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How Does an Ignition Interlock Device Work?

An alcohol ignition interlock device is connected to the starter system in the vehicle. The device works by measuring the driver’s BAC level after they blow into the system. If the BAC level registered by the device is higher than the pre-programmed level set by the company, the vehicle will not start. The pre-programmed level is set by the court, but is typically set between .02 percent and .04 percent. While the vehicle is in operation, the device will require breath samples from the driver. If the breath sample is not provided or exceeds the BAC limit that has been set, the system will record the occurrence and issue a warning to the driver. An alarm will then start consisting of the lights flashing and horn honking before the vehicle shuts down. One of the major flaws of an ignition interlock device is that using mouthwash that contains alcohol will cause the machine to register a failure.