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. Each question has three possible answer choices. Test questions come from the Commercial Driver Guide. Questions come from chapters covering: Introduction, Driving Safely, Transporting Cargo Safely, Air Brakes (if applicable), 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 and School bus.

Number of Question
Passing Score

8. In a vehicle with dual parking control valves, a separate air tank can be used:

Explanation
In a vehicle with dual parking control valves, there is a separate air tank that can be used to temporarily release the spring brakes if they have been activated due to low air pressure. Pushing in the proper control will release the spring brakes for a short period of time, allowing the driver to move the vehicle in an emergency.

9. What is brake lag?

Explanation
Because air takes time to flow through the air lines to the brakes, air brakes cannot begin working instantly. There is often a brake lag of at least one-half of a second between the moment the brake pedal is pressed and the moment the brakes begin to work.

10. A truck tractor built after March 1, 1997 must be equipped with:

Explanation
Truck tractors with air brakes built on or after March 1, 1997 are required to be equipped with Anti-Lock Braking Systems (ABS).

11. Black ice is:

Explanation
Black ice is a layer of ice that is thin and clear enough for the road to be visible through it. The surface will look like a wet road. Always be alert to black ice if the road looks wet when the temperature is below freezing.

12. If your brakes fail on a downgrade, your best hope to stop is to:

Explanation
If your brakes fail on a downgrade, you will have to look outside your vehicle for a way to stop. Using an escape ramp is the safest way to stop your vehicle.

13. While still below the legal limit, a driver operating a CMV with a detectable amount of alcohol in their system will:

Explanation
If you are found to have any detectable amount of alcohol in your system while operating a CMV but your blood alcohol concentration (BAC) is still below the legal limit of 0.04 percent, you will be put out-of-service for 24 hours. It is both illegal and dangerous to operate a motor vehicle while under the influence of alcohol.

14. Not using a safety belt while driving:

Explanation
You must always wear a safety belt while operating a commercial motor vehicle. Driving a CMV without being properly restrained by a safety belt is both illegal and dangerous.
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