ALCOHOL, IGNITION INTERLOCK (WORKING GROUP SESSION)

Transcription

1 ALCOHOL, IGNITION INTERLOCK (WORKING GROUP SESSION)

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3 The Québec Alcohol Ignition Interlock Program: Impact on Recidivism and Crashes Vézina, L. Highway Safety Research and Strategy Société de l assurance automobile du Québec Keywords Alcohol, ignition interlock, conviction, recidivism, crashes Abstract The alcohol ignition interlock program began operating in Québec in December Someone convicted of driving while impaired (DWI) is allowed under the program to drive a vehicle on condition it be equipped with an ignition interlock, and the individual's voluntary participation allows for a shortening of the period of licence revocation. This evaluation seeks to measure the program s impact on both DWI recidivism and crashes. The methodology is a cohort study comparing a group comprised of individuals convicted of DWI who took part in the ignition interlock program, and a control group made up of drivers convicted during the same period who did not participate. The data concerning first-time DWI offenders and that pertaining to repeat offenders is presented separately. Participation in the interlock program resulted in a reduction in the repeat DWI rate by 80% during the first 12 months for first-time offenders and by 74% during the first 24 months among repeat offenders. Figures for night crashes involving no more than one vehicle, when compared to overall crash data, also tend to show the effectiveness of the program in lowering the incidence of impaired-driving mishaps. In both cases, however, the effect tends to disappear after removal of the interlock, which leads to the conclusion that it serves more as a restraining device than a tool for driver rehabilitation. This suggests that extending the period of interlock use should be considered, at least for drivers who are likely to become repeat DWI offenders. Introduction The alcohol ignition interlock program was implemented in Québec in December Other countermeasures were introduced simultaneously included administrative license suspension, vehicle impoundment for driving while disqualified and mandatory evaluation for DWI repeat offenders. Enrollment in the Québec ignition interlock program is on a voluntary basis, and allows a motorist sentenced for impaired driving to obtain a restricted licence with authorization to

4 operate a vehicle equipped with an interlock device. When the ignition interlock program was implemented, it was aimed at all drivers sentenced for DWI. In fact, it was aimed as much at drivers who had been sentenced for the first offence as those who had repeated the offence, since the main criteria for eligibility were having served the entire driving prohibition period as provided for under the Canadian Criminal Code (CCC) and not having other active driving suspensions on record. Originally, a driver could therefore, upon finishing the driving prohibition of a 3, 6 or 12-month period (either a first, second or third conviction within five years), obtain a restricted licence for the time remaining in the penalty period of a total duration of one, two or three years. However, because of amendments made to the CCC, the program was solely available to drivers who have been sentenced for an initial offence within the preceding five years during the period between July 1999 and December To date, studies carried out on the interlock device tend to show that this is an effective means for reducing DWI recidivism (Morse and Elliot, Beirness et al., Tippetts and Voas, Beck et al). Accordingly, the lower rates of repeat offences of this kind observed among the group of drivers using an interlock device, compared to a control group, vary from 60% to 75% during the period in which the device is installed. However, most of these studies also show that the effect seems to wane after the device is removed. In addition, the impact on crashes has not been well documented to date as few studies have broached the topic. A preliminary evaluation of the Québec program, based on first-year results, indicated a decrease in the rate of impaired driving offences as well as a decline in the rate of crashes involving bodily injuries further to the installation of an interlock device (Dussault and Gendreau). Although this initial evaluation has revealed encouraging findings, the preliminary assessment of the before-during-after period remains incomplete due to the recent time aspect of the data and due to the absence of a control group. The objective of this study is to evaluate the impact, after a three-year period, of the interlock device on repeat DWI offences by differentiating the effects among first-time offenders from repeat offenders. It also aims to shed a certain amount of light on the impact this program has on the entire range of motor vehicle crashes and more specifically on alcohol-related crashes. Methods The methodology is a cohort study comparing a group comprised of individuals convicted of DWI who took part in the ignition interlock program (study group), and a control group made up of drivers convicted during the same period who did not participate. The study group is comprised of drivers sentenced for impaired driving after December 1997 who enrolled in the ignition interlock program, whereas the control group is made up of drivers sentenced during the same period who did not participate in the program. For every individual meeting this criterion, the first sentencing as of that date was used as a benchmark penalty for calculating repeat impaired driving behaviour. The study group is composed of 42,563 drivers sentenced for impaired driving between December 1, 1997, and January 26, Of that number, 81% (34,405/42,563) had been sentenced for the first time in a five-year period and 19% were repeat offenders (8,158/42,563). The latter group comprised

5 drivers who had been convicted for a first time but who were sentenced for more than one incident at the same time, giving rise to a penalty of two years or more. In that same period, 9,896 drivers obtained a restricted licence (8,846 first-time offenders and 1,050 repeat offenders) that allowed them to have an interlock device installed; this group accounted for 26% of the first-time offenders and 13% of repeat offenders. The percentage of repeat offenders with an interlock device is lower since that group was not eligible for the program during the period between July 1999 and December Drivers who display repeat behaviour by continuing to drink and drive are selected according to criminal sentencing or an immediate suspension of their licence, as related to an offence committed after the effective date of the benchmark penalty. Single-vehicle nighttime crashes (occurring between 9 p.m. and 6 a.m.) were used as a surrogate measure for alcohol-related crashes. The primary analysis technique used in this study is the survival analysis. This analysis allows us to take into account the length of time elapsed between the beginning of the penalty period and the occurrence of a first event (repeat offence or crash), compared to other analysis techniques that limit consideration of the rate of incidence. It also provides the advantage of being able to process censored data. Thus, the survival curves, according to the Kaplan-Meier method, are used to illustrate the probabilities of non-repeat behaviour in both groups at different times (t), based on the beginning of the penalty period and the Cox s model of proportionate rates allows us to introduce co-variables such as the characteristics of drivers belonging to either group. However, to ensure the validity of the Cox model, the impact of the factor we are seeking to measure must be constant over time. If that condition is not met, we must perform a stratified analysis over time, making the survival for each period conditional to the survival observed during the preceding period. In our case at hand, the effect of the interlock device program varies over time, so that stratification is necessary to ensure a certain degree of homogeneity. The stratification retained is different, depending on whether we consider first-time offenders or repeat offenders but the cutoff is rather clear in both cases: 12 months for the first group, and 24 months for the second. These periods closely correspond to the period with the interlock device (including the waiting period) and the post-interlock device period. Results - Demographic characteristics Drivers sentenced for impaired driving are mainly men (89 %) with an average age of 36.7 years. However, there are a few statistically significant differences between the interlock program participants and the drivers making up the control group. Among the group of first-time offenders, we find a greater proportion of men enrolled in the ignition interlock program and of a slightly older age, whereas among repeat offenders, those participating in the program are on average younger than the drivers without an interlock device

6 The tracking period of all drivers in the study lasted days on average. The length was greater for repeat offenders and drivers who had an interlock device. The average length of participation in the program was days for first-time offenders and for repeat offenders. - Impact on DWI recidivism First, the survival curves were traced for both groups according to the Kaplan-Meier method (figure 1). The differences observed between the group with interlock devices and the control group were statistically significant and indicate a lower recidivism rate for the group so equipped for the entire period covered. However, we noted changes to the appearance of the survival curves subsequent to 12 months of follow-up in the case of first-time offenders and after 24 months among repeat offenders, as the curves tend to come together beyond those two points. Incidentally, this confirms the stratified analysis according to the Cox model (table 1). Thus, among first-time offenders, the risk ratio of DWI recidivism for drivers with an interlock device as opposed to the control group was for the first 12 months, then climbing to 1.218; both results are statistically significant. Therefore, the risk of falling into repeat drunk-driving behaviour for drivers with an interlock device is significantly lower during the first 12 months, or during the period when the device can be installed and that, thereafter, it becomes significantly higher than that observed among drivers in the control group. Among the group of repeat offenders, the risk of recidivism (RR=0.260) for the first 24 months among drivers with an interlock device was significantly lower while after that period it was basically the same in both groups, even though the risk ratio is reported as Nonetheless, it is important to note that the gains observed at the outset of the period broadly offset the rises that occur afterward, resulting in significant gains for the entire period. This applies both to first-time offenders and repeat offenders. Table 1: Stratified analyses over time with the Cox model for DWI recidivism First-time offenders 12 months > 12 months Repeat offenders 24 months > 24 months Risk ratio* * adjusted for gender and age P-value < <

7 Figure 1: Survival curves according to Kaplan-Meier for DWI recidivism First-Offender Grou Repeat-Offender Group 1 1 0,98 0,98 0,96 0,96 0,94 0,94 0,92 0,92 0, month 0, month interlock no-interlock interlock no-interlock - Impact on crashes The survival analysis on single-vehicle nighttime crashes conducted using the Kaplan-Meier model (Figure 2) gives rise to non-significant differences between the groups of drivers with or without interlock devices, both as regards first-time offenders and repeat offenders. After we stratify the results, however, certain differences come to light (see Table 2). Accordingly, we noted that the risk of crash is not significantly different during the first few months after the penalty period begins and that, thereafter, the risk among drivers with an interlock device becomes greater than that of drivers belonging to the control group. Risk ratios were also computed for all crashes and we observed that the risk of crashes among drivers with an interlock device is greater in all cases. Table 2: Stratified analyses over time with the Cox model for Single-vehicle nighttime crashes (and all crashes)* First-time offenders 12 months > 12 months Repeat offenders 24 months > 24 months Risk ratio** (3.557) (1.652) (2.160) (3.867) * Results for all crashes appear in parentheses ** Adjusted for gender and age P-value (<.0001) (<.0001) (<.0001) (<.0001)

8 Figure 2: Survival curves according to Kaplan-Meier for Single-vehicle nighttime crashes First-Offender Group Repeat-Offender Group 1 1 0,995 0,995 0,99 0,99 0,985 0,985 0, month interlock no-interlock 0, month interlock no-interlock Discussion The findings of this study have confirmed the effectiveness of the interlock program to reduce DWI recidivism while the device is in place. However, we noted that the rate of recidivism observed after the penalty period runs out is either significantly higher among first-time offenders, or the same among repeat offenders who had an interlock device, compared to the control group. These last results incidentally are similar to observations made by Tippetts and Voas who noted an increase in repeat behaviour of this type among first-time offenders and repeat offenders, after the removal of the device, and those of Beck et al. who found no significant differences among repeat offenders beyond the first 12 months. Therefore, at this stage, an interlock device appears to be more of an issue of contention than a means of rehabilitation since the gains seem to dissipate when the device is removed from the vehicle. However, it has been noted that the gains realized early in the period are sufficiently great to show that, despite all, a reduction in recidivism is observed over the entire period. In terms of the impact of the program on alcohol-related crashes, the findings reported as to single-vehicle nighttime crashes seem, at first glance, to be less conclusive since the risk ratios calculated during the first few months (1.053 among first-time offenders, and among repeat offenders) are not statistically significant. Nevertheless, these findings merit special attention since it is important to consider the fact that this indicator could be contaminated by the effect of crashes not related to alcohol and that it is also very sensitive to a difference in exposure between the two groups. Although nighttime crashes involving just one vehicle represent the best approximation available for crashes attributable to alcohol consumption, this measure is not perfect as it also takes into account a certain number of crashes not related to alcohol. That is why these results become more interesting when compared with the results obtained for all crashes combined

9 Furthermore, the factor of exposure can also allow us to qualify the findings obtained for crashes since the fact of being involved in a crash reflects of course the conduct of an individual but also reflects to a great extent the distance travelled by that individual. First, we can advance the hypothesis that drivers who chose an interlock device have a greater need for their vehicle and that they generally travel a higher number of kilometres. This was observed by Morse and Elliot in a previous study. Next comes the fact that the drivers subjected to a conventional penalty simply do not have the right to drive and, even though a substantial number continue to drive anyway, they tend to cover small distances. This would explain the decrease in the risk ratio of total crashes for first-time offenders with an interlock device once the penalty period is over, or when the drivers of the control group can regain their licence. Therefore, once distinctions have been made as to the limits of the indicator chosen and the measurement of exposure, the results obtained in terms of crashes involving just one vehicle at night also tend to show the effectiveness of the ignition interlock program over the period during which it is installed. The voluntary aspect of participation in the program also raises the question of a potential selfselection bias. Indeed, it is possible that the drivers taking part in an ignition interlock program are people more inclined to comply with set rules and that this would be the major reason for the relative decrease observed among that group. However, as pointed out by Tippetts and Voas, it is not very likely that the self-selection bias could alone account for the decrease, given the greater rate of recidivism observed after the device s removal. The fact that the risk ratios of DWI recidivism and crashes potentially attributed to alcohol of the participants in an interlock program are significantly higher following the removal of the device also raises a few questions, such as the absence of the rehabilitation effect. However, it is important to once again consider the question of relative exposure. When we compare the risks after a penalty period, our analysis presupposes that the exposure of the interlock group is relatively comparable to that of the control group, even though this might not be entirely the case. We do know that a high number of drivers opt not to regain their driver s licence after a penalty period, and we could suppose that this might affect the drivers in the control group to a greater extent, since the participants in the interlock program had expressed their desire to regain their licence beforehand. The proportion of non-reintegration is perhaps smaller in Québec due to the vehicle-seizing policy in effect for driving while disqualified, but could reach 50% according to Tippetts and Voas. A way in which to solve the problem would be to take into consideration solely those drivers who recovered their driver s licence at the end of their penalty period, and conduct a new study of this subgroup to ensure all analyses are conducted on the same basis of comparison. This would be a fairer way to gauge the level of rehabilitation attained by the device. Findings from this second assessment of the Québec ignition interlock program confirmed its effectiveness in reducing the recidivism in driving while impaired (DWI). The findings also suggest that the impact on alcohol-related crashes ought to be evaluated more accurately through

10 additional studies. However, in both cases we noted that the effects tend to diminish beyond the periods covered by the interlock device. Therefore, this infers we should extend the interlock device use period, at the very least, among drivers showing a major recidivism risk. References 1. Morse, B.J. and Elliot, D.S. Effects of Ignition Interlock Devices on DWI Recidivism: Findings From a Longitudinal Study in Hamilton County, Ohio. Crime & Delinquency, Vol. 38, No. 2; pp , Beirness, D., Marques, P.R., Voas, R.B. and Tippetts, S. Evaluation of the Alberta Ignition Interlock Program: Preliminary Results in C. Mercier-Guyon (Editor). Alcohol, Drugs and Traffic Safety T '97: Proceedings of the 14 th International Conference on Alcohol, Drugs and Traffic Safety. Annecy, France; pp , Tippetts, A.S. and Voas, R.B. The Effectiveness of the West Virginia Interlock Program. Journal of Traffic Medicine, Vol. 26 (1-2), pp , Beck, K.H., Rauch, W.J., Baker, E.A. and Williams, A.F. Effects of Ignition Interlock License Restrictions on Drivers With Multiple Alcohol Offences: A Randomized Trial in Maryland. American Journal of Public Health 89(11), pp , Dussault, C and Gendreau, M. Alcohol ignition interlock: One-year s experience in Québec. In Proceedings of the 15 th International Conference on Alcohol, Drugs and Traffic Safety, May 22-26, 2000, Stockholm, Sweden, 5 p,

11 Illinois Ignition Interlock Evaluation Frank, J.F. 1, Raub, R. 1, Lucke, R.E. 2, Wark, R.I. 2 1 National Highway Traffic Safety Administration, Washington, DC 2 Northwestern University Center for Public Safety, Evanston, IL The Illinois ignition interlock law first went into effect in 1994 when the installation of ignition interlock devices was added to the package of sanctions for Driving Under the Influence (DUI) of Alcohol (625ILCS5/11-501(6)(i)). Previously, repeat offenders could petition the Secretary of State (SOS) for a restricted driving permit (RDP) after serving some period of license loss, and such permits generally were issued without other requirements. With the enacting of the ignition interlock legislation, those individuals would also need to install an interlock as an additional requirement for receiving the RDP. It was and still is an administrative program requiring the installation of an interlock as a condition of the RDP. Offenders had and have the option of not reinstating their licenses and not installing an interlock. Accordingly, the interlock users were and continue to be a group of people who are motivated to get their license back legitimately, and are, perhaps, more likely to succeed on the interlock than those who choose not to reinstate their license and install a device. The National Highway Traffic Safety Administration (NHTSA) agreed to provide some funding for an evaluation of the program in collaboration with the Illinois Secretary of State. This paper reports on the results of that evaluation. Procedures: The Comparisons The treatment group in this study consisted of all drivers who were eligible for and received an RDP, and accordingly also installed an interlock device on their car for one year during the period from July 1, 1994 through June 30, These were persons who met specific criteria set by state rules, but essentially were multiple offenders eligible for the RDP after a period of hard suspension. The comparison, or control group, consisted of a cohort of individuals who met the same criteria during the three-year period from July 1, 1991 through June 30, 1994, before the interlock law and program existed. It should be understood that during the period, individual drivers could elect not to seek an RDP and not have an interlock installed. Hence, the interlock group is, to some extent, self-selected and biased in favor of those who may have been more motivated to make the interlock work

12 Results As shown in Table 1, through December 2000, 938 drivers in the control group (68%) and 1,352 (87%) in the treatment group had not been rearrested for an alcohol- related violation 1. However, because those drivers in the control group had up to 9.5 years of driving (July 1991 through December 2000) compared to some in the treatment group having only 3.5 years (June 1997 through December 2000), including all arrests is useful only for showing possible trends in arrests. It does show that by the fourth year approximately the same percentage of persons in the treatment group as in the control group appear to be re-arrested for DUI. Table 1 Number and Percentage of Drivers Rearrested for DUI After Different Time Periods (through December 2000). Time to Arrest 1 Year 1 to 2 2 to 3 3 to 4 Total Total Group and Less Years Years Years Arrests in Group Control Percent 6,8% 7,7% 5,1% 3,4% 23,0% Treatment Percent 1,3% 3,1% 3,7% 2,9% 10,9% Table 2 displays the same data as Table 1, except that the period for comparison is limited to three years after the hearing. Within the first 3 years, 20% of the control group has been rearrested for an alcohol violation. Only 8% of the treatment group has had the same outcome. The differences are statistically significant at p < with a chi square of and 5 degrees of freedom (df). However, as both tables suggest, the differences between the two groups are beginning to disappear by the end of the third year. Those drivers in the control group who were re-arrested within three years averaged 515 days until the arrest with a standard deviation of 275 days. Those in the treatment group averaged 716 days to the arrest with a deviation of 262 days. These values are significantly different at the level based on a t-test of differences (t=5.28 with a F test showing no differences between the variances). 1 The arrests are for driving under the influence, but the conviction could have been for any alcohol related violations including failure to take a breath/blood test, DUI, or plead down to reckless driving

13 Table 2 First DUI Re-arrest: First Three Years After Receiving the RDP Time to Arrest No DUI 1 Year 1 to to 2 2 to to 3 All Total Group Arrest and Less Years Years Years Years Arrests in Group Control 1, ,384 Percent 80.3% 6.8% 4.4% 3.3% 3.2% 2.0% 19.7% Treatment 1, ,560 Percent 92.0% 1.3% 1.2% 1.9% 1.9% 1.7% 8.0% Chi square = 110.2, df=5, p<0.001 While interlock devices were installed for only one year, having three years of post-interlock data allows an examination of recidivism rates over a longer period of time than other studies have had the luxury of doing. It appears that the effects of the interlock did hold for some time after the interlock was removed, but this effect can only be characterized as a transient effect that disappeared by the end of three years. Only Weinrath (1997) has reported any sort of carryover effect after interlocks have been removed, and his n was relatively small and in need of confirmation. Logically, it makes sense that some offenders might have continued to be influenced by the yearlong experience of having had to use the interlock to get their car started. As in other studies (e.g., Beck, et al., 1999; Popkin, et al, 1992; as well as a review by Cobin and Larkin, 1999), these offenders appear to have relapsed when the interlock was not in place to prevent them from drinking and driving. Recidivism rates returning to pre-interlock levels support this explanation. Number of Arrests The Special Case of Offenders who fail, even on the Interlock This study also gave us an opportunity to examine a special group of offenders (n=152), persons in the interlock group who had their RPD rescinded for violations while they were on the interlock. This group is best characterized as the worst of the worst offenders examined in this study. This group of offenders was also followed to see whether they were subsequently rearrested for DUI, for Driving While Suspended (DWS), or were involved in a subsequent crash. Offenders showing up in any of these categories provide evidence that they were, in fact, continuing to drive. The data, presented in Table 3, are striking. In the three years following the initial hearing date, approximately 62% of drivers whose RDPs had been cancelled for an alcohol violation while they were on the BAIID and 55% of those cancelled for other reasons also while on the BAIID, had another driving action on their record. These offenders continued to be arrested for driving under the influence at a rate far in excess of the rate for the driving population in Illinois. Given a base of 11.4 million registered drivers and an average of 47,000 DUI arrests yields an annual rate of 4.2 DUI arrests per 1,000 drivers. The annual rate of arrests in the group whose BAIID was cancelled is 110 per 1,000 drivers (Etzkorn and Martin, 1997). Revoking the drivers license for those whose driving record makes them originally eligible for an RDP does not appear to deter driving, especially driving under the influence of alcohol. These data suggest that the public would have been safer had the interlocks remained on their cars, no matter what the violation rate had been. Perhaps other sanctions might be considered that would have an impact on the driver, without removing the interlock from the car, so the general driving

14 public would continue to be protected from this individual drinking and driving, at least in his own vehicle. There is a clear need to get this offender s attention, either by impounding his car and/or increasing the intensity of supervision and/or treatment. Just taking the offenders license away again does not appear to have the desired effect, or protect the general driving public from them. Table 3 Further Driving Actions for Cancelled Treatment Group Time to First Action No Time to Action Cancellation Reason Other 1 Year 1 to to 2 2 to to 3 Total Total and Next Action Actions and Less Years Years Years Years Actions in Group Alcohol Percent 38.5% 19.2% 7.7% 0.0% 19.2% 15.4% 61.5% 2nd DUI* Crash Invalid License Other Percent 45.2% 13.5% 11.1% 15.9% 8.7% 5.6% 54.8% 1st DUI Crash Invalid License * An additional 6 drivers had DUI arrest after 3 years. Conclusions During the one-year period that the breath alcohol ignition interlocks (BAIID) were installed on their vehicles, fewer drivers were arrested for DUI than a similar group without the interlocks. This finding is in agreement with what has been found by most other researchers. Even though the control group employed in this study was from a different population than that used for the treatment group, the differences between those groups were probably not large enough to offset the significant differences found in driving behavior between these two groups of offenders. These findings support the assertion that simply providing a Restricted Drivers Permit, as well as the rules and restrictions under which the license is offered, is not sufficient to prevent persons from continuing to drive after drinking. Adding a device that prevents the vehicle from starting when alcohol is detected is a critical component. Those few drivers who were arrested for DUI while the device was installed in their vehicle probably had tampered with the device, were driving another vehicle, or not yet had the device installed. The BAIID does not appear to promote a long-term change in driving behavior. By the end of three years, those who had the device installed had arrest rates roughly similar to those who had never been exposed to the BAIID. This finding is also in agreement with other research that, in general, has found even shorter carry-over affects. The finding that long-term behavior is not likely to change also implies the need to determine if the continued use of the BAIID may need to be a permanent requirement for some drivers. Currently, only in a few cases has the Illinois Secretary of State continued requiring the use of the device for more than one year. The Secretary of State may need to establish guidelines for requiring continued (long term) use of the BAIID

15 In the short-term, the interlock appears effective for those who use it. However, this group represents only a fraction of the potentially eligible drivers. No additional investigation was made of the large group (approximately 70% of the total) who may have met the conditions for use of the BAIID but did not apply for the RDP. More information concerning the likelihood that these drivers will continue to drive without a valid license is clearly needed. The literature has indicated that the large number of those with revoked licenses continues to drive. If this were confirmed as the case with Illinois drivers with multiple alcohol offences, it would call into question the strategy of employing revocation as a sanction for those drivers presenting the greatest potential danger on the road. The failure of revocation as a tool to control driving clearly was evident with the small group of drivers who had applied for the BAIID, but for multiple reasons were returned to revoked status. In the three-year period following the return to revoked status, 60% were either arrested for a driving infraction including DUI or involved in a crash; both events clearly indicating they were continuing to drive. It appears that what is needed is to increase the incentives for using BAIID while at the same time increasing the disincentives for driving while in a revoked status. In summary, BAIID appears to be a valuable tool that helps reduce driving under the influence of alcohol by those who previously were likely to continue to drink and drive. However, especially given the economic disincentives such as the costs of installation, monitoring and increased insurance premiums, many potential users will not be motivated to obtain a Restricted Driving Permit when the interlock device is required. Moreover, there is not sufficient disincentive for persons to continue driving even though their license has been suspended or revoked. Finally, for those who tamper with the BAIID, fail to report for monitoring, or do not have it installed, simply a return to revoked status is not an effective option. An approach needs to be found that will effectively prevent driving while impaired or in more severe cases, driving at all. References Beck, Kenneth H., William J. Rauch, and Elizabeth A. & Williams Alan F. Baker. Effects Of Ignition Interlock License Restrictions on Drivers With Multiple Alcohol Offenses: A Randomized Trial in Maryland. American Journal of Public Health 89, no. 11 (1999): Coben, Jeffrey H., and Gregory I. Larkin. Effectiveness of Ignition Interlock Devices in Reducing Drunk Driving Recidivism. American Journal of Preventive Medicine 16, no. 1S (1999): Etzkorn, Larry D. and Jim Martin. A Preliminary Report on the Effectiveness of the Illinois Secretary of State s Breath Alcohol Ignition Interlock Device (BAIID) Pilot Program. Paper presented at the 76 th Annual Transportation Research Board, Washington, DC: January Popkin, C. L., J. R. Stewart, C. Martell, and J. D. Brickmayer. An Evaluation of the Effectiveness of the Interlock in Preventing Recidivism in a Population of Multiple DWI Offenders. Chapel Hill: University of North Carolina Highway Safety Research Center, Weinrath, Michael. The Ignition Interlock Program for Drunk Drivers: a Multivariate Test. Crime and Delinquency 43, no. 1 (1997):

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17 A Preliminary Evaluation of the Swedish Ignition Interlock Programme and Recommended Further Steps Bjerre, B. Traffic Medicine Advisory Board, Swedish National Road Administration, S Borlänge, Sweden Abstract The Swedish alcohol ignition interlock programme for DWI offenders started as a pilot project in It is a volunteer programme, but differs in some respects from other programmes. It covers a period of two years, and includes very strict medical regulations entailing regular check-ups by a physician. Records from the five years prior to the DWI offence showed that the DWI offenders are generally in a high-risk category long before their offence. During the programme, alcohol consumption is monitored through the use of self-esteem questionnaires (AUDIT) and five different biological markers. Our preliminary data shows a noticeable reduction in alcohol consumption amongst the participants, as determined through falling AUDIT scores and significantly decreased levels in the biological markers. It must, however, be noted that the number of participants is still very small (285 individuals) compared to other programmes. Up until now, no case of recidivism has been found during the programme, but it is still too early to draw any conclusions concerning the rate of recidivism after completion of the programme, as data is not yet available for analysis. Nevertheless, the preliminary results are so promising that the programme will be expanded to cover all of Sweden, as well as include all driving licence categories. Introduction From February 1999, DWI offenders in three of Sweden s twenty-one counties were able to volunteer for a two-year alcohol ignition interlock pilot programme. In this programme, the interlock memory was checked every other month and medical check-ups using biological alcohol markers were conducted every third month. Participants had to verify a sober lifestyle during the second year to be permitted to continue. Objectives The aim of the pilot programme was to examine driver behaviour in connection with the alcohol ignition interlock and to study its effect from a recidivism and rehabilitation perspective. A further aim was to assess the potential of the interlock for reducing relapse frequency, and thereby benefit road safety. Moreover, a study was to be made of the specific effect of the alcohol ignition interlock compared to that achieved through driving licence revocation. Additionally, the rehabilitation potential through long-term follow-ups was to be examined

18 Methods The process evaluation involved a longitudinal monitoring of participants, with the main focus on any changes in life-style and drinking behaviour. This was determined through interviews, self-esteem questionnaires (AUDIT) and through the use of biological markers (the three liver enzymes GGT, ASAT and ALAT, the mean volume of the red blood corpuscles (MCV) and the carbohydrate-deficient transferrin (CDT)). Two control groups were used, one comprising DWI offenders who had abstained from participating in the programme and who therefore had had their driving licence revoked (K2), and the other consisting of matching individuals from counties not taking part in the programme (K1). The outcome evaluation involved a study of official accident statistics, the number of DWI offences, hospital discharge registers and sick leave registers. Data covering the five years prior to the DWI offence and onwards was collected. Results During the programme period under evaluation, 285 people had volunteered for the ignition interlock programme (as of December 2001). Eleven percent of these were women. Among the participants, 50% had been diagnosed as alcohol dependent and 10% as alcohol abusers. The remaining 40% had no diagnosis. The mean BAC level at the time of the DWI offence was 0.20% in the interlock group compared to 0.18% and 0.17% in the two control groups. In all, only 11% of the eligible DWI offenders in the three counties took part. Three percent of the applicants were rejected, the usual reason being simultaneous abuse of other drugs. Twenty percent were subsequently denied permission to continue, primarily because a sober lifestyle could not be verified during the second year of the programme, or due to repeated attempts to start their car while under the influence of alcohol. There were also some participants who decided to quit the programme of their own accord. In all, 60 people have now successfully completed the entire programme. Records from the five years prior to the DWI offence showed that the accident rate (road accidents involving injury reported by the police) for the participants in the interlock and control groups was 4-5 times higher than for the average driver. Their records also showed a times higher frequency of DWI offences. Ill-health statistics were also studied, whereby significant differences were found between the DWI offenders and the average Swede in the same age category: the DWI offenders, interlock participants as well as members of the control groups received hospital care (irrespective of medical diagnosis) much more frequently than the average Swede. A specific analysis of the statistics from the past five years on hospital care due to a road accident revealed that DWI offenders had been patients 3-4 times more often than the average Swede and that they were hospitalised a significantly greater number of days (Figure 1). They also reported in sick to work about twice as many days per year as compared to the average Swede

19 Figure 1: Hospital care due to road accidents during the five years prior to the DWI offence. Number of occasions and number of days at hospital per person and year in the interlock group, in the control group (K1) and in Sweden as a whole 0,09 0,08 Number per person and year 0,07 0,06 0,05 0,04 0,03 0,02 0,01 0 Interlock Control (K1) Whole Sweden Occasions of hospital care Number of days at hospital During the programme a noticeable change in alcohol habits among the participants was found, measured both through improved results from biological alcohol markers as well as through better results on the AUDIT questionnaire. The latter showed an impressive reduction in alcohol problems during the 2-year programme. Among men, the mean AUDIT score fell from 11 to 2. While 64% of the male interlock participants had an initial score of 8 or more (indicating potentially dangerous of harmful alcohol habits), only 6% had such a high score at the end of the programme (Figure 2). As a more objective measure of the alcohol consumption, five different biological markers were monitored during the two years of the programme. A noticeable change was observed through steadily diminishing values, which confirms the reduced alcohol consumption suggested by the AUDIT reports. Thus the mean level of the liver enzyme GT - having a specificity of around 75% regarding alcohol abuse was reduced by about 40% during the programme (Figure 3). CDT, with the highest alcohol specificity (about 95%) was elevated for 17% of the participants at the start of the programme and for about 6% by the end (Figure 4). Any elevated CDT-levels during the second year of the programme indicated a relapse into alcohol abuse, which in turn meant being denied permission to continue in the programme

20 Figure 2: Percent of the participants in the interlock programme having risky or harmful alcohol habits according to AUDIT (> 8 scores) at each of the eight medical check-ups Percent Months Males Females Figure 3: The mean values of the liver enzyme GT for the participants in the interlock programme at each of the eight medical check-ups (every third month from start). The GT-values are presented as a percent of the upper reference level 120% 100% 80% 60% 40% 20% 0%

21 Figure 4: Percent of the participants in the interlock programme with increased CDTvalues at each of eight medical check-ups (every third month from start) To summarize, there is reliable data showing significantly reduced alcohol consumption among the interlock participants during the programme period. A key question is, however, whether this has any impact on road safety. Preliminary data indicates an impressive effect on DWI recidivism. For the interlock group, this was reduced from the prior 4.6% per year to zero, while it remained high among those having their driving licence revoked (K2), which indicates a very high degree of illegal driving (Figure 5). Moreover, preliminary results suggest that the annual accident risk was reduced from 2.1% to about the same level as that of the average driver (0.4%) and to that of those whose licences had been revoked. However, the small number of accidents makes this data very uncertain. Figure 5: Number of DWI offences (five years prior to and after the present DWI offence) per person and year in the interlock group, in the control group who had their licence revoked (K2) and in Sweden as a whole. After the DWI offence only includes the period of participation in the interlock programme, and for the controls, the period while the driving licence was revoked 5 Percent per year 4,5 4 3,5 3 2,5 2 1,5 1 4,6 2,3 4,0 0,5 0 0,0 0,2 Interlock Control (K2) Whole Sweden 0,2 Five years prior to the DWI offence After the DWI offence

22 As a spin-off effect, tangible changes were also found in the sickness figures for the interlock group compared to members of the control groups. During the programme, an increase of almost 60% in the number of sick days per year and person could be seen (Figure 6). In the two control groups however, the increase was significantly higher, about 170% and 120% respectively. These findings probably reflect the adverse effects of driving licence revocation on the work situation and probably also unchanged drinking habits. As far as hospital care statistics are concerned, delayed registration procedures means that data showing changes during the interlock programme is not yet available. Figure 6: Days of sick leave per person and year (five years prior to and after the DWI offence). After the DWI offence only includes the period of participation in the interlock programme, and for the controls, the period while the driving licence was revoked. Only sick periods of more than two weeks duration are included Number of days Interlock Control (K1) Control (K2) Whole Sweden Five years prior to the DWI offence After the DWI offence Discussion All data from the five years prior to the DWI offence clearly demonstrates that the DWI offenders are generally in a high-risk category long before their offence. They were thus found to have a 4-5 times higher accident rate than the average driver and also a significantly higher rate of hospitalisation and of reporting in sick. These findings corroborate the observation that 60% of the interlock group were diagnosed as alcohol dependent or as alcohol abusers. In this context it is worth mentioning that epidemiological surveys have shown similar results in the United States. Miller and Windle (1990) thus found that at least 70% of DWI offenders can be diagnosed by DSM-IV as alcohol abusers or alcohol dependent. Therefore it could be suggested that the Swedish observations regarding the previous records of DWI offenders would be very much the same in other countries as well. The Swedish results, although preliminary, show that the ignition interlock programme has had a significant and positive effect. The DWI offenders have a significantly lower rate of recidivism while participating in the interlock programme than those who do not participate. In fact we have not yet observed any single case of recidivism among the participants. This is probably a result

23 of the very strict regulations concerning regular medical check-ups and the necessity of a verified sober lifestyle during the second year in the programme. The advantage of these strict regulations is demonstrated by the noticeable changes in alcohol habits among the participants. Improvements are thus observed as significantly better AUDIT scores and decreasing values for all the different biological markers studied. In all, this clearly demonstrates significantly reduced alcohol consumption among the interlock participants. As a spin-off effect, tangible changes were also found in the sickness figures for the interlock group compared to the members of the control groups. These effects probably reflect both a decreased alcohol consumption and the benefit from an employment perspective of being able to keep one s driving licence. The disadvantage to the strict medical regulations is the fact that about twenty percent of those taking part are denied permission to continue in the programme, primarily because of a relapse or that they continue drinking to the extent that the biological markers are above normal levels. Once outside the programme these individuals are beyond control and probably engage in a high degree of illegal driving. For instance, Griffin and delazerda (2000) estimated that as many as 75% of those drivers who have had their licences suspended in the United States continue to drive to some extent during the period of suspension. There is nothing that would contradict similar conditions occurring in Sweden. Several previous studies have shown similar beneficial effects in reducing DWI recidivism during the period of interlock use as has been found in the Swedish programme. (For a review, see ICADTS, 2001). However, these effects gradually dissipated, more or less, after the removal of the interlock device from the vehicle. One purpose of the Swedish interlock programme running for two years, and with strict medical regulations, was to achieve long-term rehabilitation. As yet, we do not have any follow-up data to examine the rate of recidivism of the 60 participants who have completed the entire programme. Conclusions and further steps Based on the very promising preliminary results, a recommendation that the pilot programme cover the entire country as well as all driving licence categories was presented to the Swedish Government. It appears that this recommendation has been accepted and will be effective as of the year The inclusion of truck, bus and taxi drivers in interlock programmes complies very well with the growing voluntary use of interlock devices in these types of vehicle in Sweden. It was also recommended that the interlock programme be prolonged for those participants who are unable to verify a sober life-style during the second year of the programme. This recommendation was not accepted, very unfortunately as these drivers are probably those who run the greatest risk of DWI recidivism. References Griffin III, L.I. and delazerda, S. (2000). Unlicensed to kill. AAA Foundation for Traffic Safety, Washington, DC. ICADTS Working Group on Alcohol Ignition Interlocks, Chaired by: Dr. Paul R. Marques, (USA). International Council on Alcohol, Drugs and Traffic Safety Miller, B.A. and Windle, M. (1990). Alcoholism, problem drinking and driving while impaired. In R.J. Wilson and R.E. Mann (Eds.). Drinking and driving: Advances in research and prevention. New York: The Guilford Press,

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25 Best Practices for Alcohol Interlock Programs: Findings from two Workshops Beirness, D.J., Robertson, R.D. Traffic Injury Research Foundation of Canada Abstract Since their introduction nearly two decades ago, considerable knowledge and experience have been accumulated on alcohol interlock programs. Researchers, interlock service providers, and program administrators attended two workshops the first to help identify a series of best practices for interlock program development; the second to discuss the use of interlocks as part of a licence reinstatement program for DWI offenders. Introduction Alcohol interlock devices have become increasingly popular as a means to prevent persons convicted of a DWI offence from repeating the behaviour. These devices are a form of incapacitation and serve as a bridge between full suspension and full licence reinstatement. Interlocks allow offenders to operate a vehicle legitimately within the driver licensing system while at the same time provide the public with the assurance that offenders will only be able to drive when their BAC is below a specified (low) value. Five Canadian jurisdictions and 42 American states have legislation that allows the installation of interlock devices in the vehicles of DWI offenders. However, not all jurisdictions with legislation are currently operating interlock programs. It is estimated that there are more than 40,000 interlock devices currently in use throughout North America. This is in contrast with an estimated 1.5 million DWI offenders in North America each year. Participation rates in most interlock programs are relatively low typically less than 10% of offenders participate in an interlock program. There remains significant potential for the growth of interlock programs. More and better interlock programs will undoubtedly serve to increase the number of offenders who participate in these programs. The control of DWI offenders through interlock programs will ultimately improve safety for all drivers. In this context, interlock programs have received implicit endorsement in federal legislation in both Canada and the United States. In July 1999, the Criminal Code of Canada was amended to allow provinces to reduce the mandatory period of driving prohibition for a first DWI offence from one year to three months provided the offender participates in an alcohol interlock program for the remainder of the one-year period. The legislation was amended in December 2001 to allow repeat DWI offenders the opportunity to reduce the mandatory driving prohibition if they

26 participate in an interlock program. This legislation provided the impetus for provinces to renew their interest in the development and/or expansion of such programs. In the United States, the Transportation Equity Act for the 21 st Century (TEA-21) contains a financial incentive for states to strengthen their programs to control repeat DWI offenders. Failure to comply will result in a portion of the state s highway construction funds being diverted to traffic safety programs. One of the alternatives that will assist states in their efforts to comply with this legislation involves establishing an alcohol interlock program. Not surprisingly, this has sparked renewed interest in the development of interlock programs throughout the United States. Since these laws were passed, the demand for information about interlock programs has escalated dramatically. Although considerable information exists about interlock programs, it tends to be scattered throughout scientific journals, technical reports and other documents. Those searching for the best available information on the operation and effectiveness of interlock programs must wade through an ever-expanding volume of literature containing the collective knowledge on the subject. In this context, there is a need for a collected source of information that provides legislators, policy makers and program administrators with the best possible advice for the development of interlock programs. The need for a discussion of best advice for interlock programs was the impetus for an international workshop. In light of the demonstrated effectiveness of interlock programs, there is a desire to expand programs to include more DWI offenders. To date, many interlock programs have operated on a voluntary basis i.e., DWI offenders can voluntarily participate in the interlock program, usually in exchange for a reduction in the length of licence suspension. In other programs, judges order DWI offenders to participate in an interlock program as a condition of probation. Recently, there has been interest in using interlocks as part of a licence reinstatement program essentially requiring participation in an interlock program as a condition of licence reinstatement. This approach would help ensure that as many DWI offenders as possible participate in an interlock program. In the absence of a formal evaluation of the impact of voluntary versus mandatory interlock programs, it was deemed essential to discuss the issues surrounding the use of interlocks as part of a system of licence reinstatement. This formed the basis for a second international workshop on interlock programs. Method Two one-day workshops were held the first in Montreal in September, 2000; the other in Toronto in November, In attendance was an international group of researchers, interlock manufacturers, policy makers, and program specialists. The purposes of the first workshop were to discuss the current state of knowledge on the effectiveness of interlock programs and to work towards a set of best practices for interlock programs. The purpose of the second workshop was to discuss issues surrounding the role of interlocks as part of a licence reinstatement program. Results At the first workshop, a number of issues concerning the efficient and effective use of interlocks were discussed. Of particular interest were the factors that appear to facilitate the success of

27 interlock programs as well as factors that might mitigate effectiveness or were in need of further study. The major issues included: circumvention, participation rates, program authority, program duration, eligibility, traffic safety benefits, and program cost. As a result of these discussions, a list of ten best practices for interlock programs was produced. These are summarized below and described in more detail in the report on the workshop (1). Perspective. It is deemed essential that interlock programs be viewed as more than a breath test device installed in a vehicle. Rather, it is best described as a program that consists of a set of coordinated activities -- including monitoring, communication, and rehabilitation -- designed to prevent impaired driving among participants. It is also important to view interlock programs not as an additional punishment but as a form of incapacitation that allows offenders to drive legally while at the same time preventing them from driving impaired. Legislation. The interlock program needs to be supported by strong, clear legislation that specifies the administrative authority for the program, the eligibility criteria, the conditions of participation, and supplementary provisions that prohibit the participant and others from attempting to circumvent the interlock. Equipment. The interlock device used in the program should be alcohol-specific, must meet or exceed a set of approved performance specifications, and must be certified by a reputable private or government laboratory. Service provider. In recognition of the special role played by the interlock service provider as the liaison between the participant and the administrative authority for the program, it is recommended that the firm selected as the service provider must demonstrate an understanding of the clientele and be prepared to provide a level of service commensurate with the needs of this population. Eligibility. Every effort should be made to have as many DWI offenders as possible participate in the interlock program. Exclusions should be minimal and reserved for those rare cases in which the operation of a motor vehicle is not recommended under any circumstances. Participation. Interlock programs should combine the best features of voluntary and mandatory programs. This system would ensure that all DWI offenders participate in the program but would allow offenders the option of early entry into the program either immediately upon conviction or in exchange for a reduction in the length of suspension. Program authority. Administrative authority for the interlock program should reside with the agency responsible for driver licensing and control. This does not preclude a judge from ordering participation in an interlock program for DWI offenders deemed to be at high risk and in need of a high level of supervision. Monitoring. Interlock program participants should be monitored regularly e.g., monthly and should include a review of data from the interlock data recorder. Program duration. Rather than requiring participation in an interlock program for a fixed period of time, the duration of program participation should be dependent upon the individual s success in the program. Consideration should also be given to a system of being removed from the program progressively, for example by restricting the times and days of the week during which the interlock is operational. Program integration. Every effort should be made to integrate the interlock program with other DWI countermeasure programs and sanctions, particularly rehabilitation

28 A second workshop was held to examine a number of issues that were raised during the first workshop but for which time did not allow a thorough discussion. These included: low participation rates, post-interlock recidivism, program duration, enhancing participation, failure to reinstate, and predictors of success/failure. In the interests of exploring the frontiers of interlock programs, it was decided that a discussion of these issues would be most beneficial within the context of using interlocks as part of a licence reinstatement program. The main points of discussion are summarized below. Low participation rates. Participation in voluntary programs is typically very low about 10% of DWI offenders elect to participate. The incentive for participation is often a reduction in the length of licence suspension. The fact that so few offenders participate in the program suggests that the benefits of participation (e.g., ability to drive legally) do not compensate for the disincentives (e.g., cost, inconvenience). Failure to reinstate. For many years, licensing authorities used suspension as last resort in driver improvement programs. This approach was based on the assumption that drivers valued their driver s licence would actively seek to have it reinstated. Recent evidence indicates that many DWI offenders never become reinstated. The longer the suspension the lower the likelihood the offender will seek reinstatement. Many of these individuals continue to drive under suspension. More needs to be done to understand the reasons for failure to reinstate. Having DWI offenders enter an interlock program as soon as possible after conviction would help ensure offenders drove legally and only when sober. It would also keep them under the supervision and control of licensing authorities. Enhancing participation rates. Most interlock programs operate on a voluntary basis. Those who choose to participate are often highly motivated to have their driving privileges reinstated. Offenders who are ordered to participate in the interlock program often do so reluctantly. Nevertheless, even compulsory participation results in lower recidivism during the interlock period. Serious consideration needs to be given to the further use of mandatory programs e.g., participation as a condition of licence reinstatement as a means to enhance participation in interlock programs. Eligibility. In light of the demonstrated success of interlock programs to prevent repeat DWI offences while offenders are participating in the program, it would be beneficial to have as many DWI offenders as possible participate. Offenders deemed most at risk for recidivism should not be systematically excluded from participation. Every effort should be made to ensure that they participate in the program. Judicial versus administrative authority. Interlock programs operated under the authority of the driver licensing administration use relicensing as the incentive for participation. Failure to participate as required results in continued suspension. Programs operated under judicial authority have the power to impose further sanctions for failure to participate. This approach, however, depends on a motivated judiciary and a strong probation system. Each approach has strengths and limitations. It may be possible to develop a program that includes the best features of both administrative and judicial systems. Post-interlock recidivism. Evaluations of interlock programs have repeatedly found that DWI recidivism increases once participants complete the program. A variety of strategies were discussed to deal with this issue e.g., incorporating rehabilitation into

29 interlock programs, extending the duration of interlock programs, intensive supervision of participants, altering the criteria for program completion. Program duration. Current interlock programs are usually of fixed duration. At the end of the designated period, participants can leave the program and become fully reinstated drivers. The risk of recidivism increases following the completion of the interlock program. Some have suggested that extending the duration of the interlock program would be beneficial; others argue that this might simply delay the increase in recidivism. Predicting interlock success. An alternative to simply extending the duration of the interlock program is to use the data collected by the interlock device to determine the subsequent risk of recidivism for each participant. It may be advantageous and desirable to use these data to determine the length of the interlock program on an individual basis shorter for low risk participants and longer for those deemed to be at higher risk. Participants identified as being at high risk of recidivism could be maintained on the interlock program until such time as they demonstrate their control over their alcohol problem and/or their ability to make good decisions regarding driving after drinking. This approach essentially requires participants to demonstrate they no longer need the interlock in order to complete their participation in the program. Length of hard suspension. Many jurisdictions require DWI offenders to serve at least a minimum period of hard suspension before being eligible for the interlock program. The length of this suspension period needs to be examined in light of the prevalence of failure to reinstate and the likelihood of recidivism during the period of suspension. Early interlock participation is probably better than later. Using interlock programs as part of licence reinstatement programs may enhance the beneficial effects of interlock programs by increasing participation rates. There are, however, numerous issues that remain to be resolved through experience, monitoring, discussion and evaluation. Discussion Following years of research, development, and field experience, alcohol interlock programs have come of age. State of the art technology has been employed to create a system that is able to reliably identify individuals who have consumed too much alcohol and prevent them from operating the vehicle in which it is installed. A variety of systems have been incorporated into the device to prevent virtually all attempts at circumventing the interlock device. Experience with interlocks over the past decade or so indicates that they perform exceptionally well and do the job for which they were intended i.e., to prevent those with elevated BACs from operating the vehicle in which it is installed. As interlock programs proliferate and ever-increasing numbers of DWI offenders participate, there are many issues that will have to be dealt with. The purpose of the two workshops was to bring together a group of people familiar with interlock programs to identify some of the major issues facing interlock programs and to discuss potential solutions. Most of these issues do not involve the interlock device itself but, rather, involve the administrative aspects of interlock programs e.g., when to install, duration of program participation, incentives to participate, failure to reinstate. The resolution of these issues will take time and effort. Nevertheless, it is important that we continue to monitor interlock programs, assess progress, and evaluate their impact

30 References 1. Beirness, D.J Best Practices for Alcohol Interlock Programs. Ottawa: Traffic Injury Research Foundation

31 Feasibility Study on Ignition Interlocks in Finland Kärki, O.V. The Finnish Road Administration/Vaasa Region, P.O.Box 93, Vaasa, Finland (Until May 2002: VTT Building and Transport, P.O.Box 1800, Espoo, Finland) Keywords Ignition Interlock, drunken driving, BAC, DUI offenders, Finland, experimentation Abstract The objective of the study was to assess the possibilities of using an ignition interlock in tackling drink-driving and of further implementing a field trial on interlocks in Finland. The following aspects were considered in the study: target groups, legal and technical requirements, acceptance, costs and accident reduction potential. It was suggested that a field trial on the interlocks for DUI (driving under the influence of alcohol) offenders be conducted. The target group for the prospective field trial would comprise DUI offenders who have had a provisional driving licence suspension. The field trial would be voluntary-based and user-paid. A law should be introduced to enable the use of a vehicle equipped with an interlock inside the borders of Finland for a 3-year, fixed-term probationary period. The interlock usage-time would correspond with the original driving suspension. It was estimated that fewer than 10 % of firsttime aggravated DUI offenders or recidivists would volunteer for the trial. Recidivists would benefit most from the interlock use. It was estimated that a 3-year field trial, with 50 DUI recidivists participating at a time, would prevent at least one personal injury and over driving-kilometres over 0.5 BAC (blood alcohol concentration). Introduction Alcohol is one of the major contributory factors to road traffic accidents, and in particular, to accidents with severe consequences. Even though the number of drunken drivers, with a BAC over the Finnish legal limit of 0.5 g/l, in the traffic flow has shown a slight decreasing trend (currently less than 0.2 %), the percentage of alcohol-related accidents (with a BAC of over 0.5 g/l) of all fatal motor vehicle accidents in Finland has remained at over the 25 % level (Mäkinen & Veijalainen 1997). However, the number of drunken drivers in the traffic flow in the lowerclass roads is considerably higher. In Finland the proportion of aggravated DUI offenders (BAC over 1.2 g/l) in the traffic flow is usually at least 50 %, and this group is involved in over 80 % of fatal DUI accidents. An average driving licence suspension period after first DUI offence is five months. Aggravated DUI offenders and recidivists usually get eight months licence suspension periods. A driving licence is not given to persons dependent on alcohol. Almost 50 % of DUI offenders have previous DUI offences in Finland; on top of that, this share near the capital Helsinki is over 50 %

32 Traffic regulations permitting random roadside breath tests and a support of DUI enforcement campaigns have deterred an increase in drunken driving in Finland. This will not necessarily be the case in the future, owing to steadily increasing alcohol consumption and the deregulation of strict Finnish alcohol-pricing policy that will come into effect in 2003 and 2004 with European Union regulations. The long-term traffic safety objectives require some 30 % reduction of road traffic fatalities in Finland in the next ten years. This aim requires also a reduction of alcoholrelated fatalities in traffic. One of the means recommended by the advisory board of traffic safety matters in Finland in the late 1990s was implementing an ignition interlock programme in Finland. The Technical Research Centre of Finland (VTT) studied possibilities of implementing a pilot alcohol interlock programme in Finland. The project was supervised and financed by a group comprising members from the Ministry of Transport and Communications, the Ministry of Justice, the Central Motor-Vehicle Register and the Finnish Motor Insurers Centre. Simultaneously with this study, VTT participated in a feasibility study on the interlocks in the EU context. This paper concentrates on the Finnish feasibility study. Methods The Finnish feasibility study on the interlocks was designed to help determine whether a field trial on the interlocks and further interlock programmes are feasible in Finland. At first, a literature study of the development and the current state of the art of the interlocks and the interlock programmes was carried out. Several interlock studies (Baker et al. 1997, Marques et al. 2000, Beirness 2001, etc.) were reviewed. In addition to the project s supervisory group, experts from the police and National Public Health Institute were consulted. The project benefited also from the Swedish ignition interlock programme. A questionnaire survey of drunken driving offenders was conducted in co-operation with five police districts of Finland. The objective of the questionnaire was to determine the acceptance of voluntary interlock use as an alternative to a driving ban among DUI recidivists. Furthermore, the willingness to pay for the interlock use was investigated to determine whether interlock use combined with rehabilitation would be feasible in Finland. Recommendations for the prospective field trial on the interlocks were given by VTT with the assistance of the project s supervisory group. The technical solutions and standards of the interlocks were compared by means of a literature study and expert interviews. European Union legislation was utilised in technical matters as well as in alcohol-dependence matters. The effects of the interlock use on traffic safety were estimated on the basis of expected changes in the proportion of vehicle-kilometres driven under the influence of alcohol. Rough estimates of cost-effectiveness of interlock use were also made

33 Results The questionnaire Some 200 answers were expected to the questionnaire survey, but only 99 DUI offenders answered. The questionnaire was mostly aimed at recidivists (29 answers) and first-time aggravated DUI offenders (45 answers). The main results showed that every fifth respondent would pay at least 168 a month for one year for being allowed to drive with a vehicle equipped with an interlock instead of driving licence revocation. 168 a month was estimated to be the monthly fee for participating in an interlock programme with rehabilitation. Some 40 % of the respondents would pay at least 70 a month, which was estimated to be the minimum monthly fee for interlock use without rehabilitation. Over half of the offenders would not take an interlock. Furthermore, the results showed that those DUI offenders whose households have monthly gross income over 2520 would be more willing to pay for interlock use than those with a lower income (χ 2 : df = 1, p < 0.05), (Figure 1). However, some offenders whose monthly gross income is less than 840 expressed their willingness to pay for the interlock use. Owing to low income, their ability to pay for the interlock use is questionable. Figure 1: Willingness to pay ( /month for one year) for interlock use according to monthly income of the households of DUI offenders 70 % /month /month < 50 /month 0 /month Would not take an interlock 0 < > 2520 gross income/household ( /month) There were indications that recidivists would be more willing to pay for interlock use than firsttime aggravated DUI offenders. However, this finding is not significant because of the small sample. On the basis of the results from the questionnaire and several user-paid interlock programmes, it was estimated that under 10 % of DUI offenders in Finland would pay some 80 a month for interlock use for the period their licence would be suspended because of a DUI offence, on average 5 to 8 months

34 Effects of the interlock on traffic safety Many studies have indicated that the interlocks effectively prevent drunken driving during the period of interlock installation. Once the interlock is removed from the vehicle, the recidivism rates tend to increase again to the level prior to interlock use. Despite several studies of the effects of the interlock on recidivism, there are not many studies about the effects of the interlock on crash-rates or severe accidents. At least preliminary results from the interlock programme in Quebec, Canada (Dussault & Gendreau 2000) indicated that both casualty crashes and property damage only crashes decreased significantly, both during the interlock installation period and during a short period after interlock removal. Within the frames of the Finnish feasibility study, some evaluations were made of the effects of the interlock on DUI mileage, personal injuries, and fatalities in Finland. The main calculations, which include interlock use by DUI recidivists only, are presented in Table 1. Cost-effectiveness of interlock use 2 50 interlocks for 6 months (50 interlocks at a time for a year): Costs savings because of accident reductions: (cost of a fatality) (cost of a personal injury) = Costs of the 6 months interlock use to users: = Cost effectiveness (other costs than cost to interlock users are not taken into account): / = 3.0 Recommendations for a field trial on the interlocks in Finland VTT and the project s supervisory group recommended that a field trial on the interlocks for DUI offenders be conducted. A law should be introduced to enable the use of a vehicle equipped with an interlock inside the borders of Finland for a three-year, fixed-term probationary period. The interlock usage-time would correspond with the original driving suspension. DUI offenders who have had a provisional driving licence suspension enforced by the police would be able to participate. Drug users and those dependent on alcohol would be excluded. No hard suspension would be required. The field trial would be voluntary-based and user-paid. It was recommended that the prospective field trial be administrated by the Central Motor-Vehicle Register. The objectives would be to determine the practical problems of interlock use and the development needs. In addition, the acceptability, cost-effectiveness and public opinion on using interlocks would be measured. Furthermore, requiring interlock use by recidivists as a condition of driving licence reinstatement would be considered, as well as the need for establishing a longterm interlock programme. At the moment the Ministry of Transport and Communications is preparing legislation for the field trial according to the results of the feasibility study. A final decision on implementing the field trial on the interlocks has not been made and more a detailed design is required before implementing the field trial. A decision from the Finnish parliament on the field trial is also required

35 Table 1: Evaluations of the effects of the interlock on DUI mileage, personal injuries and fatalities in Finland. Interlock use by DUI recidivists only is included in the calculations Basic data Assumptions Calculations Variable label and explanation Annual number of DUI offences by recidivists Proportion of recidivists who repeat their offence within a year Annual number of recidivists caught for DUI Annual number of fatalities resulting from DUI-accidents involving recidivists, BAC>0.5 Proportion of the total annual number of vehicle kilometres driven by recidivists, BAC>0.5 Total annual number of vehicle kilometres Proportion of recidivists who owned the car they drove when they were involved in fatal accident Number of cars Ratio of personal injuries to fatalities in DUI accidents Proportion of caught recidivists of all recidivists in traffic, BAC>0.5 Ratio of average number of DUI kilometres of recidivists suspended for DUI to that of all recidivists in traffic not suspended Interlock would prevent 70 % of DUI kilometres compared to driving licence suspension Average annual number of vehicle kilometres per car (= Tkm/Nc) Actual annual number of recidivists in traffic, BAC>0.5 (=RA/Prt) Annual number of vehicle kilometres driven by all recidivists when drunk, BAC>0.5 (=Tkm*Rp) Proportion all recidivists' total vehicle kilometres driven when drunk (BAC > 0.5), (=Rdkm/(Ra*Ckm)) Average annual number of DUI kilometres driven by recidivists not caught for DUI [=Rdkm/(2RA+(Ra-RA)) = Rdkm/(RA+Ra)] Average annual number of DUI kilometres driven by recidivists suspended for DUI (=Rkm*Ncdkm) Maximum number of fatalities preventable by alcohol interlocks (=RF*RO) Number of annual DUI kilometres preventable by 2*50 interlocks, a period of 6 months per recidivist (2*50*(6/12)*Wpkm*Sdkm)Proportion of annually preventable DUI kilometres of all DUI kilometres by recidivists (=Pkm/Rdkm) Number of annually prevented fatalities when 50 interlocks are in use (=RFP*Ikm) Number of annually prevented personal injuries when 50 interlocks are in use (=RFP*Ikm) Variable name Re RY RA RF Rp Tkm RO Nc Rpf Prt Rkm Wpkm Ckm Ra Rdkm Pr Ncdkm Sdkm RFP Pkm Lkm PF PPI Value * Discussion On the basis of the results of the questionnaire and many voluntary interlock programmes, the acceptability of the interlock is high enough to enable a small-scale field trial on the interlocks in Finland. Despite relatively short driving suspensions for DUI offences in Finland, implementing a field trial on the interlocks was recommended. It should be noted that changing the average lengths of driving suspensions because of the field trial on the interlocks is not possible. Other countermeasures, like rehabilitation only, are considered before making a decision on a field trial on the interlocks

36 In March 2002, it seems that a field trial on the interlocks will be implemented in Finland, provided that parliament accepts it. Encouraging results from foreign studies have been one factor to encourage the Ministry of Transport and Communications preparing legislation for the field trial. It may be difficult to make final conclusions of the suitability of the interlock to Finland according to the prospective field trial. However, many practical problems will probably be solved by implementing the interlock gradually, step by step. There is a clear need to fight drunk-driving also by technical means in Finland. References 1. Kärki, O Alkolukko rattijuopumuksen ehkäisyssä. Esiselvitys. [Breath alcohol ignition interlock device. Feasibility study]. Technical Research Centre of Finland. Espoo Research Notes p. + app. 2. Mäkinen, T. & Veijalainen, T Drunk-driving reduced by half in Finland. International Conference: Traffic Safety on Two Continents. Lisbon, PT, Sept Traffic Safety. Lisbon (1997) No: 23/9, 10 p 3. Baker, E., Rauch, W. & Beck, K Ignition Interlock Program Lowers Re-arrest Rate in Repeat Offencers. News release 23 th April University of Maryland at College Park. 4. Marques, P. R., Tippets, A. S., Voas, R. B. & Beirness, D. J Predictors of failed interlock BAC tests and using failed BAC tests to predict post-interlock repeat DUI's. The 15 th International Conference on Alcohol, Drugs and Traffic Safety, Stockholm, Sweden, May, Beirness, D. J Best Practices for Alcohol Interlock Programs. Traffic Injury Research Foundation. Ottawa, Canada. 6. Dussault & Gendreau Alcohol ignition interlock: One-year s experience in Québec. The 15 th International Conference on Alcohol, Drugs, and Traffic Safety, Stockholm, Sweden, May, Driving licence register of Finland. 8. The Finnish Motor Insurers Centre (VALT) Yhteenveto liikennevahinkojen tutkijalautakuntien tutkimista rattijuopumusonnettomuuksista vuosina p. + 1 app. ISBN

37 Ignition Interlock Laws and Administrative Regulations: Do Legal Constraints Prevent Implementation of Ignition Interlock License Restriction Programs in the United States? Rauch, W.J. 1, Berlin, M.M. 2, Ahlin, E.M. 1, Berlin, P.A. 1 Center for Studies on Alcohol, Westat, Rockville, Maryland, USA, 2 Criminal Justice and Public Safety Programs, Baltimore City Community College, Baltimore, Maryland, USA. Abstract Efforts at reducing the consequences of drinking and driving have met with some success over the last two decades. However, alcohol-impaired driving continues to be a major public health problem. The National Highway Traffic Safety Administration (NHTSA) set an annual goal of no more than 11,000 alcohol-related traffic fatalities by the year Over the past 7 years, the proportion of traffic fatalities involving alcohol has minimally declined (Table 1). In 2000, 40% (N = 16,653) of all traffic fatalities were alcohol related (1). It is clear that NHTSA will not meet its goal without additional countermeasures. Ignition interlocks are a technological countermeasure to alcohol-impaired driving and ignition interlock license restriction programs appear promising as a deterrent to alcohol-impaired driving. However, not all states have laws or administrative regulations allowing interlock use, and widespread utilization of interlocks has not materialized. The current research investigates potential legal barriers to effective ignition interlock implementation in the United States. Table 1: Proportion of Traffic Fatalities Involving Alcohol Year Proportion (%) Source: NHTSA Traffic Safety Facts: Alcohol,

38 Introduction Ignition interlock devices are designed to prevent an alcohol-impaired driver from starting and operating a motor vehicle equipped with the device. The interlock requires a driver to submit a breath sample, which is tested for alcohol concentration before the driver starts a motor vehicle. If the driver provides a breath sample with an alcohol concentration at or above a preset limit, the ignition will not start and will prevent an alcohol-impaired person from driving the vehicle on which the ignition interlock is installed. The device requires that periodic breath tests be submitted after the vehicle is started to prevent a driver from starting the vehicle and then drinking. The interlock also maintains a record of successful and failed breath tests. Interlocks bypass the motivational aspects of deterrence-based and educational approaches and remove the offender s ability to choose to drive while impaired by alcohol. The license restriction portion of the interlock license restriction program means that drivers are approved for license reinstatement on the condition that they agree to a license restriction prohibiting them from operating a vehicle without an ignition interlock device. The conditional interlock license restriction is prominently displayed on the driver's license of each participant in the program whether or not participants own a vehicle titled in their name. In the most scientifically valid evaluation of an ignition interlock license restriction program, a completely randomized trial of ignition interlock license restrictions in Maryland concluded that the ignition interlock license restriction program reduced the risk of an alcohol-related traffic arrest during the 1-year program by about 64 percent. During years 2, 3 and 4, when the ignition interlock license restrictions were removed, the alcohol-related traffic recidivism rates of the interlock and control groups converged and were not statistically significantly different (2-4). While ignition interlock license restriction programs appear promising as a deterrent to drinking and driving, not all states have laws or administrative regulations allowing their use. The purpose of this study was to determine current interlock use in the United States; evaluate and assess applicable Federal constitutional, state statutory, case law and administrative rules and regulations to identify potential legal constraints preventing effective implementation of ignition interlock programs; and summarize similarities in current state law and administrative regulations. Methods We conducted a telephone survey of interlock use by state and a legal review to determine current interlock use and potential legal barriers to the implementation of ignition interlock license restriction programs in the United States. Primary sources for the Federal constitutional legal review included U.S. Reports, The U.S. Code Annotated (U.S.C.A.), the Code of Federal Regulations (C.F.R.), West s Supreme Court Reporter, Federal Reporter and Federal Supplement and Federal Digest. Applicable state statutory, case and constitutional law and administrative rules and regulations were reviewed using annotated state codes, state case law and compendiums of state administrative rules and regulations and West s Regional and State Reporters and Digests. These resources were supplemented with relevant American Law Reports (A.L.R.), law reviews and legal periodicals. Electronic resources used included Westlaw, Lexis and Nexis

39 The legal review focused on constitutional (both judicial and administrative) issues that might be preventing effective interlock use. These issues included procedural due process, substantive due process, equal protection, privileges and immunities, excessive fines, double jeopardy and state civil liability concerns under the doctrine of sovereign immunity. Based on the legal review, we summarized similarities in current state law and administrative regulations as a function of interlock use to determine what laws and/or administrative regulations appear most favorable to the use of interlocks. The research question of interest is, given what is known about the efficacy of interlocks and the effectiveness of ignition interlock license restriction programs, why are so few interlocks in use? Our focus is on potential legal constraints on the imposition of ignition interlock license restriction programs. Results Forty-nine states and the District of Columbia took part in the telephone survey. As of September 2001, approximately 65,000 interlocks were in use in the United States. This is almost double the 35,000 interlocks reported to be in use in 1998 (5). This 65,000 pales in comparison to the 1.47 million drinking and driving arrests reported in 2000 (6). Forty-two states and the District of Columbia have statutes and/or administrative regulations providing for the use of interlock devices on vehicles operated by drivers who have been convicted of a first, second or subsequent alcohol-related traffic offense (Figure 1)

40 Figure 1: States Authorizing Use of Ignition Interlocks as of September 2001 States Authorizing Use of Ignition Interlocks Although courts have, on rare occasions, ruled ignition interlock programs (or pilot programs) unconstitutional at the trial level, all such decisions were reversed on appeal. Given that ignition interlocks bear a rational relationship to highway safety, a legitimate state interest, and that no suspect class is involved (i.e., race, religion or country of origin), the imposition of ignition interlocks has almost invariably been held to be constitutional provided that appropriate procedural safeguards are in place. The legal review concluded that the use of ignition interlocks under appropriate conditions typically does not violate the Fifth, Eighth or Fourteenth Amendment to the United States Constitution. Double jeopardy and excessive fines do not raise insurmountable constitutional concerns. Double jeopardy addresses the question of whether the imposition of an interlock device in an administrative setting precludes a court from pursuing a criminal action. Based on a series of court cases in Maryland and elsewhere, the answer is clearly no. State courts of appeals have ruled that a state can pursue an administrative remedy at the same time it is pursuing a conviction for a criminal offense. The excessive fines clause of the Eighth Amendment to the Constitution does not prohibit the implementation of interlocks. Although the cost of an interlock is not insignificant, this cost does not necessarily rise to the level of an excessive fine or significant deprivation provided that an indigent fund is available for offenders needing monetary assistance. Establishment of an indigent fund would address constitutional issues surrounding the poor, who are not considered to be a suspect class

41 Procedural due process (which included privileges and immunities for purposes of this review) addresses the issue of the type of trial or hearing process to which a defendant is entitled. The right to due process applies if a significant life, liberty or property interest is at stake. Courts have consistently held that there is a property interest in a driver s license, but less so if the license has already been suspended or revoked. Provision for judicial and/or administrative hearings prior to the imposition of ignition interlocks would certainly appear to satisfy constitutional procedural due process concerns. Substantive due process addresses the issue of whether the imposition of an interlock device violates (by state action, statute or rule) a fundamental constitutional guarantee. Absent a suspect class (i.e., race, religion or country of origin), courts generally interpret substantive due process in light of a rational basis test. That is, if the statute, administrative rule or state action pursues a valid government purpose and is applied appropriately, it is constitutional. Since states have a legitimate interest in highway safety, substantive due process is not a barrier to the implementation of ignition interlock license restriction programs. Current ignition interlock statutes and administrative regulations were grouped into four mutually exclusive categories based on the legal review. The four categories, as well as the number of states in each category and the category s proportion of interlock market share are as follows: (I) No Interlock Statutes or Administrative Regulations (8 states; 0.3%); (II) Administrative Regulations Authorizing Interlocks in an Administrative Setting Only (6 states; 10.8%); (III) Statutes Authorizing Interlocks in a Judicial Setting Only (23 states; 53.3%); and (IV) Statutes or Administrative Regulations Authorizing Interlocks in Both a Judicial Setting and an Administrative Setting (14 states; 35.6%)

42 Category I: No Interlock Statutes or Administrative Regulations* Alabama Hawaii Massachusetts Vermont Connecticut Maine South Dakota Wyoming * Courts or administrative agencies may, on occasion, order the imposition of ignition interlocks in the absence of specific statutory or administrative authority. Category II: Administrative Regulations Authorizing Interlocks in an Administrative Setting Only Colorado Kansas Minnesota District of Columbia Michigan West Virginia Category III: Statutes Authorizing Interlocks in a Judicial Setting Only Alaska Mississippi New Jersey Tennessee Arizona Missouri North Carolina Texas Idaho Montana Ohio Utah Indiana Nebraska Pennsylvania Washington Kentucky Nevada Rhode Island Wisconsin Louisiana New Hampshire South Carolina Category IV: Statutes or Administrative Regulations Authorizing Interlocks in Both a Judicial Setting and an Administrative Setting Arkansas Georgia New Mexico Oklahoma California Illinois New York Oregon Delaware Iowa North Dakota Virginia Florida Maryland Discussion Interlock use has doubled in the last 3 years, but it is still minuscule compared to the drinking and driving problem. There appear to be no significant legal barriers to implementation of ignition interlock license restriction programs provided that an indigent fund is available. Based on constitutional considerations, we find that laws and administrative regulations setting forth conditions for the imposition of interlocks tend to be adjudicated more favorably in administrative settings, even though 53.3% of ignition interlocks in use in the United States as of September 2001 were authorized in a judicial setting. Statutes authorizing interlocks in a judicial setting can be discretionary, mandatory or both. Based on our review and a forced classification of statutes and administrative regulations into mutually exclusive categories, legislative sentiment appears to favor judicial imposition of interlocks over administrative programs. Given that courts in the real world tend to emphasize individual sentencing (which circumvents

43 widespread interlock use because mandatory does not equal mandatory in a judicial setting), administrative ignition interlock license restriction programs appear more promising from a legal and practical perspective and should be expanded. This study did not find any significant legal barriers to the widespread use of interlocks. In fact, the climate in many states supports implementation of ignition interlock license restriction programs, especially at the administrative level. Although the use of interlocks in the United States has almost doubled since 1998, their use is still limited. Further research is needed to determine why widespread use of interlocks has not materialized. Acknowledgements This research was supported in part by Grant R01 AA11897 from the National Institute on Alcohol Abuse and Alcoholism and Contract DTNH22-97-C from the National Highway Traffic Safety Administration. The authors gratefully acknowledge the valuable assistance of Dr. James F. Frank and Steven Hatos, Esquire, of the National Highway Traffic Safety Administration and Dr. Herbert M. Baum of the Center for Studies on Alcohol at Westat for their contributions to this research. References 1. National Highway Traffic Safety Administration. Traffic safety facts 2000: Alcohol. National Highway Traffic Safety Administration, Washington (DC) 2001, DOT HS Beck KH, Rauch WJ, Baker EA, Williams AF. Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: A randomized trial in Maryland. Am J Pub Health 1999; 89(11): Rauch WJ, Zador PL, Beck KH, Ahlin EM. Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: Third year follow-up of a randomized trial in Maryland. Presented at Alcohol Policy XII, National Crime Prevention Council, Washington (DC), Rauch WJ, Zador PL, Ahlin EM, Beck KH, et al. Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: Fourth year follow-up of a randomized trial in Maryland. Alcohol Clin Exp Res 2001; 25(5):100A. 5. Rauch WJ. A review of state ignition interlock laws, administrative regulations and policy practices. Presented at the 126 th Annual Meeting of the American Public Health Association. Washington (DC), Federal Bureau of Investigation. Crime in the United States 2000 Uniform Crime Reports. U.S. Department of Justice, Washington (DC),

44

45 A Longitudinal Survival Analysis of Drivers with Multiple Alcohol-Related Traffic Offenses: Fifth Year Follow-Up of a Randomized Ignition Interlock License Restriction Trial in Maryland W.J. Rauch 1, P.L. Zador 1, E.M. Ahlin 1, H.M. Baum 1, D. Duncan 1, K.H. Beck 2, R. Raleigh 3, J. Joyce 3 and N. Gretsinger 3 1 Center for Studies on Alcohol, Westat, Rockville, Maryland, USA, 2 Department of Public and Community Health, University of Maryland, College Park, Maryland, USA, 3 Maryland Motor Vehicle Administration, Glen Burnie, Maryland, USA. Abstract Alcohol-impaired driving continues to be a major public health problem in the United States. During 2000, alcohol was involved in 40% of all traffic fatalities (1). One promising countermeasure to alcohol-impaired driving is the ignition interlock license restriction program. Ignition interlock devices are designed to prevent an alcohol-impaired driver from starting and operating a motor vehicle. License restriction means that drivers are approved for license reinstatement on the condition that they agree to a license restriction prohibiting them from operating a vehicle without an ignition interlock device. The conditional interlock license restriction is prominently displayed on the driver s license of each program participant. Ignition interlock license restrictions have shown potential for reducing recidivism among drivers with multiple alcohol-related traffic offenses (2). Later analyses of this same cohort examined recidivism rates 3 and 4 years after study entry (3, 4). In the current paper, new recidivism rates for the one year interlock license restriction program and second (i.e., first year post-interlock) through fifth year (i.e., fourth year post-interlock) of follow-up are presented using newly developed electronic data abstraction methods. There was no statistically significant difference in the recidivism rates for the interlock license restriction (4.0%) and control groups (4.8%) in the fifth year after study entry. Introduction A statewide-randomized trial of ignition interlock license restrictions was performed in Maryland and the results of that program evaluation were reported in the American Journal of Public Health (2). Participants were 1,387 drivers with multiple alcohol-related traffic offenses whose driver s licenses were either suspended or revoked for multiple alcohol offenses and who were eligible for license reinstatement after undergoing a variety of treatment programs. Drivers were randomly assigned to participate in an ignition interlock license restriction program or the usual postlicensure treatment program (control group) lasting 12 months (2-4). Figure 1 shows the geographic distribution of participants by zip code. Participants in the interlock program had a

46 restriction on their drivers licenses indicating they could drive only a vehicle equipped with an ignition interlock. Drivers who owned a car had to have the device installed within 45 days; those who did not own a car had to sign a waiver that they would not drive a car unless it was equipped with an interlock. The interlock license restriction and customary treatment programs were administered by the MVA rather than the courts. This approach ensured greater consistency of case management and handling of license restrictions and allowed the MVA to monitor and enforce compliance with the license restrictions. Figure 1: Sample Distribution by Zip Code The initial results in this cohort (2) were reproduced using a more standardized data abstraction method (3, 4). Although the recidivism rates for both the interlock and control groups were higher than those in the initial report, the analysis confirmed the earlier results. The current study differs from the previous analyses by using a standardized electronic data abstraction method, counting alcohol-related violations rather than arrests, and including all alcohol-related recidivism events by a repeat offender (i.e., not just the first event) in the analysis. All data reported in this paper uses the revised methodology. The purpose of the current study was to determine the effectiveness of the ignition interlock license restriction program in reducing alcohol-related traffic recidivism 5 years after program implementation (i.e., in the fourth year after the ignition interlock license restriction program ended). In particular, we were interested in determining whether the convergence in alcoholrelated traffic recidivism between the interlock and control groups, observed during the second, third and fourth years, would be maintained during the fifth year. We were also interested in determining whether the recidivism rates of interlock and control group participants would increase significantly beyond the levels observed during the first 4 years

47 Methods Data for this study were provided electronically by the Maryland Motor Vehicle Administration (MVA) after personal identifying information had been deleted from drivers records. Data from this file were matched to our earlier data file, an Access database into which data had been manually abstracted and double key-entered. We then compared the recidivism rates calculated using the electronic and manual abstraction methods. The differences were minor and did not change any of the conclusions previously reported. An additional manual comparison of violation codes revealed no systematic biases. We also used alcohol-related violations rather than arrests, and included all alcohol-related recidivism events by a repeat offender (i.e., not just the first event) in the analysis. Given the randomized nature of the design, all participants assigned to the interlock condition were included in the analysis whether or not they had the device installed, as appropriate under the intention-to-treat design. Thirty-one drivers died and 43 moved out of state during the study period. There were no statistically significant differences between the interlock and control groups in the proportions of drivers who died (Chi-Square = 0.90, d.f. = 4, p = 0.92) or moved out of state (Chi-Square = 7.37, d.f. = 4, p = 0.12). The analysis did not control for drivers who died or moved out of state during the study period, which may result in a slight overestimation of survival rates. Results During the first year of the study, 26 of 693 offenders in the interlock license restriction program (3.8%) and 62 of 692 offenders in the control group (9.0%) committed an alcohol-related traffic violation. This difference was statistically significant, with a relative risk of 0.40 (95% CI 0.25, 0.63). Being in the interlock program reduced a driver s risk of committing an alcohol-related traffic violation by about 60 percent. During the second year, when the ignition interlock license restrictions were removed, the alcohol-related traffic recidivism rates for anyone recidivating in year 2 in the two groups converged and were not statistically significantly different. During the second year, the ignition interlock group had a slightly lower recidivism rate than the control group (6.9% vs. 8.1%), although the recidivism rates of the two groups were not statistically significantly different. During year 3, the rates were higher for the interlock group (7.8%) than for the control group (6.5%) but the difference was not statistically significant. In year 4, the rates were also higher for the interlock group (8.8%) than for the control group (7.1%) but the difference was not statistically significant. Thus, the reduction in alcohol-related traffic recidivism for the interlock group was limited to the first year of the program, when the interlock license restriction program was in effect, and there was no evidence that the first-year benefits extended into subsequent years. Being in the interlock license restriction program significantly reduced a driver s risk of committing an alcohol-related traffic violation by about 60 percent during the first year when the program was in effect (Chi-Square = 15.78, d.f. = 1, p < ). Contrary to first year findings, second, third, fourth, and fifth year recidivism rates of drivers in the interlock program and standard treatment (control) group converged and were not statistically significantly different (Table 1)

48 Table 1: Recidivism Rates in the Interlock (n = 693) and Control Groups (n = 692) by Year of Follow-Up, Using Electronic Abstraction and Replacement Year Interlock Control Year 1 * Year Year Year Year *Chi-Square = 15.78, d.f. = 1, p < Not statistically significant (95% Confidence) During year 5, 4.0% of the 693 drivers in the interlock group (n = 28) and 4.8% of the 692 drivers in the control group (n = 33) recidivated (Table 2). This difference was not statistically significant (Chi-Square = 0.44, d.f. = 1, p = 0.51). After 4 years of increasing recidivism rates in the interlock group, the rates for year 5 are much lower for both the interlock and control groups. Table 2: Recidivism Among Drivers in the Interlock and Control Groups at the Fifth-Year Follow-up Group Drivers (N) Drivers with Violation in Year 5 % of N + Interlock Control Total 1, Chi-Square = 0.44, d.f. = 1, p = 0.51; not statistically significant Figure 2 displays cumulative survival curves for the 5-year study period for all drivers who committed an alcohol-related traffic violation, including drivers with a prior alcohol-related traffic offense during years 1, 2, 3, and/or 4. It should be noted that at the time of randomization there were no statistically significant differences in the number of previous alcohol-related traffic violations between the interlock group (mean = 3.66, SD = 1.45) and the control group (mean = 3.65, SD = 1.28). Five year survival effect of the interlock license restriction program was also analyzed using an Anderson-Gill Multiplicative Hazards Model, stratified on year. The interlock license restriction program was found to reduce the hazard ratio by about 12 percent. However, this reduction was not statistically significant (Chi-Square = 2.24, d.f. = 1, p = 0.135). In addition to overall recidivism rates, we also examined first-time recidivism (i.e., drivers who did not recidivate in years 1, 2, 3 and 4) among drivers in the interlock and control groups during year 5. Four percent of drivers in the interlock group (n = 21) and 4.5% of drivers in the control group (n = 23) recidivated for the first time since study enrollment during year 5 (Table 3). There were no statistically significant differences between interlock and control group drivers who

49 recidivated for the first time during year five (Chi-Square = 0.15, d.f. = 1, p= 0.70). The positive effects of the interlock program do not extend over the 5-year period of study. At the end of 5 years, the overall effects of the interlock license restriction program are not statistically significant (Chi-Square = 0.63, d.f. = 1, p = 0.43). Figure 2: Survival Until Recidivism, Years 1-5 Table 3: First-Time Recidivism Among Drivers in the Interlock and Control Groups During the Fifth-Year of Follow-up Group Drivers (N) Drivers Without Violation in Years 1-4 (N) % of N Drivers with 1 st Offense in Year 5 % of N + Interlock Control Total 1,385 1, Chi-Square = 0.15, d.f. = 1, p = 0.70; not statistically significant Discussion The positive effects of the ignition interlock license restriction program were limited to the first year, when the program was in effect. There is no evidence that the benefits of this program extended into years 2, 3, 4, and 5 (i.e., 4 years post-interlock), when the rate of alcohol-related traffic violations is essentially the same in both the interlock and control groups. The interlock license restriction program clearly reduced recidivism among this cohort of persistent drinking drivers during the one-year program. It is also equally clear that a one-year interlock license restriction program is not sufficient to alter drinking driving behavior once the program has ended. For persistent drinking drivers, interlock license restriction programs need to be maintained for longer than 12 months. Research suggests that having a high number of failed breath tests as recorded by the interlock datalogger is a predictor of recidivism in the first year

50 after the interlock is removed from the vehicle (5, 6). Individuals who have a high number of failed breath tests during an interlock program may need to remain in an interlock license restriction program until they learn to separate drinking from driving. The lower recidivism rates in both the interlock (4.0%) and control (4.8%) groups during year 5 may be explained by the fact that violations (not arrests) were used for this analysis. It can take more than a year before a defendant even appears in court, and there is an additional lag time before the final judicial outcomes appear on the driver record. Further research is needed to investigate why recidivism rates declined in year 5. Ignition interlock license restrictions, like license revocation, are not a foolproof system for preventing alcohol-impaired driving. They do not prevent a driver from operating a vehicle that is not equipped with an ignition interlock, just as a license revocation cannot prevent a driver from driving with a revoked license. However, like license revocation, an interlock license restriction program may lead restricted drivers in unequipped vehicles to drive fewer miles and to drive more conservatively as a result of the interlock license restriction. This study provides evidence regarding the long-term convergence of alcohol-related traffic recidivism in the two groups of interest. It is encouraging that the risk of an alcohol-related traffic violation was substantially lower (60%) for multiple offenders assigned to the interlock license restriction program during the 12 months the program was in effect. Once the interlock license restriction was removed, recidivism rates converged. This suggests that for certain chronic alcohol-related traffic offenders, interlock license restrictions may have to be maintained longer than 12 months and perhaps indefinitely. Acknowledgement This study was funded in part by Grant R01 AA11897 from the National Institute on Alcohol Abuse and Alcoholism. References 1. National Highway Traffic Safety Administration. Traffic safety facts 2000: Alcohol. National Highway Traffic Safety Administration, Washington (DC) 2001, DOT HS Beck KH, Rauch WJ, Baker EA, Williams AF. Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: A randomized trial in Maryland. Am J Pub Health 1999; 89(11): Rauch WJ, Zador PL, Beck KH, Ahlin EM. Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: Third year follow-up of a randomized trial in Maryland. Presented at Alcohol Policy XII, National Crime Prevention Council, Washington (DC), Rauch WJ, Zador PL, Ahlin EM, Beck KH, et al. Effects of ignition interlock license restrictions on drivers with multiple alcohol offenses: Fourth year follow-up of a randomized trial in Maryland. Alcohol Clin Exp Res 2001; 25(5):100A. 5. Marques, PR, Tippetts, AS, Voas, RB, Beirness, DJ. Predicting repeat DUI offenses with the alcohol interlock recorder. Accid Anal Prev 2001; 33(5): Marques, PR, Voas, RB, Tippetts, AS, Beirness, DJ. Behavioral Monitoring of DUI offenders with the alcohol interlock recorder. Addiction 1999; 94(12):

51 During Alcohol Interlock Use, Elevated BACs in Morning or Declining Vehicle Use Over Time Predicts Post-Interlock Recidivism P.R Marques, A.S. Tippetts, R.B. Voas Pacific Institute for Research and Evaluation Calverton, MD USA Abstract The alcohol interlock record is the first extensive behavioral record that has ever been available to help researchers understand DWI offenders. The average interlock device in Alberta Canada logs over 2300 breath tests during an average 9 months of interlock use. Analysis of the patterns of violations makes available new predictive information for scaling driver risk. Recent work (Marques et al., 2001, Marques et al., 2002) has shown the overall rate of elevated BAC tests during the first several months of use strongly predicts repeat DWI after the interlock has been removed. This report further analyzes the record of 5.5 million BAC tests in Alberta and finds that even after accounting for strong predictors of post-interlock recidivism such as prior repeat DWI and the overall prediction based on higher rates of failed interlock BAC tests, if the BAC tests failures occur in the morning (e.g., BAC still >=.04 gm/dl presumably from previous night drinking) there is an additional 45% higher likelihood of later having a new repeat DWI. Also, evidence is presented that offenders who decrease their overall interlock vehicle use (fewer tests taken over interlock use time) have a higher likelihood of recidivism post-interlock. Introduction Two particularly interesting findings from analysis of the interlock breath test record reported in Marques et al., (1999) warranted further investigation and the results of those analyses are now reported here. Both questions involved the topography of BAC tests logged by interlock users that were warn ( gm/dl) and fail-levels (>.04 gm/dl) during the period they were required to use an interlock. These questions relate to 1) examining time of day when elevated BAC tests are logged, and 2) the pattern elevated BAC tests during the entire period of interlock use. The purpose is to relate distribution of elevated interlock BAC tests to post-interlock recidivism. Daily patterns: are failed morning BAC tests evidence of dependence? The question is whether the time of day when BAC tests are logged at warning or fail violation levels is uniquely predictive of recidivism. In the 1999 paper we reported that the morning workday hours (7-9am), and weekend hours (10-12pm) had the highest frequency of elevated BAC tests. We ve conjectured that the occurrence high BAC at the first startup in the morning might be evidence of greater alcohol problem severity since these BAC tests may reflect alcohol from a previous evening of drinking. Higher alcohol problem severity, as indicated by high

52 consumption and elevated morning BAC, suggests more frequent episodes of impaired driving and possibly more convictions during the post-interlock years. This was considered to be of interest for several reasons but partly because during our intervention study (Marques et al., 2000), counselors reported that offenders, upon learning about the hours required for alcohol clearance from circulation at higher BACs, began to believe their own BAC might really still be elevated in the morning. The initial reaction to failed BAC tests in the early morning was to assume interlock equipment failure, but a discussion of the timeframe for detoxification of ethanol sometimes helped convince the offenders that failure to start the interlock car may have been due to residual BAC. Overall pattern: is there evidence for learning? The 1999 paper reported that, over the period of time that the interlock was used, data aggregated across all interlock users showed that the proportion of all tests taken resulting in BAC>=.02 gm/dl was greatest at the beginning of interlock use and then the violation rate declined over time, giving the appearance of learning curve which was best modeled by a quadratic function. During the period of interlock use, the proportion of all tests that were warns or fails dropped by about 50% (in the aggregate) from beginning to end. Since our finding that the rate of BAC violations logged by the interlock is a strong predictor of later DWI convictions we wanted to know if those who later received repeat offenses deviated from this pattern whether they failed to learn. Did those who lowered the rate of BAC test violations during interlock usage later have a a lower likelihood of receiving a new repeat offenses after the interlock was removed. Is failure to reduce BAC violations evidence of less learning as indicated by future DWI? Methods The detailed methods germane to this study have been reported previously in the three interlock recorder papers referenced above. Procedural detail is not repeated here. Table 1: BAC tests by day of week. Data from 2310 interlock offenders. BAC Interval (gm/dl) Pass test Warn level Fail level.008+ High Fail level Count % Count % Count % Count % SUNDAY % % % % Monday % % % % Tuesday % % % % Wednesday % % % % Thursday % % % % Friday % % % % SATURDAY % % % % Total % % % % Grand total=5,476,638 breath tests Briefly, however, between the years , 2310 convicted DWI offenders in Alberta who had between 0 and 9 prior DWI offenses used an alcohol interlock device for periods of at least 5 months ranging up over 24 months. Half of the subjects were first time offenders. The average period of use was 9 months. After the interlock was removed, 182 additional repeat offenses occurred as of late Yr 2000 representing a variable length post-interlock observation period, representing 9% of the sample. While the interlock was still on the cars, offenders provided

53 nearly 5.5 million breath tests. Only one half of one percent of these are in the warn and fail range (BAC>=.020 gm/dl), but with the large sampling base this represents 22,828 test, an average of approximately 10 elevated BAC results for each of the 2310 interlock users; 7,286 elevated BACs were in the fail range (BAC>=.040 gm/dl). Table 1 shows that the pattern of elevated BACs is highest during the weekends (Saturday, Sunday) even while the actual number of tests taken during the weekend are fewer than those on weekdays (Monday - Friday). Results Does high morning BAC reflect greater problem severity? The data in Figures 1a and 1b show failed BAC tests stacked into two ranges ( and.080+ gm/dl) and broken out by hour of the day that the fail test result occurred. Figure 1a (left) is Monday to Friday, Figure 1b (right) is Saturday and Sunday. The pattern of failed tests differs distinctly between these two periods. On typical working days, Monday-Friday, the morning hours between 6:00-9:00 has the largest number of failed tests. However, this is not because that is the time of the largest number of attempted starts. The largest number of attempted starts is during the hours 16:00-17:00 (not shown). On weekends the largest number of failed BAC tests increases gradually with a peak occurring 10:00-12:00 and then declining through the day. Failed BAC tests are an aggravation to the driver (since the car won t start), and overall these occur infrequently, so it is probably valid to assume failures were surprising to most drivers. Anyone surprised by an elevated BAC (first thing in the morning after awakening) may have a poor understanding of their level of problem drinking and this lack of awareness may reflect their drunken driving risk. In assess if there was something unique about the morning failures, these were studied in isolation of other intervals. For this purpose, five different periods were defined on the basis of the hour by day distributions. Morning was defined as encompassing the hours of 6-10 am on workdays and on weekends. The remaining intervals evaluated are as shown in Table 2. The table also shows the percent of all interlock users who had at least one fail, or two or more BAC fails (.040+ gm/dl) during the intervals noted. Previous evaluation of post-interlock recidivism with the Cox proportional hazard model (survival analysis) showed that failed interlock BAC tests and prior DWIs are the only two predictor variables that entered the equation to predict post-interlock DWI (Marques et al., 2002). These were the strongest from among a dozen or more variables tested which derived from both driver records (moving violations, driving while suspended charges) and from questionnaire data (self-report consumption, demographics etc.). New analyses were conducted using dummy-coded variables from Table 2 representing when during the day or week, 2 or more failed BAC tests occurred. In this case, as before, both the number of prior DWI and the proportion of all vehicle start attempts that are fails (BAC >=.04 gm/dl) entered the equation as significant predictors. In addition to those variables, receiving at least 2 fails in the morning hours was the only other variable that entered the predictive equation. If a driver had at least 2 fails during the morning hours, it increased the likelihood of a post-interlock repeat DWI by 45% (Exp B=1.45), significant at P=.05. No other evaluated period during the day came close to entering the equation; 2 or more nighttime fails (P=.3) was the closest

54 Figure 1: Fail level BAC tests stacked into two intervals ( and.080+ gm/dl) Data are shown by hour on weekday Fig 1a (left), or weekend Fig 1b (right). Interlock Fails Interlock Fails 500 Workday (Monday-Friday) 300 Weekend (Saturday-Sunday) gm/dl 100 gm/dl Count noon Count noon HOUR of Day Table 2: HOUR of Day Breakout of failed BAC tests into different time interval within a week Time of Failed tests Definition of interval % w/ 1fail % w/ 2+ fails (BAC>=.04) Morning 6:00-9:59 weekday, 8:00-11:59 weekend Weekday daytime 10:00-4:59 weekday Night 7:00-2:59 am any night 22 8 Weekend Saturday, Sunday only 24:00-24: Weekend night 7:00-2:59 Friday, Saturday Do later recidivists fail to change behavior over time on the interlock? The curve describing rate of change in BAC over the time that an interlock was in use (not shown here but found in Marques et al., 1999) portrays a 50% decline in the proportion of all start-up BAC test that are elevated above.02 gm/dl. Factors associated with prior DWI or breath tests were evaluated as nineteen different variables in attempt to identify predictors associated with those who ultimately recidivate post-interlock, and by so doing, show evidence of having failed to learn to control their drinking. To limit the sample to those for whom a reasonable demonstration of learning is possible, subjects with no BACs >=.04 gm/dl were excluded, as were those few who had an interlock for less than 5 months. Among the tested variables were the best predictors found so far including proportional rate of failed BAC tests during the first five months of interlock use and more prior DWI offenses. In addition to these, several variables representing BAC tests over time were added to the model. These variables include the slope of warn, fail, or high fail tests over time within subjects, the slope of total tests taken (a proxy for vehicle use), the T-score of each of these (calculated as the slope divided by the standard error) reflecting 12 months interlock learning data, the transformed or normalized rates of warns, fails and high fails during the first two or the first five months

55 The predictors, all of which represent either the offenders past driving record or their BAC performance while the interlock was installed, were analyzed with two different methods: survival analysis and logistic regression. The dependent measure in both analyses is postinterlock DWI offenses. The survival analysis takes into consideration the time frame in which the post-interlock repeat offense occurs and is therefore a continuous measure. The logistic regression only considers if the DWI occurred or did not occur. The data in Table 3 summarizes the results of the proportional hazard survival analysis and the logistic regression. Table 3: Survival analysis (upper) and logistic regression analysis (lower) to predict postinterlock recidivism 154 repeat offense events from 1570 cases analyzed (Rate 90.2% survival) Cox Regression Variables in the equation B S.E. Sig R Exp(B) Five or more prior DWI offenses (n=155) Failed BAC tests proportional to tests taken Repeat DWI offender (n=1192) Change in rate of vehicle use Rate of BAC tests >.08gm/dl in first 2 months Logistic Regression Variables in the final model equation B S.E. Sig R Exp(B) Failed BAC tests proportional to tests taken Five or more prior DWI offenses (n=155) Repeat DWI offender (n=1192) Change in rate of vehicle use Of the nineteen variables evaluated, both analyses procedures identified four common predictor variables. The relative strength of each predictor can be approximated using the R value, a square root measure of effect size. The order of presentation in the tables roughly reflects the potency of the predictor. The predictors that were dummy-coded as dichotomous (the two DWI variables) show Exp(B) values, understandable directly, and are shown in the table. The likelihood of any repeat offense (relative to those who are first time offenders) increases the likelihood of a future DWI by about 57-58%. Having five or more DWI offenses reflects on only 155 of the offenders in the sample but this increases the likelihood of a repeat DWI postinterlock by an additional 131%. In both analyses, the overall proportional rate of failed BAC tests with the interlock installed is, here again, a key predictor in both analyses. In Cox regression, the effect size and significance of this variable is similar to the high risk of 5+ repeat offenders. In the logistic regression, the failed BAC tests is substantially more potent a predictor than any of the other entries with R=.15. Notable for its absence in the equation however, is any measure of slope. This suggests that change in the rate of warn, fail, or high fail BAC tests was not predictive of greater or lesser likelihood of post-interlock repeat DWI convictions. On the other hand, in both analyses change in the rate of vehicle use did enter the equations. It is not a high potency predictor but it is consistently present. Its sign is negative meaning that over time on the interlock, those who reduced the amount of vehicle use (i.e., drivers who showed a decline in the number of times

56 they started the vehicle) had a higher post-interlock repeat DWI offense. This suggests there may be a subset of drivers who were finding it difficult to use their vehicles due to regularly elevated BAC so they decided to not use the interlock vehicle. Less vehicle use could be a form of self-imposed suspension (from the interlock vehicle). It could reflect less total driving, or it may only mean that driving shifted to a non-interlock vehicle. Shifting to a non-interlock vehicle is the weakest link in the interlock strategy since anyone stipulated to an interlock vehicle, especially people with more financial resources, can easily choose an alternate car. Discussion The alcohol interlock data recorder is the most significant source of objective driver BAC test data ever available for the understanding of DWI offenders. On average the interlock records about 265 tests each month. The occurrence of elevated BAC tests, particularly those above.04 gm/dl strongly predicts the likelihood of repeat DWI. Also, those who have failed BAC tests in the morning are 45% more likely to recidivate (even after accounting for prior offenses and higher total rates of failed tests). Licensing authorities or courts that sanction DWI offenders, and which have interlock programs, could use this information right now to improve the identification of high risk drivers. If sanctions were flexibly applied the interlock would be left on the vehicle until the driver shows evidence of having successfully reduced driving (knowingly or unknowingly) with elevated BAC. Caution is necessary, however, and other risk indicators may be needed since it now appears that some offenders who had subsequent DWIs reduced vehicle use over time when required to drive with an interlock. References Marques, P.R., Voas, R.B., Tippetts, A.S., Beirness, D.J. (Dec 1999) Behavioral monitoring of DUI offenders with the alcohol interlock recorder. Addiction. 94(12), Marques, P.R., Tippetts, A.S., Voas, R.B., Danseco, E.R., & Beirness, D.R., (2000). Support services provided during interlock usage and post-interlock repeat DUI: Outcomes and processes. In H. Laurell & F. Schlyter (Eds.). Alcohol, Drugs and Traffic Safety - T 2000: Proceedings of the 15th International Conference on Alcohol, Drugs and Traffic Safety, May 22-26, (Vol. 4). Stockholm, Sweden: ICADTS. Marques, P.R. Tippetts, A.S. Voas, R.B, Beirness, D.J. (2001). Predicting repeat DUI offenses with the alcohol interlock recorder. Accident Analysis & Prevention. 33(5), Marques, P.R., Tippetts, A.S. & Voas, R.B. (2002). Comparative and joint prediction of DUI recidivism from alcohol ignition interlock and driver records. Submitted, March 2002 Journal of Studies on Alcohol