American Championship Car Racing

American Championship car racing, also known as Indy Car racing, is a category of professional-level automobile racing in the United States and North America. As of 2016, the top-level American open wheel racing championship is sanctioned by IndyCar.

Competitive events for professional-level, single-seat open-wheel race cars have been conducted under the auspices of several different sanctioning bodies since 1902. A season-long, points-based, National Championship of drivers has been officially recognized in 1905, 1916, and since 1920. The Indianapolis 500, which itself debuted in 1911, is the marquee event of Indy Car racing.

The open-wheeled, winged, single-seater cars have generally been similar to those in Formula One, though there are important differences. The fame of the Indianapolis 500 leads many to colloquially refer to the cars that compete on the American Championship circuit as "Indy cars."

This form of racing has experienced high levels of popularity over the years, particularly in the post-World War II time frame. The "golden era" of the 1950s was followed by a decade of transition and innovation in the 1960s, which included increased international participation. The sport experienced considerable growth and exposure during the rising popularity of the CART PPG Indy Car World Series in the 1980s and early 1990s. Two organizational disputes in 1979 and 1996, respectively, led to a "split" that divided the participants (and fans) among two separate sanctioning bodies. However, an official unification took place in 2008 that brought the sport back together under one single sanctioning body.

The national championship was sanctioned by the Contest Board of the American Automobile Association (AAA). The AAA first sanctioned automobile motorsports events in 1902. At first it used the rules of the Automobile Club of America (ACA), but it formed its own rules in 1903. It introduced the first track season championship for racing cars in 1905. Barney Oldfield was the first champion. No official season championship was recognized from 1906-1915, however, single races were held. Official records regard 1916 as the next contested championship season. Years later, retroactive titles were named back to 1902. These post-factum seasons (1902-1904, 1906-1915, and 1917-1919) are considered unofficial and revisionist history by accredited historians.

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