air lines between tractor and trailer, look for:
  • A Cargo placement
  • B Loose lug nuts only
  • C Cuts, abrasions, and worn seals
  • D Engine oil leaks
Correct answer: C
Air-line condition is a typical roadside inspection focus on combinations.
Question 8 of 25
Glad hands are:
  • A Electrical connectors
  • B Brake adjustment levers
  • C Coupling devices for connecting tractor air lines to the trailer
  • D Manual transmission shifters
Correct answer: C
Glad hands have rubber seals and a metal coupler that joins the tractor and trailer air lines.
Question 9 of 25
Most tire problems on a combination vehicle:
  • A Show up only at high speed
  • B Need a mechanic to find
  • C Are caused by low fuel
  • D Can be detected during pre-trip inspection by visual and pressure checks
Correct answer: D
Visual and pressure checks catch most problems before they become roadside failures.
Question 10 of 25
A tractor jackknife happens when:
  • 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
Correct answer: A
A drive-wheel skid causes the tractor to swing into the trailer at an angle.
Question 11 of 25
Off-tracking means:
  • A Sliding sideways
  • B Driving off the road
  • C The trailer wheels follow a tighter arc than the tractor wheels in a turn
  • D Loss of traction
Correct answer: C
In a right turn, the trailer wheels cut the corner. To compensate, the tractor must swing wider.
Question 12 of 25
A skid is most likely to result in a jackknife if:
  • A You are driving slowly
  • B The drive wheels lock and the trailer pushes the tractor sideways
  • C The brakes are released gently
  • D The trailer wheels lock briefly
Correct answer: B
Drive-wheel lockup is the classic jackknife cause.
Question 13 of 25
A combination vehicle has a higher rollover risk because:
  • A Its center of gravity is high
  • B It is shorter than a straight truck
  • C It uses air brakes
  • D Its tires are wider
Correct answer: A
Loaded trailers have high centers of gravity; rollover happens at speeds the driver thinks are safe.
Question 14 of 25
Before pulling the kingpin release lever to uncouple, you must:
  • A Drain the air tanks
  • B Honk the horn
  • C Lower the trailer landing gear and chock the trailer wheels
  • D Disconnect the electrical line first
Correct answer: C
Always lower the landing gear and chock the trailer so it cannot move once you pull out from under it.
Question 15 of 25
The trailer landing gear (dolly legs) should be:
  • A Always halfway extended
  • B Disconnected before driving
  • C Fully raised before driving
  • D Lowered to the ground while driving
Correct answer: C
Landing gear must be fully raised and the crank handle secured before moving the trailer.
Question 16 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 17 of 25
During a brake check before moving, you should look for:
  • A Smoke from the cab
  • B Steering wander only
  • C Pulling, sticking, or unusual feel as you apply the brakes
  • D Engine knocking
Correct answer: C
Low-speed brake test identifies pulling, sticking, or weakness so you don't discover it on the highway.
Question 18 of 25
When you make a wide right turn, you should:
  • A Stay in the right lane and swing the front of the tractor wide enough to clear the curb without inviting cars to pass on the right
  • B Stop traffic by signaling left
  • C Use the shoulder
  • D Turn from the left lane
Correct answer: A
Use only as much room as needed and keep the right side blocked to following vehicles.
Question 19 of 25
Combination vehicles are usually harder to drive than single CMVs because:
  • A They take more skill to back, couple, and uncouple
  • B All of the above
  • C They are heavier and longer
  • D They have a higher rollover risk
Correct answer: B
All three factors apply. The Combination Vehicles section of the federal manual emphasizes the higher skill needed.
Question 20 of 25
When backing into a dock, you should:
  • A Use only mirrors
  • B Have the dispatcher in the cab
  • C GOAL — Get Out And Look — and walk around the trailer first
  • D Back at full speed
Correct answer: C
A walk-around catches obstacles, people, and overhead clearance issues before you back.
Question 21 of 25
The crank handle on the landing gear should:
  • A Be in the low position when traveling
  • B Be locked at half-height
  • C Be in the stowed (high) position when traveling
  • D Be removed
Correct answer: C
Stow the crank up so it doesn't catch on something while traveling.
Question 22 of 25
Which is true about coupling order to a trailer?
  • A Connect air emergency line first, then service line, then electrical (or per company policy) — verify with brake check
  • B Connect electrical first, then air
  • C Connect only air; electrical is optional
  • D Connect any line first; order doesn't matter
Correct answer: A
Specific orders vary by carrier, but the principle is to charge the trailer brakes before moving and to verify with a brake check.
Question 23 of 25
The fifth-wheel locking lever should be:
  • A Tied with rope
  • B Removed before driving
  • C Locked and the safety latch in place after coupling
  • D Released and visible after coupling
Correct answer: C
After backing under, the locking jaws must close around the kingpin and the safety latch must be in place.
Question 24 of 25
When parking a tractor-trailer, you should:
  • A Leave the engine running with the brakes off
  • B Use the trailer hand valve
  • C Set only the tractor parking brake
  • D Set both tractor and trailer parking brakes
Correct answer: D
For full parking, both parking brakes apply.
Question 25 of 25
Which of the following can damage a fifth wheel?
  • A Coupling with the trailer too high
  • B Backing too fast
  • C Failure to grease
  • D All of the above
Correct answer: D
All three: high trailer skips the jaws, fast backing impacts hardware, and lack of lubrication accelerates wear.

Study tips for the Utah Combination Vehicles exam

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

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

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