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 or four possible answer choices. Test questions come from the Iowa 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. Blocking cargo:

Explanation
Blocking is used to prevent cargo from sliding while in transit.

9. If you plan to transport hazardous materials, you must pass which endorsement test?

Explanation
You must have a hazardous materials endorsement to drive a vehicle of any size that is used to transport defined classes of hazardous materials.

10. Driving at night is usually:

Explanation
There are several reasons why driving at night is more difficult than driving during the day. It is more difficult for drivers to see hazards, the glare of headlights can affect drivers' vision, and there are more fatigued drivers on the road.

11. If a load is 40 feet long, it should be secured by at least ____ tie-downs.

Explanation
Cargo should be restrained by at least one tie-down for every 10 feet of cargo. However, all cargo should have at least two tie-downs, no matter the size of the cargo.

12. If you must drive in reverse, using driver's side backing:

Explanation
If you must back up, it is safest to back toward the driver's side of the vehicle. This way, as the driver, you will have the best possible view of your path of travel.

13. If approaching a railroad crossing that is being approached by a train, you should:

Explanation
Never attempt to beat a train to a railroad crossing. It is very difficult to accurately judge the speed of an approaching train. If you come upon a crossing that is being approached by a train, you must stop and wait for the train to pass before you attempt to cross the tracks.

14. The leakage rate for a single vehicle with air brakes should be no more than ____ in one minute during a static leakage test.

Explanation
When performing a static leakage test on a single vehicle with air brakes, the leakage rate should be no more than 2 psi in a minute. If the air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.
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