In sports car racing, production versions of sports cars and/or grand tourers, and sports prototype cars compete within their respective classes on closed circuits. The races are often conducted over long distances, at least 1000 km, and cars are driven by teams of two or three drivers (and sometimes more in the US), switching every few hours.
Due to the performance difference between production-based sports cars and purpose-built sports prototypes, one race usually involves several racing classes. In the US the American Le Mans Series (ALMS) was organized in 1999, featuring GT1, GT2, and two prototype classes, LMP1 Le Mans Prototype 1 and LMP2.
Manufacturers such as Audi and Acura/Honda field or support entries in the Prototype class. Another series based on Le Mans began in 2004, the Le Mans Endurance Series, which included four 1000 km races at tracks in Europe. A competing body, Grand-Am, which began in 2000, sanctions its own endurance series the Rolex Sports Car Series.
Famous sports car races include the 24 Hours of Le Mans, the 24 Hours of Daytona, 24 Hours of Spa-Franchorchamps, the 12 Hours of Sebring, and the 1,000-mile (1,600 km) Petit Le Mans at Road Atlanta.
