Tennessee Combination Vehicles CDL Practice Test
Below are 25 exam-style questions for the Tennessee Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Tennessee Department of Safety and Homeland Security. 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 Too high — it can damage the kingpin or skip over the fifth wheel
- B Loaded
- C Properly chocked
- D Empty
- A Steering wander only
- B Engine knocking
- C Pulling, sticking, or unusual feel as you apply the brakes
- D Smoke from the cab
- A They are heavier and longer
- B They take more skill to back, couple, and uncouple
- C They have a higher rollover risk
- D All of the above
- A Set only the tractor parking brake
- B Leave the engine running with the brakes off
- C Set both tractor and trailer parking brakes
- D Use the trailer hand valve
- A Listen for a click
- B Honk the horn
- C Look at the locking jaws only
- D Tug the trailer with the trailer parking brakes set
- A Electrical connectors
- B Manual transmission shifters
- C Brake adjustment levers
- D Coupling devices for connecting tractor air lines to the trailer
- A Sensors at each wheel that release brake pressure when wheel lockup is detected
- B Hydraulic brakes
- C A separate compressor
- D Hand valves
- A The brakes are released gently
- B The trailer wheels lock briefly
- C You are driving slowly
- D The drive wheels lock and the trailer pushes the tractor sideways
- A The fuel mileage
- B The trailer following the same path as the tractor in a straight line
- C Lane positioning at intersections
- D Cargo placement
- A Steering becomes easier
- B No effect on safety
- C Stopping distances increase and the trailer can swing
- D Stopping distances are normal
- A Cargo movement
- B Engine failure
- C Worn out tires
- D Driving too fast for conditions and/or too closely
- A Release the brakes to allow the trailer wheels to roll again, then steer
- B Disconnect the air supply
- C Apply the trailer hand valve harder
- D Accelerate
- A You will notice immediately because trailer brakes will not work properly
- B The horn will sound
- C The trailer brakes will be locked on
- D Nothing will happen
- A Drains the trailer reservoir
- B Sends air pressure to apply trailer service brakes
- C Sends supply air to the trailer reservoirs
- D Carries electrical power
- A Only need attention every 5 years
- B Are normal until the lining is gone
- C Should be replaced when worn beyond manufacturer specs
- D Make the truck quieter
- A Pressing the pedal once at startup
- B Asking a mechanic
- C Performing the seven-step air-brake check before each trip
- D Listening to the brake light
- A Use blocks instead
- B Leave the gear up
- C Lower the landing gear all the way until firmly on the ground, then a few extra cranks
- D Raise the gear partway
- A Last
- B First (closest to the tractor)
- C Either position is fine
- D Loaded last
- A Trailer sway in crosswinds
- B All of the above
- C Off-tracking on right turns
- D Reduced visibility along the trailer
- A The tractor service brakes only
- B The trailer service brakes only
- C Both tractor and trailer brakes simultaneously
- D The parking brake
- A Be missing
- B Be closed around the shank of the kingpin (not on the head)
- C Be open
- D Be loose
- A Shift in the middle of the track
- B Cross in a low gear without shifting
- C Honk and accelerate
- D Stop on the tracks if traffic ahead slows
- A By setting the red trailer-air-supply valve
- B By pushing in the red trailer-air-supply valve
- C By pulling out the red trailer-air-supply valve
- D By the trailer hand valve
- A Stop traffic by signaling left
- B 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
- C Turn from the left lane
- D Use the shoulder
- A It is illegal in some states
- B It is fine if you are careful
- C It can damage the cab and the trailer (cab corner crush)
- D It is the standard procedure
Study tips for the Tennessee Combination Vehicles exam
The Combination Vehicles portion of the Tennessee CDL exam is graded out of the bank of questions the Tennessee Department of Safety and Homeland Security draws from each year. While the exact bank is not published, every question is sourced from the Combination Vehicles chapter of the Tennessee 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 Tennessee 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 Tennessee Department of Safety and Homeland Security 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 Tennessee 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 Tennessee 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 Tennessee Department of Safety and Homeland Security office.
Already comfortable with this endorsement? Drill another: TN General Knowledge · TN Air Brakes · TN Hazardous Materials · TN Passenger · TN School Bus · TN Tank Vehicle · TN Doubles / Triples
New to the CDL process in Tennessee? Read How to apply for a CDL in Tennessee for the document checklist and step-by-step timeline.