 There have been numerous disputes over what constituted production and modified cars when used in motorsports.Even under Fédération Internationale de l'Automobile (FIA), the exact definition of what was (or was not) a production car was unclear and controversial, which led to rules written in 1955.Although the term is defined for particular types of vehicles, and that a certain number of a model must be produced in order to qualify as "production", it is another matter to enforce the rules.