Ignition Interlock Devices

A person convicted of a DWI or DUI offense in Washington, D.C. or Virginia can be required to install an Ignition Interlock Device (IID) on every vehicle he/she owns and operates.

An IID is a piece of equipment, similar to a breathalyzer machine, that is installed onto the dashboard of the car.  The person must blow a “clean breath sample” into the device before the car will start.  Random additional blows will be required once the vehicle is in motion to prevent potential fraud (having someone else, for example, blow into the device to start the vehicle).  If the breath sample isn’t provided or if the sample exceeds the IID’s present blood alcohol level (usually 0.02 to 0.04%), the device will record the event, warn the driver, and then turn on an alarm (e.g., lights flashing, horn honking) until either a clean breath sample has been provided or the ignition turned off.  For safety reasons, the device will NOT immobilize the vehicle that already is in motion.

The device stores the breath readings in its memory and communicates them to the proper authorities.  Attempts to tamper or circumvent the device may result in further penalties.

IIDs can be installed at designated ignition interlock service centers.  While the offender must pay for both installation and maintenance, indigent offenders may petition the court for an alternative payment schedule.