GAO-14-559, Traffic Safety: Alcohol Ignition Interlocks Are Effective While Installed; Less Is Known about How to Increase Installation Rates

TRAFFIC SAFETY

Alcohol Ignition

Interlocks Are

Effective While

Installed; Less Is

Known about How to

Increase Installation

Rates

Report to the Chairman, Committee on

Commerce, Science, and

Transportation, U.S. Senate

June 2014

GAO-14-559

United States Government Accountability Office

Highlights of GAO-14-559, a report to the

Chairman, Committee on Commerce, Science,

and Transportation, U.S. Senate

June 2014

TRAFFIC SAFETY

Alcohol Ignition Interlocks Are Effective While

Installed; Less Is Known about How to Increase

Installation Rates

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.

View GAO-14-559. For more information,

contact Susan Fleming at (202) 512-2834 or

flemings@gao.gov

Page i GAO-14-559 Traffic Safety

Letter 1

Background 2

Research Indicates Interlock Devices Are Effective While

Installed, but Installation Rates Are Low and Research on

Strategies to Increase Rates Is Limited 11

NHTSA Provided Assistance to States for Ignition-Interlock

Programs, but Some State Officials Questioned NHTSA’s

Implementation of MAP-21 Grant 20

Concluding Observations 24

Agency Comments 25

Appendix I Objectives, Scope, and Methodology 27

Appendix II Studies on Ignition-Interlock Effectiveness 30

Appendix III GAO Contact and Staff Acknowledgments 33

Tables

Table 1: States That Applied For and Were Awarded MAP-21

Ignition-Interlock Grants, Fiscal Years 2013 and 2014 5

Table 2: Summary of Ignition-Interlock Effectiveness Research 16

Figures

Figure 1: A Driver Using an Ignition-Interlock Device 7

Figure 2: A Generalized Depiction of an Ignition-Interlock Program 8

Contents

Page ii GAO-14-559 Traffic Safety

Abbreviations

AIIPA Association of Ignition Interlock Program Administrators

BAC blood alcohol concentration

CDC Centers for Disease Control and Prevention

DOT Department of Transportation

DWI driving while intoxicated

g/dL grams per deciliter

GHSA Governors Highway Safety Association

MADD Mothers Against Drunk Driving

MAP-21 Moving Ahead for Progress in the 21st Century Act

NHTSA National Highway Traffic Safety Administration

PRG Preusser Research Group

TIRF Traffic Injury Research Foundation

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Page 1 GAO-14-559 Traffic Safety

441 G St. N.W.

Washington, DC 20548

June 20, 2014

The Honorable John D. Rockefeller IV

Chairman

Committee on Commerce, Science, and Transportation

United States Senate

Dear Mr. Chairman:

In 2012, motor vehicle crashes involving alcohol-impaired drivers killed

10,322 people. While the number of such fatalities has dropped by 21

percent over the last 10 years, almost one third of all traffic fatalities

annually resulted from crashes involving an alcohol-impaired driver over

the same period. Breath alcohol “ignition interlocks” are devices that

prevent a driver from starting a car if the device detects a driver’s blood

alcohol concentration (BAC) above a certain threshold.

Ignition interlocks

represent one of the strategies states use to combat alcohol-impaired

driving. California first piloted the use of ignition interlocks in 1986 for

drivers convicted of driving while intoxicated (DWI).

According to the

National Highway Traffic Safety Administration (NHTSA), all states have

enacted legislation requiring or permitting the use of ignition interlocks.

Historically, Congress has provided funds for state programs to reduce

alcohol-impaired driving. Most recently, the 2012 surface transportation

reauthorization act—Moving Ahead for Progress in the 21st Century Act

(MAP-21)—also included funding for a new grant program for states with

laws mandating that all drivers convicted of DWI be allowed to drive only

vehicles equipped with an ignition interlock.

BAC is measured as a mass of alcohol per volume of blood. In the United States, the

standard measurement is represented as grams per deciliter (g/dL).

NHTSA assists states in

implementing these programs and, in addition to other safety

organizations, has funded research examining the effectiveness of

ignition-interlock programs.

The specific criminal offenses pertaining to alcohol-impaired driving vary across

jurisdictions and can include such terms as “driving under the influence of alcohol or drugs

(DUI),”operating under the influence of alcohol or drugs (OUI),” or “driving while

intoxicated (DWI)” In this report, the term “driving while intoxicated (DWI)” is used to

capture all types of alcohol-impaired offenses.

Pub. L. No. 112-141, 126 Stat. 405 (2012).

Page 2 GAO-14-559 Traffic Safety

In light of the toll alcohol-impaired driving takes, you asked us to review

the effectiveness of ignition interlocks and NHTSA’s implementation of

the MAP-21 ignition-interlock program. This report discusses (1) what is

known about the effectiveness of ignition interlocks in reducing alcohol-

impaired driving and (2) the extent to which NHTSA has assisted states in

implementing ignition-interlock programs, including the MAP-21 ignition-

interlock grant program.

To identify what is known about the effectiveness of ignition interlocks, we

reviewed 25 studies conducted between 1990 and 2013 that analyzed

relationships between ignition interlock devices or programs and alcohol-

impaired driving outcomes, including DWI arrests and DWI fatalities. We

identified these studies from a literature search and recommendations

from organizations that conduct research on ignition interlocks, such as

the Pacific Institute for Research and Evaluation. 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 (GHSA)

and Mothers Against Drunk Driving (MADD). We also interviewed traffic

safety, criminal justice, department of motor vehicles or licensing, and law

enforcement officials from 10 states. The states were selected based on

MAP-21 ignition-interlock grant program qualification, DWI fatality

numbers in 2012 (most recent data available), and alcohol-impaired

fatalities per 100-million vehicle-miles traveled as calculated by NHTSA.

(See app. I for more information on scope and methodology and app. II

for a list of reviewed studies.)

We conducted this performance audit from July 2013 to June 2014 in

accordance with generally accepted government auditing standards,

Those standards require that we plan and perform the audit to obtain

sufficient, appropriate evidence to provide a reasonable basis for our

findings and conclusions based on our audit objectives. We believe that

the evidence obtained provides a reasonable basis for our findings and

conclusions based on our audit objectives.

While alcohol-impaired driving fatalities have declined from over 21,113 in

1982 to 10,322 in 2012, the proportion of such fatalities as a percent of

total traffic-related fatalities has remained relatively constant—between

30 and 32 percent—over the past 15 years. Congress has targeted this

Background

Page 3 GAO-14-559 Traffic Safety

persistent problem through legislation to encourage states to reduce their

illegal per se BAC limit.

For example, beginning in 1982, federal

legislation authorized grants to states to establish an illegal per se BAC

limit of 0.10 or greater while driving a motor vehicle.

NHTSA administers safety-incentive grant programs to assist states in

their efforts to reduce traffic-related fatalities, including alcohol-impaired

fatalities.

In other words, with

respect to a BAC limit of 0.10, anyone whose blood contains 1/10th of 1

percent of alcohol or higher would be deemed to be DWI. In the late

1990s, Congress made grant funds available to states to encourage them

to further lower the illegal per se driving BAC limit to 0.08. In 2000, the

U.S. Department of Transportation Appropriations Act for fiscal year 2001

included a provision that states must enact 0.08 BAC laws by fiscal year

2004 or begin losing federal highway construction funds. According to

NHTSA, all states had complied with that provision by 2004.

Through transportation legislation—including the Transportation Equity

Act for the 21st Century

NHTSA also provides guidance and technical assistance, sets

and enforces safety performance standards for motor vehicles and motor

vehicle equipment, and conducts research on driver behavior and traffic

safety. As part of such research, NHTSA works with traffic safety

organizations, such as GHSA, MADD, and the Traffic Injury Research

Foundation (TIRF).

, the Safe, Accountable, Flexible, Efficient

Transportation Equity Act: A Legacy for Users

Per se BAC laws establish the BAC level at which it is illegal per se (in itself) for a driver

to operate a vehicle, regardless of the driver’s apparent condition or actions.

, and MAP-21—Congress

has provided funds to states for programs to combat impaired driving

(sometimes called “countermeasure programs”). These grant programs

Pub. L. No. 97-364, § 101 (a), 96 Stat. 1738 (1982). Other federal legislation has been

enacted with the goal of keeping alcohol-impaired drivers off the road, including reduced

federal funding to states if they did not raise the minimum legal drinking age to 21 and the

encouragement of “zero-tolerance laws” that set illegal per se BAC levels at 0.02 or

greater for drivers under age 21.

In fiscal year 2014, NHTSA requested a total budget of $828 million and 653 full time

equivalent employees . NHTSA personnel are located in Washington, D.C. and among 10

regional offices.

Pub. L. No. 105-178, 112 Stat. 107 (1998).

Pub.L. No. 109-59, 119 Stat. 1144 (2005).

Page 4 GAO-14-559 Traffic Safety

are designed to encourage states to adopt and implement effective

programs to reduce driving under the influence of alcohol, drugs or the

combination of alcohol and drugs. Under the most recent countermeasure

program, states qualify for federal funding based on their impaired driving

fatality rate and application requirements vary based on whether a state

has a low-, mid-, or high-range fatality rate.

• “The Secretary [of Transportation] shall make a separate grant under this subsection

to each State that adopts and is enforcing a mandatory alcohol-ignition interlock law

for all individuals convicted of driving under the influence of alcohol or of driving while

intoxicated.”

In addition, MAP-21 created

a new grant program with funds available to reward states that implement

laws requiring ignition interlocks for all individuals convicted of alcohol-

impaired driving. Specifically,

MAP-21 made up to 15 percent per fiscal year of the total amount of the

impaired-driving countermeasures grant available for the new ignition-

interlock grant—about $21 million out of $139 million in fiscal year 2013.

Any ignition-interlock grant funds that are not awarded remain available

for grants under the broader impaired driving countermeasures grant

program. In fiscal year 2013, 14 states applied for the grant and 2 were

awarded funding, while in fiscal year 2014, 12 states applied and 4 were

awarded funding. (See table 1.) States that qualify for this grant can use

the funds for any authorized traffic safety program, including state

ignition-interlock programs, other impaired driving countermeasures, or

even traffic safety activities not related to alcohol-impaired driving. States

categorized as low-range have the most flexibility in how they may use

grant funds, while mid-range and high-range states must first obtain

approval from NHTSA for some activities and meet certain conditions

before they can be reimbursed. MAP-21 funding will expire at the end of

fiscal year 2014; Congress is considering reauthorizing funding for

NHTSA categorizes states as low-, mid- or high-range based on the average impaired

driving fatality rate. (Fatality rate is fatalities per 100-million vehicle-miles traveled.) It is

calculated based on the number of fatalities in motor vehicle crashes in a state that

involve a driver with a blood alcohol concentration of at least 0.08 percent for every 100

million VMT. These calculations are based on Fatality Analysis Reporting System data

from the most recently reported 3 calendar years for a state which are averaged to

determine the rate. MAP-21 specifies that low-range states are those with an average

impaired driving fatality rate of 0.30 or lower; mid-range states are those with an average

impaired driving fatality rate higher than 0.30 and lower than 0.60; and high-range states

are those that have an average impaired driving fatality rate of 0.60 or higher.

See Section 31105(a) of MAP-21, Pub. L. No. 112-141, 126 Stat. 405, 748 (2012).

Page 5 GAO-14-559 Traffic Safety

surface transportation programs—including the ignition-interlock grant

program—for fiscal year 2015 and beyond.

Table 1: States That Applied For and Were Awarded MAP-21 Ignition-Interlock

Grants, Fiscal Years 2013 and 2014

States that applied for the

ignition-interlock grant

Fiscal year 2013

applicants and grant

awards

Fiscal year 2014

applicants and grant

awards

Alaska $0 $0

Arizona $0 $346,639

Arkansas $0 $0

Colorado $0 $0

Connecticut $199,576 $205,258

Illinois $0 $0

Kansas $0 $0

Kentucky $0

Louisiana $0

New Mexico

$179,271 $184,375

New York $0

Oregon

$0 $0

Utah $0

Virginia

$0 $0

Washington $0 $416,356

Total $378,847 $1,152,628

Source: NHTSA. | GAO-14-559

The first ignition interlock was developed in 1969, but early models relied

on alcohol sensors that were inconsistent in accurately identifying BAC. In

the early 1990s, ignition interlock manufacturers began producing more

reliable and accurate fuel cell sensors, which is a technology currently in

use.

State did not apply for ignition-interlock grant.

According to a 2013 MADD report, there were about 12 ignition interlock manufacturers

and vendors in the U.S.

In 1992, NHTSA published model technical specifications for

ignition interlocks that describe how ignition interlocks should perform and

how the device can be calibrated to meet the model specifications.

NHTSA updated these specifications in 2013.

Page 6 GAO-14-559 Traffic Safety

Ignition interlocks currently in use have four basic elements:

1. A breath alcohol sensor in the vehicle that records the driver’s BAC

and sends the signal to not start the engine if the BAC registers higher

than the predetermined limit (see fig. 1);

2. A retest system;

3. A tamper-proof system for mounting the part of the unit that prevents

the engine from starting, which is typically required to be inspected

every 30 to 60 days to prevent circumvention; and

4. A data-recording system that logs the BAC results (for the initial test

and retests) each time the vehicle is turned on and off, the time period

the vehicle was driven and mileage, and other data that may be used

by state authorities to monitor the offender’s behavior.

According to NHTSA, states’ requirements for maximum BAC thresholds vary, but

generally they are set at 0.02 or 0.025.

The ignition interlock requires the driver to submit breath samples at random times to

ensure that the driver does not drink alcohol after the engine has been started. The driver

is given several minutes to exit traffic and move to a safe location to take the test. If the

breathe sample is not provided or the sample exceeds the set point, the device may warn

the driver and activate an alarm (e.g., horn blowing, lights flashing) that will continue until

the ignition is turned off or a breath sample that is within the acceptable limits is provided.

For safety reasons, the interlock device cannot turn off the vehicle’s ignition once it has

been started.

Page 7 GAO-14-559 Traffic Safety

Figure 1: A Driver Using an Ignition-Interlock Device

According to NHTSA, currently all states have enacted legislation

requiring or permitting the use of ignition interlocks and they generally

follow the same overall installation and removal process, according to

Association of Ignition Interlock Program Administrators (AIIPA). (See

fig. 2.)

Page 8 GAO-14-559 Traffic Safety

Figure 2: A Generalized Depiction of an Ignition-Interlock Program

Page 9 GAO-14-559 Traffic Safety

State ignition-interlock programs vary in a number of ways:

• Program design—Some states may incorporate the use of ignition

interlocks pretrial

, while other states may stipulate ignition interlocks

only upon conviction (i.e., a state sanctions a “license suspension”

and then limits the offender to “interlock-restricted driving”).

Some

states impose interlock-restricted driving on all convicted DWI

offenders, while in other states this is only required of those with

multiple or high BAC convicted offenders.

For example, Washington’s Department of Licensing administratively suspends an

offender’s license after arrest but before a DWI conviction. The state provides a period of

time for the driver to contest such a sanction as a means for providing due process. This

license suspension is separate from a DWI conviction, per se, as it can occur before trial.

Further, according to

NHTSA, most states require a “hard suspension” period in which an

offender’s driving privileges are denied for a certain period of time

before he or she may be eligible for interlock-restricted driving. State

laws and requirements may prescribe ignition interlock requirements

anywhere from a few months to as long as 10 years or more, often

with progressively longer ignition interlock requirements for DWI

offenders who are repeat offenders. Some states also exempt some

DWI offenders from the application of their state interlock

requirements. For instance, some states allow employer exemptions,

which allow offenders to drive employer-owned vehicles without an

ignition interlock for work purposes. Other states allow exemptions for

medical reasons, such as allowing offenders who do not have the

breath capacity to blow a sample into an ignition interlock to not be

subject to the ignition-interlock installation requirement while at the

same time suspending their license.

States may suspend or revoke DWI offenders’ driving privileges pre- or post-conviction

for a period of time or offer the offender an option for partial license reinstatement upon

certain conditions such as the offender’s installing an interlock. In some states, an

offender may elect not to seek a partial license reinstatement, which is commonly referred

to as “wait out.” For the purposes of this report, we refer to the suspension or revocation of

a driver’s license or loss of driving privileges as imposed by either the state licensing

authority or a judicial authority as a “license suspension” and we refer to the partial

reinstatement of a driver’s license or court-ordered limitations on driving privileges as

“interlock-restricted driving.”

In some states, DWI offenders may not be eligible for interlock-restricted driving

privileges because of additional factors related to their DWI offense. For example, in

Illinois, first time DWI offenders who have caused great bodily harm or death were not

eligible for interlock-restricted driving privileges.

Page 10 GAO-14-559 Traffic Safety

• Program delivery—Requirements for interlock-restricted driving can

be delivered programmatically in three different ways: through the

judiciary within the criminal justice system, administratively within the

driver licensing system, or using a hybrid approach that incorporates

both judicial and administrative elements. According to AIIPA, 20

states have judicial programs, 20 states have administrative interlock

programs, and 10 states have hybrid programs. According to NHTSA,

in judicially-delivered interlock programs, judges have discretion to

order interlock-restricted driving and can threaten harsher sanctions

(e.g., jail time) for non-compliance. In contrast, administratively-

delivered interlock programs are more uniform in imposing

requirements for interlock-restricted driving on DWI offenders and can

extend interlock periods or withhold driver’s licenses (i.e., legal driving

privileges) to encourage compliance, but have fewer sanction options

at their disposal. There is a growing trend toward more hybrid

programs.

• Oversight agency—In some states there may be a designated central

authority that oversees implementation of certain aspects of the

state’s ignition-interlock program, such as a state department of

transportation or state law enforcement authority. This agency’s role

may consist (1) of issuing state performance specifications for ignition

interlocks; (2) of certifying the manufacturers’ equipment for use by

testing the equipment directly or by accepting test results as

conducted by third party laboratories; (3) of approving ignition

interlock vendors for business in the state; (4) of inspecting service

centers; (5) of managing data from vendors; and (6) of managing

state funds to assist indigent offenders with ignition interlock costs,

among other things.

• Program cost and funding sources—Program costs vary with the

design of each ignition-interlock program.

According to NHTSA, states typically require offenders to pay the fees associated with

an ignition interlock, which in most states range between $65 and $90 per month, plus

approximately $100 to $250 for each installation.

For example, states

choosing to monitor ignition interlock data on individual offender BAC

tests and driving habits will incur greater costs than states that do not.

Programs that mandate offender appearances before a court or

administrative body for elevated BAC tests will incur greater costs

than programs that let the immediate inability to drive serve as the

offender’s sanction for an elevated test. States have varying

approaches to funding the delivery of ignition-interlock programs,

generally using fees paid by DWI offenders. Some states allocate

Page 11 GAO-14-559 Traffic Safety

some portion of collected fees to create indigent funds available to

help low-income DWI offenders with ignition-interlock costs.

Research we reviewed consistently indicated that ignition interlocks

reduce the rate of re-arrest for DWI while they are installed on the vehicle,

but once removed, DWI re-arrest rates return to pre-interlock rates. In

addition, the percentage of DWI offenders who actually install an interlock

when ordered is estimated to be low. Several factors contribute to this low

rate, including low enforcement and monitoring to ensure offender

compliance and costly fees and penalties that DWI offenders have to pay

before they are eligible for interlock-restricted driving privileges. 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.

Research consistently indicated that ignition interlocks are effective while

installed. That is, installation of ignition interlock devices in DWI offenders’

vehicles reduces re-arrests for DWI when compared to alternative

sanctions such as license suspension. 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

percent of alcohol-impaired drivers are detected.

For research studies we included in our review, see appendix II.

A 2011 review of

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.

The studies included in this review primarily evaluated programs directed

at drivers with multiple DWI offenses or first-time offenders with high BAC

NHTSA officials noted that studies they reviewed showed that less that 1 percent of

drivers who test positive for alcohol (BAC > 0.01) are arrested, and that 2 percent of those

drivers considered impaired at the time of the study were arrested.

Research Indicates

Interlock Devices Are

Effective While

Installed, but

Installation Rates Are

Low and Research on

Strategies to Increase

Rates Is Limited

Ignition-Interlock Devices

Reduce Re-arrest While

Installed

Page 12 GAO-14-559 Traffic Safety

at arrest (usually >0.15).

As noted by the authors, the majority of studies

in this review and those that we separately identified did not randomly

assign participants to the ignition interlock; therefore, a limitation of many

of these studies remains the potential for selection bias, as individuals

who agree to install an interlock may be inherently different from

individuals who do not agree to do so.

However, we did identify two

randomized controlled trials, both in Maryland and limited to offenders

with two or more alcohol-related traffic violations, that also found that

ignition interlocks are effective at reducing re-arrests. The first, published

in 1999, found that being in the interlock program—including installing an

ignition interlock—reduced a driver’s risk of committing a violation in the

first year of the program by approximately 64 percent.

In 2011,

researchers published a study that replicated the 1999 study with a new

group of repeat offenders and found that participation in the ignition-

interlock program still reduced drivers’ risk of re-arrest by 36 percent

while the ignition interlock was installed.

Research we identified on the effectiveness of ignition interlocks also

indicates that once the devices are removed, DWI arrest rates return to

Findings regarding the effectiveness of ignition interlocks for first time offenders are

unclear, based on study limitations. For example, some studies that aimed to parse out

effects for first time offenders found no significant effects, possibly due to small numbers

of first time offenders in the study sample (Tippets & Voas, 1998; EMT Group, 1990;

DeYoung, Tashima, & Masten, 2005). Other studies not in this literature review only had

aggravated first time offenders in their sample (such as offenders with a BAC > 0.20)

which limits the generalizability of these studies to the first time offender population as a

whole (Roth et al 2007; Morse & Elliott 1992). NHTSA has an ongoing study, which it

expects to publish in 2014,on the association between state laws requiring all offenders to

install ignition interlocks and the number of ignition interlocks installed.

Additional limitations related to the body of literature we reviewed include the lack of a

national study on interlock effectiveness and a lengthy time period over which the studies

were conducted (between 1990 and 2013). Further, without randomization, there may be

some judicial bias in that judges may choose offenders with certain characteristics for the

intervention group. Despite these limitations, our review of the literature did provide

support for the effectiveness of ignition interlocks while installed.

Individuals may still be arrested for DWI while they have an interlock installed in their

vehicle, for instance if they remove the device, or if they are driving a vehicle that does not

have an interlock installed in it.

The authors of this study attributed the difference in reductions in risk of re-arrest

between the first and second randomized controlled trials to monitoring and length of

installation, which will be discussed further below.

Page 13 GAO-14-559 Traffic Safety

pre-interlock rates.

For example, a study of drivers with two or three

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. The literature review of 15 studies came to the same conclusion

that, following removal of ignition interlocks, re-arrest rates reverted to

levels similar to those for comparison groups.

Although ignition interlocks have been shown to reduce arrest for alcohol-

impaired driving while installed, researchers we interviewed estimated

that only 10 percent or less of DWI offenders ordered to install an ignition

interlock actually install one.

NHTSA officials reported that between 15

and 20 percent of offenders arrested for DWI install ignition interlocks.

Estimates in individual states vary, with one study of DWI offenders in

California reporting about a 20 percent installation rate among those

ordered to install.

However, estimating installation rates is imprecise. Federal officials told

us that it is difficult to accurately estimate installation rates because the

underlying data is often inconsistently maintained within and across

states. 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. As such, instead of

using the number of individuals ordered to install an ignition interlock, one

research group we spoke to used more easily-identifiable data such as

total population, total DWI arrests, or total DWI fatalities. The resulting

A recent evaluation completed for the Washington

Traffic Safety Commission reported 56 percent of DWI offenders ordered

to install an ignition interlock did so.

One of the Maryland studies mentioned above showed decreases in re-arrest rates once

the ignition interlocks were removed.

NHTSA officials noted that they suspected that this estimate is based on gross-level

figures and is less accurate than the higher estimates.

In the California study, offenders ordered to install an ignition interlock may have

included both those convicted of DWI and of lesser Driving-While-Suspended charges.

Several Factors Contribute

to Low Installation Rates

Page 14 GAO-14-559 Traffic Safety

measure is referred to as an installation “in-use” rate—for instance, the

number of ignition interlocks in-use as a percentage of total population.

According to state officials, limited follow up and monitoring for

compliance and prerequisites for eligibility can hinder installation.

Limited follow-up and monitoring for offender compliance—According to

the literature review cited above, monitoring DWI offenders requires

substantial administrative resources. Officials from several states

included in our study said they do not have sufficient resources to follow

up with offenders to ensure ignition interlocks have been installed once

they have been ordered by a court or sanctioned by a state department of

motor vehicles. For example, state officials in Texas told us that courts

(i.e., judges) are often overwhelmed and do not have the resources to

follow up with offenders to ensure that an ignition interlock has been

installed or to monitor the results gathered by the ignition interlock

devices. According to New York officials, the caseloads of some

probation officers who may supervise DWI offenders are also heavy, and

some probation officers may not necessarily prioritize ignition interlock

compliance. Other law enforcement entities, even those that may lead or

operate the state’s ignition-interlock program, may not have the resources

to follow up on offenders to ensure ignition interlocks have been installed

and used as required. For example, Washington’s program is overseen

by the state highway patrol, but according to a senior Washington official,

the program lacks the resources to identify offenders who may be illegally

driving with a suspended license (i.e., those offenders who claim to be

waiting out the period of time that their license was suspended by not

driving at all) or driving without an ignition interlock.

Moreover, state officials we interviewed stated that limited followup and

monitoring contributed to offenders’ decisions to wait out ignition interlock

requirements. As mentioned above, the likelihood of being stopped for a

traffic violation is estimated to be less than 1 percent of those driving

while impaired by alcohol and research suggests that DWI offenders

continue to drive while their licenses are suspended. Officials from New

York described that a continuing challenge to increasing the number of

installed interlocks were DWI offenders attempts to wait out the period an

ignition interlock is required by temporarily signing over their vehicles to

friends or family. According to these officials, in New York, quarterly

inquiries are made to each of 62 counties’ probation departments to

check vehicle registrations of DWI offenders to address such attempts to

circumvent the state’s requirements for ignition interlocks. According to an

Illinois official, there is no requirement that an offender install an ignition

Page 15 GAO-14-559 Traffic Safety

interlock in order to reinstate his or her license

Prerequisites for eligibility—There are a variety of conditions a DWI

offender may be required to satisfy before he or she can receive interlock-

restricted driving privileges.

and that requirements for

interlock-restricted driving were undermined because many DWI

offenders believed that they could avoid being caught while driving

without an ignition interlock.

• Fees and penalties—In some states, offenders may have to pay fees

and penalties before they can be eligible to install an ignition interlock

and receive a restricted license. One study of Florida’s ignition-

interlock program found that half of DWI offenders who had completed

their revocation period were still ineligible to install an ignition interlock

because they had not paid required fines and tickets. Similarly, an

Illinois official stated that a DWI offender would have to pay at least a

$380 fee in addition to any outstanding fees or penalties and enter

into a payment plan for any judgments resulting from the DWI

conviction in order to be eligible for interlock-restricted driving

privileges. Likewise, Connecticut requires offenders to pay a $100 fee

before an ignition interlock is installed. These fees and penalties are

in addition to any costs paid to the vendor for installation or lease of

the interlocks. Even in some states where there are indigent funds

available to assist offenders with the cost of ignition interlocks, some

of these fees imposed by the state may not be waived or reduced.

This contrasts with a state like Washington, where an offender must have an interlock

installed and have a certain number of consecutive months without BAC tests registering

above the predetermined level in order for their license to be reinstated.

Texas, one official described how mandatory license surcharges have

contributed to a substantial number of offenders driving illegally and

without insurance.

For example, in Washington, an offender seeking interlock-restricted driving privileges

must pay $100 to apply for reinstatement. However, if he or she qualified for assistance

from Washington’s indigent fund, this assistance may only be used for vender fees (i.e.,

costs associated with ignition-interlock installation, lease, removal, and transfer to another

vehicle) and not for the application fee. Furthermore, some states with indigent funds have

experienced challenges with the demand for this assistance. Washington officials stated

that the number of interlock drivers receiving support from the indigent fund grew from

3,066 in 2009 to 19,267 by December 2013, and the amount disbursed increased from

$775,643 to more than $1.4 million between 2011 and 2013. Washington officials said that

the number of applicants was beginning to exceed available funds.

Page 16 GAO-14-559 Traffic Safety

• Treatment programs—In some states, offenders must complete

treatment programs before they are eligible to install an interlock and

have interlock-restricted driving privileges. In Illinois, offenders may be

required by a hearing officer or judge to enter or complete treatment,

in conjunction with installing an interlock, as conditions for being

granted a restricted drivers license. Likewise, in New York, officials

noted that some jurisdictions will not allow offenders to obtain their

licenses until treatment has been completed.

Research supports the effectiveness of ignition interlocks in combating

impaired driving while they are installed, but limited research exists on

how to improve installation rates.

Table 2: Summary of Ignition-Interlock Effectiveness Research

Effectiveness research topic

Substantial

research

Limited

research

Ongoing, unpublished

studies

Interlock Devices

Effective when installed X

Effect disappears when interlock is removed X

Interlock Programs

Characteristics that could increase installation

• harsher alternatives

, such as:

• requiring an interlock for license reinstatement

X X

Characteristics that could

(NHTSA)

reduce re-arrest during and after

• length of installation

installation, such as:

• combining treatment with the interlock program

• monitoring

X X (NHTSA

, CDC

Source: GAO. | GAO-14-559

)

We refer to research as “substantial” if we identified five or more articles published on the topic

whose results we determined to be reliable. We refer to research as “limited” if we identified fewer

than five articles published on the topic whose results we determined to be reliable.

NHTSA has a cooperative agreement with GHSA, which contracted with the Preusser Research

Group to evaluate state ignition interlock use and re-arrest rates in 28 states. NHTSA expects these

studies to be published by 2015.

Limited Research Exists

on Which Program

Characteristics Could

Improve Installation or

Overall Program

Effectiveness

The Centers for Disease Control and Prevention (CDC) is currently analyzing the effect of treatment

on re-arrest. The CDC expects to publish this study in 2015 at the earliest.

Page 17 GAO-14-559 Traffic Safety

Two studies of programs in U.S. counties where judges required stricter

penalties for those not installing an ordered ignition interlock found a

higher percentage of offenders installed the ignition interlock. According

to a 2001 study, a court in Hancock County, Indiana, had required

installation of interlocks for all offenders using the threat of jail or

electronically monitored house arrest for non-compliance since 1997. The

study estimated that 62 percent of DWI offenders installed an ignition

interlock.

A 2010 NHTSA evaluation of the New Mexico ignition-interlock

program found that 71 percent of convicted DWI offenders installed an

interlock in Santa Fe County, where judges made house arrest the

alternative to ignition interlock installation. In cases where DWI offenders

pleaded they had no vehicle, the judge required them to wear an

electronic monitoring bracelet.

One study suggested that requiring an ignition interlock for license

reinstatement following a DWI could improve installation rates. As

mentioned above, one of the ways a DWI offender can avoid installing an

interlock is by simply waiting out the ordered suspension period and not

driving during that time. Yet research suggests that many DWI offenders

drive during a suspension period.

According to a 2013 MADD report based

on workshops with state officials and stakeholders from more than 30

states, imposing harsher sanctions could be a strategy for increasing

installation rates. One state official we interviewed described that

mandating alcohol monitoring as an alternative to installing an interlock

would be effective in increasing the installation rates.

This refers to the percentage of offenders who installed interlocks, not the additional

percentage attributable to Hancock County’s program; the authors did not measure the

rates of interlock installation in the surrounding counties, so we cannot isolate the effect of

Hancock County’s stricter program. In addition, the 95 percent confidence interval for this

installation rate extends from roughly 50 percent to 74 percent.

However, if a state has a separate

An electronic monitoring bracelet is a device worn on an offender’s ankle that

electronically tracks his or her location. In order to enforce house arrest, the bracelet is

linked by telephone lines to a main computer system that sends off a constant signal. If

the offender strays beyond the court-authorized radius of the receiver, the computer

system records the date and time that the interruption occurred. If the interruption

occurred at a time when the offender was scheduled to be at home, a parole officer or

other monitoring agent checks into the violation and additional sanctions may result.

Ignition-interlock studies cited in this report often use license suspension as the control

group. As stated above, ignition interlocks are more effective than license suspension,

which means that many DWI offenders continue driving and being re-arrested while their

licenses are suspended.

Characteristics That Could

Increase Installation: Harsher

Alternatives, License

Reinstatement

Page 18 GAO-14-559 Traffic Safety

administrative requirement through the department of motor vehicles, for

example, the offender cannot simply wait out the suspension period and

will have to install an ignition interlock in order to reinstate his full license.

A 2013 study on a Florida state requirement that DWI offenders install an

ignition interlock for at least 6 months in order to fully reinstate their

license observed that nearly 100 percent of offenders eligible to install an

interlock actually did so.

NHTSA is currently working with the Preusser Research Group (PRG) to

conduct a study on factors that could help states improve installation

rates. This research is being supported jointly by NHTSA and the CDC,

through a cooperative agreement with GHSA, which in turn contracted

with PRG to examine state ignition-interlock program characteristics—

such as state laws, penalties, monitoring, or other factors—that were

associated with higher ignition interlock use. NHTSA officials said they

expect this report to be issued by late summer 2014.

According to state officials, New Mexico and

Washington have a similar license reinstatement requirement.

A randomized controlled trial of DWI multiple offenders in Maryland

observed that closer monitoring of offenders’ breath tests into the

interlock device improved compliance with the ignition-interlock program.

Closer monitoring consisted of reviewing breath test data and sending

letters to offenders informing them of the results and consequences. The

control group was subject to the standard Motor Vehicle Administration

monitoring, which did not include any specific procedures for monitoring

offenders. For example, the Motor Vehicle Administration took no action

when offenders in this group disconnected the interlock or logged

numerous breath tests at or above the limit of the ignition interlock. The

authors found that the closely monitored group had significantly fewer

initial breath test failures when attempting to start their vehicles than the

control group did. The authors also observed that ignition interlock

disconnects (e.g., tampering with the device) and retest failures were

lower for the closely monitored group as well, although these latter

differences were not statistically significant. Through the GHSA study

mentioned above, NHTSA officials told us that NHTSA and the CDC hope

to identify state’s ignition-interlock program characteristics, such as

Many offenders were not eligible to install an interlock during the time of the study. In

Florida, as noted above, offenders must complete outstanding sanctions (e.g., tickets,

fines) before being eligible to install an ignition interlock.

Characteristics That Could

Reduce Re-arrest during and

after Interlock: Monitoring,

Length of Installation, and

Treatment

Page 19 GAO-14-559 Traffic Safety

monitoring, that may be associated with lower re-arrests. NHTSA officials

said this study should be completed by 2015.

We identified one study on the impact of varying lengths of ignition-

interlock installation on DWI re-arrest. The study compared the results of

the Maryland’s two randomized controlled trials mentioned above (2011

and 1999) in order to determine whether the later 2-year administrative

ignition-interlock program was more effective in reducing recidivism than

the earlier 1-year interlock program. The 2011 study did show a

significant reduction in re-arrest even after the interlock was removed, a

result that the authors attributed to the extension of the interlock period

from 1 year to 2 years, although other differences in the two randomized

controlled trials, such as increased monitoring, were noted as well.

According to researchers, pairing interlock use with alcohol treatment

could be key to reducing re-arrest once the interlock is removed, but we

did not find any published studies evaluating the combination of interlock

use with treatment programs. Four studies in our review observed the

drinking patterns of DWI offenders while they participated in an ignition-

interlock program, and two of these suggested that this data could be

used to target treatment to specific offenders.

Despite this research, authors of the literature review mentioned above

noted that research currently provides little guidance on the ideal length

of interlock program participation. Research and interviews we conducted

suggests that most states require installation for at least 5 months.

A 2014 Washington state report on its ignition-interlock program observed reductions in

re-arrest for DWI during a 2-year period following ignition interlock installation, and

hypothesized that this could have been due to longer installation periods, among other

factors. The study observed differences in re-arrest rates for first, second, and third-plus

DWI offender groups whose installation periods averaged 10.4, 13.3, and 13.8 months,

respectively. However, the study was not designed to evaluate the impact of length of

installation.

This has led researchers

and NHTSA officials to posit that treatment could reduce the overall

amount of drinking and potentially have an effect even after the ignition

interlock is removed. The CDC is currently conducting a study on the

Authors of two of these studies, conducted in Canada, noted that the BAC results

cannot be matched directly to the offender, but believe this limitation is mitigated by

findings from other studies that show that primarily the offenders are the ones driving the

interlocked vehicles. Authors of the other two studies noted that the vendor data they used

contained no demographic information and so they were not able to distinguish between

types of offenders.

Page 20 GAO-14-559 Traffic Safety

effect of a Florida state law that required alcohol treatment for DWI

offenders who fail a certain number of breath tests on their installed

ignition interlocks. CDC officials told us the results of this study would be

published in 2015 at the earliest.

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. State officials who administered

ignition-interlock programs confirmed that NHTSA’s activities were

helpful. However, some officials questioned NHTSA’s implementation of

the ignition-interlock grant program because the states that exempted

certain offenders from installing interlocks were disqualified. 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.

NHTSA offered a variety of assistance to help states establish and

improve their ignition-interlock programs. Specifically, NHTSA developed

and shared guidance, issued technical specifications, sponsored research

studies, collaborated with industry experts, and funded technical

assistance. It also administered and oversaw grants to states.

• Guidance: Since 2008, NHTSA has published reports highlighting

key features of state ignition-interlock programs, including most

recently the 2013 guideline for a model ignition-interlock program.

• Technical Specifications: In 1992, NHTSA published technical

model specifications for ignition interlocks that describe how ignition

interlock devices should perform and indicate how they can be

calibrated to meet uniform standards. In May 2013, NHTSA revised

the model specifications to address the rapid technological

general, these reports provide information about ignition-interlock

program features and highlight issues that states should consider as

they put together or further refine their ignition-interlock programs.

U.S. Department of Transportation, National Highway Traffic Safety Administration,

Model Guideline for State Ignition-interlock Programs, Report Number DOT HS 811 859

(December 2013).

NHTSA Provided

Assistance to States

for Ignition-Interlock

Programs, but Some

State Officials

Questioned NHTSA’s

Implementation of

MAP-21 Grant

NHTSA Assisted States in

Their Efforts to Implement

Ignition-Interlock

Programs

Page 21 GAO-14-559 Traffic Safety

innovations in the industry that had occurred since the original

publication. State ignition-interlock program administrators used these

model specifications to certify interlock devices offered by

manufacturers and ensure vendors and installers meet uniform

performance standards.

• Research: NHTSA funds research studies that assess and provide a

more scientific basis for assertions about the effectiveness of ignition

interlock devices. Since 2009, NHTSA has funded and published a

number of studies and reports on ignition interlocks, including the

ongoing studies mentioned above on factors that could help states

improve installation rates or program characteristics related to lower

re-arrest rates.

• Collaboration: NHTSA, either directly or through grants to other

organizations, brought stakeholders and experts together to share

information and collaborate on specific ignition-interlock program

projects. For example, in 2007, NHTSA funded an expert panel to

gather views about the effectiveness of ignition interlocks in

preventing impaired driving offenses; the views were published in a

2010 NHTSA report. In 2010, NHTSA and GHSA jointly hosted a

national ignition interlock summit, extending invitations to state

highway safety representatives and ignition-interlock program

administrators from all 50 states, interlock manufacturers,

researchers, and national organizations. NHTSA published a report

summarizing the summit in 2011. NHTSA also signed a cooperative

agreement with MADD for the organization to hold a series of ignition

interlock institutes across the U.S. between August 2009 and October

2012. The institutes were designed to bring together teams of people

and various agencies that are involved with some component of their

state ignition-interlock program in order to identify program

improvements.

• Technical Assistance: In 2007, NHTSA entered into the first of two

cooperative agreements with TIRF to support the development of a

curriculum about ignition-interlock programs and to provide direct

assistance to states that seek to improve their ignition-interlock

programs. At the request of a state’s highway safety office, TIRF

consultants review the state’s ignition-interlock program, analyze the

program’s processes, and identify possible solutions for any

weaknesses. For example, in 2009, TIRF examined Illinois’ ignition-

interlock program and identified a number of program strengths and

challenges. TIRF recommended that the state develop a process for

limiting the number of offenders who can opt out of the interlock

program, among other things. NHTSA’s cooperative agreement with

TIRF to provide technical assistance ends in August 2017.

Page 22 GAO-14-559 Traffic Safety

• Grants Administration: NHTSA also assisted state officials to apply

for DOT safety grants, such as the impaired driving countermeasures

grant, that can be used for their state’s ignition-interlock program. For

example, the agency held webinars and conducted other outreach to

educate states about the requirements of the new ignition-interlock

grant program.

State officials indicated that NHTSA’s actions assisted them in

implementing and further refining their ignition-interlock programs. For

example, two state officials noted that by attending conferences

sponsored by NHTSA they were able to leverage the experiences of other

states whose programs were more mature. Others noted that NHTSA’s

regional staff were readily available to answer questions and provide

advice and technical assistance. State officials also mentioned that they

used NHTSA’s ignition-interlock reports and guidance, such as the 2013

Model Guidelines report, to identify ways to strengthen their programs.

State officials questioned how NHTSA implemented one aspect of the

new ignition-interlock grant program; specifically that states did not qualify

for funding if they included exemptions in their alcohol ignition-interlock

programs. 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. Under NHTSA’s

implementation regulations, states must require that the ignition interlock

be used for a minimum period of 30 days. As implemented by NHTSA,

states whose ignition-interlock programs allowed DWI offenders to drive

vehicles without an ignition interlock for work and medical reasons did not

qualify for the grants because their programs were not considered

mandatory for all such convicted individuals. Officials from New York,

Illinois, Washington, and Arizona indicated that NHTSA disqualified their

state because of the employer vehicle exemptions to their state’s ignition-

interlock requirements. Illinois and New York officials stated that although

their state’s statutes allow exemptions, their programs typically grant few

exemptions compared to the number of ignition interlocks installed, and

the officials did not believe that exemptions substantially diminished the

effectiveness of their ignition-interlock program. However, state officials

noted they did not track the specific number of employer vehicle

exemptions that have been granted. For example, in New York, employer

vehicle exemptions are filed at the county level, not at the state level (i.e.,

with a state level department), and the state has little ability to access the

data in order to estimate the number of employer vehicle exemptions that

Some State Officials

Questioned NHTSA’s

Implementation of the New

Grant

Page 23 GAO-14-559 Traffic Safety

had been granted or compare this to the number of ignition interlocks

ordered.

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.

In responding to our draft report, the Department of

Transportation (DOT) provided a document that contained information on

states’ ignition-interlock laws.

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. NHTSA officials noted that

the MAP-21 grant represents a high bar for many states. 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. Further, NHTSA officials noted that the agency did not receive

comments from states related to exemptions during the public comment

period for the interim final rule.

Some state officials noted that it would be challenging to change their

laws to qualify for the ignition-interlock grant. First, officials from several

states told us that there is a lack of political support to put in place

requirements for first time offenders or to eliminate exemptions. State

officials from two states reported that their legislatures would not want to

impede employment of offenders, particularly in a poor economic climate

Statutory construction includes and often begins with construing the “plain meaning” of

the statutory language itself to determine whether the language at issue has a plain and

unambiguous meaning.

DOT periodically compiles and publishes comprehensive information on state impaired-

driving laws in its Digest of Impaired Driving and Selected Beverage Control Laws. DOT

officials stated that they anticipate updating the publication in 2016 or 2017. See U.S.

Department of Transportation, National Highway Traffic Safety Administration, Digest of

Impaired Driving and Selected Beverage Control Laws, 27

Edition, Report Number DOT

HS 811 796 (May 2012).

NHTSA officials also noted that exemptions in any form can undermine the intended

benefits of traffic safety laws and allowing offenders to drive without ignition interlocks

through the use of exemptions could negatively impact traffic safety.

Page 24 GAO-14-559 Traffic Safety

and given the expanse of areas in states that are rural, which makes

driving a necessity for daily life. Some state officials also pointed out that

the small size and short term nature of the grant funding did not support

making changes to their states’ ignition-interlock programs to qualify for

the MAP-21 ignition-interlock grant program.

Despite these challenges, two state legislatures changed their laws to

eliminate exemptions to qualify for the ignition-interlock grant in fiscal year

2014. During the first year of the grant—fiscal year 2013—only 2 states

out of 14 that applied qualified for the grant. 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.

Ignition interlocks are one promising tool states can use to combat

alcohol-impaired driving. However, in order to be effective, the devices

must first be installed in vehicles and several factors—including limited

monitoring and eligibility prerequisites—can hinder installation even when

DWI offenders are ordered to use ignition interlocks. Ongoing and

planned research by NHTSA and others may shed light on actions state

officials can take to increase installation rates and otherwise improve the

effectiveness of their ignition-interlock programs. The MAP-21 ignition-

interlock grant also has the potential to encourage the increased use of

ignition interlocks by providing funds to states that require the use of an

ignition interlock for all individuals convicted of a DWI offense. 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.

Following the first grant year, two state legislatures modified their state

ignition-interlock laws to eliminate employer and other exemptions,

thereby qualifying for the MAP-21 grant in 2014. The extent to which

Washington changed its laws so that employer exemptions could not be used in the first

30 days after a convicted DWI first-time offender is limited to interlock-restricted driving.

For repeat offenders, employer exemptions may not be used for the first 365 days of

interlock-restricted driving.

Concluding

Observations

Page 25 GAO-14-559 Traffic Safety

other states may follow suit is unclear. Some state officials noted that

even though these exemptions are not widely used, this option is critical

to allow DWI offenders to retain their jobs, particularly in rural areas or

areas without public transportation. For such states, the incentive and

relatively limited funding offered by the grant is not likely to outweigh the

challenges of changing state ignition-interlock laws to eliminate

exemptions.

We provided a draft of this report to DOT for review and comment.

Included in the draft report was a recommendation that the Secretary of

Transportation provide Congress with information about the extent to

which states’ ignition interlock laws allow exemptions. This

recommendation was intended to provide Congress with more complete

information as it considers reauthorizing surface transportation programs,

including the ignition-interlock grant program. On June 11, 2014, the

Deputy Director of Audit Relations transmitted DOT’s comments by email.

In responding to our draft report, DOT officials expressed concerns about

this recommendation and provided additional information that addressed

our recommendation. Specifically, DOT provided the Digest of Impaired

Driving and Selected Beverage Control Laws, which is a compilation of

comprehensive information on states’ impaired-driving laws. We

concluded that the Digest includes sufficient information to provide an

overview of the extent to which state laws allow exemptions and

addresses our proposed recommendation. Therefore, in light of the new

information that DOT provided, we withdrew our recommendation. DOT

also provided technical corrections, which we incorporated as

appropriate.

As agreed with your office, unless you publicly announce the contents of

this report earlier, we plan no further distribution until 30 days from the

report date. At that time, we will send copies to the appropriate

congressional committees, the Secretary of Transportation, and other

interested parties. In addition, the report will be available at no charge on

the GAO website at http://www.gao.gov.

Agency Comments

Page 26 GAO-14-559 Traffic Safety

If you or your staff have any questions about this report, please contact

me at (202) 512-2834 or [email protected]. Contact points for our

Offices of Congressional Relations and Public Affairs may be found on

the last page of this report. GAO staff who made key contributions to this

report are listed in appendix III.

Sincerely yours,

Susan A. Fleming

Director, Physical Infrastructure Issues

Appendix I: Objectives, Scope, and

Methodology

Page 27 GAO-14-559 Traffic Safety

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 what is known about the effectiveness of ignition-interlock

programs, we conducted a literature search for studies that analyzed

relationships between ignition interlock devices or programs and alcohol-

impaired driving outcomes, including DWI arrest and DWI fatality. We

started with a 2010 NHTSA report “Key Features for Ignition Interlock

Programs,” which cited 15 studies and highlighted programs and program

features that are believed to be best able to serve traffic safety interests,

including reducing alcohol-impaired driving. We then identified additional

existing studies from peer-reviewed journals, government reports, and

conference papers based on searches of various databases, such as

ProQuest, MEDLINE, and Transportation Research International

Documentation. Search parameters included studies across the U.S. and

in specific states and those on specific interlock program components,

such as mandatory for first and repeat offenders and length of installation

required. These parameters resulted in 280 abstracts, which we narrowed

to 96, in part by cross-referencing the list with Web of Science, a resource

that identifies highly cited articles. We also conducted interviews with

organizations that conduct research on ignition interlocks, such as the

Pacific Institute for Research and Evaluation, and asked them to

recommend additional research.

From these multiple sources, we identified 25 peer-reviewed articles,

government reports, and conference papers between 1990 and 2013 that

were relevant to our research objective on the effectiveness of ignition

interlocks in reducing alcohol-impaired driving. To assess the

methodological quality of the selected studies, we performed an initial in-

depth review of the findings, and then a GAO methodologist performed an

independent assessment of the study’s methodological soundness and

confirmed our reported analysis of the finding. One limitation is that the

majority of studies we identified did not randomly assign participants to

the ignition interlock; therefore there remains the potential for selection

bias, as individuals who agree to install an interlock may be inherently

different from individuals who do not agree. Additional limitations related

to the body of literature we reviewed include the lack of a national study

on interlock effectiveness, a lengthy time period over which the studies

were conducted (between 1990 and 2013), and the reliance of DWI arrest

Appendix I: Objectives, Scope, and

Methodology

Appendix I: Objectives, Scope, and

Methodology

Page 28 GAO-14-559 Traffic Safety

as a proxy for alcohol-impaired driving. Despite these limitations, our

review of the literature did provide support for the effectiveness of ignition

interlocks while installed.

We supplemented our synthesis by interviewing three of the studies’

authors who had each contributed to multiple studies. We also conducted

interviews with NHTSA officials, as NHTSA has contracted out some

published and ongoing research on the effectiveness of ignition

interlocks. We also discussed program effects with state ignition-interlock

program administrators from the 10 states we included in our review (as

discussed below) and with NHTSA officials who were knowledgeable

about NHTSA-funded published and ongoing research on the

effectiveness of ignition interlocks.

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. We also interviewed traffic safety, criminal justice, department of

motor vehicles or licensing, and law enforcement officials from a

nongeneralizable sample of 10 states. The selected states—Arizona,

Connecticut, Illinois, Montana, New Mexico, New York, Pennsylvania,

South Carolina, Texas, and Washington—were chosen to reflect a mix of

states that applied and did not apply for, as well as, states that qualified

and were disqualified from the MAP-21 ignition-interlock grant program.

To further select among states, we identified states with high DWI fatality

numbers in 2012 (the most recent year for which data are available) and

DWI fatality rates (alcohol-impaired fatalities per 100-million vehicle-miles

traveled) as calculated and categorized by NHTSA as high-, mid-, and

low-range states. We also factored in different types of programs

(judiciary, administrative, and hybrid); states with low DWI fatalities or

rates; and states with rural areas and tribal authorities, in selecting our

state sample.

Although the information gathered from these 10 states are

nongeneralizable, it provided insights about the extent of NHTSA’s

ignition interlock-related assistance, including its implementation of MAP-

21 ignition-interlock grant program, and the ignition interlock-related

research that states had conducted or participated in. In each state, we

obtained information about the state’s ignition interlock laws and program

Appendix I: Objectives, Scope, and

Methodology

Page 29 GAO-14-559 Traffic Safety

as well as any challenges in applying or qualifying for the MAP-21

ignition-interlock grant program. We also asked state officials about

NHTSA’s other ignition-interlock related assistance.

We conducted this performance audit from July 2013 to June 2014 in

accordance with generally accepted government auditing standards,

Those standards require that we plan and perform the audit to obtain

sufficient, appropriate evidence to provide a reasonable basis for our

findings and conclusions based on our audit objectives. We believe that

the evidence obtained provides a reasonable basis for our findings and

conclusions based on our audit objectives.

Appendix II: Studies on Ignition-Interlock

Effectiveness

Page 30 GAO-14-559 Traffic Safety

Beck, Kenneth H., William J. Rauch, Elizabeth A. Baker, and Alian F.

Williams. “Effects of Ignition Interlock License Restrictions on Drivers With

Multiple Alcohol Offenses: A Randomized Trial in Maryland.” American

Journal of Public Health 89(11) (1999): 1696-1700.

Bjerre, Bo. “Primary and secondary prevention of drinking and driving by

the use of Alcolock device and program: the Swedish experience,” in

Alcohol Ignition Interlock Devices, Volume II: Research, Policy, and

Program Status 2005. ed. Paul Marques (Oosterhout, Netherlands:

International Council on Alcohol, Drugs and Traffic Safety (ICADTS),

2005), 11-24.

Coben, Jeffrey H., and Gregory L. Larkin. “Effectiveness of Ignition

Interlock Devices in Reducing Drunk Driving Recidivism.” American

Journal of Preventive Medicine, 16(1S) (1999): 81-87.

DeYoung, David J., Helen N. Tashima, and Scott V. Masten. “An

Evaluation of the Effectiveness of Ignition Interlock in California” in

Alcohol Ignition Interlock Devices – Volume II: Research, policy, and

Program Status 2005. ed. Paul Marques (Oosterhout, Netherlands:

International Council on Alcohol, Drugs and Traffic Safety (ICADTS),

2005), 42-52.

Elder, Randy W., Robert Voas, Doug Beirness, Ruth A. Shults, David A.

Sleet, James L. Nichols, and Richard Compton, Task Force on

Community Preventive Services. “Effectiveness of Ignition Interlocks for

Preventing Alcohol-Impaired Driving and Alcohol-Related Crashes. A

Community Guide Systematic Review.” American Journal of Preventative

Medicine 40(3) (2011): 362-376.

EMT Group. “Evaluation of the California ignition interlock pilot program

for DUI offenders.” A report prepared for The California Department of

Alcohol and Drug Programs and The California Office of Traffic Safety,

1990.

Jones, Barnie. “The Effectiveness of Oregon’s Ignition-interlock program.”

Paper presented at the 12th International Conference on Alcohol, Drugs,

and Traffic Safety, Cologne, Germany, September 28-October 2, 1992.

Marine, William. “High-tech solutions to drinking and driving: evaluation of

a statewide, voluntary alcohol ignition-interlock program.” Final grant

report. University of Colorado Health Sciences Center (2001).

Appendix II: Studies on Ignition-Interlock

Effectiveness

Appendix II: Studies on Ignition-Interlock

Effectiveness

Page 31 GAO-14-559 Traffic Safety

Marques, Paul R., A. Scott Tippetts, and Robert B. Voas. “Comparative

and joint prediction of DUI recidivism from alcohol ignition interlock and

driver records.” Journal of Studies on Alcohol, 64(1) (2003): 83-92.

Marques, Paul R., Robert B. Voas, Richard Roth, and A. Scott Tippetts.

Evaluation of the New Mexico Ignition-interlock program. A report

prepared at the request of the National Highway Traffic Safety

Administration, 2010.

Marques, Paul R., A. Scott Tippetts, and Robert B. Voas. “The Alcohol

Interlock: An Underutilized Resource for Predicting and Controlling Drunk

Drivers.” Traffic Injury Prevention, 4:S1 (2006): 5-11.

Morse, Barbara J. and Delbert S. Elliott. “Effects of Ignition Interlock

Devices on DUI Recidivism: Findings From a Longitudinal Study in

Hamilton County, Ohio.” Crime & Delinquency 38 (2) (1992): 131-157.

Popkin, Carol Lederhaus, J. Richard Stewart, Jo Beckmeyer, and Carol

Martell. “An evaluation of the effectiveness of interlock systems in

preventing DWI recidivism among second-time DWI offenders.” Paper

presented at the 12th International Conference on Alcohol, Drugs, and

Traffic Safety, Cologne, Germany, September 28-October 2, 1992.

Raub, Richard A., Rov E. Lucke, and Richard Wark. “Breath alcohol

ignition interlock devices: controlling the recidivist.” Traffic Injury

Prevention 4 (2003):199 –205.

Rauch, William J., Eileen M. Ahlin, Paul L. Zador, Jan M. Howard, and G.

Doug Duncan. “Effects of administrative ignition interlock license

restrictions on drivers with multiple alcohol offenses.” Journal of

Experimental Criminology 7 (2011): 127-148.

Roth, Richard, Robert Voas, and Paul Marques. “Mandating Interlocks for

Fully Revoked Offenders: The New Mexico Experience.” Traffic Injury

Prevention, 8 (2007): 20-25.

Tippetts, A. Scott, and Robert B. Voas. “The effectiveness of the West

Virginia interlock program.” Journal of Traffic Medicine 26 (1998):19-24.

Vanlaar, Ward, Anna McKiernan, and Robyn Robertson. “Behavioral

Patterns of Interlocked Offenders: Phase II.” Traffic Injury Research

Foundation (2013).

Appendix II: Studies on Ignition-Interlock

Effectiveness

Page 32 GAO-14-559 Traffic Safety

Vanlaar, Ward, Robyn Robertson, Desirée Schaap, and Jan Vissers.

“Understanding Behavioural Patterns of Interlocked Offenders to Inform

the Efficient and Effective Implementation of Interlock Programs: How

Offenders on an Interlock Learn to Comply.” Traffic Injury Research

Foundation (2010).

Vezina, L. “The Quebec alcohol ignition-interlock program: impact on

recidivism and crashes.” Proceedings of the 16th International

Conference on Alcohol, Drugs and Traffic Safety, Montreal, Canada,

August 4-9, 2002.

Voas, Robert B., Anthony S. Tippetts, and Milton Grosz. “Administrative

Reinstatement Interlock Programs: Florida, A 10-Year Study.” Alcoholism:

Clinical and Experimental Research 37(7) (2013): 1243-1251.

Voas, Robert B., Kenneth O. Blackman, A. Scott Tippetts, and Paul R.

Marques. “Evaluation of a program to motivate impaired driving offenders

to install ignition interlocks.” Accident Analysis and Prevention 34 (2002):

449-455.

Voas, Robert B., Paul R. Marques, A. Scott Tippetts, and Douglas J.

Beirness. “The Alberta interlock program: The evaluation of a province-

wide program on DUI recidivism.” Addiction 94(12) (1999): 1849-1859.

Willis, C., S. Lybrand, and N. Bellamy. “Alcohol ignition-interlock

programmes for reducing drink driving recidivism (Review). The Cochrane

Database of Systematic Reviews (2004): 1-20.

Zador, Paul L., Eileen M. Ahlin, William J. Rauch, Jan M. Howard, and G.

Doug Duncan. “The effects of closer monitoring on driver compliance with

interlock restrictions.” Accident Analysis and Prevention 43 (2011): 1960-

1967.

Appendix III: GAO Contact and Staff

Acknowledgments

Page 33 GAO-14-559 Traffic Safety

Susan A. Fleming, (202) 512-2834 or [email protected]

In addition to the contact above, Sara Vermillion (Assistant Director);

Melissa Bodeau; Russell Burnett; Leia Dickerson; Sarah Farkas; Geoffrey

Hamilton; Kirsten Lauber; Gail Marnik; Josh Ormond; Friendly Vang-

Johnson; and Elizabeth Wood made key contributions to this report.

Appendix III: GAO Contact and Staff

Acknowledgments

GAO Contact

Staff

Acknowledgments

(541110)

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