1. Once the key has been put into the vehicle’s ignition, and turned on to provide power to the vehicle, the device will be activated.
  2. The device will prompt the driver to provide a breath sample.
  3. The driver will attempt to provide a valid breath sample, by blowing into the device as previously instructed.
  4. If the resultant breath alcohol concentration (BrAC) analyzed in the breath sample is below the pre-set fail level, which is typically .020 but varies by State, the engine can be started. If the BrAC is at or above the pre-set fail level, the violation will cause the ignition to be disabled and the vehicle will not start. The IID will “Lockout” for a short period of time. Once the lockout period has expired, another breath sample can be provided.
  5. At random times during vehicle operation, the IID will prompt the driver to provide another breath sample (also referred to as a “Retest”). The purpose of the Retest is to deter someone other than driver, or some other form of altered air, from providing the breath sample. If the breath sample for the retest is failed or missed, the IID will log the event, warn the driver and in some cases start up an alarm (e.g. lights flashing, horn honking, etc.) until the ignition is turned off, or a valid breath sample is provided.