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 Georgia Commercial Driver’s Manual. 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

1. If a person fails a written test, how long is the waiting period before the test may be taken again?

Explanation
If you fail a required knowledge test, you must wait a minimum of two days before retaking the test. If you have passed knowledge tests for other endorsements, you may still take the skills tests required for those endorsements.

2. In cold weather, an alcohol evaporator should be checked and filled:

Explanation
An alcohol evaporator can help prevent ice from building up in an air brake system. In cold weather, the evaporator should be checked and refilled every day.

3. All air tanks must include:

Explanation
Air brake system tanks must contain drain valves. These valves are used to drain accumulated oil and water from the tanks and may be either manually or automatically operated.

4. When traction is poor, a driver should accelerate slowly:

Explanation
Speeding up too quickly on a road with poor traction could cause a driver to lose control of their vehicle. In conditions that cause poor traction, a driver should accelerate especially smoothly and gradually.

5. An air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately ____ to come to a complete stop.

Explanation
A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

6. What does an Anti-Lock Braking System (ABS) do?

Explanation
The purpose of an Anti-Lock Braking System (ABS) is to prevent a vehicle's wheels from locking up when the driver brakes hard on a slippery surface.

7. How much water must be present for a vehicle to hydroplane?

Explanation
Hydroplaning is a phenomenon during which a vehicle's tires lose traction with the road surface and begin to glide along on water on the road. There does not have to be a large amount of water on the road for this to occur.
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