A vehicle safety system is provided that includes an alcohol concentration determining arrangement. A control unit is adapted to receive and analyze data from the alcohol concentration determining arrangement and output a blocking signal or a dissuasion signal under certain conditions. A blocking arrangement is adapted to prevent driving of the vehicle by the vehicle occupant upon receipt of a blocking signal. An output device is adapted to receive the dissuasion signal and to present a warning to the vehicle occupant to dissuade the occupant from driving the vehicle. The control unit is operable to categorize the concentration of alcohol in the occupant's blood into one of three categories: a low concentration category, in which the blocking signal will not be generated, a high concentration category, in which the blocking signal will be generated, and an intermediate category, in which the dissuasion signal will be generated.