In the U.S. the Federal Highway Administration classifies commercial vehicles by gross vehicle weight rating (GVWR). Class 5 trucks have GVWR between 16,001 and 19,500 lb; Class 6 between 19,501 and 26,000 lb; Class 7 between 26,001 and 33,000 lb; and Class 8 over 33,000 lb. Class 8 vehicles—often called heavy‑duty or semi‑trucks—include straight and tractor configurations. These classes help segment markets for production, regulations and licensing.