An alcohol ignition interlock device (IID) is a breath-test device that is connected to a vehicle’s ignition. A vehicle with an IID installed will not start unless the driver blows into the interlock and has a blood alcohol concentration (BAC) below a limit set by the court—usually .02 BAC. IIDs must be installed by a certified technician approved by the state’s department of motor vehicles (DMV). The IID will collect data (engine starts and stops, breath test results, and tampering attempts) and report it to the monitoring company, which will report it to the court.

IIDs reduce repeat offenses for DUI/DWI by approximately 70% when installed. Laws vary from state to state and courts have significant discretion, but a judge may order a person convicted of a first DUI/DWI offense to install an IID and will order a person convicted of a second or third DUI/DWI to install an IID. Courts will often order an IID installed on the defendant’s vehicle as a condition of bond (to be released from jail) and of probation (following jail or prison time, or in lieu of any or more jail or prison time). The court may order the defendant’s IID to remain on the vehicle for 1-3 years or more.

Despite these laws and programs, only about one-fifth of those arrested for DUI/DWI have an IID installed.

In New Jersey, the use of an alcohol ignition interlock device (IID) is mandated by law for certain driving under the influence (DUI) offenses. New Jersey law requires all individuals convicted of a first-time DUI with a blood alcohol concentration (BAC) of 0.15% or higher to install an IID in their vehicle. For repeat offenders, the installation of an IID is mandatory regardless of the BAC level at the time of the offense. The duration for which the IID must be installed varies depending on the number of offenses and the BAC level. For a first offense with a BAC of 0.15% or higher, the IID must be installed during the period of license suspension and for 6 months to 1 year following restoration. For a second DUI offense, the IID is required for 1 to 3 years, and for a third or subsequent offense, it is required for 2 to 4 years after license restoration. The device must be installed by a state-approved technician, and the data collected by the IID is reported to the monitoring company and the court. The use of IIDs is intended to reduce repeat DUI offenses and enhance public safety.