Clean Truck Check applies to nearly all diesel and alternative fuel heavy-duty vehicles with a gross vehicle weight rating (GVWR) over 14,000 pounds that operate on California public roads and highways even if they are not registered in California. This includes public vehicles (federal, state, and local government); motorcoaches; transit, shuttle and school buses; hybrid vehicles; commercial vehicles; personal vehicles; California registered motorhomes; single vehicle fleets; and vehicles registered outside of California (not including motorhomes).