A CDL B driver is a driver who is licensed to operate heavy vehicles. Commercial driver’s licenses (CDLs) come in 3 classes; A, B, and C. Each class is based on the weight of the vehicle and other restrictions. A CDL B is required to operate vehicles that weigh over 26,001 pounds (11,794 kilograms) or vehicles that are towing a weight over 10,000 pounds (4,536 kilograms). Vehicles that normally require a CDL B include buses and delivery trucks. A CDL B driver drives long mileage trips while safely operating a large machine.