Abstract: A vehicle ignition interlock system includes a breath analyzer and a controller operably connected to the breath analyzer and to an ignition system of the vehicle. The controller compares detected breath alcohol levels of the vehicle operator with a threshold value, and is configured to prevent vehicle ignition if a breath alcohol level detected by the breath analyzer is greater than or equal to a threshold value. The controller also requires the vehicle operator to periodically take breath analyzer retests after vehicle ignition in order to allow vehicle operation to continue. The controller can reduce the frequency of periodic retests in response to one or more retests when the breath alcohol level of the vehicle operator is below a threshold value. The system may include a transdermal alcohol sensor, a mouth contamination sensor, a mouth contamination sensor, and redundant alcohol sensors.

Abstract: A vehicle ignition interlock system includes a breath analyzer and a controller operably connected to the breath analyzer and to an ignition system of the vehicle. The breath analyzer detects the breath alcohol level of a vehicle operator and is configured to prevent vehicle ignition if a breath alcohol level is greater than or equal to a threshold value. The controller requires the vehicle operator to periodically take breath analyzer “retests” after vehicle ignition in order to allow vehicle operation to continue. The breath analyzer also includes a mouth contamination sensor that is configured to distinguish between contaminants in the mouth of a vehicle operator and alcohol contained within a deep lung breath sample of the vehicle operator. The controller may require a breath alcohol retest of the vehicle operator via the breath analyzer in response to detecting the presence of a contaminant within the mouth of the vehicle operator.

Abstract: A vehicle ignition interlock system includes a breath analyzer and a controller operably connected to the breath analyzer and to an ignition system of the vehicle. The breath analyzer detects breath alcohol level of a vehicle operator and prevents vehicle ignition if a breath alcohol level is greater than or equal to a threshold value. The controller requires the vehicle operator to periodically take breath analyzer “retests” after vehicle ignition in order to allow vehicle operation to continue. The breath analyzer includes first and second alcohol sensors. The second alcohol sensor is a backup for the first alcohol sensor and becomes operational if the first alcohol sensor malfunctions. The first or second alcohol sensors may be a mouth contamination sensor that distinguishes between mouth contaminants and alcohol contained within a deep lung breath sample. The system also includes sensors configured to detect impact (abuse) and vehicle motion.