According to the Department of Motor Vehicles (DMV) in the United States, there are basically five types of drivers' licenses. Most people have a Class C driver's license, which allows them to drive any single vehicle as long as the weight falls under 26,000 pounds (11793 kg). A Class D license is a provisional C license in which the driver is not allowed to operate a vehicle between 12:00 midnight and 6:00 a.m. The third type of driver's license, Type M, is for people driving motorcycles. Class B license, one of the most difficult of all licenses to obtain, is the fourth category.

A Class B license entails the driver to operate vehicles weighing over 26,000 pounds (11793 kg) in addition to any of the vehicles contained in Class C. Class B license also allows the holder to drive buses, farm labor vehicles, and any housecar or trailer over under 45 feet (14 m). The final Class Type is A, which is essentially the same as Class B license, except that drivers are allowed to operate truck tractor-semi trailer combinations. With a Class B license, a driver is not allowed to pull a trailing unit weighing over 10,000 pounds (4536 kg); with an A license, he can.

To obtain a Class B license, a person must already possess a C license. He or she must be at least 18, not 16, and pass a second visual acuity test and a road/skill test to upgrade from C to a Class B license. For commercial driving across state lines, a Class B driver must be over 21. A Class B license is also required to drive a single fire fighting vehicle; this is special kind of license known as "Restricted Class B Fire Fighter License." While a Class B license is valid for five years, a new medical test must be submitted every two years in order to keep the license updated.

Certain types of Class B licenses may require special endorsements. This includes drivers who will be transporting hazardous materials, pulling double/ triple trailers or tank vehicles, driving school buses, and handling vehicles not equipped with air brakes.