Delaware Combination Vehicles CDL Practice Test
Below are 25 exam-style questions for the Delaware Combination Vehicles CDL knowledge test, modeled on the FMCSA-aligned content used by the Delaware 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.
- A Leave the gear up
- B Use blocks instead
- C Raise the gear partway
- D Lower the landing gear all the way until firmly on the ground, then a few extra cranks
- A Show up only at high speed
- B Need a mechanic to find
- C Are caused by low fuel
- D Can be detected during pre-trip inspection by visual and pressure checks
- A The fifth wheel breaks
- B A wheel bearing fails
- C The trailer brakes lock up
- D The tractor brakes lock up
- A Disable the trailer parking brake
- B Connect the lines back to the tractor
- C Check that the trailer is stable on its landing gear
- D Move the tractor far away immediately without checking
- A Be loose
- B Be closed around the shank of the kingpin (not on the head)
- C Be open
- D Be missing
- A Driving too fast for conditions and/or too closely
- B Engine failure
- C Worn out tires
- D Cargo movement
- A Manual transmission shifters
- B Coupling devices for connecting tractor air lines to the trailer
- C Electrical connectors
- D Brake adjustment levers
- A 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
- B Stop traffic by signaling left
- C Use the shoulder
- D Turn from the left lane
- A Two car lengths
- B No specific rule
- C A vehicle length
- D One second per 10 feet of vehicle length below 40 mph, plus one extra second above 40 mph
- A Carries electrical signals
- B Operates the parking brake only
- C Sends supply air to the trailer reservoirs and controls the trailer emergency brakes
- D Drains the wet tank
- A Reduced visibility along the trailer
- B All of the above
- C Off-tracking on right turns
- D Trailer sway in crosswinds
- A Its center of gravity is high
- B Its tires are wider
- C It is shorter than a straight truck
- D It uses air brakes
- A Sends supply air to the trailer reservoirs
- B Sends air pressure to apply trailer service brakes
- C Carries electrical power
- D Drains the trailer reservoir
- A Set both tractor and trailer parking brakes
- B Use the trailer hand valve
- C Set only the tractor parking brake
- D Leave the engine running with the brakes off
- A The drive wheels lock and the trailer pushes the tractor sideways
- B The brakes are released gently
- C You are driving slowly
- D The trailer wheels lock briefly
- A By pushing in the red trailer-air-supply valve
- B By the trailer hand valve
- C By setting the red trailer-air-supply valve
- D By pulling out the red trailer-air-supply valve
- A Before, during, and after coupling
- B Only at the destination
- C Only at the start of the day
- D Every 3 hours
- A Is part of the tractor
- B Replaces the fifth wheel on the tractor
- C Is used only when triple-towing
- D Is used to convert a semitrailer into a full trailer for towing in combination
- A Look at the locking jaws only
- B Tug the trailer with the trailer parking brakes set
- C Honk the horn
- D Listen for a click
- A Loss of traction
- B Driving off the road
- C Sliding sideways
- D The trailer wheels follow a tighter arc than the tractor wheels in a turn
- A No effect on safety
- B Stopping distances are normal
- C Steering becomes easier
- D Stopping distances increase and the trailer can swing
- A Engine wear
- B Driver fatigue
- C Air leakage in the supply line, low pressure, or a brake-balance issue
- D Cargo placement
- A Last
- B First (closest to the tractor)
- C Loaded last
- D Either position is fine
- A Too high — it can damage the kingpin or skip over the fifth wheel
- B Properly chocked
- C Empty
- D Loaded
- A Cracks in the kingpin
- B All of the above
- C Misalignment between tractor and trailer
- D Loose or missing fifth-wheel mounting bolts
Study tips for the Delaware Combination Vehicles exam
The Combination Vehicles portion of the Delaware CDL exam is graded out of the bank of questions the Delaware Division of Motor Vehicles draws from each year. While the exact bank is not published, every question is sourced from the Combination Vehicles chapter of the Delaware 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 Delaware 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 Delaware 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 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 Delaware 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 Delaware 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 Delaware Division of Motor Vehicles office.
Already comfortable with this endorsement? Drill another: DE General Knowledge · DE Air Brakes · DE Hazardous Materials · DE Passenger · DE School Bus · DE Tank Vehicle · DE Doubles / Triples
New to the CDL process in Delaware? Read How to apply for a CDL in Delaware for the document checklist and step-by-step timeline.