In North American motorsports, a superspeedway is a race track over one mile (1.6 kilometers) in length that features only left turns. This term is used to differentiate these tracks from short tracks and road courses.
The first superspeedway built for NASCAR racing was Darlington Raceway at Darlington, South Carolina in 1950. Darlington is slightly less than a mile and a half long (1.366 mi.) and of a unique, asymmetrical design, with one end of the oval being rather smaller than the other.
The most famous superspeedway from a NASCAR standpoint is undoubtedly Daytona International Speedway in Daytona Beach, Florida. Built in 1959 as a replacement for a course combining the town's main street and its famous beach, the Daytona International Speedway holds the Daytona 500, NASCAR's most important single race.
The longest and fastest Superspeedway is the Talladega Superspeedway in Talladega, Alabama. Built in the 1960s, it is 2.66 miles (4.20 kilometers) long, and holds the current record for fastest speed in a stock car, 212 miles per hour.
Indianapolis Motor Speedway in Speedway, Indiana is a superspeedway that existed far before the term was ever coined. Like Daytona, it is two and one-half miles (approximately 4 kilometers) long. Unlike Daytona, its corners are not as steeply banked and have a tighter radius, meaning that the stock cars used in NASCAR (which now races at both venues) can not run as fast as Daytona. This allows the NASCAR races at "Indy" to be run without the use of carburetor restrictor plates like those used at Daytona and Talladega. Indianapolis 500 drivers have used the track as a superspeedway since 1911. Formula 1 drivers use the track as a road course.