The TRUCK MANUFACTURERS ASSOCIATION (TMA) is a not-for-profit technical trade association headquartered in Chicago, IL. Members are partnerships, or corporations, with principal headquarters located in North America, actually engaged in the design, development, manufacturing, marketing and sale of Class 6, 7, and 8 medium and heavy-duty trucks, truck chassis or truck tractors with greater than 8845 kilogram (19,500 pounds) gross vehicle weight rating in North America.