Patent ID: 8370027

Claim:
A vehicle safety system, comprising: an alcohol concentration determining arrangement, for making a determination as to the concentration of alcohol in the blood of a vehicle occupant; a control unit adapted to receive and analyze data from the alcohol concentration determining arrangement to create an analysis, and in dependence upon the results of the analysis, the control unit being operable to output one of a blocking signal and a warning signal; a blocking arrangement, adapted to receive the blocking signal and to prevent driving of the vehicle by the vehicle occupant; and an output device adapted to receive the warning signal and to present at least one warning to the vehicle occupant; wherein: the control unit is operable to categorize the concentration of alcohol in the occupant's blood into one of three categories, the categories including 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 blocking signal will not be generated and the warning signal will be generated; the control system being configured to automatically execute a system self-test in conjunction with each breath test, to distinguish provoked and unprovoked errors from each other; to categorize an unprovoked error in the intermediate category, and to categorize a provoked error in the high concentration category.