Air Brakes #1
Air Brakes Endorsement Test | Illinois 2026 #1 Page 3 of 4
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.
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13 . How is the parking brake released?
By tapping the accelerator twice
In vehicles with air brakes, the parking brake is controlled by a knob. The knob is pulled out to apply the brakes, and pushed in to release them.
14 . Which type of brakes do most heavy-duty vehicles have?
Gravity brakes
For safety, most heavy-duty vehicles are equipped with dual air brake systems.
15 . Vehicles with dual air brake systems:
Maintain air pressure when shut off for periods of less than four hours.
Before driving a vehicle with a dual air brake system, allow time for the air compressor to build up pressure of at least 100 psi in both the primary and secondary systems.
16 . In a dual air brake system:
One system is the main braking system and a second system is ready to be used if the first one fails.
A dual air brake system is made up of two separate air brake systems. The systems share a single set of brake controls, but each has its own air tanks, hoses, and lines.
17 . What does the air compressor governor do?
Controls the temperature of the air leaving the air storage tanks.
In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.
18 . The safety valve located on the first tank opens:
After every stop.
In an air brake system, the first tank that receives compressed air has a safety valve that releases air if the pressure gets too high. It is usually set to open at 150 psi. If the valve must open, there is a fault in the system that should be repaired by a mechanic.
2026 Illinois | Frequently Asked Questions
A CDL Class B license in Illinois allows you to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or any such vehicle towing another not exceeding 10,000 pounds. It also permits the operation of vehicles designed to transport 24 passengers or more, including the driver.
A Class B Commercial Driver's License (CDL) in Illinois allows you to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or a towed vehicle not exceeding 10,000 pounds GVWR. This includes buses, farm labor vehicles, and any vehicles designed to transport 16 to 23 passengers including the driver.
To acquire a Class B CDL license in Illinois, you must be at least 18 years old (21 for interstate driving), possess a valid non-CDL driver's license, pass a vision test, and obtain a medical certificate. You'll also need to pass written knowledge tests and a skills test, which includes a pre-trip vehicle inspection, a basic controls test, and an on-road driving exam.
In Illinois, you must be at least 18 years old to qualify for a Class B Commercial Driver's License (CDL) for intrastate driving (within Illinois only). However, to drive across state lines or to carry hazardous materials, you must be at least 21 years old.
Endorsements for a Class B CDL license in Illinois are not necessary but can be beneficial. They allow you to operate specific types of vehicles. For instance, a passenger endorsement allows you to drive a bus, while a tank vehicle endorsement lets you drive tank trucks. Each endorsement requires passing additional written and/or skills tests.
The Class B CDL skills assessment in Illinois comprises three parts: a pre-trip vehicle inspection to check your understanding of your vehicle and if it's safe to drive, a basic controls test to assess your control over the vehicle, and an on-road driving test to evaluate your driving skills in various road situations and traffic conditions.
Yes, Class B CDL license holders in Illinois are limited to operating vehicles with a Gross Vehicle Weight Rating (GVWR) of 26,001 pounds or more, or towing vehicles not exceeding 10,000 pounds GVWR. They can't operate Class A vehicles unless they have the appropriate Class A endorsement. Also, transporting passengers or hazardous materials requires specific endorsements.
Yes, in Illinois, the written Class B CDL test is available in languages other than English. The Illinois Secretary of State's office offers the test in Spanish, Polish, and some other languages. However, federal regulations require that all CDL holders must be able to read and speak English sufficiently to converse with the general public, understand traffic signs and signals, and respond to official inquiries.
Yes, if you have a disability, you can request accommodations for the Class B CDL written exam in Illinois. You'll need to provide documentation of your disability and specify the type of accommodation needed. It's advised to make this request well in advance of your scheduled test date to give the DMV time to arrange appropriate accommodations.
Yes, if you don't pass the Class B CDL written test in Illinois, you can retake it. However, you must wait until the next business day to do so. If you fail three times, you'll need to start the application process over again. Remember, there may be additional fees for retaking the test.