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Although charges of impaired/over 80 have decreased in the past two decades, these driving offences currently constitute 12% of all cases on the dockets of lower courts. With approximately 15,000 impaired/over 80 cases being heard every year in the low courts, these offences represent the largest category of offence currently being tried in this court.
Parliament first introduced the offence of “driving while intoxicated” in 1921 but it was not until the late 1950’s that law enforcement officials began to use breath testing devices as an evidentiary tool for the prosecution of impaired driving. Provision of breath samples were taken on a voluntary basis until legislative amendments in 1969 created the “over 80” offence and a mandated breath testing regime with the use of statutorily-approved instruments. With the establishment of the status offence of driving with a blood alcohol content (BAC) of more than 80/mg/100ml in 1969, the era of breath testing commenced, and with the commencement of this era numerous and varied exculpatory claims were invented – the vast majority of these claims related to procedural issues such as compliance with the statutory pre-conditions for demanding breath samples or compliance with s.9 (arbitrary detention) and s.10(b) (right to counsel) of the Charter of Rights. Many of these defence claims have been dismissed at the appellate level but one claim has survived the vagaries of changing case law. An “evidence to the contrary” claim has become one of the primary exculpatory claims raised by accused drivers, and the gist of this claim is to raise doubt as to whether the breath testing results accurately represent the accused’s BAC at the time of driving and at the time of testing.
Evidence to the contrary claims have become an indispensable mechanism for making full answer and defence, and these claims are the primary mechanism for defeating evidentiary shortcuts which have been created to facilitate proof of the accused’s BAC. Statutory presumptions were created dictating that breath test results are presumed to be an accurate rendering of the BAC at the time of driving (presumption of identity) and at the time of testing (presumption of accuracy). The Ontario Court of Appeal outlined the evolution of breath testing and the corresponding legislative presumptions:
The presumption that the Breathalyzer reading is the same as the BAC at the time of the offence is based upon conclusions reached by qualified scientists derived from research and experiments. In 1951, the Criminal Code was amended by S.C., 1950-51, c. 47, s. 14 to create the new offence of impaired driving and to permit, for the first time, the admission of the results of voluntary tests of “blood, urine, breath or other bodily substance” as evidence of that offence and the older related offence of driving while intoxicated. Eighteen years later, in 1969, this modest provision for the admissibility of test results was repealed and replaced with the present law by the Criminal Law Amendment Act, 1968-69, S.C., c. 38, s. 16. This amendment inserted s. 241(1)(c) into the Criminal Code which permits presumptive proof of BAC by Breathalyzer test results. It also enacted s. 237(b), creating the offence of driving with a BAC over 80 thus obviating the necessity of proving that a driver was intoxicated or impaired. On both occasions, the Parliamentary debates indicate the legislation was grounded upon scientific conclusions based on research in Canada, the United Kingdom, the United States and other countries: see House of Commons Debates, June 25, 1951, pp. 4666-76; idem, January 23, 1969, pp. 4717-21. 
Traditionally, the evidence to the contrary claim has been comprised of testimony from the accused, or other sources, as to the level and pattern of consumption of the accused’s drinking on the day of arrest. In turn, this evidence would then be analyzed by a toxicologist, or related expert, to determine if, based upon the stated pattern of drinking, the accused BAC would actually be below the threshold limit of 80 mg.. To mount an evidence to the contrary claim the accused need not prove anything, but rather is simply required to discharge an evidentiary burden of raising evidence to cast doubt on the presumptions.
On July 2, 2008, the Tackling Violent Crime Act, S.C. 2008, c.2 was proclaimed into force and significant changes were effected with respect to evidence to the contrary claims. In particular, an accused driver must now discharge an evidentiary burden relating to three statutory pre-conditions before a judge can consider if this evidence is sufficient to rebut the statutory presumptions: 1) that the approved instrument was malfunctioning or being operated improperly; 2) that this malfunction or improper operation caused the reading to show that the BAC was in excess of 80 mg.; 3) that the accused actual BAC was below 80 mg.. To ensure that there is little doubt about the accused’s obligation to demonstrate some form of machine error and malfunction, s. 258(d.01) was enacted to state that evidence of the accused’s drinking patterns, with a BAC calculation conducted by an expert, will never constitute sufficient evidence to rebut the presumptions.
From the outset, there were concerns that the 2008 restrictions on “evidence to the contrary” infringed upon constitutional rights by requiring the accused to discharge an impossible burden. In the past 8 months there has been a flurry of decisions on the question of whether the 2008 amendments operate retrospectively, but no resolution has been achieved on this threshold issue and on the ultimate issue of constitutionality. Judges have expressed concerns over the dozens of conflicting decisions on retrospectivity , and some have even questioned the failure of provincial Attorney Generals to refer these issues to an appellate court for resolution. 
Earlier this year an attempt was made to consolidate a group of “over 80” cases into a single application in the Ontario Superior Court of Justice seeking a declaratory order that the new amendments did not apply retrospectively and that their application violated ss.7 & 11(d) of the Charter of Rights. On January 14, 2009 the Superior Court declined jurisdiction and ordered all of the consolidated cases to proceed to trial in the lower courts. 
Scientific evidence has demonstrated that the absorption and elimination rates of an individual who has consumed alcohol will vary not only from person to person due to their individual characteristics such as age, sex, weight, height, consumption of food, etc. but also at different times for the same person. It is unlikely, if not impossible to determine the precise rate at which a person metabolizes alcohol due to the dynamic nature of some of the characteristics which affect their metabolic rate. In addition, people may have different partition ratios for measuring the conversion of breath alcohol into blood alcohol. To neutralize this scientific reality, s. 258 (1) of the Criminal Code sets out statutory presumptions, one presumption of accuracy (s.258(1)(g) and two presumptions of identity (s.258(1)(c) & (d.1). These presumptions operate as evidentiary shortcuts which are rebuttable upon the accused leading “evidence to the contrary”. Assuming all statutory requirements of these presumptions are met and no evidence to the contrary is raised, a Crown may proceed to attempt to prove her case with the benefit of these evidentiary shortcuts. The presumption of accuracy found in s. 258(1)(g) dictates that the technician’s reading has resulted in an accurate reading of the accused’s blood alcohol level at the time of the test. According to s. 258(1)(c) the presumption of identity dictates that the accused’s blood alcohol level at the time of the test was identical at the time the alleged offence was committed.
In 2005, the Supreme Court of Canada described the presumptions as follows:
14 Where samples of an accused’s breath have been taken pursuant to a demand made under s. 254(3) Cr. C., Parliament has established separate presumptions in s. 258(1) Cr. C. to facilitate proof of the accused’s blood alcohol level: two presumptions of identity and one presumption of accuracy. According to the presumption of identity in s. 258(1)(c) Cr. C., the accused’s blood alcohol level at the time when the offence was alleged to have been committed is the same as the level at the time of the breathalyzer test. According to s. 258(1)(d.1) Cr. C., where the alcohol level exceeds 80 mg at the time of the test, there is a presumption that it also exceeded 80 mg at the time when the offence was alleged to have been committed. The presumption of accuracy in s. 258(1)(g) Cr. C. establishes prima facie that the technician’s reading provides an accurate determination of the blood alcohol level at the time of the test. These presumptions have certain similarities, but they remain distinct presumptions.
15 The standard of proof that must be met to rebut the presumptions of identity and accuracy is the same: reasonable doubt. The defence has no burden of proof. 
Due to the variations in an individual’s elimination/absorption rates, and in an individual’s partition ratio, it is clear that the statutory presumptions constitute a legal fiction. The presumptions render these individual variations irrelevant and operate to provide a rebuttable presumption of an accurate BAC reading in the face of scientific evidence which casts doubt in the accuracy of the reading. As the Supreme Court of Canada recently noted:
32 As I stated in my introductory remarks, it cannot be disputed that the presumption is a legal fiction and that a breathalyzer reading that exceeds the legal limit may not be reflective of the actual concentration of alcohol in the accused’s blood at the time of the offence because it always depends on the rate at which the particular accused is metabolizing the alcohol during the relevant time period on the day in question. Yet the offence is clearly made out. 
Overriding this legal fiction by rebutting the presumption of accuracy or identity cannot be achieved by simply pointing out the fictional nature of the presumption or the margin of error inherent in breath testing devices. Even before the evidence to the contrary claim was fully developed in the jurisprudence, the Supreme Court of Canada was clear in rejecting the relevance of an outright challenge to the rationality of the mandated breath testing regime. In 1979 the Court ruled that the 10% margin of error displayed by current breath testing devices would not constitute evidence to the contrary:
14 In the case at bar, the evidence of the expert witness was to the effect that Borkenstein Breathalyzers of the kind used to analyze respondent’s breath sample were all inherently subject to a possible margin of error of 10 milligrams, more or less: the trial Judge was asked to infer that unless this approved type of instrument indicated a reading in excess of 90 milligrams of alcohol in 100 millilitres of blood, an accused ought to be given the benefit of the doubt. Such an inference might perhaps be drawn in other kinds of cases with respect to instruments other than instruments which are approved under statutory authority. For instance, expert evidence could probably be tendered to show that radars of a certain type used by the police to measure the speed of motor vehicles are subject to an inherent margin of error which would make their reading unreliable as evidence against an accused unless the margin of error was taken into account. But radars are not approved instruments under a statutory scheme. To admit the evidence of the expert witness in this case is to concede that evidence gathered through the use of certain types of approved instruments may be treated in the same manner as that obtained by ordinary instruments. The same would be true, up to a point, of approved instruments of any type since all instruments used for measurement or analysis are necessarily subject to built-in limitations which affect their precision. I think the assimilation of instruments approved under statutory authority to ordinary instrument amounts to an error in law. It seems to me that when Parliament provided for the analysis of breath samples by way of approved instruments, it was aware of the limitations inherent in all instruments. Parliament must be taken to have made allowance for these limitations in the provisions relating to the approval of certain kinds of instruments as well as in those setting the highest permissible level of alcohol in the blood at 80 milligrams in 100 millilitres of blood. 
Shortly after the Moreau decision, the Supreme Court ruled that an analyst’s certificate of analysis was not rendered inadmissible by the failure of the analyst to undertake the manufacturer’s required step of measuring room temperature. However, the Court was clear in stating that admissibility of the certificate does not foreclose the raising of an evidence to the contrary claim:
11. With respect, I cannot agree that there is another implicit condition namely, that the instrument used must be shown to have been functioning properly, and the technician had followed the manufacturer’s instructions in testing its accuracy. It is clear from the wording of the Code that the rebuttable presumption arises from the mere statements in the certificate itself….13. This does not mean that the accused is at the mercy of the technician; while the certificate is evidence by itself, the facts of which it is evidence are “deemed to be established only in the absence of any evidence to the contrary”. Thus, any evidence tending to invalidate the result of the tests may be adduced on behalf of the accused in order to dispute the charge against him. 
The 1985 Carter decision of the Ontario Court of Appeal is often-cited as the leading case on evidence to the contrary. This is somewhat surprising considering the case involved a blood sample and the evidence to the contrary largely arose out of the testimony of a Crown analyst. Nonetheless, the Court articulated a rather open-ended test which did not require an accused to speculate as to the source of error in the testing procedures and results. The Court stated:
14 Judge Robson relied on R. v. Crosthwait, 52 C.C.C. (2d) 129 but I do not read that case as authority for the proposition that the defence is limited to calling technical evidence in order to raise a reasonable doubt as to the accuracy of a breathalyzer reading. In the Crosthwait case the only evidence offered on behalf of the accused was that of a doctor in chemistry who did not claim to be an expert on the operation of breathalyzers. He did not dispute the accuracy of the results of the breath tests but questioned the check tests made to calibrate the breathalyzer machine. The Supreme Court of Canada held that this did not constitute “evidence to the contrary” which could raise a doubt as to the accuracy of the certificate of analysis introduced in evidence by the Crown under s. 237(1) of the Criminal Code. It amounted to no more than speculation that the instrument used to measure the sample might not have been functioning properly.
16 In the case at bar, the reading came from a blood sample, not a breath sample, but once again, if the appellant’s evidence is accepted, the blood sample reading must be wrong, and the appellant is not obliged to speculate where the error might have occurred; in the taking of the sample, the labelling, the testing or whatever. It is perhaps for this reason that the trial judge in his reasons made reference to the “continuity in this matter”. When the blood sample reading does not reflect the consumption of alcohol testified to by the appellant, then the appellant (if he is believed) has raised a doubt as to the accuracy of the reading and it follows that there must have been a breakdown somewhere in the procedures followed in sampling and analyzing the appellant’s blood. (emphasis added) 
After 10 years of judicial consideration of evidence to the contrary claims, the Ontario Court of Appeal affirmed that the Carter defence had not been overruled. The Court stated:
I see no basis upon which to conclude that Carter has been overruled. Nor do I think that there is merit in the Crown’s submission that it should be reconsidered. An accused who is charged with an offence, the essence of which is that he was driving with an impermissibly high blood alcohol concentration level must be able to lead evidence as to the quantity of alcohol that he consumed at relevant times. I do not think it is necessary that this kind of evidence be accompanied by an attack on the particular breathalyzer machine, or its operator. It may well be that without such an attack it may be difficult for an accused to have the tendered evidence accepted to the point of raising a reasonable doubt. That, however, does not make the evidence inadmissible generally, or, as I have said, inadmissible because it constitutes an indirect attack on the breathalyzer or its manner of operation. 
The Carter case deals primarily with evidence to the contrary to rebut the presumption of accuracy in s. 258(1)(g). This provision does not explicitly incorporate the phrase “evidence to the contrary” but by virtue of s. 25(1) of the Interpretation Act R.S.C. 1985, c. I-21 this phrase is implicitly incorporated into the presumption. To defeat the presumption of accuracy the calculation of the accused’s BAC, as based upon the evidence of the accused’s pattern of consumption, must result in a reading which would be lower than the 80 milligram threshold (in Carter if the accused’s evidence was believed then his BAC would have been close to zero). However, with respect to the presumption of identity in s.258(1)(c), the Supreme Court of Canada in the St. Pierre case held that the presumption would be rebutted upon any evidence demonstrating a discrepancy between BAC at time of testing and at the time of driving even if the discrepancy did not place the accused’s BAC below the threshold limit. This result was reached primarily as a result of statutory interpretation. The Court noted:
45 In the first place, the plain wording of the section supports the conclusion that “evidence to the contrary” means simply that the blood alcohol level at the time of the test was different from the time of the offence. It does not support the conclusion that the evidence must show that the accused’s blood alcohol level was below .08.
46 To paraphrase, the section states that the blood alcohol level at the time the accused was driving will be presumed to be the same as the blood alcohol level at the time of the breathalyzer test, unless the accused can lead evidence showing that they were not the same. 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. To rebut the presumption all that must be done is for the accused to show that his or her blood alcohol levels at the two points in time were different and, hence, to show that the temporal presumption should not apply. On this basis, I fail to see how the majority’s position can be supported on the plain wording of the section. 
In response to this decision Parliament enacted s.258(1)(d.1) which states:
(d.1) where samples of the breath of the accused or a sample of the blood of the accused have been taken as described in paragraph (c) or (d) under the conditions described therein and the results of the analyses show a concentration of alcohol in blood exceeding eighty milligrams of alcohol in one hundred millilitres of blood, evidence of the result of the analyses is, in the absence of evidence tending to show that the concentration of alcohol in the blood of the accused at the time when the offence was alleged to have been committed did not exceed eighty milligrams of alcohol in one hundred millilitres of blood, proof that the concentration of alcohol in the blood of the accused at the time when the offence was alleged to have been committed exceeded eighty milligrams of alcohol in one hundred millilitres of blood;
In amending the presumption of identity to require evidence demonstrating a BAC of less than 80 milligrams, Parliament was simply correcting a drafting error or oversight which had resulted in different approaches to rebutting the presumption of identity and the presumption of accuracy. As noted by the Supreme Court of Canada in 2005:
22 Shortly after St. Pierre, Parliament amended the Criminal Code to add s. 258(1)(d.1) Cr. C., which expands the presumption of identity. According to this new provision, where the accused’s blood alcohol level exceeded 80 mg at the time of the breathalyzer test, it will be presumed, in the absence of evidence to the contrary, to have exceeded 80 mg at the time when the offence was alleged to have been committed. The effect of the enactment of s. 258(1)(d.1) Cr. C. was not to change the type of evidence needed to rebut the presumption of identity in s. 258(1)(c) Cr. C. or the presumption of accuracy in s. 258(1)(g) Cr. C., but to reinforce the presumption of identity. 
As a result of this amendment there remains little difference between evidence to the contrary claims which rebut the presumption of identity and those which rebut the presumption of accuracy. In 2008, the Supreme Court of Canada in R. v. Gibson noted that “the distinction between the presumptions of accuracy and identity continues to exist in theory, but has lost much of its importance in practice.”  Although the 1995 amendments were significant in terms of clarifying the law, there did not appear to be any constitutional shortcomings in enacting this clarifying restriction. Although the newly-formulated presumption of identity was held to operate retrospectively without constitutional infirmity , it would be a mistake to conclude that the constitutional analysis of the 1995 amendments would govern the constitutional analysis of the 2008 amendments. The former amendments did not change the nature of the evidence required to discharge the evidentiary burden, and the 1995 amendment to the presumption of identity only served to make this presumption consistent with the “well-established”  approach to the presumption of accuracy.
In 1988 the Ontario Court of Appeal ruled that the presumption of identity in s.258(1)(c) violated the presumption of innocence enshrined in s.11(d) of the Charter; however, the Court upheld the provision as a reasonable limit under s.1. The basis for this ruling is not explicitly set out in the judgement as the Crown had conceded that the provision infringed upon the presumption of innocence (in light of the Supreme Court of Canada’s characterization of the presumptions of accuracy and identity as “legal fictions”, it is not surprising that the concession was made). However, in finding that the presumption of identity was a reasonable limit the Court was satisfied that the infringement represented a minimal and proportionate impairment of the right because the law contained numerous procedural safeguards, including the evidence to the contrary defence:
It is always open to an accused to meet the presumption by “evidence to the contrary” as provided in s. 241(1)(c). For example, evidence of the amount and time of alcohol consumption coupled with the acknowledged margin of error might, in an appropriate case, be capable of rebutting the presumption….There are a number of safeguards built into the statutory scheme which ensure that the Charter right to be presumed innocent is interfered with as little as is reasonably possible… It is, of course, open to an accused to give evidence of drinking shortly before the Breathalyzer test together with appropriate scientific evidence and thus establish that the BAC shown by the Breathalyzer test was higher than that at the time of the alleged driving offence. This would be “evidence to the contrary” which could rebut the presumption under s. 241(1)(c). 
The P.E.I.C.A. reached a similar result without the benefit of a concession of infringement from the Crown. The basis for ruling that the presumption of identity violated the presumption of innocence is as follows:
I have concluded that s. 241(1)(c) does violate s. 11(d). If the steps outlined in s. 241(1)(c) have been taken, and if there is no evidence to the contrary, the trier of fact must (not may) find that the accused had the same concentration of alcohol in his blood at the time of the alleged offence as indicated at the time of the analysis of his breath. In other words the legislation provides for the substitution of proof of the concentration at the time of the tests for proof of the concentration at the time of the alleged offence. The problem with the substitution from the standpoint of s. 11(d) is that the proven fact does not lead inexorably to the conclusion that the concentration of alcohol in the blood of the accused was the same at the time of the alleged offence. The proven fact does not eliminate all reasonable possibilities other than the presumed fact. The results of analysis obtained in accordance with s. 241, even in the absence of any evidence to the contrary, do not remove every other rational conclusion, but that the accused had the same or a higher concentration of alcohol in his blood at the time of the alleged offence. Therefore the presumption created by s. 241(1)(c) could result in an accused being convicted despite the presence of a reasonable doubt. The fact that “evidence to the contrary” only has to raise a reasonable doubt does not render s. 241(1) (c) inoffensive to s. 11(d). That is because in a particular case a reasonable doubt as to a driver’s condition at the time of an alleged offence could still exist even though there was no evidence adduced which tended to establish that the concentration of alcohol in his blood was then different than that at the time of the analysis. 
As in the Phillips case, the Court of Appeal was satisfied that the violation was minimal and proportionate because of the existence of procedural safeguards and because “the presumption in s. 241(1)(c) only applies if there is no evidence to the contrary. It yields completely when there is any credible evidence at all which casts a reasonable doubt on the validity of the presumption in a particular case (emphasis added). 
The constitutional issue has not been revisited since the enactment of s.258(d.1) in 1995, but in a recent judgement the Supreme Court of Canada appears to suggest that any further erosion of the evidence to the contrary defence beyond the 1995 amendments would run afoul of the Charter. Some members of the Court noted that:
51 Section 258(1)(d.1) presents a significant hurdle for an accused, but the presumption it provides for is not absolute, nor could it be without threatening the presumption of innocence. It creates a legal fiction, but not an absolute one…..
76 Although I will not delve too far into constitutional issues that have not been raised in this appeal, 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. For example, in Phillips, the Ontario Court of Appeal, held that the presumption of identity, the equivalent of today’s s. 258(1)(c), was prima facie unconstitutional. However, the presumption was saved under s. 1 of the Charter, in part because it was rebuttable by means of evidence to the contrary. 
In effect, the new provisions conflate the presumption of identity and accuracy, make these presumptions mandatory and conclusive, and require that any evidence of the contrary must now include evidence of machine malfunction and operator error. There are a number of constitutional problems triggered by imposing a statutory obligation on the accused to raise specific exculpatory evidence which may not be accessible to anyone other than state officials.
Before briefly addressing these problems, there are a few important preliminary issues to be considered. First, it should be noted that in colloquial terms “evidence to the contrary” is characterized as a defence (as has been done throughout this paper), but it is more properly characterized as any technique designed to cast reasonable doubt on an essential element of the Crown’s case (i.e. the accused was over 80). However, for the purposes of constitutional analysis (especially if the analysis is extended to full answer and defence considerations under s. 7), it may not make a practical difference in terms of the result.  Whether characterized as a defence or the negation of an essential element, the relevant constitutional inquiry is whether at the end of the day the accused may be convicted in the face of reasonable doubt.
Second, it is arguable that the courts have already ruled that the presumptions are violative of the Charter, and the only remaining question to be addressed is whether there exists any legislative facts and empirical evidence to demonstrate that the s.1 balancing done previously be the courts should be maintained in light of these new circumstances. In other words, a fiction remains a fiction and the presumptions will always violate s.11(d). The previous court rulings held that the impugned provisions were saved by s.1 because of the presence of a open-ended “evidence to the contrary” claim rendered the Charter impairment to be minimal. It stands to reason that the burden should now be on the Crown to demonstrate that the s.1 reasonable limit balancing still applies in its favour even though it has enacted significant restrictions upon the open-ended exculpatory claim.
Since the rulings in Phillips and Ballem in 1988 and 1990, there has been one significant development which may alter the constitutional analysis undertaken by these earlier appellate courts. Most law enforcement agencies do not use the Borkenstein breathalyzer and have been employing more advanced approved testing devices like the Intoxilyzer 5000. The Intoxilyzer used a different technology (infrared spectroscopy) to detect alcohol and it has numerous internal self-checks to detect problems such as “mouth alcohol”. There is no question that the technological advances reduce the chance of error and the state’s justification for restricting the evidence to the contrary claim may turn on an assertion of virtual infallibility with respect to advanced testing devices.
The scientific evidence relating to error rates and sources of error is far beyond the scope of this brief paper, but the constitutional analysis may turn on this issue. Putting aside the problem of whether infallibility can ever be demonstrated, I do not think that the constitutional issue should turn solely on technological advances unless the Crown can also demonstrate that each and every police force in Canada have updated their breath testing devices and are using the newest generation of approved testing devices.
Putting aside the thorny issue of scientific evidence and infallibility, with respect to the presumption of innocence, the amendments have created a requirement for the accused to prove facts of which he/she has neither knowledge or disclosure. In other words, not only do the amendments deny the accused the opportunity to have the trial judge consider evidence which is directly relevant to an essential element of the offence, the terms of the amendments themselves are virtually impossible to satisfy given the lack of access to potentially relevant information. As Lamer J. held in R. v. Vaillancourt:
Any provision creating an offence which allows for the conviction of an accused notwithstanding the existence of a reasonable doubt on any essential element infringes ss. 7 and 11(d). 
In cases dealing with evidentiary presumptions favouring the Crown, the test for determining whether the presumption violates s. 11(d) of the Charter is found in R. v. Downey:
In order to determine whether there has been an infringement of s. 11(d) it must be decided whether or not the presumption under attack could lead to the result that an accused person would be found guilty even though a reasonable doubt existed as to that guilt….
This is another way of saying that a statutory presumption infringes the presumption of innocence if it requires the trier of fact to convict in spite of a reasonable doubt. Only if the existence of the substituted fact leads inexorably to the conclusion that the essential element exists, with no other reasonable possibilities, will the statutory presumption be constitutionally valid. 
So long as there are examples of the breath testing instrument providing inaccurate results, proof of the instrument’s test results cannot “inexorably” lead to the conclusion that the accused’s BAC at the time of the offence was the same. Indeed, to avoid running afoul of s. 11(d) of the Charter, the Crown must also show that there will never be “over 80” cases where the breath test results could be inaccurate even though the defence would be unable to discharge the new evidentiary burdens imposed in s. 258 (i.e., machine malfunction or operator error) due to the inaccessibility of the information necessary to discharge those burdens. It can be assumed that every “evidence to the contrary” acquittal since Carter shows that a trier of fact was left with a reasonable doubt as to whether the accused was “over 80” at the time of the offence, notwithstanding the results of the breath tests. To uphold the new provisions, the Crown would have to contend that all of those cases were wrongly decided. Further, if the Crown then proposes to argue that there is “scientific evidence” capable of showing that the breath tests are irrefutable or infallible, one is left wondering why the Crown would not have presented that same evidence to the trial courts whenever the Carter defence had been raised previously.
Beyond the presumption of innocence considerations, it is clear that the new provisions operate to impose significant constraints on how an accused can discharge the evidentiary burden for raising an evidence to the contrary claim. A significant impairment of the right to full answer and defence constitutes a violation of the principles of fundamental justice under s.7 of the Charter. With respect to these new provisions, the violation of s.7 has two separate but related components. First, the new amendments violate s. 7 of the Charter in that they create an “illusory defence” and, second, these provisions prevent the trial judge from considering probative evidence relevant to the defence.
In deciding that the abortion provisions at issue in R. v. Morgentaler were unconstitutional, Dickson C.J.C. expressed concern about the “illusory” nature of the statutory defences or exemptions afforded to persons who should not have been convicted of the offence:
One of the basic tenets of our system of criminal justice is that when Parliament creates a defence to a criminal charge, the defence should not be illusory or so difficult to attain as to be practically illusory. 
The second constitutional shortcoming as it relates to full answer and defence is triggered by Parliament’s attempt to pigeon-hole and predetermine the weight of evidence needed to raise a reasonable doubt. Almost two decades ago, the Supreme Court of Canada in R. v. Seaboyer struck down an amendment to the Criminal Code which restricted an accused’s right to have the trier of fact hear and consider defence evidence related to a sexual assault complainant’s sexual history (i.e., the “rape shield” provision). In finding that the provision’s prohibition on this defence-relevant evidence violated s. 7 of the Charter the Court held:
… Canadian courts, like courts in most common law jurisdictions, have been extremely cautious in restricting the power of the accused to call evidence in his or her defence, a reluctance founded in the fundamental tenet of our judicial system that an innocent person must not be convicted. It follows from this that the prejudice must substantially outweigh the value of the evidence before a judge can exclude evidence relevant to a defence allowed by law.
These principles and procedures are familiar to all who practise in our criminal courts. They are common sense rules based on basic notions of fairness, and as such properly lie at the heart of our trial process. In short, they form part of the principles of fundamental justice enshrined in s. 7 of the Charter. They may be circumscribed in some cases by other rules of evidence, but as will be discussed in more detail below, the circumstances where truly relevant and reliable evidence is excluded are few, particularly where the evidence goes to the defence. In most cases, the exclusion of relevant evidence can be justified on the ground that the potential prejudice to the process of admitting the evidence clearly outweighs its value.
To summarize, s. 276 has the potential to exclude otherwise admissible evidence which may in certain cases be relevant to the defence. Such evidence is excluded absolutely, without any means of evaluating whether in the circumstances of the case the integrity of the trial process would be better served by receiving it than by excluding it. Accepting that the rejection of relevant evidence may sometimes be justified for policy reasons, the fact remains that s. 276 may operate to exclude evidence where the very policy which imbues the section — finding the truth and arriving at the correct verdict — suggests the evidence should be received. Given the primacy in our system of justice of the principle that the innocent should not be convicted, the right to present one’s case should not be curtailed in the absence of an assurance that the curtailment is clearly justified by even stronger contrary considerations…. 
It would be hard to assert that permitting trial judges to consider Carter-type defence evidence – as they have been for almost 25 years – would be prejudicial to the Crown, let alone substantially prejudicial. On the other hand, that type of evidence is directly relevant to the factual innocence of the accused. The new s. 258(1)(d.01) renders that potentially exculpatory defence evidence entirely irrelevant in the absence of evidence capable of discharging the evidentiary requirements in the new s. 258(1)(c) relating to the operation of the breath testing instrument.
There is no doubt that the most fundamental “defence” to a criminal charge is to raise a reasonable doubt as to the existence of one of the essential elements of the offence. Pursuant to the new ss. 258(1)(c)(d.01) and (d.1), it will now be virtually impossible for an accused to raise a reasonable doubt as to whether or not he/she was “over 80” at the time of the offence, no matter how cogent the defence evidence about the alcohol consumed prior to the offence. For example, an accused with an unimpeachable video record of his activities in the hours leading up to the arrest would still be convicted unless he were able to marshal evidence capable of revealing a material error by the instrument or its operator. Evidence of such errors, however, to the extent that it is preserved (or even capable of being preserved), is exclusively within the possession of the police and the Crown. Indeed, unless the defence is given timely access to the testing apparatus and the environment in which the tests were administered, its ability to investigate the source of error is significantly hampered. All in all, it is difficult to see how the accused can properly make full answer and defence in light of the restrictions placed upon the evidence to the contrary defence.
 Pereira, J. & Grimes, C. (2002). Case processing in criminal courts, 1999/00. Statistic Canada: Juristat, 22(1), 1-14; Marth, M. (2008). Adult criminal court statistics, 2006/2007. Statistics Canada: Juristat, 28(5), 1-21; Janhevich D. et. al. (2002) Impaired driving and Other Traffic Offences – 2002. Statistics Canada: Juristat 23(9), 1-21.
 R. v. Phillips (1988) 42 C.C.C. (3d) 150 (Ont.C.A.)
 R. v. Hall  B.C.J. No. 1610 (Prov.Ct.); R. v. Hayes  O.J. No. 4095 (Ont.Ct. Justice); R. v. McDonald  O.J. No. 4297 (Ont.Ct. Justice)
 R. v. Vavrishkin  O.J. No. 4439 (Ont.Ct.Justice)
 R. v. Khan et. al.  O.J. No. 111 (S.Ct)
 R. v. Boucher  3 S.C.R. 499
 R. v. Gibson  S.C.J. No. 16
 R. v. Moreau  1 S.C.R. 261
 R. v. Crosthwait  1 S.C.R. 1689
 R. v. Carter (1985) 19 C.C.C. (3d) 174 (Ont.C.A.)
 R. v. Gilbert (1994) 92 C.C.C. (3d) 266 (Ont.C.A.)
 R. v. St. Pierre  1 S.C.R. 791
 R. v. Boucher  3 S.C.R. 499
 R. v. Gibson  S.C.J. No. 16 at para. 50
 R. v. Cvitkovic  O.J. No. 50
 R. v. Gibson  S.C.J. No. 16 at para. 48
 R. v. Phillips (1988) 42 C.C.C. (3d) 150 (Ont.C.A.)
 R. v. Ballem (1990) 58 C.C.C. (3d) 46 (P.E.I.C.A.)
 Ibid at para. 10
 R. v. Gibson  S.C.J. No. 16
 R. v. Whyte  2 S.C.R. 3
 R. v. Vaillancourt,  2 S.C.R. 636 at 655
 R. v. Downey  2 S.C.R. 10 at 27-29
 R. v. Morgentaler  S.C.J. No. 1; see also, Hitzig v. Canada  O.J. No. 3873 (C.A.)
 R. v. Seaboyer  2 S.C.R. 577 at 611-612 and 620-621