Identifying Cost and Funding Alternatives for Equipping Operating While Intoxicated Offenders with Ignition Interlock Devices

Sponsor:  Wisconsin Department of Transportation

PI:  John Hill

Ignition Interlock Devices (IID) have been used in multiple states to deter repeat operating while intoxicated (OWI) offenders from further offenses.  It has been found in the state of California that a group of offenders who had an order to use an IID had a reduction in future crash rates of 24 percent, while slight changes were seen in those that were not ordered the use of an IID.  Those drivers who installed the IID also had a lower rate of future DUI convictions.   A major issue with IIDs has been compliance.  Studies have shown that as few as 10% of drivers convicted of OWI and ordered to install an IID device, actually do so.

Research Objectives
– Identify and characterize OWI offenders in Wisconsin  and develop a 10 year forecast of overall
OWI arrests and arrests of particular high risk offenders.
– Estimate IID implementation costs based on the forecast model developed and determine the
overall affordability of IID devices for OWI offenders
– Identify potential funding sources to increase IID installations.

Information regarding over 200,000 OWI offenders in Wisconsin from 2005-2009 was analyzed.  Using a logistic regression model, characteristics of OWI offenders who were likely to repeat the offense within 1 or 2 years were identified.  Additionally, a 10 year forecast model was developed which was based on annual historical arrest levels over the past 20 years, as well as monthly vehicle miles travelled an d economic data over the past 5 years.  Using this information, along with cost data collected from interviewing IID manufacturers, the overall cost to equip the vehicles of future OWI offenders was collected.  Income levels of IID offenders were also modeled using an exponential distribution to determine what proportion of offenders may be unable to afford an IID.  Finally, an analysis of potential funding sources was conducted to determine if supplementing the cost of IIDs might be a feasible means of increasing IID order compliance.