Instructions

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 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 50

Passing Score 40

1. When backing with a trailer, you should begin by:

Turning the steering wheel in the direction of the turn.

Turning the steering wheel in the direction opposite of the turn.

Turning the wheel as sharply as possible.

When backing with a trailer, begin by turning the steering wheel in the direction opposite of the turn. Once the trailer starts to turn, reverse the direction of the steering wheel to follow the trailer.

2. Broken suspension parts:

Are not a cause for concern.

Are extremely dangerous.

Cannot be identified.

The suspension system holds up a vehicle and its load while keeping the axles in place. Defects in this system are extremely dangerous.

3. Which of the following is not a reason to use your mirrors?

You are changing lanes.

You are making a turn.

You are looking at fuel prices.

While regular mirror checks should be part of your normal driving routine, checking your mirrors is especially important when turning, changing lanes, merging, and performing tight maneuvers.

4. In very hot weather, the air pressure in tires may decrease.

True

False

Air expands as its temperature increases, so air pressure in your tires is likely to increase when you are driving in very hot weather. Under such conditions, stop periodically to ensure that your tires are not at risk of blowing out or catching fire.

5. If using spring brakes when hauling a heavy load, a complete stop will:

Be impossible.

Take a long time.

Take a short amount of time.

Spring brakes do not work on all axles. If your vehicle's spring brakes activate due to low pressure in an air brake system, your vehicle will need a longer distance to stop than usual, especially if you are carrying a heavy load.

6. Which gas would cause concern due to a faulty exhaust system?

Oxygen

Carbon monoxide

Nitrogen

A leaking exhaust system can introduce carbon monoxide, which is poisonous, into the cab or sleeper berth.

7. When traveling down a steep downgrade:

The air brakes should be used.

The vehicle should be placed in a low gear and the driver should use engine braking.

The driver should continually downshift instead of using the brakes.

On long and/or steep downgrades, you should primarily use engine braking to control the speed of your vehicle. Use your brakes only as a supplement to this effect.

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