A computer-based vehicle reservation system and a method for a computer-based vehicle reservation system. According to the method: the availability of all vehicles in the vehicle reservation system is detected; a user reserves a vehicle for a determinable time and/or period and/or location by a computing unit connected to a central unit; an identification code is transmitted to a mobile radio device of the user by an SMS module of a central unit; the user is identified in an identification module by the identification code; and the vehicle is released for use. In particular, the billing process for the related services can be automated by the method and system.