Ignition Interlock Devices (IIDs): A Legislative Tool to Keep Drunk Drivers Off the Road

Breathalyzers that are wired to a car’s ignition and prevent a motorist from driving when breath alcohol is detected.

Year-after-year state legislatures try to find ways to curb drunk driving. In this search, an increasing number of states are imposing ignition interlock device (IID) requirements—or making existing IID laws stricter—for those convicted of driving under the influence (DUI). Basically, IIDs are breath-test devices that are installed in a vehicle, which prevent it from starting when the driver has a measureable breath alcohol concentration (BAC).

IID Basics

Breathalyzers—portable alcohol breath-test devices—have been around since the 1950s. The original versions, which employed “wet chemical techniques,” required police to carry around a collection of items resembling an amateur chemistry set. Eventually, scientists found ways to put modern technologies—fuel cell, semiconductor, and infrared sensors—to use in breathalyzers. These technological advancements, which resulted in more compact designs, made the creation of IIDs possible.

IIDs are essentially breathalyzers that attach to a car’s ignition system. A car that has an IID installed won’t start until someone blows into a tube with an alcohol-free breath. Most IIDs also require “rolling tests” every so often after the car is started. Typically, the IID will beep—indicating a rolling test is necessary—and the motorists has about five minutes to give a breath. If an IID detects alcohol on a rolling sample, it won’t shut the car off. But the device will record the positive result and likely notify the court or Department of Motor Vehicles.

State IID Laws

All 50 states have IID legislation. But IID laws aren’t all the same. There are laws that:

  • require IIDs for all offenders
  • require IIDs for only certain offenders, and
  • let judges choose, based on the circumstances, whether to order an IID.

For example, in Connecticut, IIDs are required for all drunk driving convictions. In Florida, on the other hand, IIDs are mandatory only for repeat offenders and offenders who had a BAC of .15% or more. And in California, it’s generally up to the judge to decide whether to impose an IID requirement.

(Cal. Veh. Code § 23575 (2017); Conn. Gen. Stat. Ann. §14-227a (2017); Fla. Stat. Ann. § 316.193 (2017).)

Hardship Licenses

In many states, it’s possible for someone whose license has been suspended for a DUI to get a “hardship” license (also called a “Cinderella” or “restricted” license). Generally, hardships licenses allow the motorist—whose license is otherwise suspended—to drive to and from places like work, school, and medical appointments. Having an IID installed is a common prerequisite for obtaining a hardship license.

(Read more about hardship licenses.)

Talk to an Attorney

If you have specific questions about the IID or DUI laws in your state, it’s always best to talk to a local DUI attorney. The facts of each case are different. A qualified DUI lawyer can tell you how the law applies in your particular situation.

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