An ignition interlock device (IID) is a breath-test machine ("breathalyzer") that's connected to a vehicle's ignition system. Once an IID is installed, the vehicle won't start until someone breathes into the IID with an alcohol-free breath. The idea, of course, is to prevent someone who's been drinking from driving the vehicle.
Lots of states are now requiring DUI offenders to install IIDs as a condition of license reinstatement. But the DUI laws in every state are different. Some states require IIDs for all DUI offenders, including those convicted of a first DUI. Other states mandate IIDs only for repeat offenders or offenders with high blood alcohol concentrations (BACs). And a number of states let judges decide, based on the circumstances of each case, whether to order an IID.
It's also common for IIDs to be a requirement for obtaining a "hardship license." A hardship license gives a person limited driving privileges for going to and from places like work and school during a suspension.
The duration of an IID requirement depends on state law and the circumstances of your case. But the length of time a driver must have an IID geneally relates to the seriousness of the offense. For example, a first DUI might come with a six-month IID requirement, whereas someone convicted of a third DUI could be required to have an IID for several years.
IIDs aren't cheap. And it's usually up to the driver to pay the costs. But for most people, the expense is preferable to not driving.
The costs of an IID can generally be broken into three parts:
Some states provide financial assistance to people who are indigent and can't afford IID costs. And IID companies sometimes offer flexible payment plans.
IIDs are installed in a way that prevents the driver from simply disconnecting them. And attempting to do so may result in damage to the IID or your vehicle.
However, IIDs have no way of identifying who provides the alcohol-free breath. So it's possible to trick an IID by having someone else blow into it. But IIDs normally require "rolling" samples every so often after the vehicle is started. Though a positive test on a rolling sample won't normally shut down the vehicle, the IID will record the result and the court and DMV will likely find out about it.
Plus, drivers who are caught tampering with or trying to evade an IID will likely face revocation of driving privileges and possibly criminal charges.