Oklahoma Tanker CDL Practice Test

This is a free 20-question practice test for the Tanker portion of the Oklahoma Commercial Driver's License knowledge exam. Questions are pulled from a pool of 50 drawn from the AAMVA CDL Manual, which is the source document the Service Oklahoma Driver License Services uses to write its actual exam.

How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in Oklahoma.

Question 1 of 20

Bonding and grounding during product transfer:

Equalizes electrical potential between the tank and receiving container, preventing static-spark ignition
Charges the battery
Cools the load
Speeds delivery

Correct. Static electricity builds up during liquid transfer. Bonding (cable between tank and receiving container) plus grounding equalizes potential to prevent ignition.

Question 2 of 20

When carrying water (a non-hazmat liquid) in a tanker, you still need:

The N endorsement, because it is a tank vehicle
No endorsement
Only the H endorsement
Just a Class B

Correct. The N endorsement is based on the vehicle being a tank, not on the cargo. Even non-hazardous water requires the N endorsement if the tank meets size criteria.

Question 3 of 20

A "baffled" tank has:

Walls with holes that slow surge but allow flow
No walls
Only one compartment
Outside reinforcement

Correct. Baffled tanks have internal bulkheads with holes — they slow surge but still allow product to flow through during loading and unloading.

Question 4 of 20

A "smooth bore" tank has:

No internal divisions
Internal baffles
Compartments
Reinforcement rings

Correct. A smooth-bore tank has no internal divisions or baffles. Surge is dramatic; brake gently to avoid being pushed forward by the load.

Question 5 of 20

You should never load a tank completely full because:

It is illegal in all states
Liquids expand when warmed and need outage; over-filling can rupture the tank
Trucks won't move
It saves no time

Correct. Liquids expand with temperature. Without outage, a warming load can over-pressurize and rupture the tank.

Question 6 of 20

Carrying a smooth-bore tank up a ramp or off a curb:

Causes minimal surge
Can produce strong front-to-back surge that affects throttle and traction
Has no effect
Improves traction

Correct. Climbing causes the load to surge backward and then forward as you level off — affecting throttle response, traction, and braking.

Question 7 of 20

Side-to-side surge is most likely to cause:

Improved fuel economy
Rollover, especially on curves and in evasive maneuvers
No effect
Better braking

Correct. Side-to-side surge can amplify side-loading forces, contributing to rollover on curves and exit ramps.

Question 8 of 20

A pressure-relief device that vents during transit:

Is a normal occurrence
Is a serious malfunction or over-fill — stop and investigate
Means the tank is empty
Means the load is cold

Correct. Continuous venting indicates over-pressure (often from over-fill or sun heating an over-filled tank). Stop and investigate; do not continue with a venting tank.

Question 9 of 20

The driver should plan extra time for:

Acceleration, braking, and turning a fully loaded tanker
Lunch
Sleep only
Refueling only

Correct. A loaded tanker accelerates slower, brakes longer, and turns wider. Plan your trip and reactions accordingly.

Question 10 of 20

In the event of a fire on a tanker:

Pull off the road, away from buildings, get out, call 911, and use the ERG to identify the response
Continue to deliver
Pour water on a fuel fire
Drive faster to put out the wind

Correct. Pull to a safe area, away from buildings and people. Get out, call 911, and consult the ERG. Some tank fires (e.g., water on flammable liquid) make matters worse.

Question 11 of 20

When the surge in a tanker pushes the rig forward at a stop, you may:

Brake harder
Be pushed past the intended stopping point
Skid backward
Have no effect

Correct. Forward surge can push the entire rig forward — past stop lines, into intersections, into the vehicle ahead. Plan your stops with extra distance.

Question 12 of 20

A tanker with an empty compartment between two full compartments may:

Slosh forward and backward, hard to predict
Be smoother
Drive itself
Have no surge

Correct. Mixed full and empty compartments produce complex surge patterns. Plan acceleration and braking conservatively.

Question 13 of 20

Vapor recovery during loading:

Is used at terminals to capture flammable vapors
Replaces the cargo
Is forbidden
Is used only at night

Correct. Vapor recovery captures flammable vapors displaced as product is loaded, returning them to storage. Required at most modern fuel terminals.

Question 14 of 20

A loaded tanker traveling 10 mph above the safe curve speed has a:

Lower rollover risk
Significantly higher rollover risk because rollover threshold scales with speed squared
Same risk
Better handling

Correct. Centripetal force scales with speed squared. Just 10 mph over safe speed can take you past the rollover threshold of a loaded tanker.

Question 15 of 20

A "bottom-loaded" tank:

Is loaded through bottom valves to reduce vapor and static
Is loaded only at the top
Carries cargo at the bottom only
Has no top vents

Correct. Bottom-loading uses sealed bottom-loading equipment with vapor recovery, reducing static and vapor escape compared to splash-loading from the top.

Question 16 of 20

Loading dock procedure for cargo tanks of flammable liquid:

Set parking brake, chock wheels, shut off engine, ground and bond, monitor loading, follow loading-rack procedures
Leave the engine running
Skip the chocks
Smoke nearby

Correct. Standard loading-rack procedure: brake set, chocks in, engine off, bond and ground, monitor loading, follow rack-specific procedures (vapor recovery, load arms, etc.).

Question 17 of 20

When driving with a load that has a low specific gravity (e.g., gasoline) versus high (e.g., asphalt), you should:

Drive the same
Adjust for the differences in surge dynamics, weight distribution, and braking
Skip braking
Run hot

Correct. Different products have different densities, surge characteristics, and weight distributions. Adjust speed and braking for the load.

Question 18 of 20

When loading a cargo tank with flammable liquid, the driver must:

Stay alert, within 25 feet, with a clear view of the tank, and ready to handle emergencies
Leave for lunch
Smoke
Run the engine at high RPM

Correct. Federal rule: driver remains within 25 feet, alert, with a clear view, ready to act in case of overflow or emergency.

Question 19 of 20

A "tank vehicle" requiring an N endorsement is generally defined as:

Any commercial vehicle
A vehicle used to transport liquid or gaseous materials in a tank with rated capacity of 1,000 gallons or more, individual tanks of 119+ gallons
Only fuel trucks
Only vehicles over 80,000 lbs

Correct. The N endorsement is required for any commercial vehicle hauling liquid or gas in a permanently mounted tank or portable tank with rated capacity of 1,000+ gallons (and individual tanks of 119+ gallons).

Question 20 of 20

A loaded tanker on a curve is most likely to:

Roll over because surge plus high CG amplifies side forces
Skid in a straight line
Brake faster
Steer easier

Correct. Side surge plus high CG creates a tipping moment well above what a flat-bed of equal weight produces. Speed reduction in advance is the only safe answer.

About the Oklahoma Tanker exam

Most states administer 20 Tanker questions and require 80% to pass. Topics include the unique handling of liquid loads, surge effects, baffles vs. smooth-bore, outage and expansion, inspection of the cargo tank, and emergency procedures.

The Service Oklahoma Driver License Services follows the federal CDL standards established by FMCSA. To earn the Tanker credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.

Want more practice? Try the full Tanker question bank or browse all Oklahoma CDL practice tests.