The United States Auto Club (USAC) is one of the sanctioning bodies of auto racing in the United States. From 1956 to 1979, USAC sanctioned the United States National Championship, and from 1956 to 1997 the organization sanctioned the Indianapolis 500. Today, USAC serves as the sanctioning body for a number of racing series, including the Silver Crown Series, National Sprint Cars, National Midgets, Speed2 Midget Series, .25 Midget Series, Stadium Super Trucks, and Pirelli World Challenge. Seven-time USAC champion is USAC's Competition Director.