Tank Vehicles Practice Test
Required to haul liquid or gas in bulk. Surge, baffles, outage, and why a partly full tank stops differently from a loaded box trailer.
This is the N endorsement knowledge test. Passing it adds N to your commercial licence.
Do you need this test?
Optional — you only need it if you will actually be driving this way. Every CDL applicant takes the general knowledge test first.
Practice now
Study the material, not just the questions
Handle the surge, stability, and stopping challenges of liquid loads.
Open the Tanker Vehicles moduleThe other tests you'll need
- General Knowledge — 50 questions · 80% to pass
- Air Brakes — 25 questions · 80% to pass
- Combination Vehicles — 20 questions · 80% to pass
- Hazardous Materials — 30 questions · 80% to pass
- Doubles and Triples — 20 questions · 80% to pass
- Passenger Transport — 20 questions · 80% to pass
- School Bus — 20 questions · 80% to pass
- LCV Doubles — 30 questions · 80% to pass
- LCV Triples — 30 questions · 80% to pass
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Sample Tank Vehicles questions
The biggest danger when hauling a liquid tanker is:
- A. Running out of fuel
- B. Tire blowouts
- C. Surge and high center of gravity
- D. Air brake failure
Show answer
C. Surge and high center of gravity — Liquid surge and high center of gravity make tankers prone to rollovers, especially in turns and when braking.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 8: Tank Vehicles · verified 2026-05-17
You should never load a liquid tank completely full because:
- A. Liquids expand and need room
- B. It reduces fuel economy
- C. It makes the tank harder to clean
- D. It increases tire wear
Show answer
A. Liquids expand and need room — Leave outage (empty space) in liquid tanks because liquids expand with temperature changes. A full tank can rupture.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 8: Tank Vehicles · verified 2026-05-17
When driving a tanker, you should corner at lower speeds because of:
- A. Higher fuel consumption
- B. Increased tire wear
- C. High center of gravity and surge
- D. More air brake lag
Show answer
C. High center of gravity and surge — Tankers have a high center of gravity. Liquid surge in turns can cause rollovers. Slow down before curves.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 8: Tank Vehicles · verified 2026-05-17
When stopping a tanker, you should brake:
- A. Gently and well in advance
- B. Hard and quickly
- C. Only at the last moment
- D. Using only the parking brake
Show answer
A. Gently and well in advance — Brake gently and early when driving a tanker. Hard braking causes liquid to surge forward, pushing the vehicle and extending stopping distance.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 8: Tank Vehicles · verified 2026-05-17
When driving a tanker in windy conditions, you should:
- A. Speed up for stability
- B. Drive in the center lane only
- C. Use cruise control
- D. Reduce speed and hold the wheel firmly
Show answer
D. Reduce speed and hold the wheel firmly — Tankers have a high center of gravity and large surface area, making them very susceptible to cross winds. Reduce speed and grip the wheel firmly.
Universal rule · checked against FMCSA Commercial Driver License Manual — Section 8: Tank Vehicles · verified 2026-05-17
Frequently asked questions
How many questions are on the Tank Vehicles test?
20 multiple-choice questions, and you need 80% correct — so you can miss 4. The federal standard is consistent across nearly every state.
Is this Tank Vehicles practice test free?
Yes. Every practice test here and everything in the DMV Prep app is free — no ads, no paywall, no account.
Where do these questions come from?
The FMCSA Commercial Driver's License Manual and 49 CFR. Every question carries its citation, which you can open from the answer explanation.
