Alcohol-impaired driving crashes in the United States accounted for 31 percent of all motor vehicle fatalities in 2012, killing 10,322 people (NCSA, 2013). Drivers with previous convictions for driving while impaired (DWI) are at increased risk of being involved in alcohol-impaired crashes (Elder et al., 2011). One way to prevent drivers who have been convicted of DWI from driving after drinking is to use ignition interlocks, breath-test devices connected to vehicle ignitions. The driver must provide a breath sample below a State-established set point to start the vehicle. Most States use a blood alcohol concentration set point of .02 grams per deciliter. While installed, interlocks are effective in reducing recidivism by a median of 67 percent (Elder et al., 2011; Willis, Lybrand, & Bellamy, 2006). Most States have laws that require some or all convicted DWI offenders to install ignition interlocks on their vehicle and all States allow interlocks to be used for some offenders (NCSL, 2014; NHTSA, 2013a). Some States have implemented incentives for offenders to install ignition interlocks when the offenders are not required to do so. All States have implemented ignition interlock programs to manage interlock issues and monitor offenders who are required or eligible to install them. Despite these laws and programs, the proportion of convicted offenders who install interlocks is low. In 2013, the number of interlocks in use was 300,000 (Roth, 2013), but approximately 1.4 million people are arrested for DWI yearly (FBI, 2012). Therefore, only about 21 percent of those arrested for DWI install interlocks. Due to the low use of interlocks, the maximum potential reductions in alcohol-impaired driving are not being achieved. In order to increase use of ignition interlocks through improving State programs, in 2010 the National Highway Traffic Safety Administration sponsored an expert panel on key features of State interlock programs. This panel identified a strong need for research to determine the benefits of different program features (Marques, 2010). In 2010, the Centers for Disease Control and Prevention (CDC) and NHTSA began collaborating on a project to evaluate ignition interlock programs in selected States. The purpose of the evaluation was to provide information and best practices to States for ignition interlock programs. The project was managed by the Governor’s Highway Safety Association and conducted by the Preusser Research Group. This report provides the results from the first part of the project that had the following objectives: • Determine how States can increase interlock use among DWI offenders who are required or eligible to install one. • Determine which changes in ignition interlock programs led to increases in ignition interlock use. • Identify the key features of ignition interlock programs. • Determine which key program features were related to higher ignition interlock use rates. (Author/publisher)
Samenvatting