An Ignition Interlock Device (IID) is a mechanism, like a breathalyzer, installed in a vehicle to deter drinking and driving. Before the vehicle can be started, the driver must deliver a breath sample into the device, and if the analyzed result is greater than the pre-programmed level, the device prevents the vehicle from being started.
In most restricted driving programs, random retests are also required as the vehicle is being driven. When requested, the driver must deliver breath samples into the device and the device will log the event. If the result exceeds the pre-programmed level, the Ignition Interlock Device will not turn off the engine while the vehicle is in motion however it will give a signal to stop.
The data received from all breath samples are sent to the department(s) (Court/DMV/Probation, etc) who ordered the device to be installed. Some states require the data be sent immediately via wireless technology after the breath sample, while other states receive the information once per month. Please watch the below video for more information on ignition interlock devices.