The land speed record (or absolute land speed record) is the highest speed achieved by a person using a vehicle on land. There is no single body for validation and regulation; in practice the Category C ("Special Vehicles") flying start regulations are used, officiated by regional or national organizations under the auspices of the Fédération Internationale de l'Automobile. The land speed record (LSR) is standardized as the speed over a course of fixed length, averaged over two runs (commonly called "passes"). Two runs are required in opposite directions within one hour, and a new record mark must exceed the previous one by at least one percent to be validated.
The first regulators were the Automobile Club de France, who proclaimed themselves arbiters of the record in about 1902.
Different clubs had different standards and did not always recognise the same world records until 1924, when the Association Internationale des Automobile Clubs Reconnus (AIACR) introduced new regulations: two passes in opposite directions (to negate the effects of wind) averaged with a maximum of 30 minutes (later more) between runs, average gradient of the racing surface not more than 1 percent, timing gear accurate within 0.01sec, and cars must be wheel-driven. National or regional auto clubs (such as AAA and SCTA) had to be AIACR members to ensure records would be recognized. The AIACR became the FIA in 1947. Controversy arose in 1963: Spirit of America was not recognised due to its being a three-wheeler (leading the to certify it as a three-wheel motorcycle record when the FIA refused) and not wheel-driven so the FIA introduced a special wheel-driven class. No holder of the absolute record since has been wheel-driven
In 1906 Dorothy Levitt broke the women's world speed record for the flying kilometer, recording a speed of 91 mph (146.25 km/h) and receiving the sobriquet the "Fastest Girl on Earth". She drove a six-cylinder Napier motorcar, a 100 hp (74.6 kW) development of the K5, in a speed trial in Blackpool. A subsequent record was held by Lee Breedlove, the wife of Craig Breedlove, who piloted her husband's Spirit of America - Sonic 1 to a record of 308.506 mph (496.492 km/h) in 1965, making her the fastest woman alive, as of 1974[update]. According to author Rachel Kushner, Craig Breedlove had talked Lee into taking the car out for a record attempt in order to monopolize the salt flats for the day and block one of his competitors from making a record attempt.