Legal Concerns

Questions & Answers

General Questions

1)How is alcohol metabolized by the body?
2) How does mouth alcohol affect an alcohol interlock device?
3) What types of foods are likely to interfere with an breath alcohol reading?
4) Is it possible to attribute a specific breath test to particular driver?
5) Who can/should be certified as an expert witness to give testimony about alcohol interlocks?
6) Is the alcohol interlock an inconvenience to other family members?
7)What about persons who are unable to provide a sufficient breath sample?
8)How much does the alcohol interlock cost?
9)How do jurisdictions determine indigency for the purposes of an alcohol interlock program?

Downloads:   Student Handout - Word file  Student Slides - PowerPoint file

1) How is alcohol metabolized by the body?

  • Ingestible alcohol, known as ethyl alcohol or ethanol, is the type of alcohol that is found in a standard drink of beer, wine, or liquor.
  • Ethanol is a central nervous system depressant, meaning it does not affect a person until it gets into his or her central nervous system (e.g., the brain, brain stem and spinal cord). Ethanol gets to the brain by getting into the blood. In order to get into the blood, it has to get into the body.
  • Once alcohol is orally ingested and gets into the stomach, it moves into the blood by absorption through the walls of the stomach. Alcohol does not have to be digested in order to be absorbed so drinking on an empty stomach creates an ideal circumstance for rapid absorption.
  • Alcohol has an affinity for water. Brain tissue has a fairly high water content so it receives a substantial share of the distributed alcohol.
  • Research shows that the male body is about 68% water; the typical female body has only about 55% water. Women also have more body fat and alcohol is less soluble in fat. Thus, when a man and a woman drink exactly the same amount of alcohol under the same circumstances, the woman’s BAC will be higher, because they have a lower water content and generally are a smaller size compared to men.
  • The majority of alcohol that is consumed is eliminated by the body through the process of metabolism. Metabolism is a process of chemical change in which alcohol reacts with oxygen in the body and changes into carbon dioxide and water, both of which are directly expelled from the body.
  • Most of the metabolism of alcohol in the body takes place in the liver. The speed at which this occurs can vary somewhat from person to person, and even from time to time for any given person. On average, a person’s BAC will drop by about 0.015 per hour.
  • Once alcohol has been consumed, there is nothing that can be done to speed up the metabolism or the process of elimination. Drinking coffee, exercise, deep breathing, or a cold shower will NOT speed up the elimination process.

2) How does mouth alcohol affect an alcohol interlock device?

  • A variety of foods, medication or hygiene products may contain alcohol. When these products are consumed or used immediately prior to blowing into an alcohol interlock device, a positive breath alcohol concentration will be registered.
  • Drivers are advised not to consume any products containing alcohol within the 5 minutes prior to providing a breath sample. This is comparable to protocols associated with evidential breath tests (e.g., waiting period).
  • Residual mouth alcohol will dissipate within a few minutes of consumption as it is absorbed into the body or taken up by saliva. Rinsing with water will also help get rid of mouth alcohol.

3) What types of food are likely to interfere with a breath alcohol reading?

  • Some foods (e.g., chocolate donuts, certain types of bread) can produce endogenous (internally produced) alcohol.
  • This alcohol is unlikely to be produced in sufficient quantities to produce a positive reading. For example, an article published in the Journal of Analytical Toxicology reported that an individual would be required to consume 3lbs. of bread to reach a BAC equivalent to that of a single 12oz beer with 4% alcohol (Logan and Distefano 1998, p.183).

4) Is it possible to attribute a specific breath test to a particular driver?

  • It has generally not been possible to attribute the results of a specific breath test to a particular driver.
  • Breath pulse, hum tone, and other similar driver recognition features on some devices can limit the extent to which other drivers are able operate the vehicle as these techniques are difficult to master without practice and/or proper instruction.
  • Manufacturers are now beginning to explore various technologies that can be incorporated into the alcohol interlock device to assist in identifying the driver of the vehicle as the person who provided the breath test. For example, some manufacturers have developed a picture identification feature that takes a picture of the driver before, during, and after the breath test. This technology is currently being piloted in some jurisdictions.

5) Who can/should be certified as an expert witness to give testimony about alcohol interlocks?

  • As a general rule, an expert is needed to testify when there is a need to discuss scientific, technical, or other specialized knowledge as part of a hearing or case.
  • In making a determination regarding who can be called as an expert, there are several factors to consider. First, there are court rules and case law in each state regarding what is required of an expert witness. Second, there is a requirement that the witness possess specialized knowledge that is relevant to the case. An expert can be someone that has, through education, experience, training, or observation, obtained the necessary knowledge on the topic over a reasonable period of time.  
  • In order to identify a suitable candidate for an expert witness, it is important to consider the subject matter that the expert will testify about.
  • If the issue is one of tampering or circumvention, then perhaps a person who is familiar with the installation process or the downloading of the data would be an appropriate choice. However, if the issue pertains to the meaning of the test results collected by the device, then a person with expertise in breath testing and analysis, and the management of the data would be more suitable.
  • Other questions that the court may want to consider include: any credentials or qualifications; how they obtained their knowledge or experience; any research the person has conducted and the type of research; authorship of any peer-reviewed publications; any licences or certificates relating to their expertise; and previous experience as an expert witness on the issue in question.

6) Is the alcohol interlock an inconvenience to other family members?

  • An alcohol interlock may pose an inconvenience to family members who must drive the interlocked-vehicle. 
  • Research suggests that family members generally agree that the inconvenience of using the alcohol interlock device is a preferred alternative to incarceration of the offender or having to “chauffeur” the offender to appointments/employment (Beirness et al. 2007).
  • Some families report that the alcohol interlock has had positive benefits for family life as a result of the offender’s reduced drinking.

7) What about persons who are unable to provide a sufficient breath sample?

  • NHTSA standards in the U.S. require a minimum of 1.5 litres of breath. Similarly, according to Canadian guidelines (2008), the minimum value for breath volume is between 0.7 and 1.2 litres. The upper threshold for breath volume falls between 1.5 and 2.0 litres.
  • Even offenders who suffer from asthma can provide a sufficient sample for testing and devices can be adjusted to require a reduced volume. It is important that any reduction not make the volume requirement so low as to allow a child to blow into the device and provide a sample.
  • A U.S. study of more than 1,500 spirometer (lung capacity) tests found that approximately 2.5% of adults would be medically incapable of delivering an appropriate sample at this volume (Patton 2007).
  • Those offenders who have undergone a tracheotomy, have chronic pulmonary disease, or other severe breathing disorders may encounter difficulty providing a sufficient sample.

8) How much does the alcohol interlock cost?

  • The cost to offenders to have the alcohol interlock device installed is approximately US $70.00 and between US $60.00 and US $90.00 per month for monitoring.
  • In some jurisdictions, these costs may be defrayed by the courts by allocating a portion of the fine towards these costs. In a few states indigent funding schemes are already in place and more programs are moving in this direction.
  • The average daily cost of this sanction is $3.00-$4.00 (or the cost of a drink), which is well below the cost for other incapacitation systems.
  • As a means to encourage and facilitate participation in the programs, some judges are able to reduce or even waive fines for offenders who install the device. In some jurisdictions indigent funding may be available.
  • Offenders who are not able to afford an alcohol interlock should not be excluded from participation in an alcohol interlock program because of cost.

9) How do jurisdictions determine indigency for the purposes of an alcohol interlock program?

  • For those states that provide funding for indigent offenders, there is no set standard that is used to determine which offenders qualify as indigent for the purposes of an alcohol interlock program. 
  • Depending on the type of alcohol interlock program, indigency may be determined by:
  • the discretion of the court;
  • qualification for a public defender;
  • qualification for food stamps;
  • federal poverty guidelines; or
  • salary levels according to the definitions of “financial hardship”.