Patent ID: 7481292

Claim:
A vehicle ignition interlock system, comprising: a breath analyzer located within a vehicle, wherein the breath analyzer is configured to detect breath alcohol levels of an operator of the vehicle; and a controller operably connected to the breath analyzer and to an ignition system of the vehicle, wherein the controller is configured to compare detected breath alcohol levels of the vehicle operator with a threshold value, wherein the controller is configured to prevent vehicle ignition if a breath alcohol level detected by the breath analyzer is greater than or equal to the threshold value, wherein the controller is configured to require periodic breath alcohol tests of the vehicle operator via the breath analyzer, and wherein the controller is configured to reduce the frequency of the periodic breath alcohol tests of the vehicle operator via the breath analyzer in response to a plurality of breath alcohol tests over a period of time spanning multiple vehicle operations via the breath analyzer indicating that the breath alcohol level of the vehicle operator is below a threshold value.