Knowledge Test Class B

This license is required for driving a single vehicle with a GVWR of more than 26,001 pounds, and a trailer not to exceed 10,000 pounds gross vehicle weight rating, or a vehicle designed to transport 24 or more people (including the.. Read More

This license is required for driving a single vehicle with a GVWR of more than 26,001 pounds, and a trailer not to exceed 10,000 pounds gross vehicle weight rating, or a vehicle designed to transport 24 or more people (including the driver). To receive this license, applicants must pass a 50-question test. To pass, applicants must answer 40 questions correctly. Test questions come from the Illinois Commercial Drivers License Study Guide. Questions come from chapters covering: Introduction, Driving Safely, Transporting Cargo Safely, Air Brakes (if applicable), Combination Vehicles, Pre-Trip Vehicle Inspection Test, Basic Vehicle Control Skills Test and On-Road Driving. Endorsements that may be used with a Class B CDL are: Hazardous materials, Tank, Passenger, HazMat and Tank, Air Brakes, School bus and Charter.

Number of Question
Passing Score

1. When approaching a curve during the on-road driving test, you must do all of the following, except:

Explanation
When approaching a curve during the on-road driving test, you should thoroughly check traffic in all directions. Before entering the curve, reduce your speed sufficiently so that further braking or shifting is not required. Keep your vehicle in its lane and continue checking traffic in all directions.

2. When checking the engine compartment:

Explanation
Before inspecting the engine compartment, make sure that the parking brakes are on and/or the wheels are chocked. Check the engine compartment before entering the cab and starting the engine.

3. If you are being tailgated, you should:

Explanation
If you are being tailgated, it is best to allow more room to open up in front of your vehicle. This will help you avoid the need for sudden stops, which could result in the tailgater rear-ending you, and will make it easier for the tailgater to pass. Speeding up may only make things more dangerous by prompting the other driver to continue tailgating you at a higher speed.

4. During a basic vehicle control skills test, you may be asked to:

Explanation
Maneuvers that may be included in the basic vehicle control skills test include straight line backing, offset back/right parking, offset back/left parking, driver side parallel parking, conventional parallel parking, and alley docking.

5. If the air pressure warning light comes on, you should:

Explanation
If the low air pressure warning signals activate, it is essential that you bring the vehicle to a safe stop while you are still able to control the brakes.

6. Mirror adjustment can only be checked properly if:

Explanation
If a trailer is attached to a tractor, the adjustment of the vehicle's mirrors can only be checked accurately if the trailer is straight.

7. What can happen if the air pressure gets too low in an air brake system?

Explanation
Pressing and releasing the brake pedal unnecessarily can let air out faster than the compressor can replace it, reducing the available air pressure. If the air pressure in an air brake system gets too low, the brakes will no longer work.
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