The State of Western Australia v West - [2021] WASC 5

JURISDICTION : SUPREME COURT OF WESTERN AUSTRALIA
IN CRIMINAL

CITATION:   THE STATE OF WESTERN AUSTRALIA -v- WEST [2021] WASC 5
CORAM:   TOTTLE J
HEARD:   14 DECEMBER 2020
DELIVERED          :   12 JANUARY 2021
FILE NO/S:   INS 25 of 2020
BETWEEN:   THE STATE OF WESTERN AUSTRALIA
Prosecution
AND
DAVID LAWRENCE WEST
Defence

Catchwords:

Criminal law - Trial of issues

Legislation:

Criminal Code (WA), s 280

Result:

Findings of fact made

Category: B

Representation:

Counsel:

Prosecution	:	K Jennings
Defence	:	A Padmanabham

Solicitors:

Prosecution	:	Director of Public Prosecutions (WA)
Defence	:	AP Legal Criminal Lawyers Pty Ltd

Case(s) referred to in decision(s):

R v Olbrich [1999] HCA 54; (1999) CLR 270
Ramsay v Watson [1961] HCA 65; (1961) 108 CLR 642

TOTTLE J:

Introduction

On 17 September 2020 David Lawrence West pleaded guilty to unlawfully killing Moira Ann Dunstall on 15 April 2019, in circumstances not constituting murder, contrary to s 280 of the Criminal Code (WA).
Issues have arisen as to the facts on which Mr West is to be sentenced. Before identifying the issues I will set out the facts not in dispute.

The material facts not in dispute

Mr West was 46 years of age when he committed the offence. His working life has been spent as a truck driver.
On Monday 15 April 2019 at about 12:49 pm Mr West drove a truck towing a semi-trailer in a southerly direction on the inside (left) lane of Tonkin Highway towards the intersection with Armadale Road, Forrestdale. The semi-trailer was loaded with a large mobile conveyor machine. The gross vehicle mass of the truck and loaded trailer was 39.4 tonnes.
The Tonkin Highway intersection with Armadale Road is a major 'multilane intersection' in all directions. Traffic lights control the traffic at the intersection. In addition to the traffic lights at the intersection itself there is a set of 'amber warning lights' situated on either side of the carriageway about 100 m prior to the intersection. The purpose of the amber warning lights is to warn approaching traffic of an imminent change in the traffic lights at the intersection. The carriageway at the intersection is sealed. On the day of the offence the road surface was in good condition, free of potholes and contaminants. The road was wet as it had been raining.
As Mr West's truck approached the Armadale Road intersection, the amber warning lights began to flash indicating that the traffic lights at the intersection were about to change to red. The traffic light at the intersection facing the direction (north) from which Mr West's truck was approaching then changed from green to amber.
Mr West did not slow his truck down in preparation for the inevitable red traffic light at the intersection but continued at a speed, estimated to have been between 80 and 100 km per hour towards the intersection. As Mr West's truck approached, the traffic lights facing north changed from amber to red.
The driver of a truck, which was travelling behind Mr West's truck, responded to the amber warning lights and the subsequent amber and red traffic light at the intersection by slowing his truck and stopping it at the white line marking the beginning of the intersection.
Ms Dunstall was driving a Mitsubishi Magna. Her vehicle was stationary on Armadale Road waiting to enter the intersection from the west. When the traffic lights changed from red to green in her favour, Ms Dunstall drove onto the intersection in order to turn right into the northbound carriageway of Tonkin Highway.
Without slowing or activating a warning device Mr West drove his truck onto the intersection approximately three to five seconds after the traffic light facing his direction changed from amber to red. His truck and semi-trailer slammed into the driver's side of Ms Dunstall's vehicle and pushed it along Tonkin Highway in a southerly direction for approximately 150 m.
Ms Dunstall died in her vehicle as a consequence of the catastrophic impact of Mr West's truck and trailer.
Mr West was arrested at the scene on suspicion of dangerous driving occasioning death.
A sample of Mr West's blood was taken that afternoon at 2.22 pm. When analysed, the sample was shown to contain 0.06 mg/L of methylamphetamine and 0.01 mg/L of amphetamine.
Mr West participated in an electronic record of interview during which he would not comment on the crash or the immediate lead up to it. Mr West said that due to taking Viagra the night before the crash he slept restlessly, however, he said he felt fine when he arrived at work the following morning.
When the offence was committed Mr West was on parole for possession of a prohibited drug (methylamphetamine) with intent to sell or supply. The parole period was due to expire on 22 April 2019.

The issues

There are two issues:
(a)Was Mr West's capacity to drive on 15 April 2019 impaired by the physiological and behavioural effects of having taken methylamphetamine?
(b)Was Mr West suffering from undiagnosed obstructive sleep apnoea on 15 April 2019, and if so, did it contribute to the offending?
In overview it was accepted by Mr West's counsel that Mr West was impaired by fatigue on 15 April 2019.[1] Counsel maintained, however, that Mr West's use of methylamphetamine had not contributed to his fatigue and that when he went to work and drove his truck that day he was not aware of his fatigue, that is, he did not drive when he knew he was in a fatigued state.
[1] ts 16 - 17, 55, 62.

Relevant standards of proof

If a fact or circumstance to be taken into account is adverse to the offender's interests it must be established beyond reasonable doubt, that is, by reference to the highest standard of proof known to the law. If the fact or circumstance is in the offender's favour it may be established on the balance of probabilities, that is, a standard of proof less stringent than beyond reasonable doubt.[2]
[2] R v Olbrich [1999] HCA 54; (1999) CLR 270 [27].
Thus, an aggravating factor, namely a fact or circumstance which increases the culpability of the offender must be proved by the State beyond reasonable doubt. The existence of impairment as a consequence of having taken methylamphetamine is an aggravating fact or circumstance that must be established beyond reasonable doubt. A mitigating factor, namely a fact or other circumstance which in the court's opinion decreases the culpability of the offender or the extent to which the offender should be punished, must be established by the offender on the balance of probabilities. Whether Mr West suffered from undiagnosed sleep apnoea in April 2019 and whether that contributed to the offending is a mitigating factor and it must be established on the balance of probabilities.

Mr West's use of methylamphetamine

Mr West was interviewed by a senior community corrections officer for the purposes of preparing a pre-sentence report. In the course of the interview Mr West told the author of the pre-sentence report that an old associate visited him at his home on the day prior to the offence and the two of them used methylamphetamine together. The author of the pre‑sentence report noted that Mr West did not believe that his use of methylamphetamine 'during the day prior to the offence impacted on his capacity to drive a motor vehicle'.
In the course of submissions Mr West's counsel said that Mr West accepted that he made such a statement in the pre-sentence report interview but maintained that he had made a mistake as to the day. Mr West's present recollection was that he had consumed methylamphetamine with his associate one day earlier than he had said in the pre-sentence interview, that is, on Saturday, 13 April 2019 and not Sunday, 14 April 2019. When interviewed by police officers on the evening of 15 April 2019 Mr West told the officers that 'his mate was over on Saturday'.[3] That statement tends to suggest that Mr West did make a mistake when he told the author of the pre-sentence report that he had taken methylamphetamine with an associate on the Sunday. The State accepted that it could not prove beyond reasonable doubt that Mr West used methylamphetamine on the Sunday rather than, as he told the police officers on the day of the offence and as he now maintains, on the Saturday.[4]
[3] Electronic Record of Interview, 12:49.
[4] ts 66.

The account of the events given by Mr West to the police

Mr West was interviewed by police officers on 15 April 2019 at 8.25 pm. When asked whether he was under the influence of drugs or medication he said, 'I don't think so'. As noted earlier he said that he had some Viagra the night before. Later in the interview he said he was in shock and 'scattered'.[5] Mr West said that he was feeling good earlier in the day[6] and had no fatigue.[7] He had not worked over the weekend. He said he woke at 5.00 am, which was his normal time of waking, and felt fine. He arrived at work at 6.30 am. He said he did not feel tired. The following exchange took place about Mr West's sleeping habits:
Police officer:     What time do you normally go to sleep at night?
Mr West:          Between 8 and 10.
Police officer:     Alright. Ok, so, is it - you say you wake up at 5, so is it fair to say you get 7 to 8 hours a night roughly – normally? Do you sleep well, or?
Mr West:          Normally pretty well, yeah.
Police officer:     What about last night?
Mr West:          Nah a bit of tossing last night.
Police officer:     A bit of tossing and turning last night so you didn't have the best sleep last night?
Mr West:          Nah.
[5] Electronic Record of Interview, 27:40.
[6] Electronic Record of Interview, 12:02.
[7] Electronic Record of Interview, 12:12.
Mr West gave an account of his work that morning. He said there were no distractions. He said that because it was raining he was driving slower than usual. He said he was not under the influence of alcohol or drugs. When asked about the accident and what happened, he said, 'no comment' and when asked about whether he had full control of the vehicle 30 seconds prior to the crash he said 'no comment'.

The State's evidence of the effects of Mr West's methylamphetamine use

The State relies on opinions expressed by Professor David Joyce in relation to the effects of intoxication with methyamphetamine. Professor Joyce's qualifications were not in issue and only brief reference need be made to them. Professor Joyce is a consultant physician who has practiced as a specialist in clinical pharmacology and toxicology since 1986. He has been the director of drug analysis services at the PathWest Laboratory since approximately 2000 and has been the Professor of Clinical Pharmacology at the University of Western Australia since 2010.
For the purposes of enabling Professor Joyce to express opinions he was provided with statements and other materials from the State's brief. These included: video recordings of the collision between Mr West's truck and Ms Dunstall's vehicle recorded on the 'dashcams' of other vehicles; video recordings of Mr West sitting in an ambulance at the scene of the accident and later at the Armadale Hospital recorded on the 'bodycams' of police officers; and the electronic record of interview.
Professor Joyce prepared a report dated 24 February 2020 that was included in the State's brief tendered as exhibit 1.
In the paragraphs that follow I set out the relevant effect of Professor Joyce's evidence.
Amphetamine-type drugs are abused because of their capacity to produce increased confidence, a sense of well-being, euphoria, a sense of invulnerability and a subjective sense of increased alertness.
A person who is intoxicated with methylamphetamine initially goes through a phase where he or she may be over-active, talkative, apparently agitated and trembling (the stimulated phase). Risk-taking behaviour, recklessness, aggression and violence are common early consequences of intoxication with methylamphetamine. The stimulated phase of methylamphetamine intoxication typically lasts around six to 12 hours.[8]
[8] ts 22.
After the period of acute stimulation, users pass into a stage of slowness, inattention, impaired reactions and lowered mood (the coming down phase). Methylamphetamine is very effective in preventing sleep. Professor Joyce described methylamphetamine use and sleep deprivation as 'inseparable'. The coming down phase is attributable to lack of sleep. Professor Joyce said that to an observer, there may seem to be little notable in the appearance of a person in the coming down phase except they may look taciturn and weary. Professor Joyce accepted that it was possible that not every user of methylamphetamine will be unable to sleep but he said that 'must be pretty uncommon'.[9]
[9] ts 32.
The coming down phase may drag on for days because methylamphetamine's interference with sleep usually takes days to resolve after an intoxicating dose. It is not possible to identify the end of the coming down phase with precision.[10] The symptoms manifested in the coming down phase resolve when the affected person gets a good night's sleep.[11] When sleep comes, it may be sudden, irresistible and outside the normal hours of sleep.
[10] ts 24.
[11] ts 29.
Methylamphetamine may influence driving through the physiological and behavioural effects described in the preceding paragraphs. Speeding, reckless driving, high-speed pursuits and crashes are common manifestations of intoxication during the stimulated phase. Defects in vehicle control arising from inattention, impaired reactions and sudden sleep underlie the increased accident risk in the coming down phase.
The relationship between drug concentration and effect is indistinct for methylamphetamine. This is partly because the time from dose to the assessment of the effects and the 'use history' influence outcomes.[12] The same dose of methylamphetamine will have different effects on different users.[13]
[12] ts 24.
[13] ts 32.
There is no consensus among forensic toxicologists about the level of concentration of methylamphetamine in a driver's blood stream from which impairment can be inferred. There is no disagreement, however, that any concentration can confer risk but there is uncertainty about the degree of risk at different concentrations.[14]
[14] ts 32.
In Western Australia around half of all the serious accidents involving methylamphetamine-using drivers occur during the coming down phase of methylamphetamine intoxication. This aspect of Professor Joyce's evidence was based on his analysis of 175 cases which had occurred between 2004 and 2019. Most of the coming down phase accidents were 'drive-off-the-road' crashes or crashes arising from straying into the path of another vehicle but intersection crashes were also not uncommon.
Based on his analysis of the 175 cases referred to above Professor Joyce considered a blood concentration of methylamphetamine of 0.06 mg/L was at the relatively low end of the broad range of concentrations found in drivers impaired by the use of methylamphetamine. Professor Joyce said that the average concentration of methylamphetamine found in the blood of methylamphetamine-affected drivers was 0.23mg/L. Professor Joyce did not accept that a concentration of 0.06 mg/L of methylamphetamine in blood was 'the absolute bottom of the range'.[15] He said this concentration was consistent with Mr West having taken a 'fairly large dose' of methylamphetamine on the Saturday immediately preceding the accident.[16]
[15] ts 31.
[16] ts 31.
Professor Joyce agreed with the proposition that it was not possible to say that Mr West was impaired at the time of his driving solely on the basis of the concentration of methylamphetamine in his blood of 0.06mg/L. His evidence as to how this concentration of the drug should be interpreted was as follows:[17]
Now, the proper interpretation of all that would be that this represents a concentration which is consistent with the driver being in the coming‑down phase after a methylamphetamine dose, and a decision about its actual contribution would then have to be put together with the circumstances that were observed by witnesses to see whether they too were pointing towards a state of methylamphetamine-affected coming-down. (emphasis added)
[17] ts 25.
Professor Joyce analysed the issue by reference to the process of making a medical diagnosis. He referred to the evidence of the concentration of methylamphetamine in Mr West's blood as the laboratory evidence and the evidence of Mr West's driving - not slowing down in response to the warning lights and driving through a red light onto the intersection - as the clinical evidence. He said that both the laboratory evidence and the clinical evidence were consistent with the conclusion that Mr West's use of methylamphetamine contributed to Mr West's capacity to control his truck being impaired. Professor Joyce added:[18]
The proper balance of evidence, though, would not go to the point of saying that this represented proof of diagnosis - it is consistent with a diagnosis.
[18] ts 27.
In his report Professor Joyce stated that the concentration of methylamphetamine found in Mr West's blood, 0.06 mg/L predicts impairment of capacity for safe driving, through effects on attention (distractibility and failure to notice hazards), alertness, behaviour, emotional stability, wakefulness and performance. (my emphasis).
There seemed to be a tension between the proposition that it was not possible to say that Mr West was impaired at the time of his driving solely on the basis of the concentration of methylamphetamine in his blood and the view that such a concentration of the drug predicted impairment. In response to a question from me, Professor Joyce clarified that his use of the word 'predicts' was not intended to convey certainty. Rather it should be understood as meaning 'gives rise to the likelihood'.[19] This aspect of Professor Joyce's evidence must also be understood in the context of the evidence given by him in cross‑examination to which I refer below, to the effect that Professor Joyce was confident that the methylamphetamine in Mr West's blood would have had an adverse effect but he could not say whether that adverse effect was the crash.
[19] ts 39.
Professor Joyce accepted that there was no evidence that following the accident Mr West showed ongoing fatigue or an ongoing tendency to 'nod off' and, that the absence of such evidence suggested that Mr West was not in the coming down phase - he said he would expect those symptoms to have continued.[20] Professor Joyce said that as he appeared in the video recordings taken on the day (both the bodycam recordings and the video record of interview) there was nothing about Mr West's appearance that pointed to the presence of a drug.[21]
[20] ts 28.
[21] ts 22.
In cross-examination Professor Joyce was asked whether the fact that no other instances of concerning driving by Mr West were observed was inconsistent with his having been in the coming down phase. The cross-examination went as follows:[22]
And would you agree with me, Professor Joyce, that it would not be consistent with him being in the come-down phase or experiencing the symptoms of the come-down phase, more precisely?---The conclusion could be given more confidently the more instances were definitely present. The definite presence of one instance, though, is, of itself, fairly convincing evidence of inattention.
Certainly it's convincing evidence of inattention but can you, Professor Joyce, go as far as to say it's convincing evidence that the inattention was the result of the drug in his system and not something else?---That's quite correct. The presence of the drug in the system offers itself as an explanation for the inattention. It doesn't offer itself as either the entire explanation or an exclusive explanation.
And would you, in your experience, expect that there might have been a period of impaired driving prior to the contravention of the signal if it were to explained by the presence of the drug alone in his system?---Now, I can't point to exhaustive experience on that because, by and large, the events which occurred prior to the signal event are not well‑documented so I can't tell you how often it is that a driver will fail to draw attention to himself until one decisive event.
[22] ts 28.

Professor Joyce was asked whether, if it was assumed that Mr West slept his 'normal number of hours' on the Sunday night that the symptoms of fatigue would have been less prevalent or noticeable and, in a follow up question, Professor Joyce was asked about the significance of the evidence that Mr West 'felt normal' when he woke up on Monday. Professor Joyce's evidence in response to these questions was as follows:[23]
I haven't really got any - some - well now looking at fairly tightly defined circumstance where I can't pretend to have exhaustive experience. So the two pieces of information that we have to deal with now are dose on Saturday - well, the clinical situation is dose on Saturday, not sleeping Saturday night but sleeping on Sunday night but still having 0.06 milligrams per litre at 2 o'clock on Monday. Now, it doesn't – doesn't - the first comment is it doesn't comfortably hold together as a story that he was able to sleep well on the Sunday night with that much methylamphetamine. But let's say that is in fact all correct, then I would have thought that somebody like that would have been better protected from the inattention than someone who had had a poor night also on Sunday.
…
… Well, again, [that Mr West felt normal on waking] doesn't hold together comfortably, but if the person told me that, then I don't think I would have authority to argue with them.
[23] ts 30.
The potential contribution of obstructive sleep apnoea to the fatigue experienced by Mr West was explored with Professor Joyce as follows:
And if there was another factor, such as obstructive sleep apnoea, which may have caused the fatigue you couldn't rule that out as being - sorry, let me start that sentence again. You couldn't rule that out as being the whole contributing factor to the fatigue in circumstances where the concentration of methylamphetamine is at 0.06, would you?---If there was an additional cause of fatigue and inattention then it, too, may be part of the story. In terms of making a diagnosis or commenting on a diagnosis of obstructive sleep apnoea, that lies a bit beyond my expertise.
The proposition I'm putting to you, Professor, is that because of the low level of methylamphetamine you wouldn't be able to rule out a different cause at the root of the fatigue or the symptom?---Yes. I can't rule out alternative or additional causes for the inattention.
Professor Joyce said if a patient suffered from difficulty sleeping, he would expect those difficulties to be compounded or aggravated by methylamphetamine use.[24]
[24] ts 40.
In his report Professor Joyce stated that, '[t]he blood concentration therefore represents evidence that methylamphetamine would have had adverse effects on Mr West's driving ability at the time of the crash'. In re-examination Professor Joyce was asked whether his evidence was that the methylamphetamine in Mr West's blood 'could have' or was 'likely to have' an adverse effect on Mr West's capacity to drive. He responded as follows:[25]
No, it would have had an adverse effect, but I can't tell you whether that adverse effect was the event that we have heard described. So the - that sort of methylamphetamine use will always have some adverse effect on - on driving, but the - lots of drugs have some adverse effect on – on - on driving. A tiny adverse effect has no consequences in driving safety, but a sufficient adverse effect does have a consequence in driving safety. And the scenario that we're examining now appears to be one in which there is a sufficient adverse effect on - on driving safety.
[25] ts 37.
In re-examination various hypotheses were put to Professor Joyce based on different assumptions concerning: when Mr West took methylamphetamine, that is on the Saturday or Sunday before the accident; how he slept on the Sunday night; and whether he suffered from sleep apnoea. Professor Joyce's evidence in response to those hypotheses may be summarised as follows:[26]
(a)If Mr West took methylamphetamine on the Saturday and slept well on the Sunday night, he would be less impaired than if he had not slept well but the presence of methylamphetamine in his system is 'solid evidence' and 'it would be difficult to set that aside and express the view that he would not be impaired'.
(b)If Mr West took methylamphetamine on Saturday and did not sleep well on 'Sunday but tossed and turned all night' that would be more consistent with the familiar consequences of methylamphetamine use and consistent with the residual methylamphetamine concentration in his blood on Monday afternoon. Professor Joyce said that his opinion would be 'pretty much the same' whether it was established that Mr West took methylamphetamine on the Saturday or the Sunday.[27]
(c)If Mr West took methylamphetamine on Saturday but did not sleep well on Sunday in part due to sleep apnoea then 'the balance of evidence would be in favour of the methylamphetamine still impairing [Mr West] on Monday'.
(d)If Mr West took methylamphetamine on the Sunday and had a methylamphetamine concentration of 0.06 mg/L in his blood on Monday there would be a consistent relationship between the administration of the dose, the consequences of the dose, and the presence of a measurable concentration of the drug in his blood.
(e)If Mr West took methylamphetamine on the Sunday and did not have a good night's sleep and one of the contributing factors to that was sleep apnoea the evidence would be consistent with methylamphetamine being the explanation for the inattention. One explanation, obstructive sleep apnoea, did not preclude the other, being in the coming down phase following methylamphetamine intoxication. When there is more than one impairing effect present then they add to one another rather than excluding one another. The situation is still consistent with a diagnosis of methylamphetamine-affected driving, whether or not there was obstructive sleep apnoea contributing as well. Professor Joyce added, however, that 'it is still short of proof that it was methylamphetamine-affected driving'.
[26] ts 35 - 36.
[27] ts 36.

The evidence Mr West suffered from undiagnosed obstructive sleep apnoea in April 2019

Mr West relied on reports that set out the basis upon which he had been diagnosed recently as suffering from obstructive sleep apnoea. Those reports also dealt with the issue of whether Mr West had suffered from undiagnosed obstructive sleep apnoea in April 2019. The authors of the reports were not called to give evidence.
In August 2020 Mr West was the subject of a sleep study. The study was the subject of a report from a sleep physician, Dr Scott Phung and the conclusion stated in the report was that Mr West suffered from severe obstructive sleep apnoea associated with frequent snoring, sleep disruption and moderate oxygen desaturation. Dr Phung noted Mr West's hypertension increased following sleep.
Mr West consulted Dr Helen Bell for treatment. Dr Bell is a consultant physician specialising in respiratory and sleep medicine. She prepared two reports - each of which was dated 9 December 2020. In the reports Dr Bell recorded:
(a)She had been treating Mr West since 20 August 2020.
(b)She had diagnosed Mr West with severe obstructive sleep apnoea.
(c)It was likely that Mr West had been suffering from this condition for at least three years.
(d)Mr West described to Dr Bell experiencing the following symptoms prior to treatment: waking from sleep coughing and with a sensation that he could not breathe (nocturnal choking episodes); getting up to pass urine two to three times a night (nocturia); waking in the morning with a very dry throat, sometimes to the extent he could not talk; waking unrefreshed from sleep in the mornings; daytime sleepiness, onset from early afternoon.
(e)Mr West has been treated with continuous positive airway pressure and there has been a significant improvement in his symptoms.
(f)Mr West was likely to be suffering from obstructive sleep apnoea on 15 April 2019 and symptoms due to obstructive sleep apnoea were a likely contributing factor to the offending.
(g)It is not possible to say definitively whether Mr West would have likely felt symptoms of tiredness in April 2019. Perception of symptoms of obstructive sleep apnoea vary between individuals and within individuals on a day-to-day basis. Symptoms of obstructive sleep apnoea can come on gradually and people with symptoms due to obstructed sleep apnoea do not necessarily recognise the extent of tiredness or sleepiness until such time that the obstructive sleep apnoea is treated. The symptoms can be difficult to notice.
(h)Dr Bell's opinion that it is likely that Mr West has been suffering from obstructive sleep apnoea for at least three years was based on the following: the diagnosis of severe obstructive sleep apnoea made on 20 August 2020; the history obtained from Mr West detailed at (d) and that he had been suffering from those symptoms for at least a year prior to the motor vehicle incident in 2019; and the development of obstructive sleep apnoea can be insidious and occur over a long period.
Mr West's counsel explained that she had not called Dr Bell because the State had not adduced any evidence to contradict Dr Bell's evidence nor had it applied for an adjournment for the purposes of seeking such evidence. She contested the proposition that Mr West was obliged to adduce evidence to establish that he had suffered the symptoms described in Dr Bell's report in April 2019.
The State objected to Mr West's reliance on Dr Bell's opinions that he had been suffering from obstructive sleep apnoea for at least three years and that symptoms due to obstructive sleep apnoea were a likely contributing factor to the offending. There were two grounds of objection. First, Dr Bell's recitation of the history given to her by Mr West did not establish the truth of the contents of the statements.[28] Consequently, at least part of the factual foundation upon which Dr Bell's opinion was based was not established by the evidence. Secondly, Dr Bell's opinion that symptoms due to obstructive sleep apnoea were a likely contributing factor to the offending was expressed as an assertion and the underlying reasoning was not explained.
[28] Ramsay v Watson [1961] HCA 65; (1961) 108 CLR 642, 648 - 649.
There was force in both of these grounds of objection. As to the first ground of objection, however, it is evident that there were three reasons for Dr Bell concluding that Mr West had suffered from sleep apnoea in April 2019. One of those reasons was the history given by Mr West to Dr Bell. The other reasons were that Dr Bell had made a diagnosis of severe obstructed sleep apnoea in August 2020 and her experience that the development of obstructive sleep apnoea symptoms can be insidious and occur over a long period. I infer from the two latter factors, taken with Dr Bell's opinion that those suffering from obstructive sleep apnoea may not realise the extent to which they are affected by it until they receive treatment, that if Mr West's account of his symptoms were disregarded (as they must be because the truth of that account, as distinct from the fact the account was given, has not been established by admissible evidence) Dr Bell would have maintained her opinion that it is likely that Mr West was suffering from obstructive sleep apnoea in April 2019.
As to the State's second objection, Dr Bell does not record her reasons for concluding that the symptoms of obstructive sleep apnoea were likely to have contributed to the offending and this certainly undermines the weight that can be given to that opinion. That said, given the nature of the symptoms described by Dr Bell and their consequences, I think it can be inferred that Dr Bell reasoned that the obstructive sleep apnoea is likely to have had the effect of depriving Mr West of sleep, this caused fatigue, and fatigue was a cause of inattention when Mr West drove on 15 April 2019.
I will allow Mr West to rely on the reports of Dr Bell and will treat the objections raised by the State as going to the weight to be attached to the opinions expressed by Dr Bell.

Consideration and conclusions

I will sentence Mr West on the basis that he took an intoxicating dose of methylamphetamine on Saturday, 13 April 2019 when his friend visited him at home. That Mr West told the police officers who interviewed him on 15 April 2019 that his friend visited him on the Saturday points to Mr West having made a mistake when he told the author of the pre-sentence report that he had consumed methylamphetamine with his friend on Sunday (the day before the accident).
With some hesitation I find on the balance of probabilities that in April 2019 Mr West suffered from undiagnosed sleep apnoea. Two matters give rise to that hesitation, first, the absence of admissible evidence about the symptoms experienced by Mr West as recounted to Dr Bell, and second, that in the course of the interview with police officers on 15 April 2019, Mr West told the police officers he 'normally [slept] pretty well'. I accept, however, that Dr Bell's evidence that obstructive sleep apnoea can progress insidiously and that those affected by the condition may not realise the degree to which they are affected provide an explanation for Mr West's statement that he normally slept pretty well. Dr Bell's evidence about the insidious progress of the condition coupled with the evidence of the severity of the obstructive sleep apnoea diagnosed by Dr Bell persuade me that it was likely that Mr West suffered from obstructive sleep apnoea in April 2019.
I am satisfied on the basis of the statements made by Mr West to the police officers who interviewed him on the evening of 15 April 2019 that on the night of 14 - 15 April 2019, in contrast to the way he considered he normally slept ('pretty well'), he had a restless night.
I am satisfied beyond reasonable doubt that the intoxicating dose of methylamphetamine taken by Mr West on Saturday, 13 April 2019 contributed to the restless night experienced by him on 14 - 15 April 2019. The various elements that contribute to this conclusion are as follows:
(a)Professor Joyce's evidence that the concentration of methylamphetamine in Mr West's blood sample taken on the afternoon of 15 April 2019 was consistent with Mr West having taken a 'fairly large dose of methylamphetamine ... on the Saturday immediately preceding the accident'.
(b)Professor Joyce's evidence to the effect that an intoxicating dose of methylamphetamine and sleep deprivation are inseparable point powerfully to the conclusion that the restlessness experienced by Mr West on the night of 14 - 15 April 2019 was caused by the 'fairly large dose of methylamphetamine' taken by him on 13 April 2020. As Professor Joyce said the coming down phase of methylamphetamine intoxication may last for several days. I acknowledge Professor Joyce's evidence to the effect that drug users are affected differently and that it is possible that a user of methylamphetamine may not be affected by sleep deprivation or not affected as severely as others (though he said this 'must be pretty uncommon'). In this case, however, it is plain that Mr West's sleep on the night of 14 - 15 April 2019 was affected.
(c)I accept that the fact that Mr West was likely to have been suffering from obstructive sleep apnoea in April 2019 may have contributed to his restlessness on the night of 14 - 15 April 2019. The existence of obstructive sleep apnoea in the factual matrix does not operate to exclude the effect of methylamphetamine intoxication. In making an assessment of potential causes it is significant that Mr West said, in effect, that he had not slept well the night before the accident, but that he normally slept pretty well. If Mr West had been experiencing ongoing problems with his sleep in April 2019 (even though they may not have been recognised by him because he thought he usually slept well) then the contrast drawn by Mr West between how he slept on the night of 14 - 15 April 2019 suggests that his sleep was noticeably worse on that night. Professor Joyce's evidence to the effect that he would expect sleeping difficulties to be compounded by the effects of taking an intoxicating dose of methylamphetamine provides an explanation why Mr West contrasted his restless night's sleep on that night with his experience of 'normally sleeping pretty well'.
(d)The conclusion that the use of methylamphetamine on Saturday 13 April 2019 contributed to Mr West's restless night on 14 ‑ 15 April 2019 is not undermined by the evidence that Mr West felt fine on the morning of 15 April 2019 nor by the absence of evidence of other examples of inattentive driving, nor by the fact that he was not observed to be nodding off or showing other signs of being in the coming down phase on 15 April 2019. It was accepted on Mr West's behalf, as it had to be, that he was fatigued. Ultimately what was in issue was the cause of the fatigue.
(e)I acknowledge Professor Joyce expressed his conclusion that methylamphetamine exposure contributed to any impairment that Mr West had in attending to the control of his vehicle as being based on the assessment that the concentration of methylamphetamine in Mr West's blood coupled with the accident were consistent with Mr West being affected by methylamphetamine on 15 April 2019 but that this evidence did not establish 'proof of diagnosis'. My understanding of this aspect of Professor Joyce's evidence is that he used the expression 'proof of diagnosis' in this context to indicate certainty. It is, however, proof beyond reasonable doubt that is required and not certainty. I have no hesitation in concluding beyond reasonable doubt that Mr West's use of methylamphetamine was a factor that contributed to his restless night on the 14 - 15 April 2019 and this indirectly contributed to the accident on 15 April 2019.
I record also that I am satisfied beyond reasonable doubt that Mr West's use of methylamphetamine on Saturday 13 April 2019 increased the risk that his capacity to drive safely when he returned to work on Monday 15 April 2019 would be impaired.
The State did not contend that Mr West drove knowing that his ability to drive was impaired. Mr West's counsel made a point of contending that such a finding was not open on the evidence. I accept that is so and find that when Mr West attended for work on the morning of 15 April 2019 he was not aware that his capacity to drive was impaired.

I certify that the preceding paragraph(s) comprise the reasons for decision of the Supreme Court of Western Australia.
AS
Associate to the Honourable Justice Tottle
12 JANUARY 2021