Air Brakes Endorsement Test | Illinois 2026 #1

Train for FREE online with our Illinois CDL air brake test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a IL Class A/Class B driver license in 2026, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that the requirements for CDL may vary from state to state.

Number of Question 25

Passing Score 20

Number of Tests 20

1 . To use the controlled braking method, you should:

Apply the brakes as hard as possible without locking the wheels.

Apply the brakes with about half-force.

Apply the brakes until the wheels lock.

Pump the brakes.

The method of controlled braking involves applying the brakes as hard as you can without locking the wheels. If you need to make large steering adjustments while using controlled braking, you should remove your foot from the brake pedal, steer, then reapply the brakes.

2 . Air tank drains:

Allow rain water to enter the tank.

Are used to drain water and compressor oil from the air tank.

Should never be opened.

Must remain open during transit.

In an air brake system, the air storage tanks must be drained to remove accumulated water and compressor oil. Failing to do so can cause damage. Manually operated drains should be used at the end of each day of driving.

3 . A dual air brake system:

Has a single air brake system, but uses two sets of controls.

Has one air brake system for each side of the truck.

Has two brakes for each wheel.

Has two separate air brake systems, but uses a single set of controls.

A dual air brake system has two separate air brake systems that use a single set of brake controls. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle.

4 . Water and compressor oil are usually found in the compressed air within an air brake system. Water and compressor oil:

Are necessary for the proper function of the air brake system.

Should be added if low.

Should be removed regularly.

Are not concerns.

Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.

5 . On newer vehicles, how do you put on the parking brake?

Move a lever to the right.

Push in the yellow, diamond-shaped knob.

Pull out the yellow, diamond-shaped knob.

Pull up on the steering column.

On newer vehicles with air brakes, the parking brake is controlled by a yellow, diamond-shaped knob. The knob is pulled out to set the brakes, and pushed in to release them.

6 . If using air tanks with manually operated drains, how often should you drain the tanks?

Every day

Once a week

Once a month

Once every 3,000 miles

To prevent the build up of oil and water in a vehicle's air tanks, manually operated air tank drains should be used at the end of each day of driving.

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2026 Illinois | Frequently Asked Questions

To acquire a CDL Tank endorsement in Illinois, you must first have a Commercial Driver's License (CDL). Next, study the Tank Vehicles section of the Illinois Commercial Driver's License Study Guide. Once prepared, schedule and pass the written tank vehicle endorsement test at a Secretary of State Driver Services facility. The endorsement will then be added to your CDL.

To obtain a CDL Tank license, it is essential to have a Commercial Driver's License (CDL) first. Then, you need to study the Tank Vehicles section of the Illinois Commercial Driver's License Study Guide. After studying, you must pass the written tank vehicle endorsement test at a Secretary of State Driver Services facility in Illinois.

While specific training or experience isn't legally mandatory for a CDL Tank endorsement in Illinois, it is highly recommended. Understanding the operation of tank vehicles and handling of liquid cargo is crucial. Studying the Tank Vehicles section of the Illinois Commercial Driver's License Study Guide and passing the written test at a Secretary of State Driver Services facility is required.

Yes, to obtain a CDL Tank endorsement in Illinois, you must pass an additional written test. This test covers specific knowledge related to the safe transport of liquid and gaseous materials in tank vehicles. The information for the test can be found in the Tank Vehicles section of the Illinois Commercial Driver's License Study Guide.

The written test for the CDL Tank endorsement in Illinois covers various subjects including: high and low center of gravity and its impact on vehicle stability, how to inspect tank vehicles, how to drive vehicles loaded with liquids or gases, and special safety considerations for hazardous materials. All these subjects are detailed in the Illinois Commercial Driver's License Study Guide.

The CDL Tank endorsement assessment evaluates your understanding of tank-specific operations. You'll be tested on handling liquid surge, inspecting tank vehicles, managing a high center of gravity, and the implications of carrying a full or partial load. However, it's primarily a knowledge test, so specific driving maneuvers aren't typically assessed in this endorsement.

Yes, drivers with a CDL Tank endorsement must comply with specific requirements and regulations. These include maintaining a clean driving record, undergoing regular medical examinations, and adhering to hours-of-service regulations. Additionally, drivers must follow safety procedures when loading and unloading tanks, and comply with hazardous materials transportation regulations if applicable.

No, you cannot legally transport liquid or gas materials without a valid CDL Tank endorsement in Illinois. This endorsement is necessary for operating a commercial vehicle designed to transport any liquid or gaseous materials within a tank or tanks having an individual rated capacity of more than 119 gallons and an aggregate rated capacity of 1,000 gallons or more.

Yes, the CDL Tank endorsement can be added to your current license in Illinois. You don't need to apply for a fresh license. However, you must pass the Tank Vehicle endorsement test. Once passed, the endorsement will be added to your existing CDL, allowing you to legally operate tank vehicles.

Yes, handling hazardous materials with a CDL Tank endorsement requires adherence to specific regulations. Drivers must pass the Hazardous Materials (HazMat) endorsement knowledge test, undergo a federal background check, and submit fingerprints. They must also follow safety protocols for loading and unloading hazardous materials, and comply with shipping paper requirements.