Tonkin v Police - [2006] SASC 145

SUPREME COURT OF SOUTH AUSTRALIA
(Magistrates Appeals: Criminal)
TONKIN v POLICE
[2006] SASC 145
Judgment of The Honourable Chief Justice Doyle
17 May 2006
CRIMINAL LAW - PARTICULAR OFFENCES - DRIVING OFFENCES - SO UNDER INFLUENCE OF LIQUOR OR DRUGS AS TO BE INCAPABLE OF CONTROL - PROOF AND EVIDENCE
The appellant was convicted in the Magistrates Court of driving a motor vehicle while there was present in his blood the prescribed concentration of alcohol contrary to s 47B of the Road Traffic Act 1961 (SA) - the appellant appeals against conviction to the Supreme Court - the question is whether evidence tendered at trial is sufficient to rebut the presumption that the results of a breath analysis instrument accurately record the concentration of alcohol in a person's blood pursuant to s 47G(1) of the Road Traffic Act 1961 (SA) - consideration of s 46G(1) of the Road Traffic Act - consideration of the adequacy of evidence tendered to rebut presumption - evidence concerns alcohol elimination rate - no error made out - appeal dismisssed.
Road Traffic Act 1961 (SA) s 47B, s 47G(1), s 47G(1a), s 47G(1a)(1), s 47G(1)(1a)(a), s 47G(1)(1a)(b), s 47G(1)(1ab), referred to.
Evans v Benson (1986) 46 SASR 317; Police v Shelmerdine (2000) 76 SASR 199, applied.

TONKIN v POLICE
[2006] SASC 145
Magistrates Appeal: Criminal

DOYLE CJ: Mr Tonkin was charged with driving a motor vehicle on 21 April 2005 while there was present in his blood the prescribed concentration of alcohol, contrary to s 47B of the Road Traffic Act 1961 (SA) (“the RTA”).
The prescribed concentration is 0.05 grams or more of alcohol in 100 millilitres of blood. (Hereafter I will for convenience express relevant concentrations as a percentage, to avoid constant repetition of the statutory expression, but it must be remembered that at all times the issue is the quantity of alcohol in 100 millilitres of blood).
Mr Tonkin pleaded not guilty. The prosecution and the defence tendered evidence. The evidence tendered by the prosecutor was in the form of certificates, a written statement and a written report from Dr Lokan. The defence tendered a certificate as to the taking of a blood sample from Mr Tonkin, a certificate reporting the analysis of that blood and a report from Dr Sykes, a chemical pathologist. No oral evidence was given. The Magistrate found Mr Tonkin guilty. He appeals against the conviction.
The appeal turns on whether the evidence tendered by Mr Tonkin was sufficient to rebut the presumption under s 47G(1) of the RTA. The presumption is that the concentration of alcohol indicated by a breath analysing instrument as being present in the blood of Mr Tonkin was present in his blood at the time of the analysis and was present throughout the preceding two hours: Evans v Benson (1986) 46 SASR 317 at 322 and at 326.
Section 47G(1a) limits the evidence that can be adduced to rebut that presumption, and also determines the means by which and the manner in which the presumption can be rebutted.
Facts and legislation
The case is governed by the first three subsections of s 47G, which provide as follows:
47G   Evidence
(1)Without affecting the admissibility of evidence that might be given otherwise than in pursuance of this section, evidence may be given, in any proceedings for an offence, of the concentration of alcohol indicated as being present in the blood of the defendant by a breath analysing instrument operated by a person authorised to operate the instrument by the Commissioner of Police and, where the requirements and procedures in relation to breath analysing instruments and breath analysis under this Act, including subsections (2) and (2a), have been complied with, it must be presumed, in the absence of proof to the contrary, that the concentration of alcohol so indicated was present in the blood of the defendant at the time of the analysis.
(1a)No evidence can be adduced in rebuttal of the presumption created by subsection (1) except—
(a)     evidence of the concentration of alcohol in the blood of the defendant as indicated by analysis of a sample of blood taken and dealt with in accordance with section 47I or in accordance with the procedures prescribed by regulation; and
(b)     evidence as to whether the results of analysis of the sample of blood demonstrate that the breath analysing instrument gave an exaggerated reading of the concentration of alcohol present in the blood of the defendant.
(1ab)If it is proved in proceedings that a concentration of alcohol was present in the defendant's blood at the time of a breath analysis, it must be conclusively presumed that that concentration of alcohol was present in the defendant's blood throughout the period of two hours immediately preceding the analysis.
Ms Downey, counsel for Mr Tonkin on appeal, accepts that the presumption created by s 47G(1) arose in the present case.
The issue for the Magistrate was whether the evidence adduced by Mr Tonkin established, on the balance of probabilities, that the breath analysing instrument had given “an exaggerated reading of the concentration of alcohol present” in Mr Tonkin’s blood.
Evans v Benson at 324 holds that Mr Tonkin had to establish the required conclusion on the balance of probabilities. Although subs (1) and subs (1a) have been amended since that decision, and subs (1ab) was inserted after that decision, this aspect of the reasoning in Evans v Benson remains relevant.
The decision of the Full Court in Police v Shelmerdine [2000] SASC 45; (2000) 76 SASR 199 also establishes that the required conclusion, that the reading was “exaggerated” is not established merely by proving that the analysis of a sample of blood demonstrates (when explained) that the concentration of alcohol in Mr Tonkin’s blood was less than that indicated by the breath analysing instrument. In Shelmerdine Prior J said at [12]-[13]:
… It is not correct to make a finding of exaggeration simply because a higher reading than that disclosed by a blood alcohol test resulted or because the breath analysis reading places the offence in a more serious penalty category. The reading prevails until properly rebutted. It was not in this case. "Exaggerated" in the context of this legislation does not simply mean greater but abnormally large or unduly magnified given the previous acceptance by this Court in Benson that a blood analysis was for the purpose of s 47G "intrinsically superior to breath analysis as a means of determining accurately the concentration of alcohol in the blood".
The defendant has to show that there was something plainly wrong with the indicated level against the assumption that the blood analysis will be lower and more accurate than that indicated by a breathalyser. The result indicated by the breath analysing instrument must be shown to be outside accepted margins for error consistent with the instrument not functioning properly or some operator error.
Martin J agreed with that approach. He referred to the legislative scheme, described it briefly and concluded at [46]:
In the context of the scheme as I have described it, I agree with Prior J that "exaggerated" in subpar (b) means abnormally large or unduly magnified in the sense that the result is plainly wrong because it is outside the accepted margins for error and indicates that the breath analysing instrument did not function properly or was not operated correctly by the operator.
The evidence established that at 8.21 pm on 21 April 2005 a breath analysing instrument indicated that there was present in Mr Tonkin’s blood 0.087% of alcohol. It was not denied that the requirements and procedures referred to in s 47G had been complied with. And so it was not denied that the statutory presumption arose.
Counsel for Mr Tonkin before the Magistrate tendered documents that established that a sample of Mr Tonkin’s blood was taken at 10.00 pm on 21 April and that on analysis it was found to contain not less than 0.05% of alcohol. It was common ground that this evidence could be relied upon by Mr Tonkin pursuant to s 47G(1a)(a).
By consent counsel for Mr Tonkin also tendered a report from Dr Sykes, a chemical pathologist. He carried out an ethanol elimination test on Mr Tonkin on 21 October 2005. On that day Mr Tonkin’s alcohol elimination rate was determined to be 0.0145 grams of alcohol in 100 millilitres of blood per hour. It was agreed that if that elimination rate was applied to the result of the blood test at 10.00 pm on 21 April, it could be calculated that at 8.21 pm, the time of the breath analysis, Mr Tonkin’s blood contained 0.073% alcohol. The evidence from Dr Sykes, and the “back calculation” that was carried out using it, were both admissible to explain the significance of the blood test in relation to the accuracy of the breath test: Evans v Benson at 321-322 and at 324 King CJ.
Submissions on appeal
Ms Downey submits on appeal that this evidence alone was sufficient to prove, on the balance of probabilities, that the breath analysing instrument gave an “exaggerated reading”.
But that submission does not allow for the effect of observations made in the tendered report from Dr Lokan. He said that a person’s alcohol elimination rate can vary from occasion to occasion. Dr Lokan calculated that the result of the blood analysis could be reconciled with the result of the breath analysis if, on 21 April 2005, Mr Tonkin’s alcohol elimination rate was 0.0188 grams of alcohol per 100 millilitres of blood per hour. Dr Lokan said that the variation between that rate and the elimination rate established by test on 21 October 2005 (which he calculated as a variation of 25.8%) was within the range of variation for individuals reported in the literature. This evidence was not challenged.
There was no evidence to support an argument that Mr Tonkin’s alcohol elimination rate could not have varied from 0.0145 grams of alcohol per 100 millilitres of blood per hour to 0.0188 grams of alcohol per 100 millilitres of blood per hour. Nor was there any evidence, even if that variation was possible, that it would not in fact have occurred in the particular circumstances. In other words, the evidence from Dr Lokan was that Mr Tonkin’s alcohol elimination rate could have been as low as the lower rate, or as high as the higher rate, and there was no evidence to suggest that either rate was more likely to have been the alcohol elimination rate on 21 April 2005.
That being so, the evidence led before the Magistrate could not establish on the balance of probabilities that the result of the breath analysis was incorrect, let alone that it was “exaggerated”. That is so because the elimination rate established by testing on 21 October 2005 was not shown to be the elimination rate on 21 April 2005. All that can be said is that it might have been, but it is equally possible that it was not the elimination rate on 21 April 2005, and that on that date the elimination rate was quite different. In my opinion that evidence cannot and does not lead to a conclusion, on the balance of probabilities, that on 21 April 2005 Mr Tonkin’s alcohol elimination rate was such that there was a discrepancy as between the result of the blood test and the result of the breath analysis, let alone that the discrepancy was such as to indicate that the result of the breath analysis was “an exaggerated reading”.
It is irrelevant, in view of the evidence, that Dr Lokan acknowledged that Mr Tonkin’s alcohol elimination rate on 21 April 2005 was not known, and could not be known. It is equally irrelevant that he acknowledged that on 21 April 2005 the elimination rate might have been 0.0145 grams of alcohol per 100 millilitres of blood per hour, the rate determined on 21 October 2005. That was obviously a possibility.
It is necessary to bear in mind that the onus was on Mr Tonkin to establish something on the balance of probabilities. Mr Tonkin had to establish on the balance of probabilities that on 21 April 2005 his alcohol elimination rate was not a rate that enabled the result of the blood analysis to be reconciled with the result of the breath analysis. That is, he had to prove on the balance of probabilities that on 21 April 2005 at 8.21 pm his blood did not contain the concentration of alcohol indicated by the breath analysing instrument. If that had been established, one would then know that the two results could not be reconciled. One would then consider whether the breath analysing instrument had given an “exaggerated reading”. The evidence that Mr Tonkin adduced showed only that the alcohol elimination rate on 21 April 2005 might not have been high enough to enable the two results to be reconciled. That was not sufficient.
The same point can be put in another way. Standing alone, the result of the blood analysis proved nothing. It had to be explained or interpreted. The result could or might indicate that the result indicated by the breath analysing instrument was wrong or unreliable, if a “back calculation”, using an alcohol elimination rate that was probably reliable or accurate, indicated that the breath analysis result was wrong. A calculation using an alcohol elimination rate that might or might not be reliable or accurate could not do this.
To some extent Ms Downey’s submission was that her primary submission should be accepted, because otherwise it was impossible to rebut the statutory presumption. But that is not necessarily so. For all I know it may be possible to show, in a given case, that the results of the breath analysis and of the blood analysis could be reconciled only by postulating an alcohol elimination rate that was outside the known rates of variation. Another possibility is that it might be possible, in a given case, to lead evidence that having regard to the circumstances or characteristics of the defendant, although the variation between the postulated rate and the test rate was not outside the range of experience, nevertheless having regard to particular circumstances the rate could not have varied by the amount that would be necessary for one to be able to reconcile the two results.
For those reasons the attack on the Magistrate’s finding of guilt fails.
In light of that, it is not necessary to consider whether the Magistrate was correct in deciding that the difference between the result indicated by the breath analysing instrument (0.087%) and the result calculated by a “back calculation” from the result indicated by the blood test (a reading of 0.073%) demonstrated that, having regard to the greater reliability of the blood test, the breath analysing instrument had given “an exaggerated reading of the concentration of alcohol present in the blood of” Mr Tonkin.
Ms Downey put a forceful submission that the difference between the result indicated by the breath analysing instrument and the result arrived at by “back calculation” did demonstrate that the breath analysing instrument had given “an exaggerated reading”. But Mr Keane, counsel for the respondent, presented a carefully thought out “corrected back calculation”. This calculation was based on the fact that the result of the blood analysis was 0.056%, but reported as not less than 0.05%. A “back calculation” performed with reference to the actual result, rather than the reported result, meant that the calculated result was 0.0799%, and that was to be compared with the result by breath analysis of 0.087%.
I prefer to express no view on the question of whether, had the calculated reading been established on the balance of probabilities to be the reading at the time, the result would demonstrate that the breath analysing instrument had given an “exaggerated reading”. There was no evidence before the Magistrate, and so none before me, explaining the type or range of variations that are inevitable, or that might be expected, nor the type or range of variation that might be thought to indicate that the reading provided as a result of the breath analysis was erroneous. Any view that I might express on this topic, unguided by expert evidence, would be an uninformed view.
As far as I can tell in Shelmerdine there was no evidence about margins for error in operating a breath analysing instrument or about the fact that an individual’s alcohol elimination can vary, nor was there any evidence explaining the extent by which it might vary. I found no reference to evidence on this topic in the reasons. In light of the fact that the evidence in this case establishes that the alcohol elimination rate can vary, and that there is data as to the rate of variation that has been found, I consider it to be unwise for me to venture an opinion on the question of what difference would lead to a conclusion that “an exaggerated reading” had been provided. That can be left to another day, and to a case in which the court is assisted by relevant evidence.
For those reasons I dismiss the appeal against conviction.