Illinois CDL Tanker Practice Test

The Illinois CDL Tanker test is a multiple-choice knowledge test you take for your commercial learner's permit. Illinois Secretary of State, Driver Services Department says you need 80% to pass (source).

Last updated Oct 15, 2026. FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC.

By Scott Wilder, Editor

Last reviewed against the Illinois CDL manual on October 15, 2026

Scott Wilder on X | scottwilderhq.com

FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC. It offers free exam-style practice tests built from the official CDL manual. FirstTry CDL is not affiliated with any DMV, FMCSA or government agency. Practice questions are exam-style questions built from the official CDL manual, not actual test questions.

Illinois CDL permit facts

What	What Illinois says	Source
Tanker pass mark	80%	Official page
Tanker test questions	20	Official page
CLP fee (adding a CLP to an Illinois non-CDL license, or renewing an original CLP)	$50	Official page
CLP fee (current CDL holder upgrading class or adding an endorsement)	$5	Official page
CLP validity	One year. An original CLP expires one year from the date it is first issued.	Official page
Test languages	CDL knowledge tests are given in English only. You can ask for the audio format, where the computer reads the test. After trying audio, you can ask facility management about an oral test read by staff.	Official page

20 question Tanker practice test

1. What does a high center of gravity do to a vehicle?
1. A. Makes it use less fuel
2. B. Makes it brake faster
3. C. Makes it harder to tip
4. D. Makes it top-heavy and easy to roll over
Show answer
Answer: D. Makes it top-heavy and easy to roll over
The manual says it makes the vehicle top-heavy and easy to roll over.
From the official CDL manual, section 8.2.1 High Center of Gravity.
2. Which action can make your vehicle skid?
1. A. Driving smoothly
2. B. Over braking
3. C. Steady braking
4. D. Slowing before a curve
Show answer
Answer: B. Over braking
Over steering, over accelerating, or over braking may cause a skid.
From the official CDL manual, section 8.3.5 Skids.
3. Why do sanitation rules forbid baffles in food tanks?
1. A. Baffles make the tank too heavy
2. B. Baffles make the inside of the tank hard to clean
3. C. Baffles cost too much
4. D. Baffles make milk expand
Show answer
Answer: B. Baffles make the inside of the tank hard to clean
Sanitation rules forbid baffles because the inside of the tank is difficult to clean.
From the official CDL manual, section 8.2.5 Un-baffled Tanks.
4. How do you often load heavy liquids?
1. A. Totally full
2. B. With no outage
3. C. Only on the left side
4. D. Only partly full
Show answer
Answer: D. Only partly full
You may often only partially fill tanks with heavy liquids.
From the official CDL manual, section 8.2.7 How Much to Load.
5. What must you do when your vehicle starts to skid?
1. A. Wait for it to stop
2. B. Speed up
3. C. Turn off the lights
4. D. Restore traction to the wheels
Show answer
Answer: D. Restore traction to the wheels
You must take action to restore traction to the wheels.
From the official CDL manual, section 8.3.5 Skids.
6. What kind of brake pressure helps control surge?
1. A. A steady pressure
2. B. Pumping on and off
3. C. Very light taps
4. D. Hard then soft
Show answer
Answer: A. A steady pressure
The manual says to keep a steady pressure on the brakes.
From the official CDL manual, section 8.3.2 Controlling Surge.
7. What may happen if the drive or trailer wheels of a tank trailer skid?
1. A. The vehicle may jackknife
2. B. The tank may shrink
3. C. The load gets lighter
4. D. The wheels get more traction
Show answer
Answer: A. The vehicle may jackknife
If the drive wheels or trailer wheels skid, the vehicle may jackknife.
From the official CDL manual, section 8.3.5 Skids.
8. Which vehicles are especially easy to roll over?
1. A. Liquid tankers
2. B. Empty flatbeds
3. C. Short vans
4. D. Light cars
Show answer
Answer: A. Liquid tankers
The manual says liquid tankers are especially easy to roll over.
From the official CDL manual, section 8.2.1 High Center of Gravity.
9. What should manhole covers have, and what should they do?
1. A. Locks only, and stay loose
2. B. Paint, and stay open
3. C. Gaskets, and close correctly
4. D. Springs, and open on bumps
Show answer
Answer: C. Gaskets, and close correctly
The manual says covers must have gaskets and close correctly.
From the official CDL manual, section 8.1.1 Leaks.
10. What must you know when you haul liquids in bulk?
1. A. The age of the tank
2. B. The color of the liquid
3. C. The outage requirement
4. D. The name of the shipper
Show answer
Answer: C. The outage requirement
The manual says you must know the outage requirement when hauling liquids in bulk.
From the official CDL manual, section 8.2.6 Outage.
11. A curve sign shows 45 mph. You drive a tanker. What do tests show?
1. A. A tanker is safe at 10 mph over
2. B. A tanker is safe at the posted speed
3. C. A tanker can turn over at the posted curve speed
4. D. Only empty tankers roll
Show answer
Answer: C. A tanker can turn over at the posted curve speed
Tests have shown that tankers can turn over at the speed limits posted for curves.
From the official CDL manual, section 8.2.1 High Center of Gravity.
12. You find a small leak in your tank. The trip is short. What should you do?
1. A. Drive carefully to the stop
2. B. Do not carry the load in the leaking tank
3. C. Drive with the load at low speed
4. D. Add more liquid to cover the leak
Show answer
Answer: B. Do not carry the load in the leaking tank
The manual says not to carry liquids or gases in a leaking tank.
From the official CDL manual, section 8.1.1 Leaks.
13. What may happen if you steer quickly while braking?
1. A. The tank may empty
2. B. Nothing, it is safe
3. C. The brakes may lock forever
4. D. The vehicle may roll over
Show answer
Answer: D. The vehicle may roll over
The manual says that steering quickly while braking may cause the vehicle to roll over.
From the official CDL manual, section 8.3.2 Controlling Surge.
14. When should you be especially careful in a smooth bore tank?
1. A. When starting and stopping
2. B. Only on straight roads
3. C. Only when parked
4. D. Only in daylight
Show answer
Answer: A. When starting and stopping
The manual says to be extremely cautious, especially when starting and stopping.
From the official CDL manual, section 8.2.5 Un-baffled Tanks.
15. What is inside a baffled liquid tank?
1. A. Nothing, the tank is smooth
2. B. Solid walls with no holes
3. C. Bulkheads with holes in them
4. D. A second smaller tank
Show answer
Answer: C. Bulkheads with holes in them
Baffled tanks have bulkheads with holes that let the liquid flow through.
From the official CDL manual, section 8.2.4 Baffled Tanks.
16. You load several smaller tanks divided by bulkheads. What must you watch?
1. A. Weight distribution
2. B. Tank color
3. C. Tire brand
4. D. Cab size
Show answer
Answer: A. Weight distribution
The manual says the driver must pay attention to weight distribution.
From the official CDL manual, section 8.2.3 Bulkheads.
17. When does a Class C vehicle need the tank endorsement?
1. A. When it hauls any water
2. B. When it hauls dry hazmat
3. C. Never, Class C is exempt
4. D. When it hauls liquid or gas hazmat in tanks of the described size
Show answer
Answer: D. When it hauls liquid or gas hazmat in tanks of the described size
Class C vehicles need it when carrying hazmat in liquid or gas form in the rated tanks described.
From the official CDL manual, section 8 Tank Vehicles (introduction).
18. What causes liquid surge?
1. A. Worn brake pads
2. B. A completely full tank
3. C. Cold weather
4. D. Movement of liquid in partially filled tanks
Show answer
Answer: D. Movement of liquid in partially filled tanks
The manual says liquid surge results from movement of the liquid in partially filled tanks.
From the official CDL manual, section 8.2.2 Danger of Surge.
19. What should you do with your following distance in a tank vehicle?
1. A. Make it shorter
2. B. Increase it
3. C. Keep it the same as a car
4. D. Ignore it when empty
Show answer
Answer: B. Increase it
The manual says to increase your following distance.
From the official CDL manual, section 8.3.2 Controlling Surge.
20. What is inside an un-baffled tank to slow the liquid?
1. A. Nothing
2. B. One baffle
3. C. Two bulkheads
4. D. A rubber lining
Show answer
Answer: A. Nothing
Un-baffled tanks have nothing inside to slow down the flow of the liquid.
From the official CDL manual, section 8.2.5 Un-baffled Tanks.

Illinois CDL Tanker questions

What score do you need to pass the Illinois CDL Tanker test?

Illinois says you need 80% to pass the Tanker test.

Is the Illinois CDL Tanker test the same as other states?

The Tanker test is built on the same federal knowledge standards in every state, so the topics match the CDL manual. Illinois uses its own handbook: https://www.ilsos.gov/content/dam/publications/pdf_publications/dsd_cdl10.pdf

How much does a CDL permit cost in Illinois?

CLP fee (adding a CLP to an Illinois non-CDL license, or renewing an original CLP): $50.

What languages is the Illinois CDL knowledge test offered in?

CDL knowledge tests are given in English only. You can ask for the audio format, where the computer reads the test. After trying audio, you can ask facility management about an oral test read by staff.

Sources

https://www.ilsos.gov/content/dam/publications/pdf_publications/dsd_cdl10.pdf
https://www.ilsos.gov/departments/drivers/basicfees.html
https://www.ilsos.gov/departments/drivers/drivers-license/cdl/cdl.html
Manual sections used in this test: 8 Tank Vehicles (introduction); 8.1.1 Leaks; 8.2.1 High Center of Gravity; 8.2.2 Danger of Surge; 8.2.3 Bulkheads; 8.2.4 Baffled Tanks; 8.2.5 Un-baffled Tanks; 8.2.6 Outage; 8.2.7 How Much to Load; 8.3.2 Controlling Surge; 8.3.5 Skids

Tanker practice test in nearby states