Ignition Interlocks based on fuel cells have been in field service in Alberta Canada starting in May of 1994. Data on models which have many of the features of this latest generation Interlocks are given based on experience in both Alberta and the state of Michigan, USA which indicate that these devices should be highly effective in deterring drunk driving. It is shown that the key to effectiveness in an Interlock is a combination of strict monitoring of the person on the program, coupled with highly effective methods of preventing the offender from "cheating" the device. Data to date indicated that these latest devices should reduce recidivism compared to license suspension by better than 90%.
The methods that are used to accomplish this high degree of anti-circumvention are discussed. In addition, the problem of making field operation reliable and accurate over the range of temperatures encountered in Alberta Canada have been overcome and will be described.
A Breath Alcohol Ignition Interlock Device (BAIID) is a breath alcohol testing instrument connected to the ignition and power system of a vehicle that is designed to prevent the vehicle from being started if the driver's blood alcohol level is above a predetermined setpoint.
Ignition interlocks were first developed in the United States, and have been available commercially in that country since 1986. Legislation mandating or providing for the use of ignition interlocks under the supervision of judicial or motor vehicle licensing authorities has been enacted in most U.S. states and 28 of these currently have active programs serving over 15,000 people.
In 1990 Canada's Province of Alberta began an interlock pilot program. The pilot program evolved into a permanent interlock program in 1994, and numbers expected to top 1000 participants by the end of the first year of full operation. Other Canadian provinces have been closely monitoring the Alberta experience, and several of these are expected to introduce programs of their own in the near future.
Outside North America, interlock pilot programs are either under way or in the planning stages in Sweden, Australia and New Zealand.
The focus of interlock use has been convicted impaired drivers. In this context interlocks are seen as a means of promoting public safety and preventing further offences.
Traditionally, interlock programs for convicted impaired drivers have tended to concentrate on repeat offenders. This group is comprised of individuals who not only have ignored a succession of media advertising campaigns and remained undeterred by the threat of detection and arrest, but who also have demonstrated by their conduct that they are unable or unwilling to respond to traditional legal sanctions (fines, licence suspension, incarceration) directed at preventing a repetition of the offence. Sometimes referred to as "hard core" drinking drivers, these individuals continue to drink and drive regardless of the risk or, apparently, the consequences. They are likely to be alcohol abusers who frequently drink to excess, or alcoholics.
Common sense would suggest that it is precisely because they are seen as problem drinkers, and therefore more likely to continue re-offending, that repeat impaired driving offenders have been the primary target group for ignition interlock programs. Indeed, in some circles the fact of a second or subsequent conviction in and of itself seems to have been regarded as a key identifying element in distinguishing problem drinkers from other impaired driving offenders. However, recent empirical evidence appears to indicate that the great majority of first time offenders also are alcohol abusers or alcohol-dependent--not just casual social drinkers who happened to make an error in judgment and drive with an elevated BAC level on an isolated occasion (National Safety Council, 1991). This reinforces the view that "the chances of an impaired driver being stopped by the police are estimated at between 1 in 200 and 1 in 2000" (Beirness and Simpson, 1991), and provides a strong argument against drawing major distinctions between first time impaired driving offenders and those with more than one conviction.
As evidence accumulates in favour of the view that most impaired driving offenders are problem drinkers, regardless of the actual number of convictions, some jurisdictions have moved toward expanding ignition interlock programs to include so-called first time offenders. (See: Alberta Municipal Affairs, 1994)
Experience with early versions of ignition interlock devices has shown that alcohol abusers and alcoholics are very adept and ingenious at overcoming technical obstacles to driving after drinking. In this regard, it is important to bear in mind in light of the comments above that we are dealing with people who, in the main, are accustomed to carrying out a variety of activities while under the influence of alcohol, and to whom dishonesty, deception and conniving has become an integral part of daily life in an attempt to conceal their drinking problem. Given the type of person likely to be using an interlock, it is perhaps not surprising to hear of examples of tampering or circumvention that include but are by no means limited to: disabling or altering the interlock device itself; disconnecting the power source; by-passing it by hot wiring or push starting the vehicle; using a bogus breath sample such as an air pump or balloon; having another person perform a breath test to enable starting of the vehicle; and leaving the vehicle running while alcohol is consumed.
North American standards for ignition interlock devices now clearly recognize the need for extensive anti-circumvention features as part of an effective interlock system, and prescribe specific features designed to prevent or at least detect, record and in some cases sanction tampering, bypassing or attempts to "fool" the device. (See: National Highway Traffic Safety Administration, 1993; Electronics Test Centre, 1993)
The most demanding anti-circumvention requirements are found in Alberta, Canada where the approach taken by administering authorities has been to marry highly sophisticated technology with a comprehensive program of close monitoring and supervision which involves active and ongoing participation by the interlock service provider.
At the time of writing, the only device that has been approved for use in Alberta is Guardian Interlock Systems' Model WR2, and this device includes the following anti-circumvention features:
During a test the user must blow into the sampling head, then introduce a hum without interrupting the air flow or altering the pressure. The hum requirement is designed to ensure that the sample being analyzed is human breath. Since the technique involved tends to be difficult for the untrained user, this feature also represents an effective way of thwarting possible attempts to obtain "curbside assistance" to start an interlock-equipped vehicle.
Additional proprietary features prevent a human subject from successfully using a filter to reduce or eliminate the level of ethyl alcohol measured by the device.
This feature ensures rejection of a breath test of insufficient pressure or duration to yield a "deep lung" sample of alveolar air for analysis.
A built-in time clock signals the driver to provide a further breath sample at random intervals. To guard against the possibility of alcohol ingestion after the initial retest, either while the vehicle is in motion or parked with the engine left running, additional retests are required throughout the period the vehicle is in operation. The interval between retests may be extended or reduced, depending on the results of the preceding test.
As a safety precaution, the driver has three minutes to comply with a retest requirement. Failure to take or to pass the test will activate an external alarm, which will continue to sound until the vehicle pulls over and the ignition is turned off.
Once the ignition is turned off following a missed or failed retest, the driver cannot restart the vehicle. Initially the lock out period is five minutes. However, a subsequent failed test will result in a 30-minute lock out.
Attempts to disable or bypass the interlock system are detected and recorded on a data logger. The data logger, in turn, has its own power source to protect it against memory loss in the event of interruption of power to the vehicle.
If the vehicle is hot wired or push started, the interlock device will immediately require a retest.
Normally the user must return to an authorized service centre every 60 days for inspection, calibration check and downloading of the data logger. However, the service recall date is automatically moved up if a Guardlink occurs. Failure to return for inspection and servicing when required will trigger a continuous lock out condition, thereby immobilizing the vehicle.
In Alberta the technical sophistication of the WR2 is matched and complimented by program delivery standards and procedures which entail close monitoring and supervision of interlock users by service providers and administering authorities so as to further minimize any opportunity for tampering or circumvention.
Under the Alberta program, users must undergo formal training in the use of the interlock at the time of installation. The initial training session affords the service provider a timely opportunity to go over the device's impressive array of anti-circumvention features and stress both the likelihood of detection and the consequences of attempted tampering or circumvention. At the same time there is also an opportunity to get to know clients and establish a constructive working relationship by helping them develop a level of confidence with the device, to meet other family members who may be using the interlock-equipped vehicle, and to emphasize the need for a positive commitment and support by all concerned.
Following installation and training, all participants are obliged to return to the service provider's establishment every 60 days for inspection and servicing. As a precaution the first service recall date is set for 30 days. At that time a full servicing will be done, including inspection of the system for evidence of tampering, verifying the calibration of the sampling head, downloading of the data logger and preparation of a summary report for administering authorities. Reviewing data logger records with the client at this time provides an opportunity to assess whether the client is experiencing any problems in using the device or difficulties maintaining compliance that need to be further addressed. The fact that these records contain full details of every event associated with the use of the client's own vehicle and interlock device since its installation is also considered to have a beneficial effect in reinforcing previous statements made to users about the ability of the device to detect attempts to circumvent.
The premise of the Alberta Interlock Program is that, given the type of individuals likely to be using an interlock and the fact that people in general will go to great lengths to circumvent machines that prevent them from doing something they are motivated to do, a program that combines the use of highly sophisticated technology with close monitoring and supervision (so as to minimize the opportunity for circumvention and maximize the probability of detection of any attempt to tamper or circumvent) will stand the best chance of success in achieving its purpose, namely, to prevent participants from driving in an alcohol-impaired condition.
In assessing interlock programs in other jurisdictions, researchers have used comparative rearrest rates as a prime measure of effectiveness. A U. S. study conducted in Hamilton County, Ohio (Morse and Elliott, 1992) tracked two groups drawn from a pool of multiple or high BAC offenders and breath test refusal cases. As an alternative to licence suspension subjects in one group were put on an interlock program using devices with some anti-circumvention features, and providing for inspection and servicing every 60 days. Those in the other group remained under suspension. Over a 30 month period, the DUI rearrest rate was found to be 65% lower for the interlock group.
More recently, the introduction in Michigan of a second generation interlock device with more extensive anti-circumvention features occasioned an investigation (Collier, 1994) of comparative rearrest rates among users of the new device and users of a device similar to the one used in Ohio at the time of the Hamilton County study. Relating the results after nine months back to the Hamilton County study, this investigation concluded that use of the new device should be expected to improve rearrest rate reductions from 65% to 90% compared to non-interlock users whose licences have been suspended.
While statistical data have not been compiled to permit a formal analysis of comparative rearrest rates in Alberta, it is known that since the inception of the pilot program in 1990 only two individuals have been arrested for impaired driving while on the program. In both cases the method of circumvention has now been eliminated with the introduction of tougher standards and Guardian's Model WR2 in May, 1994.
The results to date in Alberta are very similar to those noted in Michigan. With a superior interlock device and a program incorporating an intensive level of supervision and follow-up, Alberta's ignition interlock program is already considered to have achieved a high level of effectiveness. As for the future, a major research project is under way in Alberta that introduces a counseling component into the interlock program with a view to increasing its effectiveness in the prevention of recidivism on a long term basis. Although beyond the scope of this paper, the project is obviously one of considerable significance and many people will be looking forward to release of a preliminary report at the earliest opportunity.
Alberta Municipal Affairs: Registries (1994). Ignition Interlock Program Extended to First-Time Offnders. News Release dated May 3, 1994. Edmonton: Alberta Municipal Affairs
Beirness D.J. and Simpson, H.M. (1991). Alcohol Ignition Interlocks: Their Function and Role in Preventing Impaired Driving. Ottawa: Traffic Injury Research Foundation of Canada
Collier, D.W. (1994). Second Generation Interlocks Lead to Improved Program Efficacies. Paper presented at Transportation Research Board 73rd Annual Meeting, Washington, D.C., 1994.
Electronics Test Centre (1992). Qualification Test Specification for Breath Alcohol Ignition Interlock devices (BAIID) for Use in the Province of Alberta. Edmonton: Alberta Research Council
Morse, B.J. and Elliott, D.S. (1990). Hamilton County Drinking and Driving Study: 30 Month Report. Boulder, Colorado: University of Colorado
National Highway Traffic Safety Administration (1992). Model Specifications for Breath Alcohol Ignition Interlock Devices (BAIIDs). Federal Register 57(67): 11772
National Safety Council, Traffic Safety March/April, 1991: 11