R. v. Gibson

R. v. Gibson
Collection
Supreme Court Judgments
Date
2008-04-17
Neutral citation
2008 SCC 16
Report
[2008] 1 SCR 397
Case number
31546, 31613
Judges
McLachlin, Beverley; Bastarache, Michel; Binnie, William Ian Corneil; LeBel, Louis; Deschamps, Marie; Fish, Morris J.; Abella, Rosalie Silberman; Charron, Louise; Rothstein, Marshall
On appeal from
Nova Scotia
Subjects
Criminal law
Notes
SCC Case Information: 31613, 31546
Decision Content
SUPREME COURT OF CANADA
Citation: R. v. Gibson, [2008] 1 S.C.R. 397, 2008 SCC 16
Date: 20080417
Docket: 31546, 31613
Between:
Robert Albert Gibson
Appellant
and
Her Majesty the Queen
Respondent
‑ and ‑
Attorney General of Ontario
Intervener
and between:
Martin Foster MacDonald
Appellant
and
Her Majesty the Queen
Respondent
‑ and ‑
Attorney General of Ontario
Intervener
Coram: McLachlin C.J. and Bastarache, Binnie, LeBel, Deschamps, Fish, Abella, Charron and Rothstein JJ.
Reasons for judgment:
(paras. 1 to 33)
Reasons concurring in
the result:
(paras. 34 to 82)
dissenting reasons:
(paras. 83 to 99)
Charron J. (Bastarache, Abella and Rothstein JJ. concurring)
LeBel J. (McLachlin C.J. and Fish J. concurring)
Deschamps J. (Binnie J. concurring)
______________________________
R. v. Gibson, [2008] 1 S.C.R. 397, 2008 SCC 16
Robert Albert Gibson Appellant
v.
Her Majesty The Queen Respondent
and
Attorney General of Ontario Intervener
‑ and ‑
Martin Foster MacDonald Appellant
v.
Her Majesty The Queen Respondent
and
Attorney General of Ontario Intervener
Indexed as: R. v. Gibson
Neutral citation: 2008 SCC 16.
File Nos.: 31546, 31613.
2007: October 15; 2008: April 17.
Present: McLachlin C.J. and Bastarache, Binnie, LeBel, Deschamps, Fish, Abella, Charron and Rothstein JJ.
on appeal from the court of appeal for nova scotia
on appeal from the court of appeal for alberta
Criminal law — Evidence — Operation of vehicle with blood alcohol level exceeding legal limit — Criminal Code providing that, absent evidence to contrary, breathalyzer reading above 80 mg of alcohol per 100 ml of blood is proof that blood alcohol concentration exceeded legal limit at time of driving — Expert opinion evidence placing accused’s blood alcohol concentration in range that straddled legal limit at time of driving — Whether expert evidence of alcohol elimination rates in general population and “straddle evidence” can rebut presumption — Whether expert evidence of post‑offence testing of alcohol elimination rate of accused can rebut presumption — Criminal Code, R.S.C. 1985, c. C‑46, s. 258(1) (d.1).
The accused, G and M, were charged with driving "over 80" after failing a breathalyzer test. The first breath sample taken from G provided a reading of 120 mg and the second a reading of 100 mg. The two breath samples taken from M each produced a reading of 146 mg. At their respective trials, G and M testified as to their pattern of drinking at the material time and adduced expert evidence to rebut the presumption in s. 258(1) (d.1) of the Criminal Code that the breathalyzer readings provided proof that their blood alcohol concentrations exceeded the legal limit at the time of driving. The expert opinion evidence concerning the accused’s blood alcohol concentration at the time of driving was expressed in terms of a range of possible blood alcohol concentrations, given the amount of alcohol consumed, the pattern of drinking, and the accused’s age, height, weight and gender. In each case, the range of hypothetical blood alcohol concentrations "straddled" the legal limit of 80 mg. G’s expert testified that, if the pattern of consumption described by G was accurate, his blood alcohol concentration would have been between 40 and 105 mg at the time of driving. M’s expert provided a range of between 64 and 109 mg. In addition, the expert called on behalf of M tested his elimination rate more than six months after the alleged offence. On the basis of this test, the expert determined that M’s elimination rate was 18.5 mg per hour and that M’s blood alcohol concentration would have been 71 mg when he was stopped by the police.
The trial judge accepted both the evidence of G’s consumption and the expert evidence. He was left with a reasonable doubt that G’s blood alcohol content had exceeded the legal limit, and acquitted him. The Supreme Court upheld the acquittal. The Court of Appeal held that evidence of a hypothetical person’s elimination rates was not capable of rebutting the presumption in s. 258(1) (d.1), set aside the acquittal and ordered a new trial.
The trial judge convicted M on the basis that the expert evidence did not tend to show that his blood alcohol content had not exceeded 80 mg. Both the Court of Queen’s Bench and the Court of Appeal upheld the conviction.
Held (Binnie and Deschamps JJ. dissenting): The appeals should be dismissed.
Per Bastarache, Abella, Charron and Rothstein JJ.: Straddle evidence constitutes an attempt to defeat the statutory presumption in s. 258(1) (d.1) and, as such, does not tend to show that the accused’s blood alcohol concentration did not exceed the legal limit at the time of the alleged offence. Straddle evidence merely confirms that the accused falls into the category of drivers targeted by Parliament — namely, those who drive having consumed enough alcohol to reach a blood alcohol concentration exceeding 80 mg. Parliament, in creating this offence, clearly regarded driving with this level of consumption as posing sufficient risk to warrant criminalization. It is therefore not enough to show, based on evidence about the accused’s pattern of consumption of alcohol during the relevant time period, that the accused consumed enough alcohol to exceed the legal limit, albeit in a quantity that would place him within a range that may be somewhat different from that which could be extrapolated from the breathalyzer reading. It is clear from the wording of s. 258(1) (d.1) that the presumption can only be rebutted by evidence that tends to show that the accused’s blood alcohol concentration did not exceed the legal limit and, hence, that the accused was not in the targeted category of drivers. In order to displace the presumption, the evidence must show, therefore, that based on the amount of alcohol consumed, the accused’s blood alcohol concentration would not have been above the legal limit at the time of driving, regardless of how fast or slowly the accused may have been metabolizing alcohol on the day in question. The court need not be convinced of that fact; it is sufficient if the evidence raises a reasonable doubt. Furthermore, because it is scientifically undisputed that absorption and elimination rates can vary from time to time, nothing is really gained by post‑offence testing of an accused’s elimination rate. It is because of these inherent variations in absorption and elimination rates that the presumption of identity is needed in the first place. In order to facilitate proof of the offence, the presumption treats all persons as one person with a fixed rate of elimination and absorption. Short of reproducing the exact same conditions that existed at the time of the offence, assuming this is even possible, any expert opinion evidence based on actual tests would have to be given with the qualification that absorption and elimination rates vary from time to time, and therefore the accused’s blood alcohol level at the material time cannot be measured with precision. Ultimately, the best evidence an expert can provide is likely to be a range reflecting average elimination rates. The Court should not interpret this legislative scheme, which is intended to combat the social evils resulting from drinking and driving, as requiring accused persons, some of whom may well be battling with alcohol addiction, to submit to drinking tests in order to make out a defence. [3] [6‑8]
In the present appeals, the expert opinion evidence, in placing the accused’s blood alcohol concentration both above and below the legal limit at the time of driving depending on the accused’s actual rate of absorption and elimination on the day in question, did no more than confirm that the accused fell within the category of drivers targeted by Parliament and did not rebut the statutory presumption under s. 258(1) (d.1). Consequently, M’s conviction is upheld and, in G’s case, the order for a new trial is confirmed. [33]
Per McLachlin C.J. and LeBel and Fish JJ.: Both expert evidence of alcohol elimination rates in the general population and straddle evidence can be relevant and are therefore not inherently inadmissible for the purpose of rebutting the presumption in s. 258(1) (d.1). However, the probative value of evidence based on rates in the general population will often be so low that it fails to raise a reasonable doubt that the accused had a blood alcohol content exceeding 80 mg. Not only do elimination rates vary between individuals, but each individual’s rate will vary depending on such factors as the amount of food consumed, the type of alcohol consumed and the pattern of consumption. Thus, evidence that the blood alcohol content of an average person of the sex, age, height and weight of the accused would have been at a certain level or within a certain range will rarely be sufficiently probative to raise a reasonable doubt about the presumed fact that the actual blood alcohol content of the accused at the time of the offence exceeded the legal limit. Expert evidence of the elimination rate of the accused as established by a test is potentially more probative of the blood alcohol content he or she had while driving than evidence based on elimination rates in the general population. However, because an individual’s elimination rate varies over time based on a number of factors, the probative value of evidence based on the elimination rate of the accused will logically depend on the number of variables controlled for in the elimination rate test. Evidence of the elimination rate of the accused at the time of the offence would be more likely to rebut the presumption in s. 258(1) (d.1) than mere evidence of the elimination rate of the accused under testing conditions. [34] [67‑68]
Straddle evidence will rarely suffice on its own to raise a reasonable doubt as to the accuracy of a breathalyzer result. Once straddle evidence is admitted, it will be left to the trier of fact to determine whether that evidence, considered in light of the evidence as a whole, raises a reasonable doubt as to the accuracy of the breathalyzer result. Straddle evidence and the other evidence relied on by the defence will warrant an acquittal only if it tends to prove that the blood alcohol level of the accused at the relevant time did not exceed 80 mg. A wide straddle range cannot be considered evidence to the contrary of the breathalyzer result, since it does not tend to prove that the accused was at or under the legal limit. Similarly, a range that is overwhelmingly above the legal limit may be of limited probative value. The more that is known about probabilities within the range, the more probative the evidence may be. To foreclose the possibility of straddle evidence raising a reasonable doubt and rebutting the presumption in s. 258(1) (d.1) would inappropriately restrict the ability of an accused to defend him‑ or herself. The wording of the provision gives no indication of a legislative intent to render the fictional presumption absolute or irrebuttable in practice. It also leaves open the possibility of discrepancies between test results obtained at the time of testing and the blood alcohol content of the accused at the time of the offence. A mandatory presumption that requires the accused to raise a reasonable doubt about a fact that has not been proved by the Crown may prima facie be a limit on the presumption of innocence protected by s. 11 (d) of the Canadian Charter of Rights and Freedoms that needs to be justified under s. 1 . [73] [75‑76]
In these cases, the expert’s straddle evidence adduced by G is sufficiently relevant to be admissible and is not without foundation. However, given that it is based on elimination rates in the general population, consists of a wide range of values and includes values significantly above the legal limit, it does not, as is required to rebut the presumption in s. 258(1) (d.1), raise a reasonable doubt that G’s blood alcohol content actually exceeded 80 mg. Although the expert evidence adduced by M was also admissible, it would have been unreasonable for the trial judge to find that the straddle evidence indicating a range of 64 to 109 mg was capable of raising a reasonable doubt. The evidence of M’s own elimination rate, which supported a blood alcohol content of 71 mg, was also rejected by the trial judge because the test used to determine the elimination rate had not sufficiently approximated the conditions at the time of the alleged offence, which limited its relevance to the fact M was seeking to prove. There is no reason to interfere with that finding. In the result, M’s conviction is upheld and, in G’s case, the order for a new trial is confirmed. [78‑79] [81‑82]
Per Binnie and Deschamps JJ. (dissenting): Evidence that tends to show that the blood alcohol concentration of the accused at the time of interception did not exceed the legal limit based on an elimination rate of 15 mg per hour, or on the actual elimination rate of the accused according to test results, will suffice to raise a reasonable doubt. There is a body of scientific evidence that shows that members of the general population tend to eliminate alcohol at a rate faster than 15 mg per hour. It would therefore be speculative to assume, without any evidence, that a given accused is different from the majority of the general population and is a slow eliminator. Unless the scientific information that supports using 15 mg as a marker is contradicted by persuasive expert evidence, a judge should acquit if the prevailing direction of the straddle range favours a level that does not exceed the legal limit. The prevailing direction approach affords the accused a defence that is sufficiently complete without requiring post‑offence testing. As a matter of judicial policy, requiring accused persons to submit to drinking tests should not be encouraged by the courts. Nevertheless, post‑offence testing is not, per se, irrelevant or lacking in probative value. Just as evidence of average elimination rates in the general population is not discredited simply because such rates do not replicate the situation of an accused, evidence of post‑offence testing designed to determine the elimination rate of an individual accused should not be rejected for that reason alone. An elimination rate based on test results may constitute evidence that tends to show that an accused eliminates alcohol at a rate faster than 15 mg per hour. Although the weight given to post‑offence testing may depend on a number of variables, this should not be interpreted as requiring replication of the conditions of absorption. [84] [90‑91]
In G’s case, the expert for the defence testified that G’s blood alcohol content while he was driving would, based on average elimination rates, have been between 40 and 105 mg. There is agreement with the trial judge’s finding that the prevailing direction of the range favoured a level that did not exceed the legal limit, and that this was sufficient evidence for an acquittal. Therefore, G’s acquittal should be restored. [93]
In the case of M, the Crown failed to undermine the weight of evidence of post‑offence testing by either cross‑examining the expert or adducing contradictory expert evidence at trial. Although M’s elimination rate according to the expert’s test may not be the same as his rate on the day of the offence, nothing in the record suggests that any variation between the actual and tested elimination rates would be material or would cast doubt on the usefulness of the expert evidence. Nevertheless, the expert’s post‑offence tests can constitute evidence to the contrary only if M’s consumption scenario is found to be credible. Here, the trial judge made no express findings on this issue. He rejected the expert’s evidence on the basis that the midpoint of the straddle range was above the legal limit and that the food and the type of alcohol consumed had not been taken into account in the post‑offence tests. As he had dismissed the expert testimony, the trial judge found M guilty without making any findings concerning his credibility. Since this Court cannot enter an acquittal, as a finding on M’s credibility would have had to be made first, a new trial should be ordered on the charge of driving with a blood alcohol level exceeding the legal limit. [98‑99]
Cases Cited
By Charron J.
Distinguished: R. v. Boucher, [2005] 3 S.C.R. 499, 2005 SCC 72; referred to: R. v. Heideman (2002), 168 C.C.C. (3d) 542; R. v. Gibson (1992), 72 C.C.C. (3d) 28; R. v. St. Pierre, [1995] 1 S.C.R. 791; R. v. Proudlock, [1979] 1 S.C.R. 525; R. v. Moreau, [1979] 1 S.C.R. 261; R. v. Noros‑Adams (2003), 175 Man. R. (2d) 68, 2003 MBQB 130; R. v. Gaynor (2000), 272 A.R. 108, 2000 ABPC 104; R. v. Déry, [2001] Q.J. No. 3205 (QL).
By LeBel J.
Distinguished: R. v. Boucher, [2005] 3 S.C.R. 499, 2005 SCC 72; approved: R. v. Dubois (1990), 62 C.C.C. (3d) 90; considered: R. v. Heideman (2002), 168 C.C.C. (3d) 542; referred to: R. v. Phillips (1988), 42 C.C.C. (3d) 150; R. v. St. Pierre, [1995] 1 S.C.R. 791; R. v. Proudlock, [1979] 1 S.C.R. 525; R. v. Mohan, [1994] 2 S.C.R. 9; R. v. K. (A.) (1999), 45 O.R. (3d) 641; R. v. Abbey, [1982] 2 S.C.R. 24; R. v. Lavallee, [1990] 1 S.C.R. 852; R. v. Déry, [2001] Q.J. No. 3205 (QL); R. v. Gibson (1992), 72 C.C.C. (3d) 28; R. v. Seaboyer, [1991] 2 S.C.R. 577; R. v. Latour (1997), 116 C.C.C. (3d) 279; R. v. Moen (2007), 48 C.R. (6th) 361, 2007 BCSC 376; R. v. Noros‑Adams (2003), 190 Man. R. (2d) 161, 2003 MBCA 103.
By Deschamps J. (dissenting)
R. v. Heideman (2002), 168 C.C.C. (3d) 542; R. v. Abbey, [1982] 2 S.C.R. 24; R. v. Lifchus, [1997] 3 S.C.R. 320; R. v. Dubois (1990), 62 C.C.C. (3d) 90; R. v. Déry, [2001] Q.J. No. 3205 (QL); R. v. Bellemare, [2001] Q.J. No. 3304 (QL); R. v. Nault, [2001] Q.J. No. 3201 (QL); R. v. Thiffeault, [2001] Q.J. No. 3198 (QL); R. v. Gibson (1992), 72 C.C.C. (3d) 28; R. v. Milne (2006), 43 M.V.R. (5th) 167, 2006 ABPC 331; R. v. Hughes, [2007] A.J. No. 740 (QL), 2007 ABPC 180.
Statutes and Regulations Cited
Canadian Charter of Rights and Freedoms, ss. 1 , 11 (d).
Criminal Code, R.S.C. 1985, c. C‑46, ss. 253 , 258(1) (c), (d.1), (g).
Interpretation Act, R.S.C. 1985, c. I‑21, s. 25 .
Authors Cited
Solomon, Robert, and Erika Chamberlain. “Calculating BACs for Dummies: The Real‑World Significance of Canada’s 0.08% Criminal BAC Limit for Driving” (2004), 8 Can. Crim. L.R. 219.
APPEAL from a judgment of the Nova Scotia Court of Appeal (Saunders, Oland and Fichaud JJ.A.) (2006), 243 N.S.R. (2d) 325, 208 C.C.C. (3d) 248, 30 M.V.R. (5th) 161, [2006] N.S.J. No. 178 (QL), 2006 CarswellNS 181, 2006 NSCA 51, setting aside the accused’s acquittal and ordering a new trial. Appeal dismissed, Binnie and Deschamps JJ. dissenting.
APPEAL from a judgment of the Alberta Court of Appeal (Fraser C.J.A. and Ritter and O’Brien JJ.A.), [2006] 9 W.W.R. 711, 60 Alta. L.R. (4th) 205, 391 A.R. 140, 209 C.C.C. (3d) 481, 32 M.V.R. (5th) 163, [2006] A.J. No. 706 (QL), 2006 CarswellAlta 792, 2006 ABCA 177, affirming the accused’s conviction. Appeal dismissed, Binnie and Deschamps JJ. dissenting.
Joshua M. Arnold, Michael S. Taylor and Stanley W. MacDonald, for the appellant Robert Albert Gibson.
Alan D. Gold, for the appellant Martin Foster MacDonald.
William D. Delaney and Frank Hoskins, Q.C., for the respondent Her Majesty the Queen (31546).
Eric J. Tolppanen and David C. Marriott, for the respondent Her Majesty the Queen (31613).
Philip Perlmutter and James V. Palangio, for the intervener the Attorney General of Ontario.
The reasons of Bastarache, Abella, Charron and Rothstein JJ. were delivered by
Charron J. —
1. Overview
[1] These appeals raise the question of whether expert opinion evidence which says that the accused’s blood alcohol concentration may have been over or may have been within the legal limit at the material time, depending on the accused’s actual rates of absorption and elimination on the day in question, is capable of rebutting the statutory presumption set out in s. 258(1) (d.1) of the Criminal Code, R.S.C. 1985, c. C‑46 (see Appendix). This type of evidence will be referred to as “straddle evidence” because the range of possible blood alcohol concentrations straddles the legal limit of 80 mg of alcohol per 100 ml of blood.
[2] LeBel J. concludes that depending on a number of factors, straddle evidence may or may not provide a sufficiently probative evidentiary basis to rebut the presumption arising from the accused’s failure of the breathalyzer test. These factors may include evidence about the accused’s own rate of elimination as tested post-offence. I agree with LeBel J. that the straddle evidence adduced in both cases under appeal failed to rebut the presumption and that consequently both appeals should be dismissed. However, I arrive at this conclusion for different reasons.
[3] As I will explain, it is my view that in all cases straddle evidence merely constitutes an attempt to defeat the statutory presumption itself and, as such, does not tend to show that the accused’s blood alcohol concentration did not exceed the legal limit at the time of the alleged offence within the meaning of s. 258(1) (d.1). I also conclude, on the basis of the undisputed scientific fact that absorption and elimination rates vary continuously, that post-offence testing of the accused’s own elimination rate will rarely, if ever, add anything of value to the expert opinion evidence and, for obvious policy reasons, should not be encouraged, let alone required.
[4] It is undisputed that the human body absorbs and eliminates alcohol over time, and that absorption and elimination rates vary, not only from person to person, but also from time to time for the same individual, depending on a number of factors, some of which concern the person’s digestive process at the relevant time. It is therefore impossible to ascertain the precise rate at which the accused was metabolizing alcohol at the time of the alleged offence. Parliament can be assumed to have known that blood alcohol levels are subject to these inherent variations. Yet, it saw fit to implement the presumption. The legislative scheme must be interpreted in this context.
[5] Because absorption and elimination rates continually vary, it is readily apparent that a breathalyzer reading of 95 mg, for example, may not reflect the actual concentration of alcohol in the accused’s blood at the time of the alleged offence — it would depend on the rate at which the particular accused is metabolizing the alcohol during the relevant time period on the day in question. Yet, it can be no defence for an accused to say that the actual alcohol concentration at the material time may have been less than the legal limit based on this variable alone. To admit such a defence would obviously fly in the face of the presumption itself. It is because of these inherent variations in absorption and elimination rates that the presumption of identity is needed in the first place. In order to facilitate proof of the offence, the presumption treats all persons as one person with a fixed rate of elimination and absorption.
[6] Straddle evidence puts the accused in no better position. It merely confirms that the accused falls into the category of drivers targeted by Parliament — namely, those who drive having consumed enough alcohol to reach a blood alcohol concentration exceeding 80 mg. Parliament, in creating this offence, clearly regarded driving with this level of consumption as posing sufficient risk to warrant criminalization. It is therefore not enough to show, based on evidence about the accused’s pattern of consumption of alcohol during the relevant time period, that the accused consumed enough alcohol to exceed the legal limit, albeit in a quantity that would place him within a range that may be somewhat different than that which could be extrapolated from the breathalyzer reading. It is clear from the wording of s. 258(1) (d.1) that the presumption can only be rebutted by evidence that tends to show that the accused’s blood alcohol concentration did not exceed the legal limit and, hence, that the accused was not in the targeted category of drivers.
[7] In order to displace the presumption, the evidence must show, therefore, that based on the amount of alcohol consumed, the accused’s blood alcohol concentration would not have been above the legal limit at the time of driving, regardless of how fast or slow the accused may have been metabolizing alcohol on the day in question. Of course, the court need not be convinced of that fact. It is sufficient if the evidence raises a reasonable doubt.
[8] Further, because it is scientifically undisputed that absorption and elimination rates can vary from time to time, nothing is really gained by post-offence testing of an accused’s elimination rate. Short of reproducing the exact same conditions that existed at the time of the offence, assuming this is even possible, any expert opinion evidence based on actual tests would have to be given with the qualification that absorption and elimination rates vary from time to time, and therefore the accused’s blood alcohol level at the material time cannot be measured with precision. Ultimately, the best evidence an expert can provide, as the expert opinion evidence adduced in Mr. MacDonald’s case exemplifies, is likely to be a range reflecting average elimination rates. In any event, it is my view that this Court should not interpret this legislative scheme, which is intended to combat the social evils resulting from drinking and driving, as requiring accused persons, some of whom may well be battling with alcohol addiction, to submit to drinking tests in order to make out a defence. Surely, Parliament cannot have so intended.
2. The Proceedings Below
[9] LeBel J. has described the facts in some detail and summarized the findings of the courts below and I need not repeat this information here. For the purpose of my analysis, I will only briefly summarize the evidence.
[10] In each case under appeal, the accused was charged with driving “over 80” after failing a breathalyzer test. The first breath sample taken from Mr. Gibson provided a reading of 120 mg and the second a reading of 100 mg. The two breath samples taken from Mr. MacDonald each produced a reading of 146 mg. At their respective trials, Mr. Gibson and Mr. MacDonald testified as to their pattern of drinking at the material time and adduced expert evidence to rebut the presumption that the breathalyzer readings provided proof that their blood alcohol concentrations exceeded the legal limit at the time of driving. As is usually the case, the expert opinion evidence concerning the accused’s blood alcohol concentration at the time of driving was expressed in terms of a range of possible blood alcohol concentrations, given the amount of alcohol consumed, the pattern of drinking, and the accused’s age, height, weight and gender. In each case, the range of hypothetical blood alcohol concentrations “straddled” the legal limit of 80 mg. Mr. Gibson’s expert testified that, if the pattern of consumption described by Mr. Gibson was accurate, his blood alcohol concentration would have been between 40 and 105 mg at the time of driving. Mr. MacDonald’s expert provided a range of between 64 and 109 mg.
[11] In addition, the expert called on behalf of Mr. MacDonald tested his elimination rate more than six months after the alleged offence, explaining that this test was required of him by the Alberta Court of Appeal. The test did not involve beer or a similar pattern of drinking as on the date of the offence, but rather required Mr. MacDonald to consume a quantity of diet soda and vodka over a period of five minutes, then give breath samples periodically until his blood alcohol concentration reached a target range of between 50 and 60 mg. On the basis of this test, the expert determined that Mr. MacDonald’s elimination rate was 18.5 mg per hour. Assuming this elimination rate to be operative at the material time, the expert estimated that Mr. MacDonald’s blood alcohol concentration would have been 71 mg when he was stopped by the police. However, the expert added that “medically it’s clear” that an individual’s elimination rate can “vary from occasion to occasion”, and that food consumption and alcohol type affect alcohol absorption rates. He therefore stated that “if the rate of elimination was not 18.5 likely it would fall between 10 and 20, again, because most of the population would break alcohol down within that range” (A.R., at p. 70).
3. Analysis
[12] Before discussing the effect of straddle evidence, it may be helpful to briefly describe the evidentiary presumptions in s. 258(1) of the Criminal Code in the context of the legislative scheme and to review some of this Court’s jurisprudence on the presumptions and the nature of the evidence capable of rebutting them.
3.1 The Legislative Scheme and the Statutory Presumptions
[13] It is a criminal offence under s. 253 of the Criminal Code for a person to operate a motor vehicle while his or her ability to operate the motor vehicle is impaired by alcohol. It is equally an offence under the same provision for a person to operate a motor vehicle having consumed alcohol in such a quantity that the concentration in the person’s blood exceeds 80 mg. In criminalizing the conduct of persons who drive with a blood alcohol concentration in excess of 80 mg, regardless of whether those persons are actually impaired at the time, it can be presumed that Parliament regarded driving with this level of consumption as being of sufficient risk to warrant criminalization. Wakeling J.A. captured this point well in his dissenting reasons in R. v. Gibson (1992), 72 C.C.C. (3d) 28 (Sask. C.A.), at pp. 45‑46:
As a starting point in the consideration of this appeal, it is useful to remember the basis for the legislation in question. The decision to create an .08 standard as establishing intoxication to a point of impairment necessarily rejects an element of individuality in order to meet the higher social advantage of effectively dealing with the serious hazard created by those who drive when they have been drinking and are impaired as a consequence. Inherent in the acceptance of .08 as a standard is the recognition that alcohol does not have the same impact on everyone, depending on such differences as gender, age, weight and individual tolerance levels, but that the extent of the social concern created by impaired drivers and the tragic consequences of a failure to control that problem, dictated the change from an emphasis on an individual’s reaction to alcohol to an emphasis on a standard of general application. The standard is not intended as an absolute one in the sense that it is an accurate assessment of everyone’s state of impairment, as is evident from the fact some jurisdictions have set the figure at .100 (some states in the U.S.A.) and others as low as .06 (some states in Australia).
[14] Section 258(1) of the Criminal Code establishes three evidentiary presumptions which simplify the prosecution of the offence of driving “over 80”. In R. v. St. Pierre, [1995] 1 S.C.R. 791, Iacobucci J. explained that the presumptions are “legal or evidentiary shortcuts designed to bridge difficult evidentiary gaps” (para. 23). More recently, Deschamps J. described the legislative scheme as creating “two presumptions of identity and one presumption of accuracy” (R. v. Boucher, [2005] 3 S.C.R. 499, 2005 SCC 72, at para. 14).
[15] The presumption of accuracy is contained in s. 258(1)(g). It provides that a technician’s certificate stating the accused’s blood alcohol concentration at the time of the breathalyzer test is presumed to be accurate, in the absence of any evidence to the contrary. Although s. 258(1)(g) does not expressly include the words “in the absence of any evidence to the contrary”, this phrase is included by implication because of s. 25(1) of the Interpretation Act, R.S.C. 1985, c. I‑21 , which states as follows:
25. (1) Where an enactment provides that a document is evidence of a fact without anything in the context to indicate that the document is conclusive evidence, then, in any judicial proceedings, the document is admissible in evidence and the fact is deemed to be established in the absence of any evidence to the contrary.
[16] The first presumption of identity is contained in s. 258(1)(c). Section 258(1)(c) states that in the absence of evidence to the contrary, where breath alcohol samples have been taken in accordance with certain technical requirements, the accused’s blood alcohol concentration at the time of the breathalyzer test is presumed to be the same as his blood alcohol concentration at the time of the alleged offence. In St. Pierre, this Court considered the statutory presumption in s. 258(1)(c) and concluded that in order to rebut the presumption, the accused need only demonstrate that his blood alcohol concentration at the time of driving was different than at the time of the test. Iacobucci J. explained the Court’s reasoning in the following manner:
The section clearly does not say that the accused must show that he or she was not over .08 for the presumption not to apply. As stated earlier, the presumed fact deals with presuming blood alcohol levels to be the same at two different times. Evidence to the contrary must therefore be defined in relation to what is being presumed. [para. 46]
Following St. Pierre, Parliament enacted s. 258(1)(d.1), which effectively overruled the majority decision in that case. Section 258(1)(d.1) adds that where the breathalyzer test produces a reading above 80 mg, the accused’s blood alcohol concentration is presumed to have exceeded 80 mg at the time of the alleged offence, absent evidence “tending to show” that the accused’s blood alcohol concentration did not in fact exceed 80 mg. As a result, in order to rebut the statutory presumptions of identity in s. 258(1), an accused whose breathalyzer reading exceeds 80 mg must now show not only that his blood alcohol concentration was different at the time of driving than at the time of the test, but also that his blood alcohol concentration did not exceed 80 mg at the time of the alleged offence.
3.2 Rebutting the Presumptions
[17] It is well established that the standard of proof required to rebut the statutory presumptions is reasonable doubt. The expressions “evidence to the contrary” in s. 258(1)(c), “any evidence to the contrary” implicit in s. 258(1)(g) and “evidence tending to show” in s. 258(1)(d.1) reflect this same standard. In Boucher, the Court emphasized that the burden of proof never shifts to the accused. Rather, “it will be sufficient if, at the conclusion of the case on both sides, the trier of fact has a reasonable doubt” (Boucher, at para. 15, citing R. v. Proudlock, [1979] 1 S.C.R. 525, at p. 549).
[18] Of course, the crucial factual foundation upon which expert opinion evidence of this kind usually stands or falls is the accused’s evidence about the amount of alcohol he or she consumed and the pattern of drinking over the relevant period of time. If this factual basis is not credible and is rejected by the trial judge, the expert opinion evidence about the accused’s blood alcohol level at the time of the offence, although relevant and admissible at the time it is proffered, has no probative value and need not be considered by the court in arriving at a verdict. The issue of whether the expert opinion evidence “tends to show” that the accused’s blood alcohol level did not exceed 80 mg at the material time only arises if the accused’s evidence of consumption is believed.
[19] A review of the previous decisions of this Court demonstrates that Parliament’s intention in enacting this legislation has played a prominent role in determining what kind of evidence is capable of rebutting the presumptions in s. 258(1). In R. v. Moreau, [1979] 1 S.C.R. 261, the accused was charged with “over 80” following a breathalyzer test which showed that his blood alcohol concentration was 90 mg. Moreau was convicted, but on appeal by way of a trial de novo, he adduced expert evidence that the breathalyzer was subject to a margin of error of 10 mg. The case was appealed to the Court of Appeal and then to this Court, where the majority concluded that expert evidence of the breathalyzer’s margin of error could not constitute “evidence to the contrary” for the purposes of s. 258(1)(c). Beetz J. provided the following explanation for why such evidence was incapable of rebutting the presumption:
What evidence there is, tendered on behalf of the accused, is expert evidence from which Courts are asked to conclude, contrary to what the Code explicitly prescribes, that the result of the chemical analysis is not or ought not to be proof of the proportion of alcohol in the blood of the accused at the time when the offence was alleged to have been committed. This, in my opinion, is not evidence aimed at rebutting the presumption provided for in the section but at denying its very existence. “Evidence to the contrary” cannot be evidence solely directed at defeating the scheme established by Parliament under ss. 236 and 237.
This elaborate legislative scheme contemplates and provides for elements of positive certainty such as the official approval of certain kinds of instruments, the designation of analysts and qualified technicians, a maximum time period between the commission of the alleged offence and the taking of a breath sample, and the reading by a qualified technician on an approved instrument of a proportion of alcohol in the blood in excess of a specified proportion. Once the conditions prescribed or contemplated by this scheme are fulfilled, a presumption arises against the alleged offender which he can rebut by tendering “evidence to the contrary”. But in my opinion, no evidence is “evidence to the contrary” when its only effect is to demonstrate in general terms the possible uncertainty of the elements of the scheme or the inherent fallibility of instruments which are approved under statutory authority. Thus, the proof by expert evidence that, for physiological reasons of a general nature, the maximum time period of two hours between the commission of an offence and the taking of a breath sample is too long would not be “evidence to the contrary”. [Emphasis added; pp. 271-72.]
[20] In St. Pierre, Iacobucci J. made a similar finding with respect to s. 258(1)(c). In that case, the accused consumed two small bottles of vodka between the time she was stopped by police and when the breathalyzer test was administered. The Court concluded that this evidence was sufficient to rebut the presumption of identity. In limiting what could constitute “evidence to the contrary”, however, Iacobucci J. noted that evidence of the “normal process of absorption and elimination” could not be “evidence to the contrary”. Otherwise, “the presumption would be useless, since it could always be rebutted”. He further explained:
The effect of normal biological processes of absorption and elimination of alcohol cannot of and by itself constitute “evidence to the contrary”, because Parliament can be assumed to have known that blood alcohol levels constantly change, yet it saw fit to implement the presumption. Therefore, as Arbour J.A. states [in the Court of Appeal below], to permit this to become “evidence to the contrary” would, in effect, be nothing more than an attack on the presumption