Commercial Truck Vehicle Classification Guide. 17/12/2020 · The medium-duty trucks category includes commercial truck classes 4, 5, and 6. Class 3: This class of truck has a GVWR of 10,001–14,000 pounds or 4,536–6,350 kilograms. Class 4: This class of truck has a GVWR of 14,001–16,000 pounds or 6,351–7,257 kilograms.