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MO · N Endorsement

Missouri Tank Vehicle CDL Practice Test

Below are 25 exam-style questions for the Missouri Tank Vehicle CDL knowledge test, modeled on the FMCSA-aligned content used by the Missouri Department of Revenue. 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 vapor-recovery system on a tanker:
  • A Reduces engine noise
  • B Operates the brakes
  • C Improves fuel mileage
  • D Captures vapors during loading and unloading to reduce emissions
Correct answer: D
Vapor recovery is required by environmental rules at many facilities.
Question 2 of 25
A baffled tank:
  • A Is divided into separate compartments
  • B Is illegal in the U.S.
  • C Has internal walls with holes that slow liquid movement
  • D Has no internal structure
Correct answer: C
Baffles reduce front-to-back surge; side-to-side surge is still possible.
Question 3 of 25
The most common rollover scenario for tankers is:
  • A On a curve or off-ramp at speeds the driver thought were safe
  • B In low-speed maneuvers
  • C On straight roads
  • D In stopped traffic
Correct answer: A
Rollover happens at speeds the driver did not expect would matter; reduce more than you think.
Question 4 of 25
A tanker on a long downhill with brake fade should:
  • A Coast in neutral
  • B Look for an escape ramp
  • C Use the parking brake harder
  • D Increase speed to clear the descent
Correct answer: B
Escape ramps are designed for runaway trucks, including tankers.
Question 5 of 25
A tanker driver should always:
  • A Skip pre-trip checks of vents and covers
  • B Use the trailer hand valve as a parking brake
  • C Drive at the posted speed regardless of conditions
  • D Be ready for surge during stops, starts, and turns
Correct answer: D
Anticipating surge is the constant tanker mindset.
Question 6 of 25
A tanker driver should not:
  • A Use the trailer hand valve as a parking brake
  • B Disregard surge
  • C Skip outage
  • D All of the above
Correct answer: D
All three are unsafe practices.
Question 7 of 25
A tanker driver should inspect:
  • A Manhole covers and vents
  • B The tank shell for corrosion or damage
  • C Special pump and valve systems
  • D All of the above
Correct answer: D
Tank-specific inspection covers covers, vents, valves, and shell condition.
Question 8 of 25
A high center of gravity in a tanker means:
  • A Easier handling
  • B Higher rollover risk
  • C Faster acceleration
  • D No change in handling
Correct answer: B
High CG combined with liquid surge dramatically increases rollover risk.
Question 9 of 25
A tanker driver should plan trips to:
  • A Avoid all freeways
  • B Use the parking brake on grades
  • C Avoid steep grades and sharp curves where possible
  • D Take the shortest route regardless of grade
Correct answer: C
Route planning reduces handling demands on the tanker.
Question 10 of 25
A driver loading a tanker with a flammable liquid must:
  • A Bond only after the loading is complete
  • B Disconnect the bonding mid-loading
  • C Bond and ground before opening the manhole
  • D Skip the bonding if the load is small
Correct answer: C
Bonding before opening prevents static-spark ignition.
Question 11 of 25
A tanker that is partially loaded:
  • A Has more surge than a full or empty tank
  • B Has less surge than a full tank
  • C Has no surge
  • D Has the same surge
Correct answer: A
Partial loads have the most room for the liquid to slosh.
Question 12 of 25
A "tank vehicle" requires the N endorsement when:
  • A It carries any liquid
  • B It has a tank with rated capacity of 1,000 gallons or more (single tank or aggregate of portable tanks)
  • C It is a flatbed
  • D It carries dry cargo
Correct answer: B
N endorsement is required for permanently mounted tanks of 1,000+ gallons or aggregate portable tanks of 1,000+ gallons.
Question 13 of 25
"Outage" in tanker operations means:
  • A A tank leak
  • B The empty space left in a tank for product expansion
  • C A driver shortage
  • D Equipment failure
Correct answer: B
Outage is the unfilled space allowed for liquid expansion in heat.
Question 14 of 25
A tanker that is leaking should:
  • A Allow product to leak until empty
  • B Stop, isolate the area, and notify emergency services and the carrier
  • C Drive faster to limit the spill
  • D Continue to the destination
Correct answer: B
Leak management requires immediate stop and proper notification.
Question 15 of 25
When you brake a tanker, the surge can:
  • A Push you forward after you stop
  • B Improve traction
  • C Help you stop sooner
  • D Have no effect
Correct answer: A
Forward surge after stopping is the classic tanker hazard.
Question 16 of 25
When negotiating a roundabout in a tanker:
  • A Maintain posted speed
  • B Slow well below posted speed and watch for surge as you change direction
  • C Honk and proceed
  • D Use the inside lane only
Correct answer: B
Roundabouts combine direction changes and curves; tankers must slow more.
Question 17 of 25
When parking a tanker, you should:
  • A Use the trailer hand valve
  • B Set only the tractor parking brake
  • C Leave brakes off
  • D Set both tractor and trailer parking brakes and chock if necessary
Correct answer: D
Full parking-brake set plus chocks where needed for tanker stability.
Question 18 of 25
A compartmented tank:
  • A Is the same as smooth-bore
  • B Has no baffles
  • C Has only one section
  • D Has separate sections for different products
Correct answer: D
Compartments allow separate products and limit surge within each compartment.
Question 19 of 25
When loading product, the driver should:
  • A Allow the receiver to verify later
  • B Trust the loader to handle it
  • C Skip the verification
  • D Verify the correct product, quantity, and compatibility with the tank
Correct answer: D
Driver verification at loading prevents costly errors and contamination.
Question 20 of 25
When approaching a curve in a tanker, you should:
  • A Increase speed
  • B Slow down before the curve, not in it
  • C Brake within the curve
  • D Maintain speed
Correct answer: B
Speed reduction before the curve prevents surge and rollover.
Question 21 of 25
When a tank is unbaffled (smooth-bore), the driver should:
  • A Drive normally
  • B Allow extra following distance and brake earlier
  • C Disregard surge
  • D Use only the parking brake to slow
Correct answer: B
Extra cushion ahead and earlier braking compensate for severe surge.
Question 22 of 25
When unloading a tanker, you should:
  • A Skip the venting
  • B Open vents while pressure is high
  • C Drive while unloading
  • D Open vents only after pressure is equalized
Correct answer: D
Equalize pressure first to prevent splash, vapor release, and damage.
Question 23 of 25
When adding chemicals to a tanker, the driver should:
  • A Verify product compatibility and follow safety procedures
  • B Mix freely
  • C Allow the receiver to add chemicals
  • D Skip the safety check
Correct answer: A
Compatibility prevents reactions and contamination.
Question 24 of 25
Lane changes in a tanker should be:
  • A Smooth and gradual to minimize side-to-side surge
  • B Without signaling
  • C At any speed
  • D Sharp and quick
Correct answer: A
Smooth maneuvers reduce surge that could affect handling.
Question 25 of 25
When you discover a leak in the tank during the trip:
  • A Try to repair the leak yourself
  • B Continue to the destination
  • C Drive faster
  • D Stop in a safe location, isolate the area, and notify the carrier and authorities
Correct answer: D
Leak procedures require stop, isolate, and notify.

Study tips for the Missouri Tank Vehicle exam

The Tank Vehicle portion of the Missouri CDL exam is graded out of the bank of questions the Missouri Department of Revenue draws from each year. While the exact bank is not published, every question is sourced from the Tank Vehicle chapter of the Missouri 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 Missouri 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 Missouri Department of Revenue 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 Missouri 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 Missouri 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 Missouri Department of Revenue office.

Already comfortable with this endorsement? Drill another: MO General Knowledge · MO Air Brakes · MO Combination Vehicles · MO Hazardous Materials · MO Passenger · MO School Bus · MO Doubles / Triples

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