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VT · T Endorsement

Vermont Doubles / Triples CDL Practice Test

Below are 25 exam-style questions for the Vermont Doubles / Triples CDL knowledge test, modeled on the FMCSA-aligned content used by the Vermont Department of Motor Vehicles. 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
A doubles combination requires:
  • A No air-brake system
  • B Mechanical brakes only
  • C Air lines only on the tractor
  • D Air lines from tractor to first trailer to dolly to second trailer
Correct answer: D
Air system extends through the entire combination via glad hands at each connection.
Question 2 of 25
When approaching a curve in a doubles combination:
  • A Increase speed
  • B Brake within the curve
  • C Slow down before the curve to reduce rollover risk and trailer swing
  • D Maintain speed
Correct answer: C
Speed reduction before the curve prevents rollover.
Question 3 of 25
A "double" in trucking refers to:
  • A Two tractors pulling one trailer
  • B Two trailers behind one tractor
  • C A bus with two sections
  • D A trailer with two axles
Correct answer: B
Double = two trailers behind one tractor; triple = three trailers.
Question 4 of 25
The crack-the-whip effect refers to:
  • A A tire blowout
  • B A driver punishing the truck
  • C The rear trailer swinging more than the tractor in turns or lane changes
  • D A loose load shifting
Correct answer: C
Small inputs at the tractor multiply at the rear trailer.
Question 5 of 25
A doubles/triples driver who experiences trailer swing should:
  • A Accelerate
  • B Brake hard
  • C Steer sharply to correct
  • D Reduce speed gradually and avoid sudden steering inputs
Correct answer: D
Gradual reduction lets the trailer settle without overcorrection.
Question 6 of 25
Triples are not allowed:
  • A In Canada only
  • B Only on Interstate 80
  • C In some states; restrictions vary
  • D On all U.S. highways
Correct answer: C
Triples are restricted by state and route; the T endorsement does not override route restrictions.
Question 7 of 25
When you need to make a lane change in heavy traffic with doubles:
  • A Plan the change well in advance, signal early, and change when there is ample space
  • B Skip the signal
  • C Cut between cars
  • D Change quickly to fit in
Correct answer: A
Planning and patience prevent collisions.
Question 8 of 25
A doubles/triples driver should know that:
  • A T endorsement allows triples everywhere
  • B Restrictions apply only to hazmat
  • C There are no restrictions
  • D Federal and state rules vary; T endorsement does not override route restrictions
Correct answer: D
Endorsement allows you to pull; route restrictions still apply.
Question 9 of 25
When you turn a combination of doubles or triples right at an intersection:
  • A Off-tracking is less than a single trailer
  • B Use the left lane
  • C Off-tracking is more pronounced; swing wider than for a single trailer
  • D No off-tracking occurs
Correct answer: C
More trailers = more off-tracking; plan turns carefully.
Question 10 of 25
When the converter dolly's tires are damaged:
  • A Ignore the damage
  • B Continue with damaged tires
  • C Replace before operating
  • D Use the spare
Correct answer: C
Damaged tires must be replaced before operation.
Question 11 of 25
When the air-supply line to the second trailer disconnects accidentally:
  • A Nothing happens
  • B The tractor brakes apply
  • C The second trailer's emergency brakes apply automatically
  • D The first trailer accelerates
Correct answer: C
Loss of supply pressure triggers emergency brakes — the failsafe.
Question 12 of 25
When inspecting safety chains:
  • A Verify they are crossed under the pintle hook and not dragging
  • B Tie them in knots
  • C Skip the inspection
  • D Allow them to drag
Correct answer: A
Crossing chains catches the trailer if the hook fails; dragging chains can damage roadway and themselves.
Question 13 of 25
When a doubles combination is parked:
  • A Use the trailer hand valve
  • B Leave brakes off
  • C Set only the tractor parking brake
  • D Set parking brakes on the tractor and on the trailers
Correct answer: D
All parking brakes set for stable parking.
Question 14 of 25
When you couple the second trailer to the converter dolly:
  • A Verify the fifth wheel locks around the kingpin and test by tugging gently
  • B Trust visual inspection only
  • C Skip the lock verification
  • D Couple at high speed
Correct answer: A
Verification prevents the catastrophic loss of the second trailer.
Question 15 of 25
When the rear trailer of a doubles combination begins to sway:
  • A Accelerate
  • B Brake hard
  • C Reduce speed gradually and avoid sudden steering inputs
  • D Steer sharply to correct
Correct answer: C
Smooth reduction in speed allows the trailer to settle.
Question 16 of 25
A doubles driver should be aware of:
  • A No specific length
  • B Tractor length only
  • C Trailer length only
  • D Total combination length when turning, parking, and changing lanes
Correct answer: D
Total length affects every maneuver.
Question 17 of 25
When the second trailer is empty:
  • A It can sway and lift more easily; drive carefully
  • B No change in handling
  • C It is harder to roll over
  • D Better fuel mileage
Correct answer: A
Empty trailers are surprisingly prone to swing and roll because the wheels lock up easily under braking.
Question 18 of 25
A doubles combination needs more following distance because:
  • A It uses different brakes
  • B Total length and weight increase stopping distance and require more reaction time
  • C It accelerates faster
  • D It is shorter
Correct answer: B
More length, more weight, more time needed.
Question 19 of 25
A doubles/triples driver should never:
  • A Skip the brake-light test
  • B Skip the parking-brake test
  • C All of the above
  • D Skip the air-leak rate check
Correct answer: C
All three are required for safe operation.
Question 20 of 25
A doubles/triples driver should know:
  • A Coupling and uncoupling procedures
  • B All of the above
  • C How to inspect each connection point
  • D State and federal route restrictions
Correct answer: B
Comprehensive knowledge is essential for safe operation.
Question 21 of 25
When a triple combination encounters a tight turn:
  • A Plan the turn carefully and use multiple lanes if necessary
  • B Turn sharply
  • C Skip the planning
  • D Maintain speed
Correct answer: A
Triples require careful planning for tight turns due to extreme off-tracking.
Question 22 of 25
The pintle hook safety latch:
  • A Is the same as a fifth wheel jaw
  • B Is electrical
  • C Is decorative
  • D Prevents accidental release of the hook
Correct answer: D
Safety latch ensures the hook cannot release accidentally.
Question 23 of 25
A driver pulling doubles or triples should drive in:
  • A Any lane
  • B The left lane
  • C The shoulder
  • D The right lane on multilane highways when possible
Correct answer: D
Slower lanes are safer for long combinations.
Question 24 of 25
A doubles/triples driver should plan routes to:
  • A Avoid freeways
  • B Take the shortest route regardless
  • C Drive only at night
  • D Avoid restricted roads and minimize sharp curves and steep grades
Correct answer: D
Route planning reduces handling demands.
Question 25 of 25
When checking the dolly's pintle hook:
  • A Allow chains to drag
  • B Skip the safety chains
  • C Allow loose engagement
  • D Verify it is properly engaged and safety chains are attached
Correct answer: D
Pintle hooks must be locked and safety chains attached.

Study tips for the Vermont Doubles / Triples exam

The Doubles / Triples portion of the Vermont CDL exam is graded out of the bank of questions the Vermont Department of Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the Doubles / Triples chapter of the Vermont 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 Vermont 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 Doubles / Triples.

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 Vermont Department of Motor Vehicles 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 Doubles / Triples 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 Vermont General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the Doubles / Triples study guide and the matching chapter in the official Vermont 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 Vermont Department of Motor Vehicles office.

Already comfortable with this endorsement? Drill another: VT General Knowledge · VT Air Brakes · VT Combination Vehicles · VT Hazardous Materials · VT Passenger · VT School Bus · VT Tank Vehicle

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