Class A: Allowed to drive any tractor–trailer combination. May also drive in class D and G.
Class B: Allowed to drive any school purposes bus. May also drive in class C, D, E, F and G.
Class C: Allowed to drive any regular bus. May also drive vehicles in class D, F and G.
Class D: A motor vehicle exceeding 11,000 kilograms gross weight or registered gross weight or any truck or combination provided the towed vehicle is not over 4,600 kilograms. May also drive in class G. Class D with RV restriction ('Q'): Allowed to drive a recreational vehicle of any weight, but not allowed to drive other vehicles in Class D. May also drive in class G.
Class E: Allowed to drive any school purposes bus - maximum of 24-passenger capacity. May also drive in class F and G.
Class F: Allowed to drive any regular bus - maximum of 24-passenger capacity - and ambulances. May also drive in class G.
Class G: Allowed to drive any car, van or small truck or combination of vehicle and towed vehicle up to 11,000 kilograms provided the vehicle towed is not over 4,600 kilograms. A pickup truck towing a house trailer exceeds 4,600 kilograms, but the total combined weight of the truck and trailer does not exceed 11,000 kilograms is deemed a Class G vehicle.
Class A: Tractor-trailers (highest commercial class)
Class B: School buses (all sizes), includes lower classes
Class C: Regular buses (all sizes), includes D, F, G
Class D: Large trucks over 11,000kg, includes G
Class E: Small school buses (24 passengers max), includes F, G