Which organization sanctioned the Indianapolis 500 from 1911 to 1955?

The AAA Contest Board sanctioned the Indianapolis 500 from its inaugural race in 1911 through 1955. It was the competition arm of the American Automobile Association, commonly known as AAA, and oversaw major American automobile races during the early decades of the sport.

The Indianapolis 500 was first held in 1911, and AAA sanctioned races at Indianapolis Motor Speedway during the organization’s long tenure. The race did not run during the United States’ participation in World War I, so “1911 to 1955” describes the sanctioning era rather than an uninterrupted series of annual events.

AAA also administered national championship racing and sanctioned events such as the Vanderbilt Cup. Its role helped establish the rules, championships, and competitive structure from which modern American open-wheel racing eventually developed.

After the 1955 Le Mans disaster, the AAA Contest Board withdrew from motorsports and turned its attention to public-service activities. The United States Auto Club, or USAC, subsequently became the Indianapolis 500’s sanctioning body, while CART and IndyCar belong to later eras.