[United States Racing Association | Summit USRA Weekly Racing Series The United States Racing Association (USRA) was formed with a mission of growing local and regional dirt track racing for the future through cost-effective rules that do not hinder creativity, increased fan attendance at member tracks and lucrative sponsorship for each USRA member track. The USRA sanctions four divisions: Modifieds, Stock Cars, B-Mods and Hobby Stocks. Thousands of men and women compete in USRA events on any given weekend at the finest dirt oval speedways in America.]