Tanker Endorsement: What the N Covers and How to Get It

For CDL holders

Updated September 28, 2026

The tanker endorsement, code N on your license, lets you drive a tank vehicle. You get it by passing a knowledge test at your state licensing office. There is no skills test for it.

Federal rules define a tank vehicle by the size of its tanks, not by what is in them. The liquid or gas does not have to be hazardous.

NThe tanker code on your license

80%Passing score on the knowledge test

0Skills tests: it is knowledge only

3Endorsements allowed on a permit, N is one

This guide covers what counts as a tank vehicle, how to add N to your CDL, what the tanker test covers, and why tankers handle differently. Each rule links to its source. We haul cars, not liquids, so the last section is honest about where tanker work and car hauling part ways.

What Counts as a Tank Vehicle

The federal definition is in 49 CFR 383.5. A tank vehicle is a commercial motor vehicle built to carry any liquid or gas in a tank or tanks that meet both of these tests:

Over 119

gallons each

Each tank’s rated capacity is more than 119 gallons.

1,000

gallons or more

All the tanks together are rated for 1,000 gallons or more.

Attached either way. It counts whether the tank is attached to the vehicle or chassis for good or only for a while.
One exception. An empty storage tank, not built for transport, carried temporarily on a flatbed trailer is not a tank vehicle, even at 1,000 gallons or more.
Class matters. The CDL manual says you need N for a tank vehicle that takes a Class A or B CDL. For a Class C vehicle, you need it only if the tank carries hazardous materials.

How to Get a Tanker Endorsement

Study the tank section of your state’s manual.In the Colorado manual it is section 8. That section also points you to the sections on driving safely, air brakes, combination vehicles and hazardous materials.
Take the tanker knowledge test.Your state licensing office gives it. Federal rules require a knowledge test for N, and no skills test (49 CFR 383.93).
Score at least 80%.That is the federal passing score for every CDL knowledge test (49 CFR 383.135).
Your state adds N to your license.If you also hold the hazmat endorsement, your license shows X instead of N and H.

On a learner’s permit. N is one of only three endorsements allowed on a commercial learner’s permit, with passenger and school bus. You have to pass the N knowledge test first. With N on a permit, you may drive only an empty tank vehicle, and never one that held hazardous materials unless it has been purged of any residue (49 CFR 383.25). Your permit carries a restriction that says so.

Training. Federal entry-level driver training rules name the passenger, school bus and hazmat endorsements, not N (49 CFR 380.609). If this is your first Class A or B CDL, though, you still need entry-level training for the license itself. See our guide to entry-level driver training.

What Is on the Tanker Test

Your state writes the questions. Federal rules list what every tanker applicant must know (49 CFR 383.119):

What causes cargo surge, how to prevent it, and how it affects handling
How to brake when the tank is empty, full or partly full
Baffled or compartment tanks versus tanks without baffles
Different types of tank vehicles and how they are built
How surge changes with heavier or lighter liquids
How grades and curves affect full, half-full and empty tanks
How to use the emergency systems
Retest and marking rules for DOT specification tanks

The manual’s tank section adds the inspection side. The most important thing to check on any tank vehicle is leaks. Check the tank shell for dents or leaks, the valves, the pipes and hoses, and the manhole covers and vents. The manual warns that carrying liquid or gas in a leaking tank is a crime. Never drive with open valves or manhole covers.

Loaded car hauler driving on a highway, seen from the side

Liquid Surge and Rollover

Tankers handle differently for two reasons, the manual says: a high center of gravity and liquid that moves. Much of the load’s weight rides high off the road, so the truck is top-heavy. The manual says tests have shown tankers can turn over at the speed limits posted for curves.

Liquid surge is the liquid moving back and forth in a partly full tank. When you stop, the wave hits the end of the tank and shoves the truck the way the wave is moving. On ice, it can push a stopped truck out into an intersection.

What is inside the tank changes how much surge you get:

Bulkheads

Walls that split the tank into smaller tanks. When you load or unload them, watch the weight so you do not put too much on the front or the rear.

Baffles

Walls with holes that let the liquid through. They slow surge front to back, but side-to-side surge can still happen and can cause a rollover.

Smooth bore

No baffles at all, so front-to-back surge is very strong. These usually haul food products such as milk. Be extra slow and careful starting and stopping.

How the manual says to drive a tanker:

Drive smoothly. Start, slow down and stop very smoothly. Make smooth turns and lane changes.
Brake early and steadily. Brake far ahead of a stop and leave more following distance. Keep steady pressure and do not let off too soon.
Take curves slowly. Slow down before a curve, then speed up a little through it. The posted speed may be too fast for a tanker.
Expect longer stops. Wet roads double your normal stopping distance, and an empty tanker may take longer to stop than a full one.
Leave room to expand. Never load a tank totally full. Liquids expand as they warm, and that space is called outage. Different liquids need different amounts.

Tanker, Hazmat and X

X on a CDL means you hold both the tank (N) and hazmat (H) endorsements. You need both to drive a tank vehicle hauling hazardous materials in amounts that need placards. Hazmat adds its own knowledge test and a TSA background check. See our guide to getting a hazmat endorsement, and our CDL endorsements guide for all five endorsements side by side.

On a learner’s permit, the letter works differently. There, X is a restriction that means no cargo in a tank vehicle.

Do Car Haulers Need a Tanker Endorsement?

A car carrier hauls vehicles, not liquid in a tank, and Accelerated’s posted driver requirements list no endorsement. If you plan to drive tankers, this page is for you. If you would rather haul cars, here is how the two jobs compare.

Tanker work

Liquid or gas in tanks above the federal size lines
Needs N on your CDL, or X with hazmat
A knowledge test on surge, baffles and rollover

Car hauling with Accelerated

New and used vehicles, including OEM plant, port and rail freight
Our posted driver requirements list no endorsement
3 years of CDL-A driving and 1 year of verifiable 9-car experience
A valid Class A CDL, an acceptable MVR, a clean safety history and a current DOT medical certificate

Not at 3 years and 1 year yet? Our guide for drivers without car-haul experience explains what it takes to get there.

Tanker Endorsement FAQs

What is a tanker endorsement?

It is the N endorsement on a CDL. It lets you drive a tank vehicle, which federal rules define as a vehicle built to carry liquid or gas in tanks of more than 119 gallons each and 1,000 gallons or more in all.

How do you get a tanker endorsement?

Study the tank vehicle section of your state’s CDL manual, then pass the tanker knowledge test at your state licensing office with a score of at least 80%. There is no skills test for N.

Can you get a tanker endorsement on a permit?

Yes. N is one of three endorsements allowed on a commercial learner’s permit. You must pass the N knowledge test, and you may drive only an empty tank vehicle that has been purged if it ever held hazardous materials.

Do you need entry-level driver training for a tanker endorsement?

Not for N on its own. Federal entry-level training rules name the passenger, school bus and hazmat endorsements. You still need entry-level training if you are getting a Class A or B CDL for the first time.

What is the difference between N and X on a CDL?

N is the tank vehicle endorsement. X means you hold both the tank and hazmat endorsements, which you need to haul placarded hazardous materials in a tank vehicle.

Hauling Cars Instead?

We run OEM plant, port and rail freight across the country with contract drivers, and our requirements list no endorsement. You get a $5,000 sign-on bonus, paid in your first month. See what we ask for on our careers page.

See Driver Requirements

Have 3 years of CDL-A driving and 1 year of verifiable 9-car experience? Apply to contract with Accelerated.

Sources

Last checked September 28, 2026. Test rules and fees are set by your state. Check your state’s CDL manual and licensing office before you test.