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 two, three or four possible answer choices. Test questions come from the South Carolina Commercial Driver License 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

8. If an air compressor is belt-driven, the belt should be routinely checked to ensure that it is:

Explanation
If your vehicle has air brakes, the air compressor drive belt should be checked before each drive. Check the tightness of the belt and verify that it is in good condition.

9. The air storage tanks:

Explanation
In an air brake system, the air storage tanks hold enough air for brakes to be used several times if the compressor stops working.

10. If you are unsure if there is enough space for your vehicle to safely pass under an upcoming bridge, you should:

Explanation
If you aren't sure that you have room for your vehicle to safely fit under an overhead object, you should slow down while approaching it. Seek an alternate route, if possible.

11. Dual tires should:

Explanation
When inspecting a vehicle, you should verify that your dual tires do not come into contact with one another, or with any other part of the vehicle.

12. When driving, it is important to:

Explanation
It is essential that you are aware of what is happening on all sides of your vehicle at all times. Scan the road ahead and make regular checks of the mirrors on both sides of your vehicle while you are driving.

13. When a brake pedal is pressed and the S-cam is turned, the S-cam:

Explanation
When a brake pedal is pressed and the S-cam is turned, the S-cam presses the brake shoes against the inside of the brake drum. This causes friction and will cause the vehicle to slow.

14. If transporting 30 feet of cargo on a flatbed trailer, you should use a minimum of ____ to restrain the cargo.

Explanation
When transporting cargo on a flatbed trailer, you should use at least one tie-down for every 10 feet of cargo. Any cargo, no matter how small, should be restrained by a minimum of two tie-downs.
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