Little  research exists on which specific interlock program characteristics may  improve installation rates or otherwise improve the effectiveness of  ignition-interlock programs, but NHTSA’s ongoing and planned  research—expected to be completed between 2014 and 2015—may fill  this gap. Most studies use DWI arrest as a  proxy for alcohol-impaired driving; however researchers have noted that  arrest for DWI is a rare event, with some estimating that less than 1   A 2011 review of  percent of alcohol-impaired drivers are detected.literature assessing the effectiveness of ignition interlocks identified 15  studies (12 in the U.S., 2 in Canada, and 1 on Sweden) that observed  that ignition interlock installation reduced the risk of being re-arrested for  DWI offenders, compared to DWI offenders not using ignition interlocks. Research we identified on the effectiveness of ignition interlocks also  indicates that once the devices are removed, DWI arrest rates return to  pre-interlock rates.DWI offenses in New Mexico observed a reduction in re-arrest while the  ignition interlocks were installed, but in a period following removal of the  ignition interlock, there was no significant difference in DWI re-arrest rates  between offenders who had installed the ignition interlock and those who  had not. NHTSA officials reported that between 15  and 20 percent of offenders arrested for DWI install ignition interlocks. For example, NHTSA officials told us that in an ongoing study of  state ignition-interlock programs, they were able to identify only eight  states with sufficient data (e.g., the number of ignition interlocks ordered  and the number of DWI offenders who actually installed the ignition  interlocks) to estimate the program’s installation rate. NHTSA is currently working with the Preusser Research Group (PRG) to  conduct a study on factors that could help states improve installation  rates. NHTSA Provided Assistance to States for Ignition-Interlock Programs, but Some State Officials Questioned NHTSA’s Implementation of MAP-21 Grant

NHTSA offered a variety of assistance—including guidance, technical  assistance, research, and education—to help states establish and  improve their ignition-interlock programs, including the new ignition- interlock grant established by MAP-21. According to  some state officials, exemptions are seldom used in practice, but are  important to maintain because they facilitate the ability of offenders to  work. As described previously, states qualify for this grant by  requiring that all individuals convicted of a DWI offense be limited to  driving motor vehicles equipped with an ignition interlock. NHTSA officials stated that they based their implementation of the  ignition-interlock grant on the plain meaning of the authorizing language  in MAP-21, which did not include any reference to exemptions or  exclusions. Specifically, NHTSA’s Digest indicated  that as of May 2012 at least 5 states allowed exemptions for employer  vehicles, and additional states had other factors that would prevent them  from qualifying for the ignition-interlock grant. Based on  experience in reviewing state impaired driving laws, NHTSA officials  recognized that many states would have to change existing laws to apply  to first time offenders and eliminate exemptions. Few states were  expected to qualify in the grant’s first years because it would be difficult  for state legislatures to change their ignition interlock laws in that time  frame. Most of the states that did not  receive the grant were disqualified due to employer exemptions. State  legislatures in Arizona and Washington were able to eliminate employer  exemptions and other disqualifying factors from their laws in order to  qualify for the grant in fiscal year 2014, bringing the total grant recipients  to four that year. Because the ignition-interlock grant is relatively new, the  extent to which additional state legislatures would be willing or able to  modify their laws to qualify for the grant is unclear. In the first  2 years of the grant program, few states applied for the grant and of  those, most were disqualified because of exemptions that allowed DWI  offenders to drive employer-owned vehicles without ignition interlocks. Agency Comments

We provided a draft of this report to DOT for review and comment. DOT  also provided technical corrections, which we incorporated as  appropriate. Appendix I: Objectives, Scope, and Methodology

The objectives of our review were to determine (1) what is known about  the effectiveness of ignition interlocks in reducing alcohol-impaired driving  and (2) the extent to which the National Highway Traffic Safety  Administration (NHTSA) has assisted states in implementing ignition- interlock programs, including the Moving Ahead for Progress in the 21st  Century Act (MAP-21) ignition-interlock grant program. To identify the types of assistance that NHTSA provides to states to help  them establish and implement their ignition-interlock programs, we  interviewed NHTSA officials about their activities and reviewed reports  describing NHTSA’s ignition interlock-related research, technical  assistance, and conferences. For both objectives, we interviewed  representatives from safety advocacy organizations such as the  Governors Highway Safety Association and Mothers Against Drunk  Driving.
Why GAO Did This Study

Motor vehicle crashes involving alcohol-impaired drivers killed 10,322 people in 2012 and account for almost one third of all traffic fatalities annually. Ignition interlocks are one strategy states use to combat DWI. In 2012, MAP-21 established a grant program for states that adopt and implement mandatory alcohol ignition-interlock laws for all convicted DWI offenders. Funding authorization for this program expires at the end of fiscal year 2014.
GAO was asked to review the effectiveness of ignition interlocks and NHTSA's implementation of the new grant program. This report discusses (1) what is known about ignition interlock effectiveness and (2) the extent to which NHTSA has assisted states in implementing ignition-interlock programs, including the grant program. GAO reviewed 25 studies that analyzed relationships between ignition interlocks and DWI arrests and fatalities; interviewed NHTSA officials and reviewed reports about NHTSA's assistance to states; and interviewed representatives from safety-advocacy and research organizations, and officials involved with ignition-interlock programs from 10 states. The states were selected based on grant program qualification and the number of alcohol-impaired fatalities, among other factors. The information from these states is not generalizable. DOT officials reviewed a draft of this report and generally agreed with the findings. DOT offered technical corrections, which we incorporated as appropriate.

What GAO Found

Research GAO reviewed consistently indicated that when installed ignition “interlocks”—devices that prevent drivers from starting their cars if they have been drinking alcohol—effectively reduce the rate of re-arrest for driving while intoxicated (DWI) when installed. But once the devices are removed, DWI re-arrest rates return to pre-interlock rates. (Most studies use DWI arrest as a proxy for alcohol-impaired driving.) Further, the National Highway Traffic Safety Administration (NHTSA) estimated that between 15 and 20 percent of offenders arrested for DWI actually install ignition interlocks. Many factors contribute to low installation rates. For example, some states lack the resources to monitor offenders to ensure they install ignition interlocks; other states require that offenders pay fees and penalties to be eligible to install ignition interlocks and return to driving with interlocks. State ignition interlock programs vary in terms of how they are designed, but little research exists on which specific interlock program characteristics—such as monitoring or length of installation—could improve the effectiveness of interlock programs. NHTSA is currently conducting studies on factors that could help states improve installation rates or otherwise improve the effectiveness of their interlock programs. NHTSA expects these studies to be completed by 2015.
NHTSA has offered a variety of technical assistance, research, and education to help states establish and improve their ignition-interlock programs, as well as implement the ignition interlock grant program established by the Moving Ahead for Progress in the 21st Century Act (MAP-21). While state officials confirmed that NHTSA's overall ignition-interlock-related activities have been useful, some questioned NHTSA's implementation of the ignition interlock grant program. Specifically, NHTSA's implementation was based on the plain meaning of the authorizing language in MAP-21, which did not include any reference to exemptions. As a result, states with “employer exemptions”—programs that require offenders to drive only vehicles equipped with ignition interlocks for personal use but allow them to drive employer-owned vehicles for work purposes—were disqualified. Some state officials told us these exemptions are seldom used in practice, but are important to maintain because they facilitate the ability of offenders to work. According to NHTSA officials, they recognized that to qualify for the grant, many states would have to modify their ignition-interlock laws to make them applicable to first time offenders and eliminate exemptions; therefore, few states were expected to qualify in the grant's first years because it would be difficult for state legislatures to change their ignition-interlock laws in that time frame. In fiscal year 2013, 2 states qualified for the grant; most of the additional 12 states that applied for the grant were disqualified at least in part due to employer exemptions, but the legislatures in 2 of those states later removed such exemptions from their laws, resulting in 4 states qualifying for the grant in fiscal year 2014. Because the ignition interlock grant is relatively new, the extent to which additional state legislatures may be willing or able to modify their laws to qualify for the grant is unclear. A 2012 NHTSA review of states' impaired-driving laws found that at least 5 states' ignition-interlock laws included employer vehicle exemptions, but additional states had other factors that would prevent them from qualifying for the ignition-interlock grant.