CDL Tank Vehicles practice test

For the N endorsement, needed to haul liquids or gases in bulk. The real test has 20 questions in most states.

Want to learn it first? Take the free lesson

Study all 18 questions with answers

When is a tank endorsement required?
When hauling liquid or gas in a tank of 119+ gallons, or tanks totaling 1,000+ gallons
The N endorsement is required for individual tanks of 119+ gallons or a total of 1,000+ gallons that are permanently or temporarily attached.
What is liquid surge?
Liquid moving in a partly filled tank and pushing the truck in the direction it moves
Surge can push a stopped truck forward into an intersection or make it hard to control on slippery roads.
What do baffles inside a tank control?
Front-to-back surge, but not side-to-side surge
Baffles slow front-to-back liquid movement. Side-to-side surge still happens and can cause a rollover.
Why are smooth-bore tanks especially hard to drive?
They have no baffles, so front-to-back surge is very strong
Smooth-bore tanks, often used for food products like milk, let liquid surge freely. Brake gently and allow extra distance.
What is outage?
Room left in a tank for the liquid to expand
Liquids expand as they warm up. Never fill a tank completely; leave outage for expansion.
Why are bulkheads used in tanks?
To divide the tank into compartments
Bulkheads split the tank into separate compartments. Watch weight distribution when loading and unloading them.
Why do tankers have a high risk of rollover?
They have a high center of gravity and the load can shift
Most of the weight sits high off the road, and moving liquid can shift that weight suddenly in curves.
How should you handle curves in a tank vehicle?
Slow down before the curve, then accelerate slightly through it
Braking in a curve adds to surge and rollover risk. Slow down before you enter and keep steady power through.
When coming to a stop in a tanker, you should:
Keep steady brake pressure and avoid releasing the brakes too soon
Releasing too early lets surge push the truck forward. Brake smoothly and early, with steady pressure.
Which load is generally the hardest to control because of surge?
A partly filled tank
A partial load has room for the liquid to move. That moving weight is what makes surge dangerous.
You notice a leak in your tank. What should you do?
Don't drive; a leaking tank is illegal to drive
Driving a leaking tank is illegal and dangerous. Get it fixed or call for help.
Why might a tank carrying a dense liquid be only partly full?
The weight limit is reached before the tank is full
Heavy liquids like some acids can hit legal weight limits long before the tank is full.
Before driving, manhole covers and valves should be:
Closed and secured
Check that all manholes and valves are closed and secure before moving.
How fast should you take curves in a tank vehicle?
Well below the posted speed limit
Tankers can roll over at the posted speed for curves. Go well below it.
Why are bonding or grounding cables used when loading flammable liquids?
To prevent sparks from static electricity
Static sparks can ignite flammable vapors. Bonding and grounding prevent that.
On a wet road, a tanker should be braked:
Smoothly and early, with extra distance
Surge and a high center of gravity make wet roads especially risky. Leave extra room and brake smoothly.
Where should you know the location of on a tank vehicle?
The emergency shutoff valves
Know where the emergency shutoffs are in case of a leak or fire.
What is the biggest danger of side-to-side surge?
It can cause a rollover
Side-to-side surge shifts weight in curves and lane changes, which can tip the tanker over.

Other practice tests

Tools for drivers

Truck Parking Club Reserve a safe truck parking spot ahead of time, or earn money listing your own yard.Find parking Ad

Roadside Masters 24/7 nationwide roadside assistance for trucks, so a breakdown doesn't leave you stuck.Sign up your truck Ad

DAT Load Board Looking for freight once you're driving? Get 10% off a DAT load board subscription.Try DAT Ad

LodoShop Big brands, bigger savings. Discount deals on everyday gear, tools and household goods.Shop deals