High Quality Content by WIKIPEDIA articles! Since 1916 there has been a recognized United States national automobile racing National Championship for drivers of professional-level, single-seat open wheel race cars. The championship has been under the auspices of several different sanctioning bodies since 1909. Since 1911, the Indianapolis 500-mile race has been regarded as the marquee event of the National Championship. As of 2008, the top-level American open wheel racing championship is sanctioned by the Indy Racing League. The open-wheeled, winged, single-seater cars have generally been similar to those in Formula One, though there are important differences. Due to the fame of the Indianapolis 500, the term Indy Car (or IndyCar, Indycar) is a more popular term used to describe the cars that would typically compete in U.S. Championship car racing, popularized during the rising popularity of CART PPG Indy Car World Series racing in the early 1990s.