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CDL knowledge test

CDL Tank Vehicles Practice Test 2026

For the N endorsement: which vehicles need it, inspecting tank vehicles, driving them safely, liquid surge, baffles and outage.

28 practice questions, all written from Commercial Driver's License Manual (Version 07/20/2026 (form DMV 60A), AAMVA, Virginia DMV edition). Every answer shows the manual section it comes from. Free, no sign-up.

  • 28 questions
  • 20 per attempt
  • Pass mark: 80%
Start the practice test See sample questions

Start the Tank Vehicles practice test

20 questions. Passing score: 80%. No sign-up needed.

Choose how you want to practice:

Test format

Passing score At least 80% correct (49 CFR 383.135 (eCFR))
Number of questions Varies by state. Check the CDL manual from your state’s licensing agency.
Our practice test 20 questions per attempt, drawn at random from 28. Pass mark: 80%.

Topics covered

  • Driving tank vehicles 9 questions
  • Inspecting tank vehicles 8 questions
  • Safe driving rules 7 questions
  • Tank vehicle endorsement 4 questions

Sample questions

A few questions from the set. Try to answer before opening each explanation.

  1. Sample question 1

    What kind of liquid surge can still happen in a baffled tank?

    • ASide-to-side surge, which can cause a rollover
    • BNone, because baffles stop all surge
    • COnly surge when the tank is completely full
    • DOnly forward surge when the truck speeds up
    Show answer

    Answer: A. Baffles help with front-to-back movement, but the liquid can still slosh sideways and tip the vehicle over.

    Source: Commercial Driver's License Manual, Version 07/20/2026 (form DMV 60A), section 8.2.4 Baffled Tanks.

  2. Sample question 2

    Compared with a full tank vehicle, how might an empty tank vehicle stop?

    • AIt may take longer to stop
    • BIt always stops in half the distance
    • CIt stops in exactly the same distance
    • DIt cannot skid when braking
    Show answer

    Answer: A. A lighter load does not always mean a shorter stop; an empty tanker can need more distance than a loaded one.

    Source: Commercial Driver's License Manual, Version 07/20/2026 (form DMV 60A), section 8.3.4 Stopping Distance.

  3. Sample question 3

    What does a high center of gravity do to a tank vehicle?

    • AMakes it steadier in curves
    • BMakes it easier to stop on wet roads
    • CMakes it top-heavy and easy to roll over
    • DMakes it less likely to skid on ice
    Show answer

    Answer: C. With much of the load's weight carried high above the road, the tanker is top-heavy and can tip over easily.

    Source: Commercial Driver's License Manual, Version 07/20/2026 (form DMV 60A), section 8.2.1 High Center of Gravity.

  4. Sample question 4

    Because tank vehicles come in many types and sizes, where should you check to learn how to inspect your own tank vehicle?

    • AThe cargo's shipping papers
    • BThe vehicle's operator manual
    • CThe tank's capacity plate
    • DThe last driver's trip log
    Show answer

    Answer: B. Inspection items differ between tank designs, so the operator manual for your vehicle tells you how to inspect it.

    Source: Commercial Driver's License Manual, Version 07/20/2026 (form DMV 60A), section 8.1 Inspecting Tank Vehicles.

  5. Sample question 5

    What may happen if you steer quickly while braking in a tank vehicle?

    • AThe brakes may fade completely
    • BThe vehicle may roll over
    • CThe engine may stall
    • DThe tank valves may open
    Show answer

    Answer: B. Sharp steering during braking can tip a tanker over, so keep steering inputs gentle while you brake.

    Source: Commercial Driver's License Manual, Version 07/20/2026 (form DMV 60A), section 8.3.2 Controlling Surge.

How to prepare

  • Read the matching sections of your state’s CDL manual before you practice.
  • Use practice mode first: it shows the explanation and the manual reference after each answer.
  • For every missed question, reread the whole manual section we cite.
  • Switch to exam mode when you score well above 80% without help.

More detail in our guide How to Study for the CDL Knowledge Tests.

Other CDL practice tests

Which tests you need depends on your license class and endorsements, as explained in CDL Classes, Endorsements and Restrictions Explained.

Frequently asked questions

What score do I need to pass?

Federal rules require at least 80% correct on each CDL knowledge test (49 CFR 383.135 (eCFR)).

Are these the questions on the real test?

No. Real test questions are not public. We write our own questions from the official manual, so they cover the same material but are not copies of test questions.

Is the CDL manual the same in every state?

State CDL manuals are built on the same national model manual from AAMVA, so the knowledge content is largely the same. We compared 3 state editions for this test: 28 of 28 quotes appear word for word in the same section of all of them. Your own state’s manual is the final word if anything differs.

How do you check the answers?

Each question stores the manual section (or page) and an exact quote that a script checks against the manual text, then an independent AI review answers it from that part of the manual alone. See our editorial policy. Found a mistake? Tell us.

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20 questions, pass mark 80%. Free, no sign-up.

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Sources

Questions cite the newest edition we have. We also check every quote against the other state editions of the same model manual, section by section.