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 Oklahoma, an alcohol ignition interlock device (IID) is a mechanism that prevents a vehicle from starting if the driver's breath alcohol concentration (BAC) is above a preset limit, typically .02 BAC. Oklahoma law mandates the use of IIDs for certain DUI offenders. The device must be installed by a state-approved certified technician. For first-time DUI offenders, the court may require an IID based on the judge's discretion. However, for individuals convicted of a second or subsequent DUI, the installation of an IID is generally mandatory. The duration for which an IID must be installed can vary, but it often ranges from 1 to 3 years, depending on the severity of the offense and the court's decision. The IID records data such as engine starts and stops, breath test results, and any attempts at tampering, which is reported to the monitoring company and then to the court. While IIDs are proven to significantly reduce the rate of repeat DUI offenses, compliance rates are not as high as the law intends, with only a fraction of those arrested for DUI/DWI actually having an IID installed.