USAC took over Indianapolis 500 sanctioning in 1956. The change followed the American Automobile Association’s decision to withdraw from automobile racing after the 1955 season.
From 1911 through 1955, the AAA Contest Board governed the Indianapolis 500 and the wider national championship. The 1955 Le Mans disaster, along with other fatal racing accidents, intensified concerns about the organization’s role in motorsport. AAA ultimately dissolved its Contest Board and returned its focus to general motoring activities.
Indianapolis Motor Speedway owner Tony Hulman helped create the United States Auto Club, commonly called USAC, in 1956. USAC then became the race’s sanctioning body and governed American championship racing for decades. The 1956 Indianapolis 500 was therefore the first running officially sanctioned by USAC, with Pat Flaherty winning for car owner John Zink.
A common mix-up is choosing AAA because it governed the event for its first 45 years. NASCAR was a stock-car organization, while CART was not formed until 1978. USAC’s original role was open-wheel championship governance, including the Indy 500.