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

1. When making a left turn, you should start the turn:

Explanation
When making a left turn, you should wait until you reach the center of the intersection before actually beginning to turn. Due to off-tracking, the left side of your vehicle could hit another driver if you begin turning too early.

2. When accelerating on a surface with poor traction, such as a wet road, a driver should:

Explanation
You should accelerate very gradually when driving under conditions that create poor traction.

3. Convex mirrors:

Explanation
Many large vehicles have curved, convex mirrors. Convex mirrors allow drivers to see a wider area than flat mirrors. However, they also make objects seem smaller and farther away than they really are.

4. ____ make up the emergency brake system.

Explanation
In an air brake system, there are three different braking systems: a service brake system, a parking brake system, and an emergency brake system. The emergency brake system uses parts of both the parking and service brake systems.

5. Failing to drain air tanks could result in:

Explanation
In an air brake system, the air tanks must be periodically drained to remove accumulations of water and compressor oil. If water is not removed, it could freeze in cold weather and cause brake failure.

6. What is the maximum legal weight to be placed on a single axle?

Explanation
The allowable gross weight of a bus or truck depends on its tire size, the number of axles, and the spacing of axles (or axle groups). In Washington State, the weight of a commercial vehicle is limited to no more than 20,000 pounds on any single axle.

7. If driving so slowly that you could impede other drivers, you should:

Explanation
If you must drive so slowly that you will impede the flow of traffic, you should turn on your four-way flashers to alert drivers behind you (as long as local laws allow the use of flashers).
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