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DE · N Endorsement

Delaware Tank Vehicle CDL Practice Test

Below are 25 exam-style questions for the Delaware Tank Vehicle 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.

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 "tank vehicle" requires the N endorsement when:
  • A It carries dry cargo
  • B It carries any liquid
  • C It is a flatbed
  • D It has a tank with rated capacity of 1,000 gallons or more (single tank or aggregate of portable tanks)
Correct answer: D
N endorsement is required for permanently mounted tanks of 1,000+ gallons or aggregate portable tanks of 1,000+ gallons.
Question 2 of 25
A "cargo tank" on a vehicle is:
  • A Permanently mounted to the vehicle
  • B A portable tank set on the vehicle
  • C All of the above can be a cargo tank
  • D A trailer-mounted tank
Correct answer: C
Cargo tanks can be permanently mounted, portable, or trailer-mounted; specifications vary.
Question 3 of 25
A baffled tank:
  • A Has no internal structure
  • B Is divided into separate compartments
  • C Has internal walls with holes that slow liquid movement
  • D Is illegal in the U.S.
Correct answer: C
Baffles reduce front-to-back surge; side-to-side surge is still possible.
Question 4 of 25
When making a sudden stop in a tanker, the load can:
  • A Cause rollover
  • B Cause loss of control
  • C All of the above
  • D Push the vehicle through an intersection
Correct answer: C
Surge consequences include all three; brake earlier and harder than expected.
Question 5 of 25
When loading product, the driver should:
  • A Allow the receiver to verify later
  • B Verify the correct product, quantity, and compatibility with the tank
  • C Skip the verification
  • D Trust the loader to handle it
Correct answer: B
Driver verification at loading prevents costly errors and contamination.
Question 6 of 25
After unloading, the driver should:
  • A Close vents and covers, secure equipment, and inspect for leaks before leaving
  • B Allow the receiver to close everything
  • C Skip the post-unload inspection
  • D Drive away with vents open
Correct answer: A
Post-unload inspection ensures the tank is secured before transport.
Question 7 of 25
When a tank is unbaffled (smooth-bore), the driver should:
  • A Drive normally
  • B Use only the parking brake to slow
  • C Allow extra following distance and brake earlier
  • D Disregard surge
Correct answer: C
Extra cushion ahead and earlier braking compensate for severe surge.
Question 8 of 25
A tanker is more sensitive to wind because:
  • A It uses air brakes
  • B Its high center of gravity and large surface area increase wind effects
  • C It is shorter
  • D It is heavier
Correct answer: B
Wind can push and tip a tanker; reduce speed in heavy crosswinds.
Question 9 of 25
When loading or unloading a flammable liquid, the driver must:
  • A Walk away to take a break
  • B Allow the receiver to handle everything
  • C Stay within reach of the controls and maintain a clear view of the operation
  • D Stand at least 50 feet away
Correct answer: C
Continuous attendance is required for safety.
Question 10 of 25
When you discover a leak in the tank during the trip:
  • A Drive faster
  • B Stop in a safe location, isolate the area, and notify the carrier and authorities
  • C Continue to the destination
  • D Try to repair the leak yourself
Correct answer: B
Leak procedures require stop, isolate, and notify.
Question 11 of 25
Bonding and grounding for flammable liquids is intended to:
  • A Improve fuel mileage
  • B Reduce noise
  • C Prevent static-electricity sparks during loading and unloading
  • D Prevent corrosion
Correct answer: C
Bonding equalizes electrical potential; grounding sends static to earth.
Question 12 of 25
When a tanker is in a long downgrade and brakes start to fade:
  • A Use the escape ramp
  • B Increase speed
  • C Maintain pressure on the brakes
  • D Coast in neutral
Correct answer: A
Escape ramps are the engineered solution for runaway tankers.
Question 13 of 25
When unloading a tanker, you should:
  • A Open vents while pressure is high
  • B Open vents only after pressure is equalized
  • C Skip the venting
  • D Drive while unloading
Correct answer: B
Equalize pressure first to prevent splash, vapor release, and damage.
Question 14 of 25
When unloading at the destination:
  • A Allow the receiver to handle everything
  • B Begin unloading immediately
  • C Skip the verification
  • D Verify the receiver is ready and the receiving tank has capacity
Correct answer: D
Verification prevents overfilling and spills at the receiving tank.
Question 15 of 25
When the tank is full of dense liquid (such as oil):
  • A There is no effect
  • B Surge is severe
  • C It stops faster
  • D The vehicle is heavy and stops slower; surge is reduced but mass is high
Correct answer: D
Full tanks reduce surge but increase total mass and stopping distance.
Question 16 of 25
A tanker that is leaking should:
  • A Drive faster to limit the spill
  • B Allow product to leak until empty
  • C Continue to the destination
  • D Stop, isolate the area, and notify emergency services and the carrier
Correct answer: D
Leak management requires immediate stop and proper notification.
Question 17 of 25
A tanker driver should not:
  • A All of the above
  • B Skip outage
  • C Use the trailer hand valve as a parking brake
  • D Disregard surge
Correct answer: A
All three are unsafe practices.
Question 18 of 25
A "wet line" on a tanker is:
  • A An air-brake line
  • B A pipe that contains residual liquid product
  • C A frozen pipe
  • D A fuel line
Correct answer: B
Wet lines contain liquid that can leak from valves; check during inspection.
Question 19 of 25
In emergency response, a tanker driver should:
  • A Wait for the carrier to instruct
  • B Refer to the ERG and shipping papers for product-specific guidance
  • C Open all vents
  • D Rely on memory only
Correct answer: B
ERG and shipping papers give the immediate emergency procedure.
Question 20 of 25
A tanker driver loading at a self-serve facility should:
  • A Follow site procedures and verify equipment before loading
  • B Allow another driver to load for them
  • C Skip the site procedures
  • D Begin loading without checking
Correct answer: A
Site procedures are designed to prevent spills and ensure safe loading.
Question 21 of 25
When loading a tank, you should:
  • A Fill the tank completely
  • B Overfill if running low on time
  • C Leave room for product expansion (outage)
  • D Skip the outage if the product is cold
Correct answer: C
Outage prevents pressure damage and spills as product warms.
Question 22 of 25
When you stop quickly in a tanker, you should:
  • A Disengage the clutch
  • B Hold the steering wheel firmly because the load may push you forward
  • C Release the wheel
  • D Apply the parking brake immediately
Correct answer: B
Surge forces require firm steering control during and after the stop.
Question 23 of 25
A tanker on a downgrade should:
  • A Use parking brake intermittently
  • B Coast in neutral
  • C Be in low gear and use steady moderate brake application
  • D Increase speed
Correct answer: C
Standard heavy-vehicle downgrade rule plus extra concern for surge.
Question 24 of 25
A tanker driver who must back the truck should:
  • A Use only mirrors
  • B GOAL — Get Out And Look — and use a spotter when possible
  • C Skip the visual check
  • D Back at full speed
Correct answer: B
Backing risk is high; visual check and spotter are key.
Question 25 of 25
Lane changes in a tanker should be:
  • A At any speed
  • B Sharp and quick
  • C Smooth and gradual to minimize side-to-side surge
  • D Without signaling
Correct answer: C
Smooth maneuvers reduce surge that could affect handling.

Study tips for the Delaware Tank Vehicle exam

The Tank Vehicle 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 Tank Vehicle 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 Tank Vehicle.

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 Tank Vehicle 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 Tank Vehicle 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 Combination Vehicles · DE Hazardous Materials · DE Passenger · DE School Bus · 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.