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Wyoming Combination Vehicles CDL Practice Test

Below are 25 exam-style questions for the Wyoming Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Wyoming Department of Transportation. 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 proper test of a good fifth-wheel coupling is:
  • A Listen for a click
  • B Tug the trailer with the trailer parking brakes set
  • C Look at the locking jaws only
  • D Honk the horn
Correct answer: B
After coupling and locking, gently pull forward against the locked trailer brakes to confirm engagement.
Question 2 of 25
When the trailer begins to skid, you should:
  • A Accelerate
  • B Release the brakes to allow the trailer wheels to roll again, then steer
  • C Disconnect the air supply
  • D Apply the trailer hand valve harder
Correct answer: B
Releasing the brakes lets the wheels rotate again so the trailer can recover its tracking.
Question 3 of 25
A converter dolly:
  • A Is part of the tractor
  • B Is used only when triple-towing
  • C Replaces the fifth wheel on the tractor
  • D Is used to convert a semitrailer into a full trailer for towing in combination
Correct answer: D
A converter dolly turns a semitrailer into a full trailer that can be coupled behind another trailer.
Question 4 of 25
When a tractor pulls a trailer with brakes that are out of balance:
  • A No effect on safety
  • B Stopping distances increase and the trailer can swing
  • C Steering becomes easier
  • D Stopping distances are normal
Correct answer: B
Brake imbalance makes the rig pull, lengthens stopping distance, and increases the chance of trailer swing.
Question 5 of 25
You should never back under a trailer that is:
  • A Empty
  • B Too high — it can damage the kingpin or skip over the fifth wheel
  • C Properly chocked
  • D Loaded
Correct answer: B
A trailer set too high can skip over the fifth-wheel jaws and not lock, or damage the coupling.
Question 6 of 25
When you drive a combination vehicle, watch for:
  • A Off-tracking on right turns
  • B All of the above
  • C Reduced visibility along the trailer
  • D Trailer sway in crosswinds
Correct answer: B
All three are routine combination-vehicle considerations.
Question 7 of 25
When you make a wide right turn, you should:
  • A Stop traffic by signaling left
  • B Use the shoulder
  • C Turn from the left lane
  • D 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
Correct answer: D
Use only as much room as needed and keep the right side blocked to following vehicles.
Question 8 of 25
A heavy combination vehicle in a curve is most likely to:
  • A Spin out
  • B Lose engine power
  • C Stop suddenly
  • D Roll over before sliding
Correct answer: D
Loaded trailers reach the rollover threshold before they slide. Slow before the curve.
Question 9 of 25
Which is true about combination braking?
  • A Drive wheels never lock
  • B Brake balance is irrelevant
  • C ABS prevents jackknife in all cases
  • D Trailer wheels lock more often than drive wheels in panic stops
Correct answer: D
Empty trailer wheels lock easily and contribute to jackknife and trailer-swing risks.
Question 10 of 25
Tracking refers to:
  • A Lane positioning at intersections
  • B The trailer following the same path as the tractor in a straight line
  • C The fuel mileage
  • D Cargo placement
Correct answer: B
Tracking is how well the trailer follows the tractor; misalignment can indicate suspension or tire problems.
Question 11 of 25
A safe combination-vehicle following distance is at least:
  • A Two car lengths
  • B No specific rule
  • C One second per 10 feet of vehicle length below 40 mph, plus one extra second above 40 mph
  • D A vehicle length
Correct answer: C
A 60-ft combination needs at least 6 seconds under 40 mph, 7 seconds above 40 mph.
Question 12 of 25
Trailer air supply valves on tractors are typically:
  • A Triangular, green, marked SERVICE
  • B Round, blue, marked TRACTOR
  • C Square, white, marked CHARGE
  • D Octagonal, red, marked TRAILER AIR SUPPLY
Correct answer: D
The trailer air-supply valve is the red, octagonal knob — a federal standard.
Question 13 of 25
When parking a tractor-trailer, you should:
  • A Set only the tractor parking brake
  • B Set both tractor and trailer parking brakes
  • C Use the trailer hand valve
  • D Leave the engine running with the brakes off
Correct answer: B
For full parking, both parking brakes apply.
Question 14 of 25
The trailer landing gear (dolly legs) should be:
  • A Fully raised before driving
  • B Always halfway extended
  • C Disconnected before driving
  • D Lowered to the ground while driving
Correct answer: A
Landing gear must be fully raised and the crank handle secured before moving the trailer.
Question 15 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 tires are wider
  • D Its center of gravity is high
Correct answer: D
Loaded trailers have high centers of gravity; rollover happens at speeds the driver thinks are safe.
Question 16 of 25
If you are pulling two trailers, the heavier trailer should be:
  • A Loaded last
  • B First (closest to the tractor)
  • C Either position is fine
  • D Last
Correct answer: B
Heavier trailer first reduces the rear-trailer crack-the-whip effect.
Question 17 of 25
The seven-pin connector on a tractor-trailer carries:
  • A Air for the brakes
  • B Fuel
  • C Hydraulic fluid
  • D Electrical power for trailer lights and ABS
Correct answer: D
The seven-pin (or older five-pin) is electrical, supplying lights, brake-light signal, and ABS.
Question 18 of 25
A combination vehicle with empty trailers:
  • A Stops faster than when loaded
  • B May actually take longer to stop because brakes are designed for the loaded weight
  • C Stops in the same distance
  • D Stops only with parking brake
Correct answer: B
Empty trailers can lock up easily and skid, which counterintuitively increases stopping distance.
Question 19 of 25
The "emergency" line (supply line) on a tractor-trailer:
  • A Drains the wet tank
  • B Carries electrical signals
  • C Sends supply air to the trailer reservoirs and controls the trailer emergency brakes
  • D Operates the parking brake only
Correct answer: C
Loss of pressure on the emergency line causes the trailer's emergency brake to apply automatically.
Question 20 of 25
During a brake check before moving, you should look for:
  • A Engine knocking
  • B Smoke from the cab
  • C Steering wander only
  • D Pulling, sticking, or unusual feel as you apply the brakes
Correct answer: D
Low-speed brake test identifies pulling, sticking, or weakness so you don't discover it on the highway.
Question 21 of 25
When backing a trailer, small steering inputs cause:
  • A No effect
  • B Large trailer angle changes; small inputs are key
  • C Small trailer movement
  • D Loss of brake pressure
Correct answer: B
Trailer responds aggressively to small wheel inputs in reverse — back slowly and correct quickly.
Question 22 of 25
The trailer hand valve should NOT be used to:
  • A Hold the vehicle when parking
  • B Test the trailer brakes
  • C Both for parking and to prevent jackknife
  • D Apply trailer brakes momentarily
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 23 of 25
A worn or damaged fifth wheel can cause:
  • A The trailer to come uncoupled
  • B Rust on the cab
  • C Tire wear only
  • D Engine damage
Correct answer: A
Worn locking jaws or a cracked structure can fail and release the trailer in motion.
Question 24 of 25
Why should you not jackknife to get out of a tight spot?
  • A It is fine if you are careful
  • B It can damage the cab and the trailer (cab corner crush)
  • C It is illegal in some states
  • D It is the standard procedure
Correct answer: B
Bending the tractor too sharply against the trailer can cause body damage and disconnect the lines.
Question 25 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 A height that requires the tractor to drop down to fit
  • D Maximum legal height
Correct answer: A
The trailer should be slightly lower than the fifth wheel so backing in lifts the trailer.

Study tips for the Wyoming Combination Vehicles exam

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

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

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