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NH · T Endorsement

New Hampshire Doubles / Triples CDL Practice Test

Below are 25 exam-style questions for the New Hampshire Doubles / Triples CDL knowledge test, modeled on the FMCSA-aligned content used by the New Hampshire Division 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 Air lines from tractor to first trailer to dolly to second trailer
  • B Air lines only on the tractor
  • C Mechanical brakes only
  • D No air-brake system
Correct answer: A
Air system extends through the entire combination via glad hands at each connection.
Question 2 of 25
When you need to back a doubles combination:
  • A Back at full speed
  • B Have a passenger guide you
  • C Avoid it; if necessary, uncouple to a single trailer first
  • D Use only mirrors
Correct answer: C
Backing doubles is extremely difficult; uncouple if possible.
Question 3 of 25
A "double" in trucking refers to:
  • A Two tractors pulling one trailer
  • B A trailer with two axles
  • C A bus with two sections
  • D Two trailers behind one tractor
Correct answer: D
Double = two trailers behind one tractor; triple = three trailers.
Question 4 of 25
When you need to make a lane change in heavy traffic with doubles:
  • A Skip the signal
  • B Change quickly to fit in
  • C Cut between cars
  • D Plan the change well in advance, signal early, and change when there is ample space
Correct answer: D
Planning and patience prevent collisions.
Question 5 of 25
A doubles/triples driver who experiences trailer swing should:
  • A Steer sharply to correct
  • B Brake hard
  • C Accelerate
  • 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 Only on Interstate 80
  • B On all U.S. highways
  • C In some states; restrictions vary
  • D In Canada only
Correct answer: C
Triples are restricted by state and route; the T endorsement does not override route restrictions.
Question 7 of 25
A doubles/triples driver should be especially aware of:
  • A Potential rollover at curves
  • B All of the above
  • C Lane changes that swing the rear
  • D Crosswind effects on the rear trailer
Correct answer: B
All three considerations apply to multi-trailer combinations.
Question 8 of 25
When the second trailer fishtails:
  • A Accelerate
  • B Steer sharply
  • C Reduce speed gradually and avoid sudden steering inputs
  • D Brake hard
Correct answer: C
Gradual reduction allows recovery without overcorrection.
Question 9 of 25
When uncoupling a converter dolly:
  • A Disconnect at high speed
  • B Allow the dolly to roll
  • C Set the parking brake or chock the wheels before disconnecting
  • D Skip the parking brake
Correct answer: C
Brake setting prevents dolly movement during disconnect.
Question 10 of 25
A doubles driver should be aware of:
  • A No specific length
  • B Tractor length only
  • C Total combination length when turning, parking, and changing lanes
  • D Trailer length only
Correct answer: C
Total length affects every maneuver.
Question 11 of 25
Safety chains on a doubles combination:
  • A Are required only on triples
  • B Provide a backup connection in case the primary coupling fails
  • C Carry electrical signals
  • D Are decorative
Correct answer: B
Safety chains hold the trailer if the primary coupling fails.
Question 12 of 25
When inspecting safety chains:
  • A Verify they are crossed under the pintle hook and not dragging
  • B Skip the inspection
  • C Tie them in knots
  • 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
A "B-train" is:
  • A A type of bus
  • B A train carrying buses
  • C A combination with a second trailer that has a kingpin attached to the first trailer
  • D A type of car carrier
Correct answer: C
B-trains use a fifth wheel on the first trailer instead of a converter dolly.
Question 14 of 25
A doubles combination has more tires, which means:
  • A Better handling
  • B Fewer inspection points
  • C More opportunities for tire failure and more inspection points
  • D No effect on safety
Correct answer: C
More tires = more inspection time and more potential failures.
Question 15 of 25
When the driver brakes a doubles combination:
  • A Only the first trailer brakes
  • B Brakes are uneven
  • C Only the rear trailer brakes
  • D All trailers should brake together if the system is functioning correctly
Correct answer: D
Air-brake system applies all wheels simultaneously when functioning correctly.
Question 16 of 25
A doubles/triples driver should know:
  • A All of the above
  • B How to inspect each connection point
  • C State and federal route restrictions
  • D Coupling and uncoupling procedures
Correct answer: A
Comprehensive knowledge is essential for safe operation.
Question 17 of 25
When the air-supply line to the second trailer disconnects accidentally:
  • A The tractor brakes apply
  • B Nothing happens
  • 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 18 of 25
When pulling doubles or triples, the heaviest trailer should be:
  • A Last (furthest from the tractor)
  • B In the middle
  • C It does not matter
  • D First (closest to the tractor)
Correct answer: D
Heavier trailer first reduces sway and improves handling.
Question 19 of 25
When you turn a combination of doubles or triples right at an intersection:
  • A Off-tracking is more pronounced; swing wider than for a single trailer
  • B No off-tracking occurs
  • C Off-tracking is less than a single trailer
  • D Use the left lane
Correct answer: A
More trailers = more off-tracking; plan turns carefully.
Question 20 of 25
A doubles combination needs more following distance because:
  • A It uses different brakes
  • B It is shorter
  • C Total length and weight increase stopping distance and require more reaction time
  • D It accelerates faster
Correct answer: C
More length, more weight, more time needed.
Question 21 of 25
When inspecting doubles or triples, you should check:
  • A All of the above
  • B Dolly air-tank pressure
  • C Glad hands and seals at every connection
  • D Pintle hooks and safety chains
Correct answer: A
Each connection point is a potential failure; check thoroughly.
Question 22 of 25
In a panic stop with doubles, the:
  • A Speed is reduced faster
  • B Brakes work better
  • C Tractor cannot jackknife
  • D Rear trailer can swing out and cause loss of control
Correct answer: D
Trailer swing and rollover are major risks during panic stops.
Question 23 of 25
A doubles/triples driver should never:
  • A All of the above
  • B Drive faster than conditions allow
  • C Back without a spotter when possible
  • D Skip the air-brake check
Correct answer: A
All three are violations of safe doubles/triples operation.
Question 24 of 25
A doubles combination on a slick road:
  • A Should be driven slowly with extra following distance
  • B Should brake hard
  • C Can maintain normal speed
  • D Should change lanes frequently
Correct answer: A
Slick road + multiple trailers = extra caution.
Question 25 of 25
When coupling a converter dolly to the rear of the first trailer:
  • A Skip the air check
  • B Verify the dolly's air tank has air pressure and lock the dolly's parking brake before backing under the second trailer
  • C Allow the dolly to roll freely
  • D Couple without verifying
Correct answer: B
Pre-coupling checks prevent dolly movement during the second-trailer coupling.

Study tips for the New Hampshire Doubles / Triples exam

The Doubles / Triples portion of the New Hampshire CDL exam is graded out of the bank of questions the New Hampshire Division 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 New Hampshire 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 New Hampshire 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 New Hampshire Division 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 New Hampshire 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 New Hampshire 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 New Hampshire Division of Motor Vehicles office.

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

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