Sebring

Sebring International Raceway is a road course near Sebring in the south of Florida, in the United States. It occupies the site of Hendricks Army Airfield, a training base for B-17 pilots that operated from 1941 to 1946. After the war, the aeronautical engineer Alec Ulmann saw that the runways and service roads could stage a sports car endurance race modelled on Le Mans. The first race took place on New Year's Eve 1950, and the first 12 Hours of Sebring followed on 15 March 1952.

The circuit still uses sections of the old airfield runways, some of them with the original concrete surface. The joins between the concrete slabs are very bumpy, and because Florida is flat, there is hardly any change in elevation. The track has 17 corners, long straights, several fast bends and slower, technically demanding sections. Turn 17 is a long, quick right-hander wide enough for three cars to run side by side.

In 1959 Sebring staged the United States Grand Prix as a round of the Formula One World Championship. Bruce McLaren won the race for Cooper, and it settled the drivers' championship. It was run on the layout of the time, which measured 8.36 km. It remained the only World Championship race at Sebring: because of poor attendance and high costs, the next United States Grand Prix moved to Riverside in southern California.

The layout was changed several times. After the 1966 12 Hours, in which several people lost their lives, parts of the track were widened and the Webster Turn gave way to the faster Green Park Chicane. In 1983 the course was shortened so that the track and one of the runways could be used at the same time. Further changes followed in 1987 and 1991. In 1997 the hairpin was removed because of insufficient run-off and replaced by what is known as the safety pin.