Mississippi Doubles / Triples CDL Practice Test
Below are 25 exam-style questions for the Mississippi Doubles / Triples CDL knowledge test, modeled on the FMCSA-aligned content used by the Mississippi Department of Public Safety. 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.
- A Use the spare
- B Replace before operating
- C Continue with damaged tires
- D Ignore the damage
- A Skip the testing
- B All air lines and electrical lines should be connected and tested
- C Some lines may be optional
- D Test only one line
- A Only the rear trailer brakes
- B Only the first trailer brakes
- C All trailer service brakes simultaneously
- D Tractor and trailer brakes
- A Provide a backup connection in case the primary coupling fails
- B Carry electrical signals
- C Are decorative
- D Are required only on triples
- A Steer sharply
- B Reduce speed gradually and avoid sudden steering inputs
- C Brake hard
- D Accelerate
- A Better handling
- B More opportunities for tire failure and more inspection points
- C Fewer inspection points
- D No effect on safety
- A Has the same rollover risk
- B Cannot roll
- C Is less likely to roll
- D Is more likely to roll than the first
- A Tractor to second trailer first
- B Random order
- C Drop first trailer, hook converter dolly to first trailer, back tractor to second trailer, etc.
- D Trailers first, then tractor
- A Fuel tanks
- B Air lines, electrical lines, and connection points
- C Engines
- D Drivers
- A Prevents accidental release of the hook
- B Is the same as a fifth wheel jaw
- C Is electrical
- D Is decorative
- A Skip the inspection
- B Verify they are crossed under the pintle hook and not dragging
- C Tie them in knots
- D Allow them to drag
- A Skip the air-brake check
- B Back without a spotter when possible
- C All of the above
- D Drive faster than conditions allow
- A Mechanical brakes only
- B No air-brake system
- C Air lines from tractor to first trailer to dolly to second trailer
- D Air lines only on the tractor
- A Reduce speed gradually and avoid sudden steering inputs
- B Steer sharply to correct
- C Brake hard
- D Accelerate
- A Verify the fifth wheel locks around the kingpin and test by tugging gently
- B Skip the lock verification
- C Couple at high speed
- D Trust visual inspection only
- A A bus with two sections
- B A trailer with two axles
- C Two tractors pulling one trailer
- D Two trailers behind one tractor
- A In the middle
- B Last (furthest from the tractor)
- C First (closest to the tractor)
- D It does not matter
- 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
- A Crosswind sensitivity
- B Increased rollover risk in curves
- C All of the above
- D Reduced visibility around the second trailer
- A Avoid freeways
- B Avoid restricted roads and minimize sharp curves and steep grades
- C Drive only at night
- D Take the shortest route regardless
- A Potential rollover at curves
- B Crosswind effects on the rear trailer
- C All of the above
- D Lane changes that swing the rear
- A The first trailer accelerates
- B The second trailer's emergency brakes apply automatically
- C Nothing happens
- D The tractor brakes apply
- A In some states; restrictions vary
- B Only on Interstate 80
- C On all U.S. highways
- D In Canada only
- A Federal and state rules vary; T endorsement does not override route restrictions
- B There are no restrictions
- C Restrictions apply only to hazmat
- D T endorsement allows triples everywhere
- A A trailer for transporting animals
- B A short trailer commonly used in doubles and triples
- C A converter dolly
- D A tractor only
Study tips for the Mississippi Doubles / Triples exam
The Doubles / Triples portion of the Mississippi CDL exam is graded out of the bank of questions the Mississippi Department of Public Safety draws from each year. While the exact bank is not published, every question is sourced from the Doubles / Triples chapter of the Mississippi 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 Mississippi 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 Mississippi Department of Public Safety 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 Mississippi 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 Mississippi 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 Mississippi Department of Public Safety office.
Already comfortable with this endorsement? Drill another: MS General Knowledge · MS Air Brakes · MS Combination Vehicles · MS Hazardous Materials · MS Passenger · MS School Bus · MS Tank Vehicle
New to the CDL process in Mississippi? Read How to apply for a CDL in Mississippi for the document checklist and step-by-step timeline.