A class B commercial driver's license holder can drive buses, farm vehicles and other types of vehicles as long as they are under 26,000 pounds in gross weight. License holders can also pull a trailer behind the vehicle if it is less than 10,000 pounds and under 45 feet long.
Operators must have a class C commercial driver's license to be eligible to test for a class B. State examination procedures vary, but typically require applicants to be over 21 years of age and pass both a visual acuity test and a road skills examination. Additional endorsements can be added by taking tests for specific types of vehicles and cargo.