3 As we understand the case, there is no basis to suggest that Mr Tucker could have or should have anticipated the axle failure. However, the plaintiff argued at trial that if Mr Tucker was driving at about 110 kph when the axle failed, he should have been able to keep the car upright, exercising a reasonable degree of skill. If, on the other hand, he was driving at about 140 kph when the axle failed, the plaintiff's case in negligence rested on an allegation that Mr Tucker was driving too fast in the circumstances, and that the excessive speed caused or materially contributed to the loss of control, the consequent roll-over of the car and the plaintiff's injuries. The plaintiff's case appears to have been that at that speed there was little or no hope of keeping the car upright.

4 As a further alternative or variant of the latter proposition the plaintiff argued that the risk of the loss of control and roll-over in the event of a mechanical failure was materially increased by travelling at about 140 kph, compared with that risk at a lesser and prudent speed, that that risk materialised, and accordingly Mr Tucker was liable to the plaintiff.

5 Considerable attention was given at trial to the question of whether Mr Tucker's speed, when the axle failed, was about 110 kph (the applicable speed limit) or was about 140 kph (a finding for which the plaintiff contended). The Judge did not make the finding for which the plaintiff contended. The Judge appears to have found that Mr Tucker was driving at between 110 kph and 120 kph when the axle failed. The Judge found that Mr Tucker was not negligent in driving at the speed at which he was driving when the axle failed. The Judge also found that Mr Tucker handled the emergency reasonably. He found in effect that Mr Tucker had no hope of controlling the car once the axle failed. The Judge dismissed the claim.

6 On appeal, much of the argument for the plaintiff was directed to an attack on the Judge's finding as to speed, and to a contention that the Judge should have found that Mr Tucker was driving at 140 kph. As will appear, we reject that submission. Nevertheless, because we conclude that Mr Tucker was driving at a speed in excess of the speed limit, it is necessary for us to consider whether that was a breach of his duty of care and whether his manner of driving was the cause of the plaintiff's injuries. Although our conclusion is that, in driving at the speed at which he was driving, Mr Tucker did not fail to drive with due care, it is desirable to deal with the issue that would arise if our conclusion on that point is wrong. We think it is also desirable to consider what would follow if the correct finding was that Mr Tucker was driving at 140 kph.

7 We add, in these introductory remarks, that the Judge did not deal with the question of whether Mr Tucker would have been able to maintain control, or whether the chance of him maintaining control would have been materially improved, had he been driving at a lesser speed than about 110 kph. That is, the Judge made no finding identifying a lower and prudent speed at which the accident could have been avoided.

8 There are four main issues in this appeal. First, what was the Judge's finding about Mr Tucker's speed when the axle failed, and is that finding erroneous? Second, did Mr Tucker breach his duty of car in driving at the speed at which he drove? Third, could Mr Tucker have avoided the accident by exercising reasonable skill as a driver? Fourth, if it was a breach of duty to drive at that speed, did the driving at that speed cause the plaintiff's injuries? That fourth issue raises the question of whether Mr Tucker's ability to maintain control of the motor car was materially reduced by driving at the speed at which he was driving, compared with the ability to maintain control at some lesser and prudent speed. Putting the fourth issue another way, the issue can be said to be whether the axle failure would have resulted in a loss of control and roll-over, or was likely to have done so, even if Mr Tucker had been driving at a lesser and prudent speed.

9 At the hearing of the appeal the plaintiff also sought to adduce further evidence in support of his appeal.

10 We have had the benefit of considering the reasons of Gray J. The facts that are to be found in those reasons. We will repeat the facts only to the extent necessary to explain our reasons.

11 We agree with Gray J that the evidence of the conversation between Mr Nikolavcic and Mr Tucker should not be admitted. The evidence would not have produced a different result if it had been available at trial. Allowing for the circumstances of the conversation the evidence is inconclusive, as Gray J points out.

12 We agree with Gray J that on appeal the Court can take into account the manner in which the evidence was obtained, in deciding in its discretion whether to admit the evidence or not. We agree with Gray J that the evidence was obtained by unfair means, and that that is an independent reason for the Court to exercise its discretion against admitting the evidence on appeal. We also consider that the manner in which the conversation was conducted to some extent undermined its reliability. There is no reason to doubt the accuracy of the recording and of the transcript of the recording with which we were provided. But the circumstances of the conversation were such that we are hesitant about relying on remarks made by Mr Tucker, in the manner in which the plaintiff seeks to rely on them. Taking all those matters into account we would exercise our discretion not to receive the evidence, having regard to its inconclusive nature and the circumstances under which it was obtained.

13 We agree with Gray J that the conversation may have been recorded in circumstances that involved a breach of the Listening and Surveillance Devices Act. We agree that there may have been a breach of the applicable professional conduct rules by the solicitor concerned. However, as these matters were not fully argued we refrain from making any finding on the point. A conclusion adverse to the plaintiff on these points would be a further discretionary reason for refusing to admit the further evidence.

14 We would not admit the further evidence as to the position of the speedometer on the instrument panel of the motor car. There is no good reason why the evidence could not have been led at trial, if reasonable diligence had been exercised in that respect. Nor are we satisfied that the evidence would have produced a different result. We agree with Gray J in that respect.

At what speed was Mr Tucker driving when the axle failed?

15 The plaintiff led evidence from the other passengers, and gave evidence himself, that when Mr Tucker shared the driving on the way to Coober Pedy, he drove fairly steadily at about 130 kph or more, until the stage at which they began to tow another vehicle. Mr Tucker denied this. Mr Peek QC, counsel for the plaintiff on appeal, submitted that the Judge should have rejected Mr Tucker's evidence on this point, and that the rejection of his evidence would have reflected on his credibility. In his reasons the Judge accepted Mr Tucker's evidence on this point, and said that he had reservations about the reliability of the witnesses called for the plaintiff.

16 On the return journey, when the accident happened, Mr Deeble was the only passenger awake. He was sitting in the back seat of the car, in the centre and between two other men. He gave evidence that Mr Tucker was driving at about 140 kph, and had been driving steadily at that speed. The Judge did not accept this evidence. In particular, he did not accept his evidence that from where he was sitting he was able to see the speedometer on the dashboard, and could tell the speed in that way.

17 Mr Tucker's evidence was that driving south from Coober Pedy he was driving at a speed between 110 kph and 120 kph, that on occasions the speed crept up to 130 kph to 140 kph, but when he realised that had happened he would bring the speed of the car back to 110 kph to 120 kph. Mr Tucker said that he did not know at what speed the car was travelling when the axle failed, but agreed that his speed was "much the same" as that at which he had been travelling. The road was "pretty straight", and a good wide road. The Judge accepted this evidence. He said:

"I think it is more likely than not that the driving of Tom Tucker was varying between his cruising speed of 110 to 120 kilometres per hour and occasionally creeping up to 130 to 140 kilometres per hour, where as soon as he noticed it he brought the speed back to his usual travelling speed. He does not know at what speed he was travelling at the time of the accident, nevertheless I find there is no inconsistency with his evidence and that of Mr Hall."

18 Gray J has set out criticisms made by Mr Peek of the basis upon which the Judge accepted evidence of Mr Tucker.

19 We agree that the Judge incorrectly stated the effect of the evidence for the plaintiff in one respect, but that in itself is not of any great significance. We agree that the Judge may have given undue weight to the fact that the other men in the motor car did not protest when Mr Tucker took over the driving at the start of the return journey. But in a matter this like this, that depended so much on the reliability of the witnesses, the impression that Mr Tucker made on the Judge is an important matter, and that was a favourable impression. There is also the fact that the Judge was not willing to accept the evidence of Mr Deeble about the speed at which the car was travelling, and he was the only other person in the car who was awake at the time.

20 Bearing in mind that the plaintiff's contention was that Mr Tucker was driving at 140 kph at the time, and that the defence case was that this was not so, it might also be said that Mr Tucker's candid admission that at times his speed got to that level, and that he could not state the actual speed at which he was travelling at the time, was of some significance in assessing his credibility.

21 Taking into account the favourable impression that Mr Tucker made on the Judge, the effect of Mr Tucker's evidence, and the fact that the Judge was not satisfied in a number of respects with the evidence supporting the plaintiff's case on the issue of speed, our view is that it was open to the Judge to accept the evidence of Mr Tucker, and that there is no basis for setting aside his acceptance of that evidence, unless his acceptance of that evidence depends upon or is significantly affected by his treatment of the evidence of Mr Hall in relation to speed. We will come to that issue in a moment.

22 The Judge's reasons are not as clear as they could have been in relation to the speed at which the car was travelling when the axle failed. However, having regard to what the Judge said in the paragraph set out above, and to what he said at [65], we are satisfied that the Judge's finding was that when the axle failed the motor car was travelling at a speed between 110 kph and 120 kph. We consider that it is a clear inference from the Judge's reasons that he was rejecting the submission that the motor car was travelling at 140 kph or something close to that. Having regard to the evidence before him, it was not possible for the Judge to make a more precise finding than the one we have identified.

23 Mr Hall based his estimate as to speed on a number of assumptions put to him in evidence. They included the assumption that the vehicle veered to the right after the wheel became dislodged; that there was no evidence of skid marks on the roadway; that there was moderate braking for a distance before the car left the roadway; and that the braking occurred over a distance of approximately 50 metres which was the approximate distance travelled from the time the brakes were applied to the point at which the car went over the edge of the bitumen and then began to roll.

24 These assumptions were based mainly on a report prepared by a police officer who investigated the accident. Photographs were taken at the scene and a rough plan was prepared from measurements taken and observations made by the police officer.

25 The vehicle was travelling in a southerly direction at the time of the accident and there were two gouge marks on the road (G1 and G2) which were consistent with having been made by a part of the vehicle coming into contact with the road surface after the wheel ceased to provide support for the vehicle. G2 was in the vicinity of the centre of the roadway, but on the left carriageway. It was ten paces in length. G1 was south of G2 and on the right carriageway. It was nearer to the centre line than the edge of the roadway. It was seven paces in length.

26 It seems clear that the vehicle veered to the right of the road after the wheel was dislodged and after the mark G2 had been made. There was no evidence of skid marks on the road, but it would appear that the vehicle travelled over onto the right-hand carriageway and eventually left the bitumen and went onto the dirt verge. At some point it began to roll. There is a ditch a few metres from the bitumen edge and it would seem reasonable to assume that the rolling motion commenced at the ditch.

27 The distance from the edge of the bitumen to the nearest part of the car at the point where it came to rest was 61 paces. The distance from the point at which the vehicle left the road to the southern end of the gouge mark G2 was shown on the plan as 48 paces. The length of this gouge mark was ten paces.

28 Given this information, Mr Hall assumed that the distance from G2 to the edge of the bitumen was approximately 50 metres. In his view, the wheel would have become dislodged within a matter of seconds after severance from the axle. He assumed that the respondent commenced to apply the brakes after a reaction time of about one and a half seconds. Mr Hall assumed that moderate to heavy braking took place over a distance of about 50 metres before the vehicle started to roll.

29 In our view, the assumptions made by Mr Hall were not unreasonable in the circumstances. Mr Peek attacked the assumption that braking was applied over a distance of approximately 50 metres. It is important to have regard to the examination-in-chief of Mr Hall in relation to this assumption:

"A The other piece of information I would require would be the distance over which the moderate braking occurred prior to it leaving - going into a roll condition.

1. Are you able to reach a figure or to adopt an assumption that you would be comfortable with, having regard to your experience generally, but also with what you know of this accident?
2. Over what distance?
3. Would you be able to reach an assumption or adopt an assumption you would be comfortable with?
4. Not really, because I am faced with information here E to F being approximately 34 m, say if we assume nine paces to about one metre, I see marking G2 being further north of that, so it may be at least, say, 50 m, given that there is a separation between G1 and G2, and that G2 is approximately 10 m long. So, G2 may be around 50 m prior to the vehicle leaving the bitumen.
5. The effect of adopting braking would in any event have the effect, wouldn't it, of increasing the speed of the vehicle prior to the axle separation?
6. Yes.
7. Just for the purpose of a first calculation, can we assume there is braking over that 50 m, moderate braking over that 50 m?
8. Yes.
9. That would give perhaps a slightly inflated speed of the vehicle prior to separation, if, in fact, there was no braking, or there was moderate braking over a lesser distance, is that right?
10. Yes.
11. So, again let's assume moderate braking for that period of 50m, assume that the vehicle moves off the roadway on its wheels, but begins a spin after the dirt verge, and lands 60 paces, as indicated, and also lands on its wheels?
12. Yes."

30 In our view, Mr Hall's comment about not being comfortable with adopting the assumption reflected his view before he started to work out the distance to the commencement of G2. This distance was not able to be calculated until certain distances were added together. He appears to have worked this out in the course of the evidence and eventually he reached the view that the relevant distance was approximately 50 metres.

31 It is apparent from the plan itself that the distance which the vehicle travelled from G2 to the edge of the bitumen was approximately 50 metres. It does not appear to be unreasonable to assume that the gouge mark was made a short time after the wheel left the vehicle. In the light of Mr Hall's evidence that the wheel would come away from the vehicle in a very short time and, bearing in mind the reaction time before brakes would be applied, it would be reasonable to assume that the brakes were applied at about the same time as the vehicle caused the first gouge mark.

32 It is also important to bear in mind that the respondent said in evidence that he had no recall as to whether he applied the brakes. He did say that he attempted to steer the vehicle in a straight line. The premise that there was moderate braking was an assumption favourable to the plaintiff If there had been no braking, Mr Hall's estimate of the speed of the vehicle when the axle failed would have been lower.

33 Furthermore, Mr Hall allowed for inaccuracy in the assumptions. Although the speed he calculated was 109 kph, he was prepared to concede a range from 110 kph to 120 kph.

34 Even if contrary to what we have said, the evidence of Mr Hall provided no support for the evidence given by Mr Tucker as to speed, it is our view that the Judge's acceptance of Mr Tucker did not rest to any significant degree on the evidence given by Mr Hall.

35 In the passage set out above from the Judge's reasons, the Judge referred to the fact that there was "no inconsistency" between Mr Tucker's evidence and that of Mr Hall. If Mr Hall's evidence is put to one side, it remains the case that there is no expert evidence inconsistent with Mr Tucker's evidence as to his speed. We are not satisfied that, despite the negative manner in which the Judge made use of the evidence of Mr Hall ("no inconsistency"), the Judge relied on Mr Hall as providing affirmative support for the evidence of Mr Tucker. Our view is that the Judge was prepared to accept the evidence of Mr Tucker, and was doing no more than noting that Mr Hall's evidence did not undermine Mr Tucker's evidence.

36 Accordingly, our view is that the Judge's finding as to Mr Tucker's speed should stand.

Was it negligent to drive at the speed at which Mr Tucker was driving?

37 The plaintiff's case at trial and on appeal rested largely on the contention that Mr Tucker was driving at about 140 kph when the axle failed. Our conclusion that the Judge's rejection of that contention should stand disposes of the main basis upon which the plaintiff's case rested. However, our conclusion that the Judge's finding of a speed between 110 kph and 120 kph should stand, leaves for consideration the question of whether to drive at that speed was negligent.

38 If driving at that speed was negligent, the issue of causation must then be considered. That issue arises even if Mr Tucker was driving at a speed of 140 kph.

39 When considering whether Mr Tucker was driving negligently, we must take into account the fact that he was driving on a main highway that was in good condition and was of reasonable width. The road was fairly straight. The speed limit was 110 kph. On the Judge's finding, Mr Tucker was driving slightly in excess of the speed limit.

40 He was driving a motor car that was about 18 years old. It was not his motor car. There is no suggestion in the evidence that it was not in a sound condition. As we understand it, it had been driven from Adelaide to Coober Pedy without anything happening to indicate the need for particular care when driving this motor car.

41 We all know that with increased speed, and especially at higher speeds, there is an increased risk of an accident in many situations. We all know that the chance of dealing safely with an unexpected event, such as mechanical failure, is likely to be less at a high speed than at a low speed. Nevertheless, the duty of a driver to exercise reasonable care does not require a driver to remain at a speed such that there is no practical risk of an accident, or no practical risk of the driver being unable to deal with an unexpected mechanical failure. If the duty of a driver was as stringent as that, it would always be a breach of the duty of care to drive at a speed of the order of 110 kph. We say that because we are prepared to assume that at that speed there is a high risk of a driver being unable to deal with an unexpected mechanical failure, whereas at a speed of, say about 50 kph, there is a fairly good chance that a driver could deal safely with such an event. In short, it is not a breach of a driver's duty of care to drive at a speed such that the driver has little opportunity to deal with an unexpected mechanical failure. Or, to put it more accurately, the mere fact that a driver is driving at a speed such that the driver is unable to deal safely with an unexpected mechanical failure, is not itself proof of negligence. All of the circumstances have to be considered.

42 We therefore begin from the premise that a breach of duty by Mr Tucker is not demonstrated by showing, as was the case, that he was unable to deal safely with the axle failure at that speed, even though one might reasonably surmise that had he been driving at about 50 kph he could have dealt safely with the axle failure.

43 The fact that a defendant is driving at a speed above the speed limit is evidence of negligence. Speed limits are fixed with a view to the safety of road users. But they are fixed as absolute and general rules. The speed limit does not determine the speed at which a reasonably careful driver should drive in a particular situation. We consider that Mr Tucker would have been negligent had he driven past a stationary school bus from which children were alighting, at a speed between 100 kph and 110 kph. There will be many situations in suburban streets in which reasonable care requires a driver to drive well below the speed limit.

44 Likewise, in some situations, it would not be a breach of a driver's duty of care to exceed the speed limit. When considering what the duty of a driver to drive with reasonable care requires in relation to speed, the content of the duty is determined according to the particular circumstances of the case, taking into account the fact of the general rule, but not treating the general rule as determinative of the outcome in a particular case.

45 In the circumstances, we do not consider that it was negligent to drive at a speed between 110 kph and 120 kph, the speed at which the Judge found Mr Tucker was driving. While recognising that increased speed brings with it increased risks, our view is that the relatively modest excess over the speed limit would not, in the judgment of the reasonable driver, be regarded as significantly increasing the risk of injury to the passengers.

Did the Judge err in concluding that there was nothing that Mr Tucker could have done to avoid the accident?

46 The appellant called two expert witnesses, Mr Wearing and Mr Pudney. Their qualifications and experience are set out in the reasons for judgement of Gray J.

47 Mr Wearing was examined on the voir dire hearing as to his qualifications. At the conclusion of the voir dire counsel for Mr Tucker indicated that he objected to the witness giving evidence "of a mechanical nature", but that he did not object to him expressing views on driver behaviour. Counsel for the plaintiff stated that the evidence would be focused on driver behaviour and submitted that the witness should be allowed to give evidence of "rudimentary mechanical matters". The trial judge intimated that the witness could give evidence along the lines suggested by the plaintiff's counsel.

48 The witness then gave evidence concerning the likely behaviour of the vehicle after the axle failure and the most appropriate method of controlling it. The witness expressed the view that the degree of control necessary for a vehicle to be driven safely at 140 kilometres per hour is far greater than that required at 110 kilometres per hour. Although there is some ambiguity in his report and evidence on the issue, he appears to have suggested that Mr Tucker should have been able to control the vehicle after the axle failure if it had been travelling at a speed of 110 kilometres per hour.

49 Mr Pudney's expertise to express opinions on the matters he was asked about in evidence-in-chief was not challenged. He gave evidence of the process involved in the failure of a rear axle. He said that if the break in the axle was due to fatigue, that process would occur over a period of time. He was asked if high speed over an extended period would accelerate the process. He said:

"A I would say the speed would probably accelerate the process. If the fatigue is obviously getting towards the point where it is going to break, it would have accelerated the fracture at the point where it would have broken sooner than probably if a vehicle was travelling at a slower speed.

1. Is it the case that you can't be dogmatic to what extent?
2. No, it is very hard to prove to what extent. Because with the higher speed you have got wheels spinning at a much faster rate, and there could be some imbalance in the tyre that creates extra stress on the axle, so all that would certainly come into play."

50 Mr Pudney described in some detail the events involved in the wheel becoming dislodged from the axle. He said it might take up to five seconds before the wheel finally comes away from the vehicle after being trapped in the wheel arch. In cross-examination, Mr Pudney said he believed it would take longer than a second for the wheel to come away completely from the vehicle after being dislodged from the axle, but he said he could not be dogmatic about the matter.

51 Mr Pudney did not express a view in his examination-in-chief as to whether a person in the respondent's position should have been able to control the vehicle at a speed of 110 kilometres an hour in the event of an axle failure. In our view he was not qualified to express such an opinion. His qualifications and experience were as a motor mechanic. However, he gave the following evidence when cross-examined:

"Q If a vehicle is travelling at 110 km/h and this suddenly occurs, and the vehicle veers off to the right because of the loss of the wheel, and a person is unable to regain control, that is not in any way unusual or uncommon, is it?

1. It does happen. You do hear of that, people losing control from a tyre blow-out, or whatever, at a lesser speed than that, but the thing is, as I said, I have been in that situation and I didn't have any trouble controlling the vehicle with a rear tyre blow-out.

1. You are suggesting this person should have been reasonably able to control it in those circumstances if it was travelling at 110. What if it was travelling at 140. Would his option of controlling it be less?
2. Yes, it would be, yes. He would have less chance - the higher the speed - because, I guess, there is less correction because you are travelling the distance faster, there would be less - you probably could have a tendency to perhaps oversteer if you were trying to correct it at a faster speed."

52 It would appear that the comment made by the trial judge prior to asking the above question was in reference to the witness's example of a blow-out.

53 Mr Hall, who was called by counsel for Mr Tucker, gave extensive evidence in relation to relevant mechanical issues and the likely behaviour of the vehicle in the circumstances of the accident. It was not suggested that he lacked expertise to give the evidence which was led from him in evidence-in-chief.

54 In his report dated 16 September 1996 Mr Hall assumed that the vehicle was travelling at 110 kilometres per hour. After considering the circumstances of the accident he expressed the following view:

"I am of the opinion that the wheel separated from the vehicle while it was travelling along the Stuart Highway. The failure would have been sudden and unexpected, and immediate loss of control was the most likely outcome. It was unlikely that the driver would have been able to achieve effective steering once the rear continued to dip at the right."

55 In his evidence Mr Hall explained the process whereby the wheel would become dislodged from the axle and how it would then come out from under the vehicle. He said this would happen in a very short time and, at this point, it was unlikely that steer input or the application of brakes would alter the outcome. If a reaction time of two to three seconds was assumed, the situation could not have been contained. The effect of this evidence was that, in Mr Hall's view, there was nothing the driver could have done to avoid the accident.

56 Mr Hall said that axle failure of this nature was very uncommon and most drivers would not have experienced such an occurrence. He said it would be extremely difficult to judge how much steering input and braking would be required to bring the vehicle to rest without loss of stability. He confirmed the view expressed in his report that immediate loss of control was the most likely outcome. He agreed that if the axle failure occurred at 140 kph, the vehicle would be more difficult to control.

57 After setting out extracts from the evidence of these three witnesses, the trial judge said:

"Having regard to the whole of Mr Hall's evidence, not only the extracts to which I have referred, I am satisfied and so find that he concluded that on the balance of probabilities there was nothing the defendant could have done to avoid the accident.

This finding is consistent with the evidence of the defendant and Frank Deeble.

I find that Mr Hall is the only witness who is qualified to give appropriate evidence in this matter and I accept without hesitation his evidence as a whole and also where it conflicts with the evidence of Mr Wearing or Mr Pudney. I accept Mr Hall's analysis of events and the reactions of drivers in these circumstances. I accept his evidence that the driver did not omit to do anything that he should have done, nor do anything that he should not have done."

58 We are unable to agree with the suggestion that these remarks reveal a usurpation of the judicial function by expert evidence given by Mr Hall although they are awkwardly expressed. Mr Hall did not express his view on whether the respondent could have avoided the accident by reference to the balance of probabilities. He simply stated that the loss of control of the vehicle was unavoidable bearing in mind what, in his opinion, would have occurred after the wheel broke off from the axle. It would have been better if the judge had not referred to the standard of proof when dealing with the expert's view, but it is apparent from the judge's further remarks that he applied his mind to the essential question as to whether he accepted or rejected the evidence of the expert.

59 Mr Hall gave evidence of the reasons for his view on this issue. The trial judge quoted extensively from that evidence before stating that he accepted the witness's analysis of events. It is true that he did not analyse the evidence in any detail in his reasons, but it was open to him to accept the opinion and the basis for it.

60 There was a further suggestion that Mr Hall's evidence may have contravened a rule to the effect that an expert is not to be asked the ultimate question which the court must decide. In our view, the evidence given by Mr Hall on this topic was relevant and admissible. There appears to have been a significant relaxation of the attitude previously adopted by the courts of preventing a witness from giving an opinion on the very issue the court has to decide. In Murphy v The Queen [1989] HCA 28; (1989) 167 CLR 94 at 110 Mason CJ and Toohey J expressed the view that it was doubtful that there was an absolute rule precluding an expert witness from expressing a view as to the ultimate issue. In the same case Deane J said (127):

"Nor is it an acceptable answer to assert that expert evidence is not admissible on the very question which a jury is required to decide. Such an assertion is plainly unacceptable as a general rule of the law of evidence. It would, for example, preclude expert opinion that a bullet admittedly fired by an accused was the cause of death in a case where the only defence to a charge of murder was that death had resulted from some other cause."

61 This is not to say that no restriction should be placed on the giving of expert opinions as to the ultimate issue. The following analysis by Giles J in R W Miller and Co Pty Ltd v Krupp (Australia) Pty Ltd (1994) 34 NSWLR 129 at 130 provides a practical guide to this issue:

"It is almost impossible for a rule in those terms to be applied, there are many cases in which an expert has given such an opinion, and a rule in those terms has been doubted in the High Court: see Murphy v R [1989] HCA 28; (1989) 167 CLR 94 at 110 and 126-127. A lesser restriction has been recognised, that the expert may not give an opinion on an ultimate issue where that involves the application of a legal standard - for example, that the defendant was negligent, that a risk was reasonably foreseeable, that a testator possessed testamentary capacity, that a representation was likely to deceive or that a publication was obscene. This view has been particularly espoused by Glass JA, judicially in Grey v Australian Motorists & General Insurance Co Pty Ltd [1976] 1 NSWLR 669 at 675-676 and R v Palmer [1981] 1 NSWLR 209 at 214, and extra-judicially in, for example, Glass 'Expert Evidence' (1987) 3 Aust Bar Rev 43 at 48-49. His Honour added in the article last-mentioned (at 49):

'It is no less objectionable for questions to be put to the expert or answers to be given which appeal to a legally irrelevant standard of judgment such as whether the defendant's conduct was or was not wrong, improper, unjustifiable, unreasonable or something which should not have happened.'

These last observations, with which I respectfully agree, are ultimately founded on relevance."

62 In our view, the opinions expressed by Mr Hall in the present case were not such as to warrant exclusion under these principles. The court was entitled to receive expert opinion on whether there was anything which the respondent could have done from the time he was aware that there was a problem with the vehicle. Mr Wearing commented on action which he considered could have been taken in the circumstances. That evidence was clearly relevant. So also was the evidence led from Mr Hall that there was no time for such action and that, in any event, it would have been ineffective.

63 In the light of Mr Hall's qualifications and experience, coupled with the reasons which he gave for the opinions which he expressed, we are of the view that the trial judge was justified in accepting his evidence that loss of control of the vehicle was unavoidable in the circumstances and that there was nothing the respondent could have done to correct the situation.

64 Mr Hall's evidence was given on the basis that the car was travelling at between 110 kph and 120 kph when the axle failed. Each of the three witnesses seems to have accepted that at 140 kph the chance of Mr Tucker avoiding a roll-over was less. Clearly, on Mr Hall's evidence, there was no prospect of avoiding a roll-over at that speed. The Judge no doubt would have so found, if it had seemed necessary to do so.

65 Finally, despite the awkward manner in which the Judge expressed his conclusion on the expert evidence, we are satisfied that he gave proper consideration to the evidence of Mr Wearing and Mr Pudney, but preferred that of Mr Hall.

The circumstances in which Mr Hall's evidence was led

66 According to one of the grounds of appeal a miscarriage of justice arose out of the circumstances in which Mr Hall's evidence as to speed was led. Mr Hall did not provide his own estimate of the speed of the vehicle in his statement. However, he was asked to calculate the likely speed when giving evidence-in-chief. No objection was taken to this evidence at the time it was given. However, the appellant's counsel advised the trial judge that he wished to obtain instructions on the evidence before cross-examining the witness. The trial judge then said he would give counsel whatever time he needed before cross-examining the witness. Counsel nevertheless commenced to cross-examine the witness immediately and the cross-examination continued into the following day. No application for any further adjournment was made.

67 An affidavit sworn by counsel for the appellant at the trial was tendered on the hearing of the appeal. In it counsel stated that he was taken by surprise when Mr Hall gave evidence of an estimate of the speed of the vehicle based on calculations carried out by him. Counsel said he erred in not objecting to the evidence. Counsel also stated in his affidavit that, when the trial judge intimated that he would give counsel whatever time he needed before cross-examining the witness, he took that to mean that the time given would be overnight. It is clear that the trial judge did not place any such restriction on the time which would be allowed.

68 Counsel went on to say in the affidavit that, during the trial, he did not consider the question whether he should have requested more time in order to consult an expert to advise on cross-examination and give rebuttal evidence if necessary.

69 Counsel for the appellant did test the evidence of Mr Hall on the topic of speed during cross-examination. In our view it is not open to the appellant on appeal to claim that a miscarriage of justice has resulted from his failure to object to evidence or seek assistance from an expert when an opportunity would have been provided to his counsel if it had been requested. In these respects the appellant is bound by the course which was followed on his behalf at the trial.

70 Our view is that the plaintiff's case at trial and on appeal failed to confront an important issue.

71 Assume for present purposes that Mr Tucker was driving at a speed of 140 kph when the axle failed, and that at that speed there was no prospect of him avoiding the accident. If there was no prospect of him avoiding the accident at a speed between 110 kph and 120 kph, exercising reasonable skill as a driver, the question arises of whether it can be said that driving at an unsafe speed (assuming a speed of 140 kph to be an unsafe speed) caused or materially contributed to the occurrence of the accident. Thus if the Judge's finding that there was no practical prospect of avoiding the accident at a speed of between 110 kph and 120 kph is to stand, a question of causation arises even if Mr Tucker was travelling at about 140 kph when the axle failed.

72 The Judge did not address this issue, and it appears to us he did not do so because it was not identified at trial as an issue arising in the case.

73 We respectfully disagree with the approach of Gray J that because the risk of being unable to handle safely a mechanical failure increases with speed (an assumption that in general terms we are prepared to accept), it follows that if Mr Tucker drove at 140 kph then the speed at which Mr Tucker drove "materially contributed" to the plaintiff's injury: see Gray J at [201].

74 In our respectful view that conclusion follows only if it is demonstrated that in the circumstances Mr Tucker should have driven at a lesser and identified speed at which he could have averted the accident, or at which the chance of him doing so was materially improved. For example, if there was no significant prospect of him averting the accident if driving at a speed of about 110 kph, and if no‑one contends that he should have been driving at or below that speed, can it be said that driving at a speed of 140 kph caused or materially contributed to the occurrence of the accident?

75 There is no evidence identifying a particular speed at which a reasonably competent driver in Mr Tucker's position would have been able to avert the accident, or identifying a speed at which the chance of doing so was materially increased.

76 Having made those comments, we now come to the issue of causation that arises on the approach taken by Gray J.

77 It is generally accepted that in a negligence claim the plaintiff must establish on the balance of probabilities that the defendant's negligence or breach of duty caused or materially contributed to the injury suffered by the plaintiff. That question is one of fact, and is to be answered by reference to common sense and experience. It is one into which considerations of policy and value judgments necessarily enter. The "but for" test is not the appropriate test of causation in all situations. For these propositions it is unnecessary to do more than cite the decision of the High Court in March v Stramare [1991] HCA 12; (1991) 171 CLR 506.

78 In some situations these propositions require elaboration. One such situation is when the Court considers liability for an injury that is the result of concurrent or successive tortious acts. As to that, we refer to March v Stramare in particular. Another such situation is when the Court considers liability for an injury that results from an omission to act, and in particular from a failure to take a precaution against damage occurring to another person through the act or default of a third party or through accident. A situation of that kind was considered by the High Court in Bennett v Minister of Community Welfare [1992] HCA 27; (1992) 176 CLR 408. The application of the fundamental principle identified in March v Stramare must be undertaken in a manner that reflects the circumstances of the particular situation under consideration, and in a manner that reflects the fact that the Court is concerned with the attribution of liability for a particular event, on the basis of fault.

79 In our opinion it would be inconsistent with basic principle to hold, because the higher the speed the less is the ability of a driver to deal safely with an unexpected mechanical failure, that it follows that the occurrence of a mechanical failure causing an accident leads to the conclusion that driving at the particular speed in question caused or materially contributed to the resulting accident and injury. Our view is that if, in such a case, the case for the plaintiff rests on conduct said to materially increase the risk of an accident, it is necessary to show that there is a material increase in the likelihood of an accident at the speed in question, compared with an identified speed at which the driver should have driven. If this is not done one would, in effect, be reviving a proposition rejected long ago, that a driver of a motor car should drive at a sufficiently low speed such that there is no real risk of an accident occurring at all in the event of an unexpected event or a mechanical failure.

80 In short, our view is that principle requires that even if Mr Tucker was driving at 140 kph when the axle failed, it has to be shown that had he driven at some identified lesser speed, at which it can be said he should have driven, the chance of him avoiding the accident, exercising reasonable care and skill, would have materially increased. That lesser speed need not be identified precisely. However, it is not enough to say at large that the speed at which he was driving materially increased the risk of an accident occurring.

81 In our view the decision of the High Court in Bennett does not say anything to the contrary.

82 Bennett was a case of an omission or failure to act. The Director, in breach of duty, failed to obtain proper advice for a ward of the State about the ward's right to recover damages for an injury suffered by the ward. Before the limitation period expired, the former ward obtained legal advice, but was wrongly advised that he had no claim. The limitation period then expired. The issue was whether the Director's breach of duty caused the former ward to lose his claim for damages upon the expiry of the limitation period, even though the former ward was later given incorrect advice. This was a different sort of case. The High Court held that the Director's breach of duty did cause the loss of the claim.

83 Mason CJ, Deane and Toohey JJ applied the principles stated in March v Stramare. Having done so, they referred in passing, but without expressing a view, to the position that would have arisen if the later advice that the former ward obtained had been correct advice. In that context they referred in passing to a possible argument that the Director would still be liable, on the basis (at 416) that:

"A failure to take steps which would bring about a material reduction of the risk amounts to a material contribution to the injury."

84 Gaudron J agreed in the result. In the course of her reasons she said (at 420):

"Leaving aside cases involving some positive act and those in which an omission can be treated as a positive act, a case based on omission or a failure to act will, in certain respects, fall for analysis in a way that differs from that appropriate for a case based on a positive act. Thus, in the case of a positive act, questions of causation are answered by reference to what, in fact, happened. In the case of an omission, they are answered by reference to what would or would not have happened had the act occurred. In that exercise, the larger philosophical questions are brushed aside and the issue is approached on the basis that 'when there is a duty to take a precaution against damage occurring to others through the default of third parties or through accident, breach of the duty may be regarded as materially causing or materially contributing to that damage, should it occur, subject of course to the question whether performance of the duty would have averted the harm'". (Footnotes omitted)

She went on to consider what would have happened if the Director had discharged his duty to obtain advice for the ward. As we understand her reasons, her conclusion did not depend on the propositions just cited. What she said was in the context of the issues presented by Bennett. And, we suggest, it is important to bear in mind that in the passage just cited she concluded by referring to the question whether "performance of the duty would have averted the harm". Implicit in this, if this passage is to be applied to the present case, is the proposition that it is necessary to show that had Mr Tucker driven at an identified and appropriate speed, he could have averted the accident, or would have had a materially improved chance of doing so. McHugh J decided the case on what we understand to be the ordinary application of the principles in March v Stramare: see in particular at 428‑429.

85 In our view there is no departure in this case from what we regard as basic principle. The case itself was, as we have said, quite different from the present case and understandably required a somewhat different approach.

86 In Chappel v Hart [1998] HCA 55; (1998) 195 CLR 232 one finds some statements similar to those made by Gaudron J in Bennett.

87 In Chappel the plaintiff underwent throat surgery. No criticism was made of the manner in which the surgery was performed. The plaintiff was not warned of the possibility that during the surgery a perforation of the oesophagus might occur without any lack of care or skill, that infection might result and that she might suffer damage to her voice as a result. That unfortunate result did ensue, without any lack of due care by the surgeon. The plaintiff needed to have the operation at some time. However, if advised of the risk, the plaintiff would have delayed the surgery and would have had it performed by the most experienced surgeon in the field. Even so, there remained the possibility of the perforation, infection and injury. The Court held that in the circumstances the surgeon was in breach of his duty of care in failing to advise the plaintiff of the risk of injury. The issue was whether that failure to advise was the cause of the loss, bearing in mind that the operation was carried out with due care and skill, that the plaintiff had to have the surgery at some stage, and that whenever the surgery was performed there was a risk of the injury occurring.

88 As these facts indicate, Chappel was a very different and difficult case on the issue of causation.

"It was not disputed in this Court that Dr Chappel was under a duty to inform Mrs Hart of the possible consequences in the event of the perforation of her oesophagus and subsequent infection, including the possibility of damage to her voice. The duty was called into existence because of the foreseeability of that very risk. The duty was not performed and the risk eventuated. Subject to a further question in the case of a duty to provide information, that is often the beginning and the end of the inquiry whether breach of duty materially caused or contributed to the harm suffered." (Footnote omitted)

It is understandable, when a statement like this is put in the context of the facts, that breach of duty coupled with the occurrence of a foreseen risk should suffice to support a conclusion that the breach caused or contributed to the harm suffered. McHugh J dissented in the result. He said at [27]:

"Before the defendant will be held responsible for the plaintiff's injury, the plaintiff must prove that the defendant's conduct materially contributed to the plaintiff suffering that injury. In the absence of a statute or undertaking to the contrary, therefore, it would seem logical to hold a person causally liable for a wrongful act or omission only when it increases the risk of injury to another person. If a wrongful act or omission results in an increased risk of injury to the plaintiff and that risk eventuates, the defendant's conduct has materially contributed to the injury that the plaintiff suffers whether or not other factors also contributed to that injury occurring. If, however, the defendant's conduct does not increase the risk of injury to the plaintiff, the defendant cannot be said to have materially contributed to the injury suffered by the plaintiff. That being so, whether the claim is in contract or tort, the fact that the risk eventuated at a particular time or place by reason of the conduct of the defendant does not itself materially contribute to the plaintiff's injury unless the fact of that particular time or place increased the risk of the injury occurring. (Footnotes omitted)

As to that passage, we would emphasise the need to consider what is involved in proof that an act or omission resulted in an increased risk of injury. In the present case, our view is that that requires proof, at least, of a material increase of risk at the speed in question compared with the risk at a speed at which a reasonably careful driver would have driven. If the risk of a roll-over was the same at the speed at which a reasonably careful driver would have driven, and at the speed at which Mr Tucker is found to have driven, then it cannot be said that there has been an increased risk of injury. Accordingly, if a person driving a car at about 110 kph would not have been able to avoid an accident as a result of the axle failing, driving at the speed at which the Judge found Mr Tucker was driving (110 kph to 120 kph) or driving at the speed for which the plaintiff contended (140 kph) is not an act that increases the risk. We add that there is no evidence to establish that an accident or roll-over at a speed of 110 kph would have caused materially different injuries or significantly less serious injuries to the plaintiff.

90 The passage which we have just cited is relevant to one other point that Mr Peek made. In the course of argument he suggested that by driving as fast as he did, Mr Tucker produced the result that the axle failed at a time and place different from that at which it would have failed had he driven at a lesser speed. But even if the premise is accepted, there is no evidence that the time or place at which the accident happened increased the risk of the injury occurring.

91 Gummow J was one of the majority. In the course of his reasons he said at [68]:

"Here, the injury to Mrs Hart occurred within an area of foreseeable risk. In the absence of evidence that the breach had no effect or that the injury would have occurred even if Dr Chappel had warned her of the risk of injury to the laryngeal nerve and of the consequent risk of partial or total voice loss, the breach of duty will be taken to have caused the injury. (Footnote omitted)

Once again, we would emphasise the context in which this statement was made. We do not consider that that approach can simply be transplanted to a case like the present one.

92 Kirby J was also part of the majority. His approach was broadly consistent with that of Gaudron and Gummow JJ. He said at [98]:

"Once Mrs Hart showed the breach and the damage which had immediately eventuated, an evidentiary onus lay upon Dr Chappel to displace the inference of causation which thereupon arose. He failed to do so. Nor, in my view, causation being established, did he prove that Mrs Hart would have been exposed to the same, or substantially the same, possibilities of like injury if she had postponed the procedure and had it done by someone more experienced, as was her right. On the contrary, the evidence demonstrated that the chances of her receiving such injury in any other operation were miniscule."

93 Hayne J dissented. In the course of his reasons he said at [146]:

"I agree with McHugh J that there is insufficient evidence in this case to say, on the balance of probabilities, that the appellant's failure to warn exposed the respondent to greater risk of injury. The respondent would have had the operation at some time. The operation has risks even if performed by the most skilled surgeon available. There was very little evidence on the difference between the risk of injury actually faced by the respondent and the risk that she would have faced had the operation been performed by, say, Professor Benjamin."

We draw attention to the emphasis that he placed upon a need to prove exposure to greater risk of injury.

94 There is a good deal more to be found in Chappel that bears on the issue of causation. Each member of the Court also explored the facts of the case, and to some extent different approaches appear to have depended upon slightly different assessments of the facts. But allowing for all that, the fact remains that it was a special case. There was a known but low risk the performance of the operation, whenever it was done, would result in a perforation of the oesophagus, infection and damage to the voice. In the circumstances there was a duty to advise of that risk, and the duty was breached. The relevant risk, perforation, infection and damage eventuated. Had advice been given, the majority accepted that the plaintiff would have followed a course that might have meant, although not necessarily, that adverse result would not ensue. In those circumstances, the majority decided that breach of the duty to advise or warn caused the loss. We do not consider that the majority approach to that case is of much assistance in the present case.

95 In Naxakis v Western General Hospital (1999) 197 CLR 269 Gaudron and Callinan JJ referred with apparent approval to the passage which we have just cited from the reasons of McHugh J in Chappel: at [31] and [127] respectively. For the reasons that we have explained, we consider that what McHugh J said in Chappel is consistent with the approach that we would take to the present case.

96 In the cases to which we have referred, there is a number of references to the decision of the House of Lords in McGhee v National Coal Board [1972] UKHL 7; [1972] 3 All ER 1008. That decision, or at least the reasons of Lord Wilberforce, has been seen as supporting an approach to causation under which it is sufficient to prove a breach of duty involving an increase of risk in an area of known risk, without establishing a causative link, or at least an approach under which in such a situation causation is made out unless the defendant can prove that the breach of duty had no effect or that the injury would have occurred even if the duty had been performed. In Chappel Kirby J discussed this approach at [93]. The proposition for which McGhee is authority has been controversial. As we understand the position, Lord Wilberforce's approach has not been authoritatively endorsed in Australia. We note that in Fairchild v Glenhaven Funeral Services Ltd [2002] UKHL 22; [2003] 1 AC 32 the House of Lords has held that proof that breach of duty has materially increased the risk of injury is sufficient to satisfy the causal requirement for liability, but only in circumstances (the claim was by a worker for injuries sustained in the course of employment) that included the fact that in the state of then current medical knowledge the onset of the relevant condition (mesothelioma) could not be attributed to a particular wrongful exposure to asbestos dust, and the issue was which of one or more employers who had exposed the worker to asbestos dust was to be found liable. Our view is that there is nothing in McGhee that bears on the present case.

97 Bendix Mintex Pty Ltd v Barnes (1997) 42 NSWLR 307 was a mesothelioma case. These issues, and the English cases, are discussed at some length there. Bendix was also a case in which the plaintiff sued multiple employers alleging exposure to asbestos in the course of employment with them. The case is sufficiently different for it to be put to one side. However, we respectfully agree with the general analysis of the law by Mason P, and in particular with his conclusion (at 316) and as things stand High Court authority is contrary to the proposition, at least as a general rule, that proof of an injury occurring within an area of foreseeable risk is proof of causation, unless the defendant is able to prove that the breach had no effect. Stein JA appears to have taken a different view (at 348), and the approach of Beazley JA was dependent upon the facts.

98 Seltsam Pty Ltd v McGuiness [2000] NSWCA 29; (2000) 49 NSWLR 262 was another asbestos case. In this case the injury was renal cell carcinoma. Much of the case was concerned with epidemiological evidence, and the relevance of a proved increase in risk. As we understand his reasons, Spigelman CJ, with whom Davies AJA agreed, agreed with the approach of Mason P which he said at [103] was:

"... that the law does not regard an increase in risk as satisfying the legal requirements of causing, or materially contributing to, injury..."

"There is a tension between the suggestion that any increased risk is sufficient to constitute a 'material contribution', and the clear line of authority that a mere possibility is not sufficient to establish causation for legal purposes. The latter is too well‑established to be qualified by the former. The reconciliation between the two kinds of references is to be found in the fact that, as in Chappel v Hart and in the cases that suggest the former, the actual risk had materialised. The 'possibility' or 'risk' that X might cause Y had in fact eventuated, not in the sense that X happened and Y had also happened, but that it was undisputed that Y had happened because of X."

We gratefully adopt that statement of the position. Applied to the present case it means that the approach in Chappel would be relevant if it was undisputed that the roll-over and accident happened because of the excessive speed, and that it is not sufficient that there was excessive speed and a roll-over. In the present case the issue is whether the roll-over happened because of excessive speed, because the defendant's case is that the roll-over would have happened at 110 kph, or at a speed between 110 kph and 120 kph, and would have been avoided only by driving at a relatively low speed which, as we understand it, no‑one has suggested Mr Tucker should have observed.

99 In Sabatino v The State of New South Wales [2001] NSWCA 380 Mason P returned to the issue of causation, and in substance reiterated the view that he had expressed in Bendix. Priestley JA and Beazley JA agreed with the reasons of Mason P and, we take it, with his approach to the issue of causation.

101 As we have already said, our understanding of Mr Hall's evidence, which the Judge accepted, is that travelling at a speed of about 110 kph Mr Tucker had no realistic chance, exercising ordinary care and skill, of avoiding an accident once the axle failed. If that is so, even if he was driving at 140 kph it cannot be said that to drive at that speed materially increased the risk of injury to the plaintiff. Accordingly, even if the plaintiff made out his case on speed, causation was not established, unless the Judge's acceptance of Mr Hall's evidence is set aside.

102 With respect to Gray J, we cannot agree that it suffices to show that speed increases risk, and that the higher the speed the greater is the risk or danger of a driver being unable to cope safely with a mechanical failure. We do not agree that the authorities support that approach to causation.

103 Nor was causation made out on the basis of the Judge's finding as to the speed at which Mr Tucker was driving. It was not made out because it was not shown by the plaintiff that at some lesser speed, that a reasonably prudent driver would have observed, the risk of being unable to cope safely with a mechanical failure is materially less.

104 Gray J refers in passing to the fact that the motor car was almost 20 years old, and to the fact that it had been driven at high speed for a lengthy period. On our understanding of the evidence, the age of the vehicle was not a reason why Mr Tucker should have driven at a lesser speed, nor was there evidence suggesting that the period of time for which the motor car was driven at a high speed was material to the risk of the occurrence of the axle failure. We have already explained why we do not agree that Mr Tucker was negligent in being unable to state the speed at which he was driving. Our view of his evidence is that he meant that he could not state the speed with any degree of accuracy. But even if the correct conclusion is that he was driving at 140 kph, the fact that he was unaware that he was driving at that speed does not advance the plaintiff's case in the particular circumstances. That case would still founder on the issue of causation. Gray J also refers to the fact that because of the speed, the roll-over occurred at a higher speed than otherwise would have been the case, and that that brought with it an increased risk of injury. In our respectful view there is no evidence to support the conclusion that a roll-over at 140 kph would have produced significantly different consequences for the plaintiff than a roll-over at 110 kph.

105 For all those reasons, we consider that the appeal should be dismissed.

106 Following a motor vehicle rollover on a sealed rural highway a passenger brought an action against the driver in negligence. The trial proceeded in the District Court. This is an appeal against the judge's decision to dismiss the passenger's claim.

107 On Monday 12 June 1995 at about 2.40 pm Tom Tucker, the defendant and respondent, was driving a 1978 Chrysler station wagon in a southerly direction on the Stuart Highway. The rollover occurred approximately 21 kilometres north west of Pimba on a straight stretch of road. Frank Van Den Heuvel, Jason Tucker, Stephen Nikolavcic and Frank Deeble were passengers in the vehicle. All sustained personal injury. The vehicle was owned by Mr Van Den Heuvel's brother.

108 It was common ground that the vehicle left the road following rear axle failure. The vehicle crossed the western carriageway and moved onto the dirt verge before coming to a ditch. It then rolled over and came to rest about 40 metres west of the road. Police attended at the scene about 40 minutes later. By this time the vehicle was burnt out. Fire and ambulance services were still in attendance.

109 No police officers gave evidence at the trial. However a copy of the police report was tendered. The report disclosed that at the time of the rollover the road was dry. It was a cool and overcast day. There was no sign of recent rain. Visibility was clear. The police examination at the scene revealed two gouge marks. One was 10 paces in length, on the eastern carriageway close to the centre line, and the other, seven paces in length to the southwest on the western carriageway[1].

110 One police officer apparently made observations at the scene and prepared a rudimentary plan. The plan was not to scale but formed part of the police report. The plan indicated the course of travel. It disclosed marks on the road surface. These commenced 14 paces south of the northernmost gouge[2]. The marks extended to 34 paces in length. The marks indicated a curved course of travel from the eastern carriageway through to the western bitumen edge. They broadened as they reached the western carriageway. The marks suggested that the vehicle was by this time travelling partly side on. The plan showed the course of travel to be 61 paces from the bitumen edge of the sealed road to the point where the vehicle came to rest. The nature of the marks observed by the police officers were not disclosed. Photographs of the scene suggested that tyre marks were left as a vehicle crossed the dirt verge. There was no evidence as to when the photographs were taken.

111 Henry Kutek an expert engineer examined the axle to determine the cause of the failure:

The fracture surface is typical of a fatigue fracture which normally originates as a small crack at a stress raiser such as a surface defect. Under normal loads the crack grows slowly resulting in the characteristic beach marks and polished area until the remaining metal can no longer support the load.

The small final fracture area indicates that the axle had not been heavily loaded at the time of fracture. The crack may have originated tens of thousands of kilometres before final failure.

The surface defect appeared to be a severe pit located beneath the inner race of the bearing, the cause of which could not be determined without expending considerably more effort. ...

The axle failed as a result of a fatigue crack which initiated at a surface defect located below the inner race of the bearing.

112 Mr Van Den Heuvel's case was that Mr Tucker was driving at high speed. It was said that he was driving at about 140 kilometres an hour. Associated stress hastened the failure of the axle. The excessive speed minimised Mr Tucker's opportunity to take steps to react to the axle failure. It made it more difficult for him to regain control of the vehicle. If Mr Tucker had been travelling at an appropriate speed then he would have been able to avoid the rollover or at least minimise its seriousness and subsequent damage. The excessive speed increased the risk that Mr Tucker would lose control. That risk eventuated. The excessive speed was a material cause of the rollover.

113 Mr Tucker had driven in breach of the Road Traffic Act 1961 (SA). He had exceeded the statutory speed limit of 110 kilometres an hour. This was prima facie evidence of a breach of Mr Tucker's common law duty of care. It followed that travelling at a speed in excess of the statutory limit increased the risk of a dangerous incident occurring.

114 Mr Van Den Heuvel and other passengers gave evidence. Their evidence was said to directly and indirectly support a finding that Mr Tucker was driving at about 140 kilometres an hour at the time the axle failed. Experts addressed the issue of the failure of the axle and the consequent effect on a driver's ability to control a vehicle at speed.

115 Mr Tucker gave evidence. He admitted that as he drove towards the scene of the incident the vehicle had a cruising speed of between 110 and 120 kilometres an hour. He said that at times the speed of the vehicle would "creep up" to as much as 140 kilometres an hour. When he became aware that this had occurred he reduced the vehicle's speed to the cruising speed. Mr Tucker was unable to say over what periods the vehicle had travelled at speeds in excess of 120 kilometres an hour. He was unaware of his speed at the time of the axle failure.

116 It was Mr Tucker's case that he should not be criticised for the rollover. There had been no breach of duty. The axle collapsed without warning and the vehicle went out of control. There was nothing he could do at the speed at which he was travelling. A prudent driver could not have controlled the vehicle. Even if Mr Tucker had been travelling at a speed within the statutory limit, this was an unavoidable and inevitable rollover. The defence relied on the opinion of an accident reconstruction expert.

117 The judge accepted Mr Tucker's evidence and rejected the evidence of Mr Van Den Heuvel and his witnesses:

Having found that [Mr Van Den Heuvel's witnesses'] observations were spasmodic and likely to occur when they felt the speed had increased I find I accept the evidence of Mr Tucker notwithstanding his vagueness that he was usually travelling at 110 to 120 kilometres per hour, occasionally increasing the speed unconsciously and then when he became aware of that decelerating back to a normal speed. There are other matters in the evidence which make me think that is the most likely turn off events that were happening in the driving of the car. ...

The evidence of Mr Tucker was both vague and casual.

After considering his manner of giving evidence I find his evidence to be more persuasive than the other persons in the car.

He was candid that many events of the drive were so inconsequential that he could not remember. He made no attempt to reconstruct events that you would expect him not to remember.

I find that notwithstanding his limitations in memory he was a candid witness.

The judge did not make any finding about the speed of the vehicle at the time the axle failed.

118 The judge did not make any finding about the police observations at the scene or the plan. The gouge marks on the bitumen surface were not the subject of any findings. The judge did not make a finding that the other marks on the road were left by Mr Tucker's vehicle.

119 The judge accepted the evidence of the defence expert Christopher Trentan Hall. He concluded that Mr Hall gave the only "appropriate" expert evidence. He said that Mr Hall had concluded that on the balance of probabilities there was nothing that Mr Tucker could have done to avoid the "accident":

Having regard to the whole of Mr Hall's evidence, not only the extracts to which I have referred, I am satisfied and so find that he concluded that on the balance of probabilities there was nothing the defendant could have done to avoid the accident.

This finding is consistent with the evidence of the defendant and Frank Deeble.

... I accept his evidence that the driver did not omit to do anything that he should have done, nor do anything that he should not have done.

There is no liability without fault.

The plaintiff has not satisfied me that the defendant was guilty of any negligence whatsoever. On the question of liability I find for the defendant.

To constitute an inevitable accident the occurrence must have taken place in such a manner as not to be capable of being prevented with the exercise of all the skills an ordinary driver is expected to have and with the exercise of that degree of diligence generally found in persons who discharge their duty.

I find that the accident was an inevitable accident and that there was nothing whatsoever that the defendant could have done or failed to do to remedy the situation. In my opinion, the plaintiff has not shown that there was any negligence whatsoever and I therefore dismiss the plaintiff's claim.

There were no findings as to the factual basis or reasonableness of Mr Hall's assumptions. The judge did not separately identify or consider the assumptions made by Mr Hall.

120 The powers and functions of a Court of Appeal were discussed by the High Court in Fox v Percy[3]. Gleeson CJ and Gummow and Kirby JJ reviewed the earlier High Court decisions of Warren v Coombes[4], Jones v Hyde[5], Abalos v Australian Postal Commission[6] and Devries v Australian National Railways Commission[7] and observed:

Within the constraints marked out by the nature of the appellate process, the appellate court is obliged to conduct a real review of the trial and, in cases where the trial was conducted before a judge sitting alone, of that judge's reasons. Appellate courts are not excused from the task of "weighing conflicting evidence and drawing [their] own inferences and conclusions, though [they] should always bear in mind that [they have] neither seen nor heard the witnesses, and should make due allowance in this respect". In Warren v Coombes, the majority of this Court reiterated the rule that:

[I]n general an appellate court is in as good a position as the trial judge to decide on the proper inference to be drawn from facts which are undisputed or which, having been disputed, are established by the findings of the trial judge. In deciding what is the proper inference to be drawn, the appellate court will give respect and weight to the conclusion of the trial judge but, once having reached its own conclusion, will not shrink from giving effect to it.

As this Court there said, that approach was "not only sound in law, but beneficial in ... operation.

After Warren v Coombes, a series of cases was decided in which this Court reiterated its earlier statements concerning the need for appellate respect for the advantages of trial judges, and especially where their decisions might be affected by their impression about the credibility of witnesses whom the trial judge sees but the appellate court does not. Three important decisions in this regard were Jones v Hyde, Abalos v Australian Postal Commission and Devries v Australian National Railways Commission. This trilogy of cases did not constitute a departure from established doctrine. The decisions were simply a reminder of the limits under which appellate judges typically operate when compared with trial judges.

The continuing application of the corrective expressed in the trilogy of cases was not questioned in this appeal. The cases mentioned remain the instruction of this Court to appellate decision-making throughout Australia. However, that instruction did not, and could not, derogate from the obligation of courts of appeal, in accordance with legislation such as the Supreme Court Act applicable in this case, to perform the appellate function as established by Parliament. Such courts must conduct the appeal by way of rehearing. If, making proper allowance for the advantages of the trial judge, they conclude that an error has been shown, they are authorised, and obliged, to discharge their appellate duties in accordance with the statute.

Over more than a century, this Court, and courts like it, have given instruction on how to resolve the dichotomy between the foregoing appellate obligations and appellate restraint. From time to time, by reference to considerations particular to each case, different emphasis appears in such reasons. However, the mere fact that a trial judge necessarily reached a conclusion favouring the witnesses of one party over those of another does not, and cannot, prevent the performance by a court of appeal of the functions imposed on it by statute. In particular cases incontrovertible facts or uncontested testimony will demonstrate that the trial judge's conclusions are erroneous, even when they appear to be, or are stated to be, based on credibility findings.

121 On appeal, counsel for Mr Van Den Heuvel tendered proposed further evidence. The tender was by affidavit. The evidence addressed two topics relevant to the judge's finding of speed. It was said that after the trial Mr Tucker had admitted lying about his speed when giving evidence. It was alleged that he had committed perjury. The other topic was the location of the speedometer in the vehicle.

122 The right to appeal is a statutory right. Section 43 of the District Court Act 1991 (SA) provides:

(1) A party to an action may, in accordance with the rules of the appellate court, appeal against any judgment given in the action.

(2) The appeal lies -

(a) in the case of a judgment given by a Master or the Court constituted of a Master - to the Court constituted of a judge;

(b) in the case of an interlocutory judgment given by a judge - to the Supreme Court constituted of a single judge;

(c) in any other case - the Full Court of the Supreme Court.

The rules of this court govern the procedures for appeals from the District Court. Rule 95.15(b) provides:

The Full Court when hearing an appeal:

(b) may in its discretion receive further evidence upon any question of fact;

Rule 95.15(b) was the subject of comment in Chakravarti v The Advertiser[8] where Doyle CJ and Perry J in their joint judgment observed:

The Court has a wide discretion to receive further evidence on the hearing of an appeal. The power is conferred by r95.15(b) which provides that when hearing an appeal the court 'may in its discretion receive further evidence upon any question of fact.' The terms of this rule, unlike its predecessor O48 r14(1), do not distinguish between evidence of matters occurring before trial and after trial. However, the discretion is expressed in completely general terms. There is no reason why, within the ambit of such a generally expressed discretion, the more liberal approach taken under the previous rule to the admission of evidence of facts occurring after trial should not continue to be taken.

123 In CDJ v VAJ[9] the High Court considered the approach to be taken to the reception of further evidence on appeal. McHugh, Gummow and Callinan JJ considered that the terms of a statutory right to appeal determined the nature of the appeal and the right, if any, to adduce further evidence. The power to receive further evidence was regulated by the statutory provision and not by common law doctrines. The statutory power under consideration was in relevantly similar terms to the South Australian rule. Their Honours observed:

One consideration in construing s 93A(2) is its remedial nature. Its principal purpose is to give to the Full Court a discretionary power to admit further evidence where that evidence, if accepted, would demonstrate that the order under appeal is erroneous. The power exists to facilitate the avoidance of errors which cannot be otherwise remedied by the application of the conventional appellate procedures. A further, but in practice subsidiary, purpose is to give the Full Court a discretion to admit further evidence to buttress the findings already made.

Another consideration is the effect of the principle that a provision conferring judicial power upon a court should be construed liberally and without the making of implications or the imposition of limitations not found in the words used by the legislature. That is so whether the limitation derives from the common law principles governing the grant of new trials upon proof of fresh evidence or from some other source. ...

124 The discretion conferred by Rule 95.15(b) to receive further evidence on appeal is not expressed to be limited in any way. In particular the sub-rule does not require that "special grounds" be shown before the evidence can be adduced. McHugh, Gummow and Callinan JJ continued:

Ordinarily, where it is alleged that the admission of new evidence requires a new trial, justice will not be served unless the Full Court is satisfied that the further evidence would have produced a different result if it had been available at the trial. Without that condition being satisfied, it could seldom, if ever, be in the interests of justice to deprive the respondent of the benefit of the orders made by he trial judge and put that person to the expense, inconvenience and worry of a new trial.

...

No doubt the Full Court will readily admit further evidence which is not in dispute and which the Court is able to evaluate and take into account in considering the appeal without the necessity to have the proceedings re-heard. Further evidence of this kind is particularly likely to be admitted where the evidence relates to events occurring after trial. In the case of undisputed evidence which the Full Court can evaluate as part of the evidence in the appeal, the discretion to admit the evidence may even be properly exercised without the Full Court considering what effect it would have had on the trial judge's decision. In that context, the likely effect of the further evidence on the Full Court's view of the evidence before the trial judge is the important consideration.

...

The failure to have adduced the evidence before the primary judge will be a variable factor, the weight of which will depend upon all the other factors pertinent to the case. Where the evidence has been deliberately withheld, the failure to call it will ordinarily weigh heavily in the exercise of the discretion. In other cases, the failure to call the evidence even if it could have been discovered by the exercise of reasonable diligence may be of little significance. No invariable rule concerning the failure to call the evidence can or should be laid down in view of the wide discretion conferred on the court by the section.

125 The proposed evidence described a meeting that took place in October 2001 between Mr Van Den Heuvel and other passengers from the vehicle. Solicitor and counsel were also present. Discussion occurred about the appeal to this court and its prosecution. It was suggested that Mr Tucker had admitted giving false evidence about speed at trial.

126 With a view to enhancing the prospects of this appeal it was suggested that one of the passengers, Mr Nikolavcic, would approach Mr Tucker with a hidden tape recorder in order to record an "admission". Counsel advised "off the cuff" that this process would not involve a contravention of the Listening and Surveillance Devices Act 1972 (SA).

127 Some time later Mr Nikolavcic sought out Mr Tucker. A conversation took place. A secret recording was made. The recording and a transcript were tendered to this court. The court listened to the recording and reviewed the transcript. Counsel for Mr Van Den Heuvel claimed that there was a marked departure between Mr Tucker's account of his speed in this conversation and his evidence. The conversation was said to demonstrate that Mr Tucker had committed perjury.

Listening and Surveillance Devices Act

128 The Listening and Surveillance Devices Act relevantly provides:

4. Except as provided by this Act, a person must not intentionally use any listening device to overhear, record, monitor or listen to any private conversation, whether or not the person is a party to the conversation, without the consent, express or implied, of the parties to that conversation.

Maximum penalty: $10 000 or imprisonment for 2 years.

...

7. (1) Section 4 does not apply to or in relation to the use of a listening device by a person (including a person to whom a warrant is issued under this Act) where that listening device is used -

(a) to overhear, record, monitor or listen to any private conversation to which that person is a party; and

(b) in the course of duty of that person, in the public interest or for the protection of the lawful interests of that person.

129 Counsel for Mr Van Den Heuvel submitted that the recording was made "in the public interest or for the protection of the lawful interests of [Mr Nikolavcic]." The lawful interests were said to be the ascertainment of the truth. This submission should be rejected. The purpose would appear to have been to entrap Mr Tucker. Unfair means were used in an attempt to enhance the prospect of this appeal and the other passengers' claims.[10]

130 This matter has not been fully explored in evidence before this court. It is sufficient to conclude that a breach of the Listening and Surveillance Devices Act may have occurred.

131 The Law Society of South Australia's professional conduct rules provide:

10.2 Practitioners shall not directly or indirectly communicate with a client of another practitioner in the same transaction, except with the express approval of such other practitioner.

10.3 Practitioners may instruct an agent to make observations of an opposing party if such observations are directed towards the ascertainment of evidence which might be tendered at the trial of a matter but a practitioner shall not instruct an agent:-

(a) to communicate with such a party with a view to obtaining any admissions contrary to the case of that party;

(b) to commit any illegal conduct; or

(c) to do anything which would be improper for the practitioner to do.

132 No apparent consideration was given to the relevant professional conduct rules. At the time the recording was made Mr Tucker was a party to ongoing litigation including this appeal. On the evidence before this court it appears that the recording of the conversation made in breach of the professional conduct rules.

133 From the outset Mr Nikolavcic set out to compromise Mr Tucker. The legal advisers appear to have approved the proposed conduct. The end result was one of entrapment. Mr Nikolavcic approached Mr Tucker and took advantage of their friendship to engage in a casual conversation. A number of everyday matters were discussed before the topic of Mr Tucker's evidence arose. At the critical stage of the conversation emotional pressure was evident. Mr Nikolavcic spoke about the adverse consequences that Mr Tucker's evidence had on the claims of Mr Van Den Heuvel and the other passengers. Mr Nikolavcic pretended that an appeal was not being pursued in the Van Den Heuvel matter. It was suggested by Mr Nikolavcic that Mr Tucker was not exposed to any risk if he told the truth. Mr Nikolavcic was aware that the very purpose of recording the conversation was to obtain evidence to improve the prospects of this appeal.

134 The basic requirements of fairness were missing. There was no notice of the purpose of the discussion. No warning or caution was given. Lies were told by Mr Nikolavcic. The recording left the impression that Mr Nikolavcic was in control of the situation. Mr Tucker was put under emotional pressure. He appeared agitated and concerned.

135 The whole process was unsatisfactory. Such conduct is to be deplored. As earlier observed it appears that a breach of the Listening and Surveillance Devices Act and the professional conduct rules occurred. A calculated, dishonest, wholly opportunistic and unfair process took place. On the evidence before the court it appears that entrapment occurred. These matters must weigh heavily against the reception of the proposed evidence.

136 Counsel for Mr Van Den Heuvel relied on Mazinski v Bakka[11] to suggest that a civil court has no discretion to exclude evidence on the ground of unfairness or for reasons of public policy. Mazinski concerned non compliance with a regulatory scheme involving the taking of blood for analysis and the subsequent admission of evidence at trial. The present case is not concerned with the admission of evidence at trial. It is concerned with the reception of further evidence on appeal. Mazinski can be distinguished. A further matter sets this case apart. An allegation of perjury was advanced in the present case. It was not in Mazinski.

137 In any event in Mazinski the court contemplated that a residual discretion to exclude evidence may still exist. As Wells J observed[12]:

To the general rule there is, in my opinion, one qualification: although the discretion of the trial Judge in a criminal trial is lacking in a civil case, there remains, as always, the residual power of any court to prevent abuse of its processes, whether in the criminal jurisdiction (see The Queen v O'Loughlin; Ex parte Ralphs) or in the civil jurisdiction Metropolitan Bank v Pooley; Willis v Earl Beauchamp; and Lawrance v Norreys). It seems to me that if a piece of evidence was obtained by means of conduct that was deliberately and cynically criminal or otherwise outrageous, a civil court to whom such evidence was tendered, and who was made aware of the facts surrounding its intention, might be moved to say, modelling itself on Wilmot CJ in Collins v Biantern:

No polluted hand shall touch the pure fountains of justice. Whoever is party to felonious and wicked acts to obtain evidence shall not come in an unclean manner to ask a Court of justice to help him by using the evidence thus obtained. Procul, O! procul este profani.

138 The proposed evidence has been carefully reviewed. The contents of the secretly recorded conversation do not disclose any gross inconsistency with Mr Tucker's evidence. To the contrary a degree of consistency is demonstrated. Generally Mr Tucker's account was that he was travelling at between 110 and 140 kilometres an hour. He had no knowledge of his speed within this range. Although Mr Tucker spoke of "sitting on" 140 kilometres an hour in the recorded conversation, he immediately qualified this by saying that he was unsure how fast he was travelling. The allegation that perjury occurred must be rejected. At most the material may be capable of demonstrating some minor inconsistency with Mr Tucker's evidence. However there was no substantive change.

139 As earlier observed the proposed evidence also related to the position of the speedometer in the vehicle. It was said that the judge had misunderstood the view that the passengers had of the speedometer on the dashboard. It was contended that this misunderstanding was relevant to his findings of the passengers' credibility. It was argued that this court should take into account a number of photographs. The photographs were said to be of the dashboard of a vehicle relevantly identical to the vehicle involved in the rollover. It was said that the photographs were taken from different positions within the vehicle to demonstrate the view that the passengers would have had of the speedometer.

140 The position of the speedometer in the vehicle was a matter referred to during the course of the trial. The proposed evidence could have been adduced. No reason has been advanced to explain why the evidence was not before the trial judge. Even if the further evidence was admitted it would not allow for the conclusion that the result of the case would probably have been different. The tender of the proposed evidence should be rejected.

141 Counsel for Mr Van Den Heuvel submitted that the judge's acceptance and use of the expert testimony was flawed. This was a general complaint involving all of the experts. The judge erred in concluding that Mr Hall gave the only "appropriate" evidence. Mr Hall's opinion had been seriously weakened by the "fragile basis" of his assumptions. One critical assumption had not been established by the evidence. This was an assumption about the distance over which braking occurred. The judge erred in deferring to Mr Hall on the issue of breach of duty - an ultimate issue in the case. Part of the judge's judicial function was usurped by Mr Hall.

142 In Fox v Percy[13] Callinan J made the following observations concerning the utility of evidence from accident reconstruction experts:

Here [the witness] was described by counsel ... as an 'accident reconstruction expert'. That is an ambitious claim. Three things may be said about the evidence in this case and running down cases generally. Rarely in my opinion will such evidence have very much, or any, utility. Usually it will be based upon accounts, often subjective and partisan accounts, of events occurring very rapidly and involving estimates of time, space, speed and distance made by people unused to the making of such estimates. Minor, and even unintended but inevitable discrepancies in relation to any of these are capable of distorting the opinions of the experts who depend on them. It is also open to question whether variables in relation to surfaces, weather, and the tyres, weight and mechanical capacities of the vehicles involved can ever be suitably accounted for so as to provide any sound basis for the expression of an opinion of any value to a court. The engagement of experts in running down cases, other than in exceptional circumstances, is not a practice to be encouraged.

The second matter is the reception, apparently without question, of the whole of the contents of the expert reports in this case. Some of the deficiencies to which reference has already been made would require that, either in law, or in the proper exercise of a discretion, much of them should have been rejected. In the long run the undiscriminating tender of inadmissible, unreliable or valueless evidence, the acquiescence in its tender by counsel on the other side, and its reception into evidence, will prolong and increase the costs of trials. It will increase the margin for judicial error as occurred here, and will also lead to uncertainties and difficulties in courts of appeal. No court is bound to accept evidence of no probative value and evidence of slight probative value will rarely provide a foundation for any confident finding of fact, particularly if strong contrary evidence is available.

143 Des Ronald Pudney was a technical liaison engineer with the Royal Automobile Association of South Australia. He was a qualified motor mechanic and held a foreman's certificate. He had worked as an engineer with the RAA for more than 10 years. His duties included the inspecting of dismantled motor vehicle components to ascertain the cause of apparent failure. There was no challenge to Mr Pudney's expertise. He provided a short written report and gave evidence. He expressed his view as to the cause of the axle failure and the significance of travelling at speed if axle failure occurs.

144 The judge set out in his reasons a lengthy extract from Mr Pudney's evidence. There was no suggestion that Mr Pudney was not a qualified expert. There was no explanation as to why Mr Hall's evidence was preferred over Mr Pudney's evidence where it conflicted. No reasons were provided for the judge's conclusion that Mr Pudney was not qualified to give "appropriate" evidence.

145 Mr Pudney was well qualified. He provided probative expert evidence relevant to issues before the court. It was wrong for the judge to conclude that his evidence was not "appropriate" evidence. It was wrong for the judge not to consider Mr Pudney's evidence along with the other evidence before the court.

[Mr Wearing] then goes on to give his opinion about what might have occurred when the vehicle being driven by the defendant was involved in an accident. I find that Mr Wearing's qualifications are not such that he is competent to analyse the mechanics of what happened to the vehicle at the instant when problems occurred and what would be the appropriate action to take. I find his evidence is based on an academic perfection which is not the operation of a normal driver faced with an untoward and unexpected incident as in this case.

147 Cameron Baird Wearing worked as a professional driver. For more than 10 years he had been involved in teaching driver training. He had trained in the techniques of basic "on road" driving, low and high speed vehicle control and high performance driving. He had taught at all levels of motor sport including tarmac and gravel racing. He had worked as a precision driver.

148 Mr Wearing attended seminars and education programmes conducted by the Federal Office of Road Safety and the Professional Drivers Trainers Association. He kept up to date with developments in the field of driving. Knowledge of vehicle and suspension set ups and of vehicle behaviour was a necessary part of his work.

149 Mr Wearing had been contracted by public companies as an adviser for their crash reduction programs. He developed a particular interest in country driving. He conducted a driver training study for a major employer with extensive rural interests. This study addressed vehicle control on dirt roads and fatigue management. The employer's business had widespread distribution outlets. Its employees were expected to drive extensive distances on rural roads. Mr Wearing trained the employees in safe driving techniques. His work included highway, freeway, rural and dirt road training as well as "basic evasive scenarios". He explained that his driver training courses predominantly taught defensive driving techniques.

150 Mr Wearing did not have graduate qualifications. He explained that in his area of work such qualifications were not available and not required. He was licensed pursuant to an agreement with the Department of Transport of South Australia to conduct post licence driver training. He provided information and reports to the Department and the Minister of Transport. He spoke at seminars. He outlined his experience in the reconstruction of motor vehicle crashes.

151 Mr Wearing also spoke of his work with the RAA where he analysed data about driving on rural roads and developed driver training programs. He said that he kept abreast of literature in the area of automotive mechanics, engineering and more particularly reconstructive engineering. He was familiar with a number of publications that addressed average reaction times and stopping distances. Mr Wearing was familiar with the work of the road accident research unit at the University of Adelaide.

152 No objection was taken to Mr Wearing's evidence about driver behaviour under emergency conditions. However objection was taken to him giving expert mechanical engineering evidence. Counsel for Mr Van Den Heuvel submitted that although Mr Wearing was not a mechanical engineer he had a level of mechanical knowledge from which he could reasonably form his opinions. The judge appeared to accept this submission. His reasons provide:

He knows a car has two wheels and a steering wheel, doesn't he, but he says he is not an [sic] mechanical engineer. I acknowledge that a lot of people can gain considerable experience in particular fields without any academic qualifications, and he is one of those sorts of persons. I am satisfied that he can give evidence in relation to what his experience qualifies him for, but that doesn't, I wouldn't have thought, relate to mechanical matters that you would expect to have come from somebody with a mechanical engineering background.

153 Mr Wearing was qualified to express an opinion about driver behaviour under emergency conditions. He had a particular knowledge and expertise of the likely response when high speed driving on rural roads was involved. Mr Wearing had considerably more knowledge about vehicle mechanics than the ordinary person. He was entitled to draw on that knowledge when expressing his opinion about driver response to emergency situations.

154 It is difficult to understand the judge's rejection of Mr Wearing's evidence and his finding that it was not "appropriate" evidence. Driver responses to a mechanical mishap such as axle failure were within Mr Wearing's expertise. The observation of the judge that Mr Wearing's evidence was based on "an academic perfection" was not supported by the evidence.

155 Mr Wearing's experience with respect to the practical aspects of rural driving would appear to be more extensive than that of Mr Hall. Mr Wearing's opinion was relevant and probative. It was admissible evidence. The judge's conclusions concerning Mr Wearing's expertise may have been based on a misunderstanding of his area of expertise and his evidence. To find that Mr Wearing was unable to give "appropriate" evidence was to misconstrue the role of an expert witness. The judge erred.

156 As earlier observed the judge accepted and acted on the evidence of Mr Hall:

I find that Mr Hall is the only witness who is qualified to give appropriate evidence in this matter and I accept without hesitation his evidence as a whole and also where it conflicts with the evidence of Mr Wearing or Mr Pudney.

157 It was accepted by counsel for Mr Van Den Heuvel that Mr Hall was a qualified expert. It did not follow that the judge could elevate Mr Hall's conclusions so that they were determinative of an ultimate issue at trial. This was said to have occurred.

158 Counsel for Mr Van Den Heuvel submitted that in providing his opinion Mr Hall drew on a number of assumptions. It was submitted that each of his assumptions needed to be established by evidence. The identification, proof and acceptance of the assumptions were critical. It was said that these matters had not been addressed. Mr Hall did not attend the scene. He did not examine the vehicle. He had regard to photographs without apparent enquiry or knowledge as to when they were taken. He made assumptions about police observations at the scene that were not established in evidence. Mr Hall's initial opinions and conclusions were based on an assumed vehicle speed of 110 kilometres an hour. Subsequently Mr Hall expressed the view that the speed was 109 kilometres an hour although he later broadened his opinion to a range of 100-120 kilometres an hour.

159 The facts on which an expert's opinion are based must be capable of scrutiny. The factual basis of an opinion must be identified and proven. In Paric v John Holland (Constructions) Pty Ltd[14] the High Court observed:

It is trite law that for an expert medical opinion to be of any value the facts upon which it is based must be proved by admissible evidence: Ramsay v Watson [1961] HCA 65; (1961) 108 CLR 642. But that does not mean that the facts so proved must correspond with complete precision to the proposition on which the opinion is based. The passages from Wigmore on Evidence cited by Samuels J.A. in the Court of Appeal (Wigmore on Evidence, (3rd ed, 1940) vol II, 680, p 800; 2 Wigmore, Evidence 680 (Chadbourn rev. 1979), p 942) to the effect that it is a question of fact whether the case supposed is sufficiently like the one under consideration to render the opinion of the expert of any value are in accordance with both principle and common sense.

As Wigmore states (pp 941-942, Chadbourn rev),

the failure which justifies rejection must be a failure in some one or more important data, not merely in a trifling respect.

160 A critical aspect of Mr Hall's evidence was his opinion about the speed of the vehicle at the time the axle failed. Mr Hall made a number of assumptions in forming his opinion. He indicated that a "required" assumption was the distance over which the vehicle braked. Counsel for Mr Tucker asked Mr Hall to assume that moderate braking occurred over a distance of 50 metres. Mr Hall did so despite being "uncomfortable" with this assumption. The assumption was critical to his opinion about speed because it followed that the further the distance over which the braking occurred the higher the speed of the vehicle. Mr Hall's evidence was conditioned by the assumption put to him by counsel for Mr Tucker.

161 No evidence was led to justify or support the reasonableness of the assumption. Mr Hall did not consider the assumption of 50 metres to be reasonable. The judge erred in accepting and acting upon Mr Hall's estimate of speed given that it was inextricably linked with what can only be described as a tentative assumption about braking distance. The judge failed to have regard to Mr Hall's unwillingness to accept the reasonableness of the critical assumption that the braking occurred over a distance of 50 metres. The judge erred in failing to recognise that this assumption had not been established by evidence.

162 An additional difficulty arises. Although the judge said that he accepted and acted on Mr Hall's evidence his finding as to Mr Tucker's general speed was at odds with Mr Hall's estimate of 109 kilometres an hour. As earlier observed Mr Tucker's evidence was that the vehicle was generally travelling at a cruising speed of 110 to 120 kilometres an hour and that his speed "crept up" to as much as 140 kilometres an hour. The judge accepted that Mr Tucker was unable to say for how long he travelled at higher speeds or what his speed was at the time of the axle failure. This difficulty was compounded by the absence of a finding about Mr Tucker's speed at the time the axle failed.

163 Mr Hall's "discomfort" with the estimate of distance over which braking may have occurred is understandable. There was no evidentiary, scientific or mathematical basis for counsel's estimate. There were no braking marks on the road surface. The police report and photographs did not assist. Mr Tucker's evidence did not assist. He said that his speed could have been anywhere between 110 and 140 kilometres an hour. He did not know. The distance over which braking occurred could have been substantially more than 50 metres. In these circumstances estimates of speed were always going to be unreliable. Little or no weight could be attributed to Mr Hall's estimate of speed without a proper evidentiary basis.

164 There were a number of other assumptions made by Mr Hall that could be described as "fragile". They included his assumption as to reaction time, the degree of braking and the course of travel. These matters called for close examination. Findings of fact should have been made.

165 It is settled that it is undesirable to allow experts to become involved in the judicial decision making process. The danger is that a court's function will be usurped by an expert answering questions that only a court can decide. Accordingly an expert witness may not be asked the ultimate question which the court itself must decide. In Cavanett v Chambers[15] Bray CJ observed:

More importantly that answer is directed to the vital issue in the case which the Court had to decide for itself, and a witness cannot usurp this function of the Court and ought not to be allowed to give evidence amounting to such usurpation: R v Davies (1962) 3 All ER 97). It is true that this rule is one which is often ignored in practice, and it may be that there are now some exceptions to it, especially where purely scientific questions are involved. I refer to the authorities cited in the dissenting judgment of Turner J in Blackie v The Police ((1966) NZLR 910, at pp 918-919.) Though it is not necessary to decide the point, I prefer with all respect His Honour's reasoning to that of the majority in the same case. In England it appears that such evidence is still regarded as technically inadmissible: per Lord Parker CJ in Director of Public Prosecutions v A & B C Chewing Gum Ltd ((1967) 3 WLR 493, at p 497). However, it is clear, I think, that very little weight should be accorded to such evidence, even if admitted, when it proceeds from a non-scientific source and from one identified with the prosecution: Blackie v Police ((1966) NZLR 910).

Bray CJ reiterated his view in Samuels v Flavel:[16]

One of the topics canvassed during the argument was one that frequently arises in these cases, namely the propriety of a witness, particularly an expert witness, giving evidence in terms of the ultimate issue to be decided by the court. I mentioned this subject incidentally in Cavanett v Chambers ([1968] SASR 97), and I do not see any reason to depart from the views I expressed there. Such evidence is probably still strictly inadmissible (Director of Public Prosecutions v A & BC Chewing Gum Ltd [1967] 2 All ER 504) per Lord Parker CJ at p 506), though it is, in fact, often admitted without objection and there may be cases where it must be admitted, such as evidence of insanity within the M'Naghten Rules, because it is impossible for the opinion of the expert to be conveyed in any other form. But in my view it should be allowed only where absolutely necessary, and in cases like this it is not absolutely necessary. In this case the choice of the word 'appreciable' was the choice of the witness, not the choice of counsel. Presumably he chose it because he knew that it appeared in the statute, but it appeared subsequently from the cross-examination that he did not attach to it, or at least that he may not have attached to it, the meaning which this Court has held that it bears. That illustrates the danger of the practice. I respectfully but emphatically agree with the remarks of Turner J, in his dissenting judgment in Blackie v Police ([1966] NZLR 910, at pp 919-920):-

I approach the problem with an acute sensibility that there is always danger in allowing an expert witness, or indeed any witness, to answer the very question which the Court is called upon to decide. Once this is done and an answer given which is accepted by the Court, the chances of success on an appeal on fact are slight indeed, since there is direct and acceptable evidence on the very point at issue. The consequences of the answer may therefore be nothing less than disastrous from the point of view of the defendant. The only justification which can be advanced for allowing the question must be the impossibility or extreme difficulty of arriving at the truth in any other way; and even in such cases it is indispensable that there must be both a high degree of skill and a complete impartiality in the witness called.

In Murphy v The Queen[17] Mason CJ and Toohey J observed:

It is unnecessary to spend time on the question whether an expert may give an opinion on the very issue of fact or law which the court has to determine. It is doubtful that there is now an absolute rule precluding an expert witness from expressing a view as to the ultimate issue: see Cross on Evidence, 3rd Aust ed (1986), p717.

In Naxakis v Western General Hospital[18] Callinan J considered that the court should generally uphold an objection if the question goes to an ultimate issue.

166 An issue for the judge to decide on all of the evidence and after having regard to the applicable legal principles was whether Mr Tucker acted in breach of his duty of care. The judge had to determine whether Mr Tucker did something he should not have done or omitted to do something that he should have done. It was for the judge to reach a conclusion on the balance of probabilities on all of the evidence. The judge's reasons do not demonstrate or suggest that this course was undertaken. To the contrary, the judge's finding was that "[Mr Hall] concluded that on the balance of probabilities" there was no breach of duty:

I am satisfied and so find that [Mr Hall] concluded that on the balance of probabilities there was nothing the defendant could have done to avoid the accident ...

I accept [Mr Hall's] evidence that the driver did not omit to do anything that he should have done, nor do anything that he should not have done.

The judge then adopted Mr Hall's conclusion as his own ultimate finding:

I find that the accident was an inevitable accident and that there was nothing whatsoever that the defendant could have done or failed to do to remedy the situation. In my opinion, the plaintiff has not shown that there was any negligence whatsoever and I therefore dismiss the plaintiff's claim.

The judge incorrectly allowed Mr Hall to usurp his judicial function.

167 A further difficulty was that Mr Hall's evidence was given subject to qualification. In his second report Mr Hall expressed the following qualification:

I am of the opinion that there would have been an immediate loss of control of the vehicle, and Mr Tucker's ability to regain control would have depended on his level of experience and the condition of the road and vehicle. At highway speeds, the ability to regain control is significantly reduced, and given the complex reaction of the vehicle, coupled with the likelihood that Mr Tucker did not realise what was causing the vehicle to dip and steer, complete loss of control would not be unexpected. ...

168 Mr Hall did not conclude as the judge suggested, that Mr Tucker "did not omit to do anything that he should have done nor do anything that he should not have done." Mr Hall's reference to "highway speeds" was an important qualification. As earlier observed he had assumed the vehicle to have been travelling at a speed of 109 kilometres an hour.

From the evidence presented to me, I am of the opinion that the loss of control was unavoidable and resulted from a mechanical failure which was sudden and was not reasonably detectable in advance.

This opinion was based on the assumptions previously referred to including that Mr Tucker's speed was 109 kilometres an hour.

170 The judge failed to recognise that Mr Hall's evidence was based on a critical assumption. Mr Hall did not accept the reasonableness of the assumption. It was not independently established. Other assumptions made had a tenuous factual base. The judge did not assess or address those assumptions. The judge did not consider the qualifications to Mr Hall's opinions. His reliance on Mr Hall's evidence was misplaced. The judge allowed Mr Hall to usurp his judicial function. The judge failed to have regard to the relevant and probative evidence of Mr Pudney and Mr Wearing. He incorrectly excluded their evidence.

I think it is more likely than not that the driving of Tom Tucker was varying between his cruising speed of 110 to 120 kilometres per hour and occasionally creeping up to 130 to 140 kilometres per hour, where as soon as he noticed it he brought the speed back to his usual travelling speed. He does not know at what speed he was travelling at the time of the accident, nevertheless I find there is no inconsistency with his evidence and that of Mr Hall.

172 Counsel for Mr Van Den Heuvel submitted that the judge erred in concluding that Mr Tucker had not breached his duty of care. It was submitted that Mr Tucker's admission that he was driving at more than 110 kilometres an hour was prima facie evidence of negligence.

173 A prudent driver should be aware of the vehicle's speed at all times. A prudent driver should know whether the vehicle being driven is travelling at 110 or 140 kilometres an hour. Mr Tucker's level of attention was such that he was unaware whether he was driving at 110 or 140 kilometres an hour or at some speed in between. This is suggestive of serious inattention.

174 As earlier observed the statutory maximum speed limit for a vehicle travelling on the section of road where the rollover occurred was 110 kilometres an hour. The statute established a standard of conduct which Mr Tucker was bound by law to observe. The purpose of this statutory requirement is the prevention and minimisation of road collisions and other incidents rather than the maintaining of public order or the raising of revenue. Mr Tucker breached a statutory provision designed to protect other road users. He admitted exceeding the speed limit. This admitted breach constitutes prima facie evidence of a breach of his duty of care to other road users.[19]

175 Mr Tucker had an obligation to drive defensively and protectively. Although made three decades ago, the observations of Wells J in Stoekel v Harpas[20] remain apposite:

Three or four decades ago it was, speaking generally, reasonable to expect a driver to deal with the exigencies of motor and pedestrian traffic as they presented themselves from moment to moment, but he was not asked to look very far ahead and to seek out possible trouble. Today, I think that the situation has changed fundamentally. Population has increased; a high proportion of families have at least one car and not infrequently two; accidents are numerous; and death on the roads has become tragically familiar. In these circumstances, I think courts, when performing the role of a jury, are entitled, indeed bound, to require of motorists a measure of what is sometimes called defensive driving, or a look out that not only sees immediate, or immediately developing, danger, but looks well ahead and searches for potential danger. Nowadays, for example, a young child on the footpath is not just a person so many feet away, but is a human being that may suddenly present himself in your path; a green light is not just an authority to spring off the mark without further thought, but is an invitation to look to right and left before moving off in case someone is trying unsuccessfully to beat the lights; a bus is not just a stationary vehicle, but represents cover from which, at any time, a pedestrian may emerge; a car with its turning flicker on may not be going to turn, but may have left his flicker on inadvertently; the car that you are following is to be kept a respectable distance in front of you because, at any moment, the driver may stop or slow down virtually without notice; a crest in the road is not just another part of the road, but is a danger point where a motorist, coming in the opposite direction, may well seek to pass on the rise. All these situations, and countless others besides, call for consideration by the reasonable driver because experience has repeatedly shown that perils on the road, as time goes by, seem to be giving less and less warning of their emergence. Of course, what I have said has its corollaries for other road users, but because of the marked increase in the power, weight and speed of today's vehicles, as compared with those of the immediate post-war period, the implications for the drivers of motor vehicles are, in my view, stronger. The courts have, from time to time, spoken of the need to guard against human follies, but, in my opinion, there is a need for courts to emphasize that the guarding referred to includes an ever-present attempt to foresee dangers well ahead of the immediate driving situation.

In Walton v Rowbottom[21] von Doussa J observed that community expectations for careful driving had heightened since 1971:

...The cost to the community of death, bodily injury and property damage on the road, has continued to grow. In an effort to encourage greater care and to deter bad driving penalties for offences under the Road Traffic Act have been progressively increased. The community now requires not only a measure of defensive driving, but a measure of protective driving - to protect drivers, cyclists or pedestrians. Drivers must guard against all reasonably foreseeable dangers. Prominent amongst the foreseeable risks which drivers must have in mind is the one that other road users may be careless. ... Many provisions of the Road Traffic Act establish arbitrary standards the breach of which is punishable. They do not establish immutable 'rights' to drive up to the limits prescribed regardless of prevailing circumstances. ...

When addressing rural driving in Green v The Police[22] Bleby J remarked:

160 kph, even on a straight sealed road, in daylight, is a very high speed, especially on a single carriageway or traffic travelling in both directions. It makes no allowance for the unexpected, the sudden emergence of a kangaroo or some other animal, or the unexpected appearance of another vehicle, or some mechanical mishap, any one of which might have caused the vehicle to become, at that speed, irretrievably out of control.

176 When driving at high speed on a rural road awareness of the vehicle's speed is important. To be driving without knowing whether the vehicle is travelling at a speed of 110 or 140 kilometres an hour is a departure from the standard of care required of a prudent driver. A speed increase of 30 kilometres an hour from 110 to 140 kilometres an hour creates an increased risk. It involves an extra distance travelled of more than eight metres each second.

177 In Wyong Shire Council v Shirt[23] Mason J addressed the foreseeability of a risk of injury:

In deciding whether there has been a breach of the duty of care the tribunal of fact must first ask itself whether a reasonable man in the defendant's position would have foreseen that his conduct involved a risk of injury to the plaintiff or to a class of persons including the plaintiff. If the answer be in the affirmative, it is then for the tribunal of fact to determine what a reasonable man would do by way of response to the risk. The perception of the reasonable man's response calls for a consideration of the magnitude of the risk and the degree of the probability of its occurrence, along with the expense, difficulty and inconvenience of taking alleviating action and any other conflicting responsibilities which the defendant may have. It is only when these matters are balanced out that the tribunal of fact can confidently assert what is the standard of response to be ascribed to the reasonable man placed in the defendant's position.

A reasonable driver travelling at a speed above the statutory limit, on a rural road would foresee the possibility of a mechanical mishap occurring that could give rise to a loss of control. One example is tyre blowout. Another is axle failure.

178 At high speed a driver's ability to control an unexpected occurrence such as axle failure is reduced. A driver's ability to regain control of a vehicle at 140 kilometres an hour will be less than at 110 kilometres an hour. If a driver is unaware of the speed of travel that driver's ability to handle an emergency situation will be further impaired.

1. Quite clearly then, the faster the vehicle was going, the more likely the yaw to be uncontrollable.
2. Once again, you have to consider how quickly the yaw develops. You can be travelling very quickly and have a slow development in yaw, and that becomes easy to control. In fact, drivers, more skilled drivers, deliberately put their vehicles in yaw and control the vehicle through that yaw because they are able to develop a slow rate of yaw that then is controllable. We see that with rally drivers on dirt roads all the time. So, the speed is only an issue if the same rate of yaw is developed, then the faster you are going, the harder it is to control, but that presumes the same rate of yaw at both the lower speed and the higher speed.
3. But this situation happening at 140 km/h is going to be more difficult to control than, say, at 110 km/h.
4. Yes.
5. that degree of difficulty is [exponential].
6. Not exponentially, but more of a square relationship, because the amount of energy you have is related to the square of the speed, the distance required to slow the vehicle is related to the square of the speed, but if you take it in relation to travelling time because you take it further, then it is only related directly to the speed difference, not to any square relationship, so it is a linear relationship in that case.

1. Both of those insufficiencies would have been aggravated if the car had been travelling at a speed in the vicinity of 140 km/h as opposed to 110 km/h.

1. Similarly reaction times would have been aggravated by that same increase in speed.
2. No, because in saying 'yes' to your first question, I am [taking] into effect the reaction time. That is why I am saying it would have been aggravated because they would have travelled further through that reaction period than if - you travel further in a reaction period at a higher speed than a lower speed.
3. In fact, it would be fair to say the whole situation and every component of the situation would have been aggravated if he had been doing 140 km/h instead of 110 km/h.
4. When you say 'aggravated', I take it that you are saying it -
5. The likelihood of an increased yaw, the lessening of the reaction time, the speed of the failure; all individual components that contributed to this vehicle leaving the road, it would be fair to say were aggravated, or increased, if he had been doing 140 km/h instead of 110 km/h.
6. There wouldn't necessarily be any change to the reaction time, but the higher speed for that given reaction time will create a condition where it is more likely the vehicle will run off the road, because it will travel further before the driver can actually try to overcome the change in direction.

1. It could well be that the separation of the axle and the loss of the wheel was extremely quick and a matter of less than a second.
2. I guess it is hard - because the bearing, the stub is still retained in the bearing, there is still part of it in there. That has to come out and we have got the brake shoes which are going to try and retain it. I would say - I believe it would be longer than a second, but once again you can't prove it.
3. You can't be dogmatic about it.
4. You can't be dogmatic about it. I believe it would probably be longer than that.
5. I suppose the best we could say it could be less than a second, but I would expect it could be maybe a bit more; is that a fair way to summarise it.
6. Yes, I guess if we are travelling at a high speed certainly it could be certainly quicker.
7. Even if we were travelling at a speed of 100 to 110 km/h, the separation of the axle to the loss of the wheel could be extremely quick and somewhere in the range of less than a second up to perhaps as much as five seconds. That is a fair comment, you agree.
8. Yes, I would say probably a second to five seconds probably could be.

1. You are suggesting this person should have been reasonably able to control it in those circumstances if it was travelling at 110. What if it was travelling at 140. Would his option of controlling it be less.
2. Yes, it would be, yes. He would have less chance - the higher the speed - because, I guess, there is less correction because you are travelling the distance faster, there would be less - you probably could have a tendency to perhaps oversteer if you were trying to correct it at a faster speed.

1. Let us be more specific here. I would like you to assume that he was driving at 140 km/h.

1. When this incident happened. Is that in accord with going driving practice.
2. According to the Road Traffic Act, no.
3. Let us forget about the legality of it, and just based on good driving practice. Is that good driving practice.
4. Essentially, no. There was a study done on behalf of the Minister for Transport, Laidlaw, where it was being investigated from north of Clare whether there would be a speed limit increase to 130 km/h. that was actually thrown away because the amount of energy required to sustain a car at that speed influenced an earlier onset of fatigue, but there is also the control factor. Control of a vehicle at 140 is far greater than that required at 110. Even if you are in a straight line -

...

Q. The faster you go, the worse the scenario.

A. Disproportionately, yes.

1. And most of these propositions were put to you at a speed of 110 km/h. Do you agree with me that no matter what the views are as to the catastrophic nature of what happened, it is certainly going to be greatly enhanced, disproportionately, at a speed of 140 km/h.
2. I would agree with that.

1. At 140 you would think he wouldn't have time to do anything.
2. The exponential graph that we were talking of earlier in relation to speed -
3. It would be less likely that he could cope with these propositions you are suggesting if the speed was 140.
4. It would make it jolly difficult, yes.
5. It would make it difficult for you.
6. I wouldn't expect it to, with all respect, but it definitely makes it more difficult.

180 The vehicle being driven by Mr Tucker was manufactured in 1978. Mr Pudney's evidence was that travelling at high speed in a vehicle of that age would accelerate the rate of fatigue failure. Although Mr Tucker could not reasonably have been aware of the axle problem, he should have been aware that there was a risk of mechanical mishap occurring. As Mr Wearing observed:

1. My question is this: from a good driving practice point of view, we have established that we are unfamiliar with this car, only having driven it for the first time some 60 hours previously, but I would like you to assume we are not familiar with its mechanical condition, so there is no entitlement to assume it is in good sound condition. From a good driving practice, do you have any comment as to the desirability of doing speeds in the vicinity of 130 to 140 km/h by an unfamiliar driver, not knowing the mechanical nature of the car, but also having regard to the fact that this car, at the time of the accident, was nearly two decades old.

A. It doesn't come as wise thing to be doing.

Q. It is not consistent with going driving practice, is it.

A. No, no, it isn't, no. I won't argue with that.

181 A reasonable driver in the position of Mr Tucker would have foreseen that his conduct involved a risk of injury to his passengers. The risk arose as a result of driving at a speed in excess of the statutory limit without an awareness of his speed. Mr Tucker's ability to cope with the emergency that confronted him was reduced. He had no reason to speed. He had no excuse for speeding. Mr Tucker was negligent in his manner of driving. He acted in breach of his duty of care towards his passengers and in particular towards Mr Van Den Heuvel. An issue that remains is whether Mr Tucker's breach of duty was causative of Mr Van Den Heuvel's injury.

182 Counsel for Mr Van Den Heuvel submitted that the judge's findings on credibility and reliability were flawed. It was said that his reasons were deficient and did not adequately explain his conclusions. More particularly it was contended that the reasons for accepting Mr Tucker's evidence and rejecting the evidence of Mr Van Den Heuvel and the passengers were superficial and inadequate.

183 The judge gave reasons for his conclusions on the issue of credibility and reliability. Counsel for Mr Van Den Heuvel was able to fully develop his complaints on appeal. The judge's reasons were sufficient to allow this court to perform its appellate function.

184 Decisions on credibility and reliability are notoriously difficult for a trial judge to make and for an appeal court to assess. As Kirby J observed in State Rail Authority of New South Wales v Earthline Constructions Pty Ltd (in liq):[24]

The true advantages in fact-finding which the trial judge enjoys include the fact that the judge hears the evidence in its entirety whereas the appellate court is typically taken to selected passages, chosen by the parties so as to advance their respective arguments. The trial judge hears and sees all of the evidence. The evidence is generally presented in a reasonably logical context. It unfolds, usually with a measure of chronological order, as it is given in testimony or tendered in documentary or electronic form. During the trial and adjournments, the judge has the opportunity to reflect on the evidence and to weigh particular elements against the rest of the evidence whilst the latter is still fresh in mind. A busy appellate court may not have the time or opportunity to read the entire transcript and all of the exhibits. As it seems to me, these are the real reasons for caution on the part of an appellate court where it inclines to conclusions on factual matters different from those reached by the trial judge. These considerations acquire added force where, as in the present case, the trial was a very long one, the exhibits are most numerous, the issues are multiple and the oral and written submissions were detailed and protracted. In such cases, the reasons given by the trial judge, however conscientious he or she may be, may omit attention to peripheral issues. They are designed to explain conclusions to which the judge has been driven by the overall impressions and considerations, some of which may, quite properly, not be expressly specified.

All of the foregoing considerations leave to be weighed, in some cases at least, the impression which the trial judge holds of a particular witness, perhaps influenced by the witness's demeanour and the kinds of considerations commonly referred to such as hesitation or displays of partisanship not readily conveyed, or conveyed at all, by the printed record. One can hold different views about whether such considerations should intrude in the assessment of qualified expert witnesses. One can strive to minimise resort to such considerations in the case of lay witnesses, out of recognition of the fallibility of human assessment of credibility from appearances. But because trials remain public procedures for the resolution of disputes, it is inescapable that, in some cases at least, credibility assessments will be required where there is no documentary, electronic or other incontrovertible evidence to resolve the conflict presented for decision. In such cases it will remain the fact that, try as it might, the appellate court cannot procure from the printed record exactly the same materials on which to base the judicial decision as the trial judge had.

This conclusion may, as I think, be true of a relatively limited class of case: basically those where the decision depends upon resolving a clash of critical oral testimony, oath against oath. But in such cases, because the appellate court cannot, in presently available records, recapture all of the information properly used to assist the trial judge's decision, the old strictures about that judge's advantage remain as relevant today as they were when first written more than a century ago. In such cases, the appellate court's rehearing must be conducted within a constraint which is set by the somewhat more restricted data available to it. This limitation is not confined to Anglo-Australian law. It is recognised in other countries of the common law and doubtless beyond.

185 Counsel for Mr Van Den Heuvel submitted that the judge was influenced by extraneous and irrelevant considerations. It was said that they permeated his decision to prefer the evidence of Mr Tucker to the other witnesses. Attention was drawn to the judge's finding:

I find it inconsistent to accept the complaints of speed of driving of the defendant on the previous section, Woomera to Coober Pedy, when [the passengers] all accept him to drive on the same section going home.

It was submitted that this finding overlooked the fact that two of the three passengers were prohibited from driving and that the one passenger who was able to drive gave evidence that he was concerned about the speed and volunteered to drive on several occasions.

186 Counsel for Mr Van Den Heuvel then drew attention to the following observations of the judge:

When [Mr Van Den Heuvel] handed over the car to the defendant to drive from Woomera to Coober Pedy his evidence is that the defendant drove at excessive speeds and it was suggested that he travelled at a speed beyond which the vibration had any effect. Notwithstanding that it seems that all the passengers in the car were content and happy with the driving of Tom Tucker.

When they were returning from Coober Pedy on Monday morning there was no suggestion by anybody that they were uncomfortable with Tom Tucker driving. In particular the plaintiff, Frank Van Den Heuvel, whose car it was and whose decision it was as to who was to drive the car, asked Tom Tucker to drive on that occasion.

Counsel contrasted this observation with the evidence of Mr Van Den Heuvel and Mr Nikolavcic that they were unhappy with Mr Tucker's speed.

187 Counsel for Mr Tucker submitted that the judge's observations were findings that had been made after having regard to all of the evidence including the evidence of Mr Tucker. This is implausible. The judge had not made his findings of credibility and reliability at this time. There is some force in counsel's submission that the judge proceeded to assess credibility and reliability against the general background that the passengers were comfortable with Mr Tucker's driving. This appears to have been a factor in the judge's rejection of the passengers' evidence about speed.

188 Counsel for Mr Van Den Heuvel further complained about a statement incorrectly attributed to his client by the judge:

[Mr Van Den Heuvel] drove the car from Adelaide to Woomera on the way up and said in his evidence that he only liked to travel at about 100 kilometres per hour and if he travelled at any greater speed in this car, say 110 kph, it produced a difficult vibration that made the car hard to control. He also felt uncomfortable and would do anything to avoid travelling at greater than 100 kilometres per hour and said that he always travelled at that speed.

Counsel attacked the judge's observation that Mr Van Den Heuvel would "do anything to avoid travelling at greater than 100 kilometres an hour". Mr Van Den Heuvel did not give this evidence. The judge contrasted this finding with the conclusion that all passengers in the vehicle were comfortable with Mr Tucker's driving. It was submitted that the incorrectly attributed statement was wrongly used to reach adverse conclusions about Mr Van Den Heuvel's credibility and reliability.

189 Counsel for Mr Tucker accepted that Mr Van Den Heuvel had not given evidence as described by the judge. However it was said that the judge had simply summarised the effect of his evidence. This explanation is unacceptable. The judge placed a gloss on Mr Van den Heuvel's evidence.

190 As earlier observed discretionary findings as to credibility and reliability may be set aside when it can be demonstrated that a judge has had regard to materially irrelevant considerations.

191 An important matter on which the judge based his conclusions was the contrast drawn between alleged passenger concerns about speed and the lack of any complaint. A further matter was his contrast of Mr Van Den Heuvel's assertion that he was prepared to do anything to avoid travelling at more than 100 kilometres an hour with his lack of any action to prevent high speed. These comparisons, for reasons mentioned earlier, were incorrect.

192 If these matters had stood alone it may have been difficult to interfere with the judge's acceptance of Mr Tucker and his rejection of the passengers' evidence. However when combined with the approach the judge took to Mr Hall's evidence the problem is compounded. The judge appears to have found support for Mr Tucker's account from Mr Hall's opinions. For reasons expressed earlier the judge's approach to Mr Hall's evidence was flawed. In these circumstances the judge's findings on credibility and reliability of the lay witnesses should be set aside.

193 In Fitzgerald v Penn[25] the High Court observed that causation "is all ultimately a matter of commonsense" and "in truth the conception in question [causation] is not susceptible of reduction to a satisfactory formula." Judicial writings in the ensuing years have added little to these observations. There has been a similar experience in other jurisdictions. In Alphacell Ltd v Woodward[26] Lord Salmon observed that causation is:

...essentially a practical question of fact which can best be answered by ordinary commonsense rather than abstract metaphysical theory.

194 In March v Stramare (E & MH) Pty Ltd [27] the High Court adopted the commonsense view of causation advanced in Fitzgerald. The Court has subsequently affirmed this approach in Medlin v State Government Insurance Commission[28], Bennett v Minister of Community Welfare[29] and Chappel v Hart[30]. In Bennett[31] McHugh J summarised the position as follows:

Whether or not a causal connexion exists between a breach of duty and any harm suffered by the person to whom the duty is owed is a question of fact to be decided on the balance of probabilities. The existence of the causal connexion is to be determined in accordance with common sense notions of causation and not in accordance with any philosophical or scientific theory of causation or any modification or adaptation of such a theory for legal purposes.

195 A common sense answer cannot be provided to the question of causation for the purpose of attributing responsibility under some rule without knowing the purpose and scope of the rule[32].

196 The law imposes a duty on the drivers of motor vehicles to drive with due care. This duty includes the obligation to drive defensively and to guard against foreseeable consequences. As earlier observed mechanical failure is one such consequence. Tyre blowouts and brake and axle failures are examples. These incidents are foreseeable. They are not far fetched or fanciful. A driver must take precautions to guard against the risk of such mishaps occurring. The greater a driver's speed, the greater the difficulty of controlling a vehicle should the risk of mishap eventuate.

197 Mr Tucker was obliged to take reasonable care to guard against foreseeable mishaps. He did not do so. As earlier observed he admitted exceeding the statutory speed limit and lack of knowledge about the speed at which he was travelling. This conduct was in breach of his duty of care.

198 In the present case the vehicle rollover and the injuries to the passengers resulted from momentum and mechanical failure. Axle failure per se did not cause the vehicle to rollover. The vehicle must have momentum. Both were materially contributing causes of the rollover. Accordingly it follows that Mr Tucker's negligent conduct was prima facie a material cause of the rollover.

199 Members of the High Court have discussed the circumstances in which a prima facie case of causation may rise. At times the judges have referred to a reversal of the evidentiary onus. In Chappel v Hart McHugh J addressed the question as follows[33]:

... the onus of proving that the failure to warn was causally connected with the plaintiff's harm lies on the plaintiff. However, once the plaintiff proves that the defendant breached a duty to warn of a risk and that the risk eventuated and caused harm to the plaintiff, the plaintiff has made out a prima facie case of causal connection. An evidentiary onus then rests on the defendant to point to other evidence suggesting that no causal connection exists.

The duty was called into existence because of the foreseeability of that very risk. The duty was not performed and the risk eventuated. Subject to a further question in the case of a duty to provide information, that is often the beginning and the end of the inquiry whether breach of duty materially caused or contributed to the harm suffered. As Dixon J pointed out in Betts v Whittingslowe, albeit in relation to a statutory duty, 'breach of duty coupled with an accident of the kind that might thereby be caused is enough to justify an inference, in the absence of any sufficient reason to the contrary, that in fact the accident did occur owing to the act or omission amounting to the breach.'

Here, the injury to Mrs Hart occurred within an area of foreseeable risk. In the absence of evidence that the breach had no effect or that the injury would have occurred even if Dr Chappel had warned her of the risk of injury to the laryngeal nerve and of the consequent risk of partial or total voice loss, the breach of duty will be taken to have caused the injury.

Kirby J discussed the shifting evidentiary onus[36]:

One means of alleviating the burden cast by law on a plaintiff to establish a causal relationship between the breach and the damage concerns the evidentiary onus. Australian law has not embraced the theory that the legal onus of proof shifts during a trial. Nevertheless, the realistic appreciation of the imprecision and uncertainty of causation in many cases - including those involving alleged medical negligence - has driven courts in this country, as in England, to accept that the evidentiary onus may shift during the hearing. Once a plaintiff demonstrates that a breach of duty has occurred which is closely followed by damage, a prima facie causal connection will have been established. It is then for the defendant to show, by evidence and argument, that the patient should not recover damages. In McGhee v National Coal Board, a Scottish appeal, Lord Wilberforce explained why this was so. Although Lord Wilberforce's statement in McGhee has proved controversial in England, it has received support in this Court. Its principle has also been accepted by international experts such as Professor Giesen. I find Lord Wilberforce's exposition compelling:

'T]he question remains whether a pursuer must necessarily fail if, after he has shown a breach of duty, involving an increase of risk of disease, he cannot positively prove that this increase of risk caused or materially contributed to the disease while his employers cannot positively prove the contrary. In this intermediate case there is an appearance of logic in the view that the pursuer, on whom the onus lies, should fail - a logic which dictated the judgments below. The question is whether we should be satisfied, in factual situations like the present, with this logical approach. In my opinion, there are further considerations of importance. First, it is a sound principle that where a person has, by breach of a duty of care, created a risk, and injury occurs within the area of that risk, the loss should be borne by him unless he shows that it had some other cause. Secondly, from the evidential point of view, one may ask, why should a man who is able to show that his employer should have taken certain precautions, because without them there is a risk, or an added risk, of injury or disease, and who in fact sustains exactly that injury or disease, have to assume the burden of proving more: namely, that it was the addition to the risk, caused by the breach of duty, which caused or materially contributed to the injury? In many cases ... this is impossible to prove, just because honest medical opinion cannot segregate the causes of an illness between compound causes. And if one asks which of the parties, the workman or the employers, should suffer from this inherent evidential difficulty, the answer as a matter of policy or justice should be that it is the creator of the risk who, ex hypothesi must be taken to have foreseen the possibility of damage, who should bear its consequences.'

200 Given the prima facie case of causal connection the evidentiary onus of establishing that there was no causal connection between breach of duty and damage rested with Mr Tucker. An immediate difficulty confronting Mr Tucker in that discharge of the evidentiary onus was that he had no knowledge of and was unable to establish his speed at the time the axle failed. Earlier extracts from the expert evidence have been recounted. All agree that a speed of 140 kilometres an hour would make it more difficult for a driver to control a vehicle following axle failure. This accords with common sense. Even if Mr Tucker's speed was less than 140 kilometres an hour the evidence did not establish that speed was not a contributing cause. In these circumstances Mr Tucker has not satisfied the evidential onus. Causation is established on the balance of probabilities.

201 Mr Tucker was under a duty to guard against injury to his passengers. A mechanical mishap such as axle failure was one foreseeable possibility. Mr Tucker could have guarded against the consequences of such a mishap by driving at or within the statutory speed limit. By driving at an appropriate speed his opportunity of controlling the vehicle if a mishap occurred would be increased. Reduced speed would lessen the risk of loss of control. Mr Tucker's breach of duty materially contributed to the injury sustained by Mr Van Den Heuvel.

202 An alternative approach is to consider the issue of increased risk. In Chappel v Hart McHugh J concluded[37]:

If a wrongful act or omission results in an increased risk of injury to the plaintiff and that risk eventuates, the defendant's conduct has materially contributed to the injury that the plaintiff suffers whether or not other factors also contributed to that injury occurring.

203 Mr Tucker drove at an excessive speed and without due care. He breached his duty of care to Mr Van Den Heuvel. Travelling at a speed in excess of 110 kilometres an hour without an awareness of speed increased the risk to his passengers and to other road users. Speed above the statutory limit increased the risk that Mr Tucker would be unable to cope with a danger that was not far-fetched or fanciful. One such danger was the risk of mechanical mishap occurring in a vehicle that was almost 15 years old. The vehicle had been driven at high speeds for a lengthy period. It was not necessary that Mr Tucker foresee the precise mechanical mishap that may occur. It was enough that he appreciated that there was a risk of mechanical mishap and that travelling at a speed above the statutory limit increased that risk. From a common sense point of view Mr Tucker's breach of duty was a material cause of the rollover and the injury sustained by Mr Van Den Heuvel.

204 In TC v New South Wales[38] Mason P stressed that the test formulated by McHugh J included not only an increased risk of injury but also the eventuation of that risk. In the present case the risk that mechanical mishap may occur at high speed eventuated. The axle failed. The risk that Mr Tucker would be faced with an emergency situation at a speed in excess of the statutory limit eventuated. Mr Tucker was confronted with an emergency at high speed. His ability to address the risk that confronted him was impaired. The test of causation promulgated by McHugh J is satisfied in the present case.

205 Another approach was discussed in Bennett v Minister of Community Welfare[39] where Gaudron J observed:

Leaving aside cases involving some positive act and those in which an omission can be treated as a positive act, a case based on omission or a failure to act will, in certain respects, fall for analysis in a way that differs from that appropriate for a case based on a positive act. Thus, in the case of a positive act, questions of causation are answered by reference to what, in fact, happened. In the case of an omission, they are answered by reference to what would or would not have happened had the act occurred. In that exercise, the larger philosophical questions are brushed aside and the issue is approached on the basis that 'when there is a duty to take a precaution against damage occurring to others through the default of third parties or through accident, breach of the duty may be regarded as materially causing or materially contributing to that damage, should it occur, subject of course to the question whether performance of the duty would have averted the harm.'

In practice, it is not always necessary to inquire what would have happened in the circumstances under consideration had a positive duty been performed. Thus, in the case of a statutory duty, a breach of duty coupled with an accident of the kind that might thereby be caused is enough to justify an inference, in the absence of any sufficient reason to the contrary, that in fact the accident did occur owing to the act or omission amounting to the breach of statutory duty.

And although it is sometimes necessary for a plaintiff to lead evidence as to what would or would not have happened if a particular common law duty had been performed, generally speaking, if an injury occurs within an area of foreseeable risk, then, in the absence of evidence that the breach had no effect, or that the injury would have occurred even if the duty had been performed, it will be taken that the breach of the common law duty caused or materially contributed to the injury.

206 In the present case the risk of a mechanical mishap was within the area of foreseeable risk. The evidence established that excessive speed impaired Mr Tucker's ability to cope with a mechanical failure or other emergency. The evidence did not establish that regardless of the excessive speed, the rollover and injury would have occurred. Mr Tucker breached his statutory obligation to drive at or less than 110 kilometres an hour. His positive act of speeding without an awareness of the particular speed at which he was travelling was a material cause of the rollover.

207 If Mr Tucker's conduct is characterised as an omission it is to be observed that he failed to drive defensively and protectively so as to guard against the loss of control of the vehicle in the event of a mechanical mishap or other emergency. Mr Tucker departed from the standard of care one would expect from the prudent driver. The emergency occurred within an area of foreseeable risk. It was not established that Mr Tucker's breach of duty of care had no effect, or that the injury would have occurred even if the duty had been performed. Mr Tucker's breach of duty should be regarded as having materially contributed to the rollover and injury.

208 These varied approaches to causation all lead to the conclusion that Mr Tucker's breach of duty was a material cause of the vehicle rollover and the injury to Mr Van Den Heuvel. Whether the preferred approach should be to assess increased risk, to reverse the evidentiary onus, or to articulate breach by positive act or omission, the end result is the same. To apply the overriding and ultimate test, as a matter of common sense, excessive speed and inattention were material causes of the rollover and injury.

209 In many respects the evidence at trial was unsatisfactory. Without seeing and hearing the lay witnesses it is not possible for this court to come to conclusions about their credibility and reliability. However it does not follow that a new trial is necessary. There was a narrow debate on the question of speed. Mr Tucker admitted that he was travelling in excess of the statutory limit. He was exceeding this speed limit at the time the axle failed. It is also reasonable to conclude from the evidence that Mr Tucker was unaware of his speed at that time the axle failed and that his speed may have been as high as 140 kilometres an hour. Mr Tucker drove without due care.

210 Mr Tucker's conduct increased the risk that he would be unable to control foreseeable events that may arise. This included such matters as tyre blow out, axle failure or other mechanical mishap. The greater the vehicle's speed the less opportunity Mr Tucker had to exercise or regain control of the vehicle. The risk of mechanical failure eventuated. The wrongful act and omission of Mr Tucker resulted in an increased risk of injury to Mr Van Den Heuvel. That risk eventuated. Mr Tucker's conduct materially contributed to Mr Van Den Heuvel's injury. This was so despite the fact that mechanical mishap also contributed to the rollover and injury.

211 The judgment dismissing Mr Van Den Heuvel's claim should be set aside. Judgment should be entered for Mr Van Den Heuvel in the amount of the agreed damages.

LIST OF CITATIONS AS THEY APPEAR IN THE JUDGMENT

1 There was no evidence about the distance of a pace as to whether it was a metre or more or less than a metre.

2 It is unclear from the plan whether the pacing was from the northern or the southern end of the ten pace gouge.

3 [2003] HCA 22

4 [1979] HCA 9; (1979) 142 CLR 531

5 [1989] HCA 20; (1989) 63 ALJR 349

6 (1991) 71 CLR 167

8 (1998-99) 72 SASR 361 at 371-372

10 T v Medical Board (1992) 58 SASR 382

11 (1979) 20 SASR 350

12 (1979) 20 SASR 350 at 381

13 [2003] HCA 22 at [149-150]

15 [1968] SASR 97 at 104

16 [1970] SASR 256 at 261

17 [1989] HCA 28; (1988-1989) 167 CLR 94 at 110

18 (1998-99) 197 CLR 269 at 306 see also Fox v Percy [2003] HCA 22 per Callinan J at [122]

19 Henwood v The Municipal Tramways Trust SA [1938] HCA 35; (1938) 60 CLR 438

20 (1971) 1 SASR 172 (n) at 172-173.

22 [1999] SASC 412

23 [1980] HCA 12; (1980) 146 CLR 40 at 47-48

24 [1999] HCA 3; (1999) 73 ALJR 306 at [90-92]

25 [1954] HCA 74; (1954) 91 CLR 268 at 277-278

26 [1972] UKHL 4; [1972] AC 824 at 847

27 [1991] HCA 12; (1991) 171 CLR 506

28 [1995] HCA 5; (1995) 182 CLR 1

29 [1992] HCA 27; (1992-93) 176 CLR 408

30 (1998-99) 195 CLR 232

31 [1992] HCA 27; (1992-93) 176 CLR 408 at 428

32 Environmental Agency v Empress Car Co (Abertillery) Ltd [1998] UKHL 5; [1999] 2 AC 22 at 31 see also Chappel v Hart (1998-99) 195 CLR 232 at 256

34 (1998-99) 195 CLR 232 at 238-239

[1924] HCA 51; 35 (1998-99) CLR 232 at 257

36 (1998-99) 195 CLR 232 273-274

37 (1998-99) 195 CLR 232 at 244

38 [2001] NSWCA 380 at [66]

39 [1992] HCA 27; (1992-93) 176 CLR 408 at 420-421

[1] There was no evidence about the length of a pace.

[2] It is unclear from the plan whether the pacing was from the northern or the southern end of the 10 pace gouge.

[3] [2003] HCA 22

[4] [1979] HCA 9; (1979) 142 CLR 531

[5] [1989] HCA 20; (1989) 63 ALJR 349

[6] (1991) 71 CLR 167

[8] (1998-99) 72 SASR 361 at 371-372

[10] T v Medical Board (1992) 58 SASR 382

[11] (1979) 20 SASR 350

[12] (1979) 20 SASR 350 at 381

[13] [2003] HCA 22 at [149-150]

[15] [1968] SASR 97 at 104

[16] [1970] SASR 256 at 261

[17] [1989] HCA 28; (1988-1989) 167 CLR 94 at 110

[18] (1998-99) 197 CLR 269 at 306 see also Fox v Percy [2003] HCA 22 per Callinan J at [122]

[19] Henwood v The Municipal Tramways Trust SA [1938] HCA 35; (1938) 60 CLR 438

[20] (1971) 1 SASR 172 (n) at 172-173.

[21] Unreported Judgment No 9362 17 September 1986

[22] [1999] SASC 412

[23] [1980] HCA 12; (1980) 146 CLR 40 at 47-48

[24] [1999] HCA 3; (1999) 73 ALJR 306 at [90-92]

[25] [1954] HCA 74; (1954) 91 CLR 268 at 277-278

[26] [1972] UKHL 4; [1972] AC 824 at 847

[27] [1991] HCA 12; (1991) 171 CLR 506

[28] [1995] HCA 5; (1995) 182 CLR 1

[29] [1992] HCA 27; (1992-93) 176 CLR 408

[30] (1998-99) 195 CLR 232

[31] [1992] HCA 27; (1992-93) 176 CLR 408 at 428

[32] Environmental Agency v Empress Car Co (Abertillery) Ltd [1998] UKHL 5; [1999] 2 AC 22 at 31 see also Chappel v Hart (1998-99) 195 CLR 232 at 256

[34] (1998-99) 195 CLR 232 at 238-239

[35] (1998-99) CLR 232 at 257

[36] (1998-99) 195 CLR 232 at 273-274

[37] (1998-99) 195 CLR 232 at 244

[38] [2001] NSWCA 380 at [66]

[39] [1992] HCA 27; (1992-93) 176 CLR 408 at 420-421