(1) Appeal dismissed with costs;
(2) Upon the Summons for leave to cross-appeal,
(a) grant leave to cross-appeal with respect to liability,
(b) direct that Notice of Cross-Appeal be filed and served within
7 days,
(c) save as aforesaid, dismiss the Summons.
(3) Dismiss the Cross-appeal, with costs of the application for leave to cross-appeal and of the cross-appeal.
292 GZELL J: These reasons address The Nominal Defendant's summons for leave to cross appeal against the entry of a verdict against it by her Honour Judge Gibb. The application for leave to cross appeal against her Honour's refusal to order the legal representatives of Daniel Rory de Groot to pay costs has been addressed in the reasons for judgment of Bryson JA.
293 Leave is required because the verdict was less than $100,000 (District Court Act 1973, s 127(1)(c)).
294 Daniel was an infant travelling in the front seat of a motor vehicle. A prime mover with trailer passed in the opposite direction. Daniel was struck on the head by a wheel cleat that came off the trailer, penetrated the windscreen of the motor vehicle and struck him on the head. Her Honour awarded Daniel damages of $18,344.45.
295 The application for leave was based upon the high level of costs incurred in the matter. It proceeded before her Honour on 46 days and was recorded in over 3,000 pages of transcript.
296 In my view leave should be granted. The Nominal Defendant has a reasonably arguable case for challenging her Honour's finding of liability. Although the damages assessed by her Honour are modest, a much larger claim was made and high levels of costs were incurred by The Nominal Defendant in meeting that claim.
297 For the reasons that appear below, however, I am of the view that the appeal should be dismissed.
298 A wheel cleat is a cast iron object weighing about 450 grams. It is part of a system securing an inner hub of the outer of the dual wheels of a heavy truck or trailer to the outer rim that carries a tyre. A wheel cleat is roughly triangular in shape and has a hole through it. It is passed over a wheel stud tapped into the hub or "spider". A nut is threaded onto the stud. When the nut is tightened the wheel cleat exerts pressure on the rim thus holding it tight up against the spider. The prime mover and trailer were not identified.
299 Her Honour found that the cleat became detached from a wheel of the trailer. That finding was not challenged by The Nominal Defendant.
300 Her Honour analysed the possible causes for the detachment of the cleat. One possibility was a manufacturing defect in a stud.
301 John Jamieson was a master of engineering science, traffic and transportation from the University of New South Wales. Her Honour noted that Mr Jamieson had conceded that a stud could fracture as a result of a manufacturing error.
302 Mr Jamieson also gave evidence that wheel cleats were secured by a single nut and were thus vulnerable to work loose or come off if the securing nut had not been done up properly. Nuts were vulnerable to work loose if they were insufficiently tightened when installed. Mr Jamieson explained that nuts worked loose, typically, because they were either damaged, stripped through over-tightening or they were insufficiently tightened and were unable to withstand dynamic loads from a rotating wheel on a rough surface. He could not say whether a nut that may have been stripped or a nut that may have been insufficiently tightened was the more likely occurrence.
303 Grant Johnston held a bachelor of civil engineering degree in transport engineering and engineering construction from the University of New South Wales. Her Honour noted that Mr Johnston had, on one occasion, retrieved a cleat and a stud.
304 Mr Johnston also said that cleat detachment could occur in one of two ways. First, by not properly tightening the wheel nut so that it worked loose from the retaining stud. Secondly, the stud could fail in a shear type failure, most likely from fatigue loading, as cleats were generally protected in their inward position from direct impact.
305 Mr Johnston had given other evidence on imputed impact speed and the probability of head injury from such an impact. Her Honour placed little weight on the report and opinions of Mr Johnston. She found him to be an unreliable and intemperate witness of very limited expertise. She completely disregarded any opinion he expressed on matters medical on the basis that he lacked relevant skill and qualification.
306 Dr Peter Sweatman held a doctor of philosophy in mechanical engineering - vehicle dynamics and a bachelor of engineering honours degree from Melbourne University. A report of his was in evidence.
307 Her Honour noted that Dr Sweatman had said that many years of experience in the manufacture and use of the spoke-cleat system had resulted in high reliability in an engineering sense. She noted the submission that stud failure was far less likely a cause than a loose nut. Her Honour said that, nonetheless, stud failure was a real possibility on the evidence before her.
308 Dr Sweatman's report also stated that an intact wheel cleat might come loose because of gross failure correctly to attach the dual wheels. He said the action of all cleats was interdependent and it would be virtually impossible to leave one cleat loose without all or most cleats also being loose or gross misalignment occurring. Another possibility was damage to the cleat. He said this would be obvious during wheel mounting and would make the entire securing process difficult. He said cleats were extremely robust and immune to damage once they were correctly in place. The third possibility was the failure of the attachment stud or thread. He said this would require significant over-tightening during fitment together with over-stress caused in service. Finally he said the cleat attachment nut might work loose. He said this possibility was unlikely because once the attachment nuts were tightened, the cleat acted as a tensioning and locking method.
309 Her Honour then discussed the issue of maintenance. She noted Mr Jamieson's evidence that nuts were vulnerable to work loose if they were insufficiently tightened when installed. She accepted Dr Sweatman's evidence that wheels and tyres should be checked at least weekly including a visual check and checks of the presence and tightness of wheel nuts. Dr Sweatman had said that experience showed that it was possible for wheel nuts to come loose but this normally caused increased vibration that might be noticed by a driver. With respect to this latter opinion, her Honour preferred other evidence.
310 Philip John Scott, an automotive engineer, had been employed in the Australian army engineer corps over a three year period, initially as an operator of heavy vehicles, but subsequently with the responsibility for the maintenance of heavy vehicles including ensuring that drivers maintained their own vehicles properly. Many of the vehicles were fitted with spider wheel systems. Mr Scott then worked for a year at Mount Newman where he was involved in the maintenance of exceptionally heavy road transport vehicles fitted with spider wheel systems working off-road. Mr Scott was then engaged in dealerships at Wagga Wagga and on the central coast of New South Wales. He performed service calls on heavy vehicles fitted with spider wheel systems. Following a nine year period during which he taught at the Department of TAFE, training mechanics in proper maintenance practice in relation to heavy vehicles, he entered a consultancy business involving inspection of heavy vehicles and reviewing failures of vehicle system components.
311 Her Honour accepted the evidence of Mr Scott that, in practice, a driver might not be aware that a cleat was missing. Her Honour also accepted Mr Scott's observation that wheel nuts and cleats might become detached from vehicles despite the best care and standard having been applied.
312 Mr Scott had also said that on many occasions during his service in the army he noticed that cleats were missing. Whilst not a daily occurrence, it was sufficiently frequent to make it necessary to carry a supply of replacement cleats and nuts. In the majority of cases where a cleat was missing, the retaining wheel nut was also missing. On comparatively rare occasions, he estimated one in six, a stud was either fractured or missing. Mr Scott said that whenever a nut was missing, the cleat was also missing.
313 At Mount Newman, Mr Scott said the incidence of vehicles returned to the workshop missing a cleat was somewhat higher than his experience in the army, but the same pattern emerged: in five out of six cases, the stud would be there but the nut and cleat would not.
314 During his subsequent engagement in service calls on heavy vehicles, Mr Scott observed missing cleats and nuts with the occasional missing stud. As a consultant, he said he continued to find a similar incidence of missing cleats, nuts and studs in roughly the same proportions.
315 Her Honour then addressed a truck driver's maintenance obligations. She noted Mr Scott's concession that a driver might not observe a latent defect or an over-tightened nut. She accepted his evidence of the steps a driver should take.
316 Mr Scott had said that proper maintenance of spider wheel systems required wheel studs to be inspected for any visible impact damage to threads and for any bending of studs. The thread of the stud and nut had to be clean. Wheel nuts had to be tensioned to manufacturers' specifications. The design of the wheel nut had to suit the cleat being used on the wheel. When mounting a wheel onto a hub, care had to be taken to ensure that the wheel rim did not impact on the stud. That might result in damage to the thread of the stud and cross threading of the retaining nut. Wheel nuts had to be progressively tightened in the correct sequential order, alternating to opposite sides of the wheel. After each progressive step, the wheel had to be rotated to check for any run-out of the wheel. Wheel nuts had to be re-tensioned after initial use. This usually occurred between approximately 50 kilometres and approximately 350 kilometres.
317 Her Honour accepted Mr Scott's statement that in his experience, vehicles maintained carefully had a significantly lower incidence of missing cleats and nuts and also of stud failure.
318 Mr Scott had also said that on the road, drivers carried a wheel brace and a pipe to fit on the wheel brace to increase pressure when loosening nuts to change a tyre. Nut tightening by a wheel brace was a matter of subjective perception by the driver. Air-driven tension wrenches on which an appropriate torque might be set, were confined to the workshop. Mr Scott said it was possible for a driver to over-tighten or under-tighten a nut on the road without being aware of it. Over-tightening might cause a nut to break. Over time, vibration from a heavy load on a rough road might affect a nut. Mr Scott had the experience of checking the nuts on the wheels of a trailer yet finding a nut and cleat missing when checking again after about 120 to 150 kilometres.
319 If a driver tested a nut and found that it was tight, Mr Scott agreed the driver had no idea if it was over-tightened. It was also possible that a nut might have a manufacturing defect not discoverable by visual inspection. A wheel nut that appeared to be sufficiently tightened, might work loose as the wheels flexed under load and vibration worked the nut loose. It was possible that this might occur if a truck travelled along a section of rough road.
320 Her Honour noted that the relevant section of the roadway where the incident occurred was very rough and the possibilities open by way of explanation of the cleat detachment included the roughness of the road surface.
321 Her Honour then set out the various causes of cleat detachment that might arise:
"Even with the exercise of due care, a wheel nut and cleat may come adrift. There are various explanations open: manufacturing error/defect; spontaneous fracture; the condition of the road surface; speed (of which there is no acceptable evidence); failure to correctly tension the nut/stud; over-tightening; a cross threaded nut; metal fatigue due to the age of the stud or nut; a combination of any of these; or an act or omission by someone other than the defendant."
322 Her Honour then asked herself the question whether it was open to her to draw the inference that the detachment of the cleat occurred by reason of some act or omission on the part, either of the driver of the prime mover, or the owner of the trailer. She referred to Nominal Defendant v Haslbauer (1967) 117 CLR 448. That was a res ipsa loquitur case. The plaintiff was a passenger in a stationary vehicle hit from behind by an unregistered vehicle with defective brakes. She received an award of damages from a jury. On appeal she failed in her submission that in the absence of evidence of knowledge by the driver of the defective vehicle of the condition of the brakes, negligence could be inferred from the fact of the collision. Her Honour referred to passages from the judgment of Sir Garfield Barwick including the following, at 452, on the inference that might be drawn:
"To make a prima facie case in a claim based on the defendant's negligence, a plaintiff may be content to rely upon such inferences as can be drawn from the fact of the occurrence which he claims to be due to the defendant's negligence. An inference of such negligence may be drawn where, in the ordinary course of human affairs, such an occurrence is unlikely without want of care on the part of a person in the situation of the defendant. In such a case, the occurrence itself may be said to bespeak the lack of care. Or if his pleadings are wide enough, a plaintiff may rely both upon such an inference and upon evidence, beyond that of the occurrence itself, of specific acts or omissions of the defendant indicating a want of care."
323 Her Honour must have been thinking of drawing an inference from acts or omissions of the driver or trailer owner beyond the fact of the occurrence, because she had already noted that the plaintiff did not rely upon res ipsa loquitur and the principle was not open where the cause of an occurrence was determined. Her Honour had quoted that proposition from Schellenberg v Tunnel Holdings Pty Ltd (1999-2000) 200 CLR 121 at [42] to [45].
324 Her Honour went on to state that she drew the inference that the cleat detached because the nut was not correctly secured, the driver of the prime mover failed properly to check the tensioning of the nut and a proper check would have revealed the deficiency:
"Notwithstanding the range of possible explanations for the detachment of the wheel cleat ( sic ) (and therefore the cleat), I draw the inference that this cleat came adrift from the wheel of the approaching semi-trailer because the nut was not correctly secured and tensioned; and that, ultimately, the responsibility for checking the security of the wheel nuts rested with the driver of the vehicle. I infer that the defendant - the driver - failed properly to check and ensure that the nut was properly tensioned; and that had a proper check been made, the deficiency could and would have been identified and rectified."
325 Her Honour did not explain why she reached this conclusion as distinct from other conclusions that were open to her. Her train of thought has not been revealed.
326 It was submitted that her Honour misdirected herself with respect to the evidentiary test in Luxton v Vines (1952) 85 CLR 352 at 358 that in civil proceedings circumstances raising a more probable inference in favour of what is alleged is sufficient.
327 Her Honour was aware of this principle. She set out the passage in her reasons for judgment. And she had regard to the discussion on reliance upon inferential reasoning to prove negligence in a case to which res ipsa loquitur did not apply in Schellenberg.
328 In my view it is a fair reading of her Honour's judgment that what she meant by drawing the inference that the cleat came adrift in the way she specified was that she concluded, on the balance of probabilities, that the cleat coming adrift in the way she specified was the more likely explanation. Mindful of the principles in the authorities which she cited, her Honour must be taken to have concluded that the case was not one of competing causes of equal likelihood.
329 Although her Honour did not reveal her train of thought, and drawing an inference is often not readily susceptible to precise explanation, I consider that her Honour's conclusion was open and, on the evidence, was correct.
330 From the evidence of Dr Sweatman and Mr Scott, there was a high probability that the cleat detached because of loosening of the nut rather than because of stud failure, including failure due to over-tightening the nut. As a broad measure of that probability, Mr Scott's experience was of stud failure as a one in six occurrence. Dr Sweatman's evidence of the general reliability of the system underlined the high probability that the incident occurred because of the loosening of a nut rather than gross failure correctly to attach a wheel.
331 What then had to be taken into account was the probability of negligent failure initially to tighten the nut or, perhaps more significantly, negligent failure to check the tightness of the nut, as distinct from the nut working loose despite initial proper tightening and proper checking, as Mr Scott recognised could happen. This probability was to be assessed in light of Mr Scott's experience that carefully maintained vehicles had a significantly lower incidence of missing cleats and nuts as well as of stud failure. In this respect, it was not only a case of re-tensioning 50 to 350 kilometres after initial tensioning, or after an earlier inspection, as stated by Mr Scott, but also of checking at least weekly as stated by Dr Sweatman and accepted by the Trial Judge.
332 These probabilities must be combined in arriving at the probability that negligence caused Daniel's injury (see Hodgson, The Scales of Justice: Probability and Proof in Legal Fact-finding (1995) 69 ALJ 731 at 746-750).
333 It would be unrealistic to ascribe numbers to the probabilities and, mathematically, compute a probabilistic conclusion. Judicial fact-finding in circumstances such as the present is not a mathematical operation.
334 In my opinion, the evidence established, on the balance of probabilities, that negligence did cause Daniel's injury. If it be a different thing, her Honour was entitled to infer that the cleat became detached because of a loose nut, the tightness of which was not properly checked and rectified.
335 As a check upon the process of inference, an 80% probability of a loose nut rather than some other problem with the attachment of the cleat and a 65% probability of failure in checking would result in a 52% probability of negligence. Numbers of that order appear to me to be warranted on the evidence.
336 In my view The Nominal Defendant has failed to demonstrate that her Honour erred in concluding that the driver of the truck was negligent.
337 I agree with the orders proposed by Bryson JA. I agree with his Honour's reasons save insofar as Giles JA has departed from them. I agree with the reasons of Giles JA and join him in respectfully diverging from the reasons of Bryson JA in the limited circumstances discussed by his Honour.