The Circuit des 24 Heures du Mans, also known as Circuit de la Sarthe (after the 1906 French Grand Prix triangle circuit) located in Le Mans, Maine, France, is a semi-permanent race course chiefly known as the venue for the 24 Hours of Le Mans auto race. Comprising private, race-specific sections of track in addition to public roads which remain accessible most of the year, its present configuration is 13.626 kilometres (8.467 mi) long, making it one of the longest circuits in the world. Capacity of the race stadium, where the short Bugatti Circuit is situated, is 100,000. The Musée des 24 Heures du Mans is a motorsport museum located at the main entrance of the venue.

Up to 85% of the lap time is spent on full throttle, meaning immense stress on engine and drivetrain components. However, the times spent reaching maximum speed also mean tremendous wear on the brakes and suspension as cars must slow from over 200 mph (320 km/h) to around 65 mph (100 km/h) for the sharp corner at the village of Mulsanne.

History

The track, which was a triangle from Le Mans down south to Mulsanne, northwest to Arnage, and back north to Le Mans, has undergone many modifications over the years, with CIRCUIT N° 15 being in use since 2014. Even with the modifications put in place over the years, the Sarthe circuit is still known for being very fast, with prototype cars achieving average speeds in excess of 230 km/h (140 mph).

In the 1920s, the cars drove from the present pits on Rue de Laigné straight into the city, and after a sharp right-hand corner near the river Sarthe Pontlieue bridge (a hairpin permanently removed from the circuit in 1929), before exiting the city again on the rather straight section now named Avenue Georges Durand after the race’s founder. Then 17.261 kilometres (10.725 mi) long and unpaved, a bypass within the city shortened the track in 1929, but only in 1932 the city was bypassed when the section from the pits via the Dunlop Bridgeand the Esses to Tertre Rouge was added. This classic configuration was 8.369 miles (13.469 km) long and remained almost unaltered even after the 1955 tragedy. Its frighteningly narrow pit straight was narrowed off to make room for the pits and was part of the road itself, without the road becoming wider just for the pits. The pit straight was about 12 feet (3.7 m) wide (the pit straight was widened in 1956) and the race track and pits were not separated for another 15 years. The pit area was modified at a cost of 300 million francs, the signalling area was even moved to the exit of the slow Mulsanne corner, and the track was resurfaced.

Car speeds increased dramatically in the 1960s, pushing the limits of the “classic circuit” and sparking criticism of the track as being unsafe, after several trials related fatalities occurred. Since 1965, a smaller but permanent Bugatti Circuit was added which shares the pit lane facilities and the first corner (including the famous Dunlop bridge) with the full “Le Mans” circuit. For the 1968 race, the Ford chicane was added before the pits to slow down the cars. The circuit was fitted with Armco for the 1969 race. The “Maison Blanche” kink was particularly harrowing, claiming many cars over the years (including three Ferrari 512 variants) and several lives, including the legendary John Woolfe in 1969 behind the wheel of a 917 Porsche . The circuit was modified ten more times—in 1971 (a year where the prototypes were averaging over 240 km/h (150 mph), and was also the last year the classic circuit was used). Armco was added to the pit straight to separate the track from the pits, and in 1972, the last part of the race track was revamped considerably with the addition of the quick Porsche curves bypassing “Maison Blanche” and part of the first straight and all of the second straight between the pits and Maison Blanche.

In 1990, two chicanes were added onto the Mulsanne Straight (explained in more detail below), and in 1994, the Dunlop chicane was tightened. In 2002, the run to the Esses was reconfigured in the wake of renovations to the Bugatti Circuit. The Le Mans circuit was changed between the Dunlop Bridge and Esses, with the straight now becoming a set of fast sweeping turns. This layout allowed for a better transition from the Le Mans circuit to the Bugatti circuit. This layout change would also require the track’s infamous carnival to be relocated near the Porsche curves, and in 2006, the ACO redeveloped the area around the Dunlop Curve and Dunlop Chicane, moving the Dunlop Curve in tighter to create more run-off area, while also turning the Dunlop Chicane into a larger set of turns. As part of the development, a new extended pit lane exit was created for the Bugatti Circuit. This second pit exit re-enters the track just beyond the Dunlop Chicane and before the Dunlop Bridge.

Following the fatal crash of Danish driver Allan Simonsen at the 2013 race at the exit of Tertre Rouge into D338, Tertre Rouge was re-profiled again. The radius will be moved in approximately 200m for safety reasons with new tyre barriers at the exit.

Le Mans was most famous for its 6 km (3.7 mi) long straight, called Ligne Droite des Hunaudières, a part of the route départementale (for the Sarthe département) D338 (formerly Route Nationale N138). As the Hunaudières leads to the village of Mulsanne, it is often called the Mulsanne Straight in English, even though the proper Route du Mulsanne is the one from or to Arnage.

After exiting the Tertre Rouge corner, cars spent almost half of the lap at full throttle, before braking for Mulsanne Corner. The Porsche 917 long tail, used from 1969 to 1971, had reached 362 km/h (225 mph),.^[4] After engine size was limited, the top speed dropped until powerful turbo engines were allowed, like in the 1978 Porsche 935 which was clocked at 367 km/h (228 mph). Speeds on the straight by the Group C prototypes reached over 400 km/h (250 mph) during the late 1980s. At the beginning of the 1988 24 Hours of Le Mans race, Roger Dorchydriving for Welter Racing in a “Project 400” car, which sacrificed reliability for speed, was clocked by radar travelling at 405 kilometres per hour (252 mph). Fatal high speed accidents in the 1980s happened to Jean-Louis Lafosse in 1981 and to Jo Gartner in 1986.

As the combination of high speed and high downforce caused tyre and engine failures, two roughly equally spaced chicanes were consequently added to the straight before the 1990 race to limit the achievable maximum speed. The chicanes were added also because the FIA decreed it would no longer sanction a circuit which had a straight longer than 2 kilometres (1.2 mi). which is roughly the length of the Döttinger Höhe straight at the Nürburgring Nordschleife.

The fastest qualifying lap average speed dropped only from 249.826 to 243.329 km/h (155.235 to 151.198 mph) in 1992, and it rose up to a record 251.882 km/h (156.512 mph) in 2017, beating the previous all-time of 250.069 and 251.815 km/h (155.386 and 156.471 mph) set by the Porsche 917 and 962, respectively. Regarding the lap record in the race itself, 2017 saw the fastest ever, thanks to turbos and hybrid power.