Conclusion
24The primary judge found, relevantly in my view, that Andrew's operative negligence was steering back onto the beaten track even though he could not see through the cloud of dust his brother's vehicle was creating. Andrew knew there was a risk that there might be another vehicle on the beaten track because, on his evidence, that was where everyone drove on the Old Dip Road. Notwithstanding that knowledge he did not reduce his speed as he approached the rear of his brother's vehicle, drove into the cloud of dust effectively blind and, as he did so, steered back onto the beaten track.
25It is an available inference which it was open to the primary judge to draw (as he clearly did), that had Andrew not steered back onto the beaten track, the collision would not have happened, even if, at the time he did so Andrew's truck had not passed the notional centre line of the road. He steered his truck onto a part of the road where he knew he might encounter vehicles driving in the opposite direction. Immediately before changing the path of his vehicle, he had passed Sam's truck, albeit narrowly. It is an available inference that Sam was also driving on the beaten track both because that was the custom and also because the respondent (who agreed she was on that part of the road) was driving behind him. The only step Sam took when he saw Andrew's truck was to brake - he did not give any evidence of steering his truck to the left so he could pass Andrew's. Had Andrew not steered back onto the beaten track, accordingly, his truck would have passed the respondent's vehicle just as it had passed Sam's.
26Accordingly, the primary judge did not err in concluding that Andrew's negligence was a necessary condition of the respondent's harm as, too, was the respondent's. As Allsop P (Young JA agreeing) said in Zanner v Zanner [2010] NSWCA 343; (2010) 79 NSWLR 702 (at [11]) "[b]oth the driver who goes through the red light and the driver with whom he collides who is not paying attention contribute to the accident" and (at [12]) "[t]here is no reason why the appropriate apportionment of respective responsibility is not best allocated through contributory negligence".
27MACFARLAN JA: I agree that for the reasons given by Ward JA the appeal and cross-appeal should be dismissed with costs. Her Honour's analysis assumes, in my view correctly, that in the circumstances confronting Andrew Clift it was unreasonable for him not to have kept his vehicle to the far left of the road until, when the dust cleared, he was able to see what lay ahead of him. Bearing in mind the frequency with which drivers on roads such as that upon which the accident occurred drive on "the beaten track", that is, straddle the centre of the road, it was unreasonable for Mr Clift to return his vehicle towards the centre of the road until his vision was clear, even if his vehicle remained wholly on his side of the road.
28Ms Bacon did not seek to justify the result at first instance by reference to s 5D(2) of the Civil Liability Act 2002 (NSW). If she had, I would likely have found it to be applicable. On this basis, even if, contrary to Ward JA's analysis, Ms Bacon's vehicle would have hit Mr Clift's vehicle if he had kept as far as possible to his left, the decision below would nevertheless have stood.
29On this hypothesis, there were two sufficient causes of the accident. If Mr Clift had not steered his vehicle towards the middle of the road, but had remained as far as possible to his left, the accident would still have occurred because Ms Bacon had driven towards the middle of the road and, on the present hypothesis, there was insufficient room for the two vehicles to pass. It could not then be said that "but for" Mr Clift's negligence, the accident would not have occurred. In other words, Mr Clift's negligence was not a necessary condition of the harm sustained by Ms Bacon.
30However a similar analysis is applicable to Ms Bacon. If she had not driven towards the middle of the road but had remained as far on her left as possible, the accident would still have occurred because, with Mr Clift's vehicle at or nearing the middle of the road, there was no room for the vehicles to pass. Thus, it could not be said that "but for" Ms Bacon's negligence the accident would not have occurred, or that her negligence was a necessary condition of the harm she suffered.
31At common law, "when separate and independent acts of negligence on the part of two or more persons ... directly contributed to cause injury and damage to another, the person injured [could] recover damages from any one of the wrongdoers, or from all of them" (Grant v Sun Shipping Co Ltd [1948] AC 549 at 563; Bennett v Minister of Community Welfare [1992] HCA 27; 176 CLR 408 at 429 per McHugh J). Thus "each sufficient condition [was] treated as an independent cause of the plaintiff's injury" (Strong v Woolworths Ltd [2012] HCA 5; 246 CLR 182 at [18] and [28]; March v E & MH Stramare Pty Ltd [1991] HCA 12; 171 CLR 506 at 534). The "but for" test did not adequately deal with such cases of separate and sufficient causes (March v Stramare at 516 and 523) and was not therefore applied at common law in them.
32Section 5D(1) and (2) of the Civil Liability Act state the following concerning causation:
"5D General principles
(1) A determination that negligence caused particular harm comprises the following elements:
(a) that the negligence was a necessary condition of the occurrence of the harm (factual causation), and
(b) that it is appropriate for the scope of the negligent person's liability to extend to the harm so caused (scope of liability).
(2) In determining in an exceptional case, in accordance with established principles, whether negligence that cannot be established as a necessary condition of the occurrence of harm should be accepted as establishing factual causation, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party."
33Satisfaction of subsection (1) requires the negligence of the defendant to have been a "necessary condition of the occurrence of the harm". That is, but for that negligence the plaintiff's injuries would not have been suffered. As I have said above, on the hypothesis with which I am presently dealing, that test was not satisfied in the present case.
34However in my view, subsection (2) was applicable to Ms Bacon's claim.
35The Ipp Report ("Review of the Law of Negligence: Final Report September 2002"), upon which the late 2002 amendments to the Civil Liability Act introducing s 5D were based, said in [7.26]:
"Although there are some cases with which the 'but for' test does not deal satisfactorily (involving 'causal over-determination' of harm - that is, harm that is attributable to more than one sufficient condition), the law has devised rules for resolving such cases in ways that are generally considered to be satisfactory and fair. We therefore make no recommendations on this aspect of the law".
36As I read this passage, the authors of the Report assumed that what became s 5D of the Civil Liability Act would not prevent the continued application of the common law rules for dealing with cases where the plaintiff's injury resulted from more than one sufficient condition. These are the rules to which I have referred in [31] above and which the authors of the Ipp Report thought to be satisfactory and fair. Such cases are exceptional cases of the type contemplated by the opening words of s 5D(2) and the application of the common law would result in a determination of those cases, using the next words in s 5D(2), "in accordance with established principles".
37Moreover, the consideration required by the remaining words of s 5D(2) in my view leads to the conclusion that "responsibility for the harm should be imposed on the negligent party". In this connection, there is no reason to depart from the Ipp Report's view that the relevant common law principles are "satisfactory and fair". Imposition of liability on each of the negligent parties is particularly appropriate where the parties in question are the plaintiff and defendant, and their respective responsibilities for the accident can be reflected in a reduction of the plaintiff's award to account for his or her contributory negligence.
38In his Second Reading Speech in relation to the Civil Liability Amendment (Personal Responsibility) Bill 2002, the relevant Minister said in relation to what was to become s 5D:
"The bill will also deal with causation. Its intention is to guide the courts as they apply a commonsense approach. The rules for factual causation are set out, including the very limited exception to the 'but for' test. This exception was developed by the court for those rare cases, often in the dust diseases context, where there are particular evidentiary gaps. By including this exception in the bill it is not intended that the bill extend the common law in any way. Rather, it is to focus the courts on the fact that they should tread very carefully when considering a departure from the but for test.
It is only for the most limited and exceptional circumstances where any departure can be justified".
39This passage refers only to a single exception to the "but for" test, being one that is not presently applicable as it relates to cases where there are particular evidentiary gaps. The speech thus overlooks the exception at common law, referred to in the Ipp Report, where harm is attributable to more than one sufficient condition. However, as the High Court noted in Adeels Palace Pty Ltd v Moubarak [2009] HCA 48; 239 CLR 420 at [55], the exceptional cases contemplated by s 5D(2) are undefined. Whilst obedience must be paid to its express limitation to "exceptional" cases and to its requirement for determinations in accordance with "established principles", the subsection's terms do not justify its limitation to the single instance referred to in the Second Reading Speech, particularly when the further (and presently relevant) exception to the "but for" test was referred to in the Ipp Report to which the Second Reading Speech referred approvingly.
40Nor is my approach to s 5D(2) inconsistent with binding authority.
41In Strong v Woolworths, the majority at [18] noted that the "but for" test stated in s 5D(1) "produces anomalous results in particular cases, exemplified by those in which there is more than one sufficient condition of the plaintiff's harm", and said at [28]:
"As earlier noted, the limitations of the 'but for' analysis of factual causation include cases in which there is more than one sufficient condition for the occurrence of the plaintiff's injury. At common law, each sufficient condition may be treated as an independent cause of the plaintiff's injury. The Ipp Report noted the conceptual difficulty of accommodating cases of this description within a 'but for' analysis, but made no recommendation because the common law rules for resolving cases of 'causal over-determination' were generally considered to be satisfactory and fair. How such cases are accommodated under the scheme of s 5D does not call for present consideration" (citations omitted).
42Nor did the High Court's judgment in Adeels Palace v Moubarak embark on a consideration of s 5D(2). Whilst the Court did understandably say that the statute should be applied rather than the High Court's approach to causation in March v Stramare, it was referring to the "common sense" approach to causation discussed in the latter case and contrasting it to s 5D(1)'s treatment of "factual causation and scope of liability as separate and distinct issues" ([43] and [44]).
43WARD JA: Ms Bacon was injured in a motor vehicle accident on an unsealed country road near Breeza. She was driving a Ford Fiesta sedan. Her car collided with a semi-trailer being driven by the second appellant, Mr Andrew Clift. As Mr Clift's vehicle was unregistered and uninsured, Ms Bacon claimed damages from the Nominal Defendant for alleged negligence on the part of Mr Clift. A cross-claim by the Nominal Defendant against the owners of the truck driven by Mr Clift was settled before the hearing.
44Ms Bacon was successful in the District Court in obtaining a verdict against the Nominal Defendant. Her damages were reduced by 50% for contributory negligence on her part. The Nominal Defendant appeals from the finding of negligence and, in the alternative, from the assessment of contributory negligence at 50%.