how does the IID work?

When a driver enters a vehicle, he is prompted to give a breath sample by cues from the device. In the winter, the device may take a few minutes to warm up. To ensure that the sample is not created by mechanical means, some IIDs require a particular breath pattern to be followed; others measure the driver’s breath temperature. A recent Pennsylvania study noted that the correct pattern of blowing/sucking/humming was one of the primary obstacles to proper IID use (USA Today 13 January 2003).

The device immediately displays a pass, fail, or inadequate sample reading. Passing allows the car to be started immediately. Three successive failures locks the ignition. The inadequate sample reading is caused by not providing enough air, stopping in the middle of the process, or failing to blow/suck/hum in the correct manner. If an inadequate sample is drawn, the device prompts you to try two more additional times.

The driver has three chances to provide a valid sample. If he fails to do so, the IID records a violations reset, requiring the driver to return the unit to the service provider within seven days or risk permanent lockout. When the driver successfully provides a sample below the set point, the car can start. Five minutes after ignition and then randomly in 5-30 minutes increments, the IID will request additional breath samples, called rolling retests. Rolling retests are designed to remove the possibility of a sober friend from assisting an intoxicated driver – the drunk driver cannot get far. Three consecutive refusals to provide a rolling retest, or three breath tests over the set point will start the horn honking and emergency lights flashing. This continues until the driver turns off the ignition, immobilizing the car for 15 minutes. This event, or any attempt to tamper with or subvert the IID, is recorded in the IID as a violations reset, requiring the driver to bring the IID in for service. Routine service is required every 60 days, and failure to service will lead to a permanent lockout. Seven days prior to the service deadline, the driver sees or hears a reminder from the IID. At the servicing, stored unit data is downloaded and reviewed, device accuracy is checked, and a tampering inspection is performed.

This entry was posted on Tuesday, November 11th, 2008 at 12:09 pm and is filed under ignition interlock system. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.