The Act established three separate classes of commercial driver's licenses. Every state issues licenses in these categories:
Class A: Any combination of vehicles with a gross vehicle weight rating (GWVR) of 26,001 or more lbs., provided the GVWR of the vehicle(s) being towed is in excess of 10,000 lbs.
Class B: Any single vehicle with a GVWR of 26,001 or more lbs., or any such vehicle towing a vehicle not in excess of 10,000 lbs. GVWR.
Class C: Any single vehicle, or combination of vehicles, that does not meet the definition of Class A or Class B, but is either designed to transport 16 passengers or more, including the driver, or is placarded for hazardous materials.http://www.dmv.org/wy-wyoming/apply-cdl.php