The CDL Tank Vehicle endorsement test is a knowledge exam that checks whether you understand how liquid cargo changes the way a commercial vehicle handles, brakes and turns. To pass, you must correctly answer at least 80 percent of the questions.
This page is a free tanker endorsement practice test and study guide built around the topics that exam covers: liquid surge, braking with different loads, baffles and compartments, tank construction, hills and curves, and emergency equipment. Use it to find your weak areas before you sit the real test at your state licensing agency.
The Tank Vehicle endorsement, often called the N endorsement or tanker endorsement, is a specialized add-on to a commercial driver's license. Federal rules set the knowledge standard for it, and your state driver licensing agency gives the test. This site is independent and is not affiliated with FMCSA or any state agency.
You need it if you drive a vehicle that hauls liquid or gaseous material in a tank or tanks that are permanently or temporarily attached to the vehicle or chassis. That includes fuel haulers, milk and water trucks, chemical carriers and many bulk liquid operations. Drivers who move into tanker work from general freight take it most often, along with new drivers whose first job is a tanker.
It is an extra test on top of the CDL knowledge and skills tests, not a replacement for them. Some states let you add the endorsement while holding a commercial learner's permit. In Texas, for example, the Tank Vehicle endorsement can be held on a CDL or a CLP. Check your own state's rules, because the process differs from place to place.
The content is narrower than the general CDL manual. The test centers on one idea: liquid moves, and a moving load changes everything about stopping and steering.
Facts verified Nov 9, 2026 against U.S. DOT Federal Motor Carrier Safety Administration (49 CFR Part 383). Each state driver licensing agency (DMV/DPS) adm. Dates that have passed are removed automatically.
| Item | Detail | Official source |
|---|---|---|
| Number of questions | Knowledge test required for the Tank (N) endorsement | U.S. DOT Federal Motor Carrier Safety Administration (49 CFR Part 383). Each state driver licensing agency (DMV/DPS) adm |
| Passing score | At least 80% correct | U.S. DOT Federal Motor Carrier Safety Administration (49 CFR Part 383). Each state driver licensing agency (DMV/DPS) adm |
| Eligibility | Specialized endorsement test on top of the CDL knowledge and skills tests | U.S. DOT Federal Motor Carrier Safety Administration (49 CFR Part 383). Each state driver licensing agency (DMV/DPS) adm |
Facts verified Nov 9, 2026 against U.S. DOT Federal Motor Carrier Safety Administration (49 CFR Part 383). Each state driver licensing agency (DMV/DPS) adm. Dates that have passed are removed automatically.
Prepare for the Tank Vehicle Endorsement Knowledge Test exam with our free practice test modules. Each quiz covers key topics to help you pass on your first try.
Each practice quiz below matches one content area of the Tank Vehicle Endorsement Knowledge Test. Start with the area you know least.
Surge is the movement of liquid inside a tank, and it is the central idea of this endorsement. This area covers how liquid sloshes forward and backward when you brake or accelerate, and from side to side in turns. It also covers why a partly filled tank is the hardest to control, since the liquid has room to build momentum. Study how surge can push a vehicle in the direction the liquid is moving, how it affects stopping distance, and how smooth, gradual inputs reduce it. Know the difference between how liquid behaves and how solid cargo behaves.
This area asks how load level changes stopping. Study how a full tank, an empty tank and a partly filled tank each respond to braking, and why none of them is the same as hauling solid freight. Pay attention to following distance, brake timing, and why sudden braking is dangerous when liquid can shift. Expect scenario questions, such as which load condition produces surge and what a driver should do differently. Review the manual's guidance on speed, spacing and smooth stops, and be able to explain the reasoning behind each answer.
Tank design controls how much liquid can move. This area covers baffles, which have holes that let liquid pass through while slowing front-to-back surge, and bulkheads, which divide a tank into separate compartments. Learn the difference between the two designs and what each does and does not prevent. Study why baffled tanks still have side-to-side movement, and why smooth-bore tanks are the least restrained. Be ready for questions asking which design limits which kind of movement, and what that means for how you drive.
Not all tanks are built alike, and the test expects you to recognize the main kinds. This area covers differences in construction, how a tank's shape and the cargo it carries affect stability, and why some tanks are more prone to rollover than others. Study the term outage and why liquid needs room to expand, and how that connects to loading practice. Review the vocabulary the manual uses for tank parts and designs, since questions often hinge on a precise term rather than a general idea.
This area applies tank behavior to real roads. Study how a high center of gravity and moving liquid raise rollover risk, especially in curves and on ramps. Learn why speed that is safe for other trucks may be too fast for a tanker, and how hills affect a load that can shift. Cover safe handling practices such as slowing before curves, avoiding sudden steering, and managing grades with proper gear and braking technique. Questions here tend to be practical, asking what a careful driver would do in a given situation.
This area covers the safety equipment and rules tied to tank vehicles. Study the emergency features the manual describes, how to respond to a leak or spill, and the basic regulatory expectations for tank operations. Learn which inspection items matter most before a trip, including checks of valves, fittings and covers. Know when a situation calls for reporting or specialized help. Regulations can vary by cargo and by state, so read your manual closely and note anything the test material states directly.
Federal rules require a knowledge test for the Tank Vehicle endorsement. The rules do not fix the number of questions. Each state sets its own count, so the length of your test may differ from what a driver in another state sees. The same is true of time limits, fees and scheduling, which your state agency controls.
The passing standard is consistent: you must correctly answer at least 80 percent of the questions. That leaves little room to guess on whole topics. If you skip an area such as surge or baffles, a handful of missed questions can put you under the line.
Questions are multiple choice and are drawn from the tank vehicle material in your state's CDL manual. Expect scenario wording, such as what happens when you brake hard with a partly filled tank, or which feature limits front-to-back liquid movement.
Because the format and counts vary, always confirm details with your state before test day. Look up:
Use the official FMCSA CDL page linked at the top of this page, and your state agency's site, for registration.
You do not need a long study campaign for this endorsement, but you do need to cover each content area. A workable plan looks like this:
Spread these steps over several short sessions rather than one long one. Flashcards work well for the vocabulary, and practice quizzes show which topics need another pass. Keep a short list of every question you miss and the reason you missed it.
Plan the logistics ahead. Confirm where your state tests, whether you need an appointment, and what identification and paperwork to bring. Your state agency's website is the right place for those requirements, since this page cannot register you for anything.
On the day itself:
Remember the bar: you need at least 80 percent correct. If you are unsure about one question, move on and return to it rather than spending your focus there.
After the exam, your state will tell you the result and what happens next. If you pass, the endorsement is added to your license or permit according to state procedure. If you do not pass, ask your agency about its retake rules and waiting periods, since those are set locally. Use the missed topics as your study list, and return to the practice quizzes below before you try again.
The quizzes on this page are split by subject so you can aim at weak spots instead of repeating everything. They are practice material written for study. They are not the real test, and they do not predict your score or your state's question set.
A good routine:
Pair the quizzes with the flashcards and checklist on this page. If a concept keeps tripping you up, such as how a partly filled tank affects stopping, write the explanation in your own words. If you can teach it back, you know it.