A Class B driver's license is a type of commercial driver's license that allows the driver to operate a large truck under certain conditions. The license restricts the size of the trailer that the truck is allowed to carry.
A Class B license is issued at the state level. Each state has similar restrictions on drivers with this type of commercial license. The license is valid for trucks with a Gross Vehicle Weight Rating, usually referred to as the GVWR, of 26,001 pounds or more. The truck, however, is not allowed to carry a trailer that has a GVWR of more than 10,000 pounds.