How does an ignition interlock device work?
Before starting the vehicle, a driver must blow into the device. If the driver’s blood alcohol concentration (BAC) is above the pre-set limit, the vehicle will not start.
Once the vehicle is started, the interlock device requires the driver to provide breath samples at random pre-set times while the engine is running. If a sample is not provided, or if the BAC exceeds the limit, the device will issue a warning, record the event and activate specific alarm systems (e.g., lights flashing, horn honking, etc.), until the ignition is turned off.