Beswick v Tamarack Pty Ltd
[2009] TASSC 109
•11 December 2009
[2009] TASSC 109
COURT: SUPREME COURT OF TASMANIA
CITATION: Beswick v Tamarack Pty Ltd [2009] TASSC 109
PARTIES: BESWICK, Harley Dene
v
TAMARACK PTY LTD (ACN 009 562 510)
NOMINAL INSURER
FILE NO/S: 553/1999
DELIVERED ON: 11 December 2009
DELIVERED AT: Hobart
HEARING DATES: 21 – 24 April, 28, 29 April, 6 May 2009
JUDGMENT OF: Porter J
CATCHWORDS:
Torts – Negligence – Essentials of actions for negligence – Duty of care – As between employer and employee – Employed driver of log truck – Rollover of loaded truck on bend of highway – Alleged deficiencies in suspension and load measuring systems – Interference in suspension settings by fellow employee – Whether employer negligent – Whether employee contributorily negligent.
Aust Dig Torts [26]
Evidence – General – Means of proof – Photographs – Whether substantive evidence – Interpretation of what is depicted.
Aust Dig Evidence [15]
Blacktown City Council v Hocking [2008] NSWCA 144; Warren v Gittoes [2009] NSWCA 24, followed.
Evidence – Opinion evidence – Expert opinion – In general – Admissibility – Opinion based on specialised knowledge – Admissibility distinguished from weight – Evidence Act 2001, s79.
Sydneywide Distributors Pty Ltd v Red Bull Australia Pty Ltd [2002] FCAFC 157, applied.
Aust Dig Evidence [55]
REPRESENTATION:
Counsel:
Plaintiff: K E Read
Defendants: P L Jackson and A J Hall
Solicitors:
Plaintiff: Ogilvie Jennings
Defendants: C N Dockray
Judgment Number: [2009] TASSC 109
Number of paragraphs: 212
Serial No 109/2009
File No 553/1999
HARLEY DENE BESWICK v TAMARACK PTY LTD
and THE NOMINAL INSURER (ACN 009 562 510)
REASONS FOR JUDGMENT PORTER J
11 December 2009
TABLE OF CONTENTS
PARAGRAPH
Introduction............................................................................................................................... [1] – [7]
The pleadings............................................................................................................................. [8] – [9]
The issues......................................................................................................................................... [10]
Legal axle loads...................................................................................................................... [11] – [15]
Heavy vehicle safety and truck rollovers................................................................................. [16] – [21]
The plaintiff's driving
- Experience and training.............................................................................................. [22] – [27]
- Negotiating the Plenty bends........................................................................................ [28] – [30]
The prime mover's suspension system
- The system in general.................................................................................................. [31] – [47]
- Adjusting the height control valves (HCV's) to increase the ride height......................... [48] – [51]
- Handling problems with the plaintiff's truck................................................................. [52] – [59]
- The fitting of high flow HCVs to the plaintiff's truck ................................................... [60] – [65]
and the alteration of the ride height
· Findings of fact........................................................................................................... [66] – [78]
The load measuring system
· The evidence of the plaintiff and other employees........................................................ [79] – [90]
· The expert evidence............................................................................................................... [91]
· Findings of fact..................................................................................................................... [92]
The particular load on the truck
- The evidence.............................................................................................................. [93] – [100]
- Findings of fact....................................................................................................... [101] – [102]
The rollover of the truck..................................................................................................... [103] – [107]
The cause of the rollover — the expert opinions
- The use of photographs............................................................................................ [108] – [112]
- Mr Lambert's opinion.......................................................................................................... [113]
oLoad weighing system................................................................................... [114] – [129]
oThe suspension system, the HCVs and the raising of the ride height............................. [130]
Dr McLean's opinion................................................................................................ [131] – [140]
oThe plaintiff's speed around the corner...................................................................... [141]
Dr Prem's opinion
oAn admissibility issue.................................................................................... [142] – [166]
oMr Lambert's response.................................................................................. [167] – [168]
oFurther aspects of Dr Prem's second report.................................................... [169] – [180]
The causes of the rollover and whether the defendant was negligent
- Discussion............................................................................................................... [181] – [186]
· The suspension factors.............................................................................................. [187] – [189]
· Uneven loading......................................................................................................... [190] – [192]
· The plaintiff's speed.................................................................................................. [193] – [199]
Causation........................................................................................................................... [200] – [204]
Contributory negligence..................................................................................................... [205] – [211]
Order............................................................................................................................................. [212]
Serial No 109/2009
File No 553/1999
HARLEY DENE BESWICK v TAMARACK PTY LTD
and THE NOMINAL INSURER (ACN 009 562 510)
REASONS FOR JUDGMENT PORTER J
11 December 2009
Introduction
The plaintiff, Harley Beswick, was a log truck driver. He was employed by Tamarack Pty Ltd, which I will simply call "the defendant". (The company has been de-registered; hence the presence of the Nominal Insurer as second defendant.) In September 1996, he was driving a semi-trailer combination, being a prime mover with a single trailer "log jinker" attached. Most of his work was carting logs to the paper mill at Boyer, using the Lyell Highway. On 27 September 1996 at about 11.40pm, he was at Plenty travelling south towards New Norfolk. On the last of a series of bends adjacent to the Derwent River — a left hand bend — his loaded truck rolled over, coming to rest against a tree on the river bank, at a point off to his right hand side of the roadway. (I use the term "rollover" loosely, because there is some debate about the extent to which the truck actually rolled over before it struck the tree.) The plaintiff was injured and has brought this action against his employer for damages. Those damages are agreed; liability is the issue.
The prime mover was a Kenworth model. It had a single steer axle with bogie (dual) drive axles. The drive axles were factory fitted with a Hendrickson WD2-460 air suspension system. The jinker was a tri-axle single stanchion trailer which could be longitudinally folded at about its centre point, in order to be piggybacked when not loaded. The tri-axle group was also equipped with an air suspension system. Fitted at intervals of about 3.5 metres from front to back along each side of the trailer, were four steel vertical posts, each about two metres high, referred to as bolsters. The sections created by the two sets of forward bolsters and the two sets of rear bolsters are known as "bunks". With this truck, the forward-most bunk was located at the very front of the trailer, putting it above and just behind the line of the front axle of the drive axles. The centre of this bunk was about 700mm behind the second drive axle. The rear-most bolster sat approximately above the back of the rear-most wheels of the trailer, with the next bolster about in line with the forward-most wheel of the tri-axle group. The centre of this bunk was about 150mm behind the second trailer axle. The practice was to load one pile of logs onto the front bunk, with a second pile of logs onto the rear bunk.
The fundamental issue is what caused the log truck to roll over. There is much to be considered in that exercise. Unfortunately, the action came on for trial nearly 13 years after the event. The writ was not issued until July 1999. No explanation for the delay became apparent during the hearing. It seemed to me that the delay did cause some difficulty in relation to what evidence was called, and the way in which it emerged. To a very large extent, the case between the parties was conducted as a contest between two expert engineers called by the plaintiff, and one called on behalf of the defendant, all of whom had impressive credentials in the field. The earliest of the expert reports is dated February 2006.
None of the experts were able to inspect the prime mover or trailer, or had the opportunity of visiting the scene within a reasonable time after the accident. Each attempted to interpret skid marks and other features shown in photographs of the scene which were apparently taken a few days after the accident. The person who took the photographs was not called. As to the opinion evidence in general, some of the factual assumptions made were not capable of easy identification, some were proved differently in the evidence than as assumed, and with no consequent revision; some were not proved at all. It is a matter to which I will return, but at the time of the accident, both parties seemed to have an erroneous view of the law as to permissible axle loads, and all experts proceeded on the basis of similar erroneous views.
The plaintiff alleges a lack of proper training in relation to driving the loaded log truck with its particular or potential characteristics. Further, based on expert evidence, the plaintiff's case is that the truck rollover commenced from the drive axles and was caused by:
· the inherent characteristics of the airbag suspension system on the bogie drive axles of the prime mover, which gave rise to handling difficulties and general instability.
· an exacerbation of that situation by the re-setting of the height of the suspension by a fellow employee on the shift before that of the plaintiff, of which the plaintiff was not made aware.
· a load indicator system installed on the trailer which, when used in accordance with the defendant's instructions, resulted in the truck being overloaded, with a particular overload on the drive axles of the prime mover.
The defendant's case, based on its expert evidence, is that there was but one simple cause of the accident, and that was the plaintiff's excessive speed into and around the corner. The defendant claims that numerical and whole of vehicle animated modelling, along with some photographic evidence of the scene, demonstrates that the rollover commenced from the rear of the trailer. The defendant's argument as to speed, as pursued at trial, did not raise any response to the plaintiff's allegation that this resulted from an absence of proper training.
It is common ground that a speed advisory sign of 55km/h was erected just before the particular series of bends at Plenty. Depending on how the characterisation is done, there were either five or six bends in the series. The sign showed a vertical "wavy" line, rather than a single curve, and it seems to be accepted, and in any event I find, that the sign applied to all of the bends. The plaintiff accepts that he attempted to negotiate the last corner at about 70km/h. A printout from a built-in computer on the prime mover (the "Tripmaster" system) reveals a speed of 72km/h at a point in the corner.
The pleadings
The plaintiff alleges that the defendant was negligent in the following ways:
"(a)required and/or permitted and/or allowed the plaintiff to drive the truck which was unsuitable and/or dangerous by reason of the facts that:
(i) the load was unevenly distributed
(ii) the load weighed in excess of the safe load (the plaintiff relies on inference from all the evidence that the weight was excessive)
(iii) the centre of gravity of the load was higher
(b)failed to train the plaintiff in driving the truck, in particular that by reason of the suspension system and/or overloading and/or unevenly distributed load he should enter corners cautiously at a reduced speed and that the truck may become destabilised after successive corners.
(c)failed to install an accurate load indicating system on the truck such as a Lodec.
(d)fitted levelling valves to the suspension system were unsuitable and/or not in accordance with the manufacturer's specifications.
(e)allowed a course its employer, Michael Pearson, [sic Pearton] to interfere with the mechanism of the levelling valves of the suspension system.
(f)required the plaintiff to drive an inherently unstable truck."
The defendant alleges that the plaintiff, by his own negligence, caused or contributed to his injuries. The particulars of the negligence alleged are that the plaintiff:
"(a)failed to keep any or any proper lookout.
(b)failed to keep his vehicle under any or any proper control.
(c)drove his vehicle at a speed which was excessive in the circumstances.
(d)failed to apply the brakes on his vehicle in time or at all to avoid the said collision.
(e)failed to steer or control his vehicle so as to avoid the said collision.
(f)failed to ensure that his load was evenly distributed before commencing his journey.
(g)failed to direct the loader operator to re-distribute his load in the event that it was unevenly distributed before commencing his journey.
(h)failed to ensure, whether by way of examination, inspection or inquiry, that:
(i) his load was unevenly distributed;
(ii) his load was not in excess of a safe load;
(iii) the centre of gravity of his load was evenly balanced;
before commencing his journey;
(i)drove his truck and load through successive corners at a speed in excess of the signposted advisory limit for all motor vehicles at 55km/h, namely 72km/h."
The issues
The resolution of the case requires the consideration of seven issues. Matters concerning the truck and the rollover itself, involve examining the expert evidence. The last two issues depend on findings of fact in relation to the earlier ones. The seven issues are:
· the plaintiff's driving, — generally (including his training), and on the night of the accident;
· the suspension of the prime mover and the fitting of high flow height control valves to that suspension at some time prior to the accident;
· whether the ride height of the prime mover's suspension was altered by a fellow employee, Mr Pearton, on the day of the accident;
· the air pressure load measuring system on the prime mover and trailer, and its effect on how the truck was loaded;
· the weight and dimensions of the load on this particular occasion;
· the cause of the rollover; and
· the liability of the defendant for any of its acts or omissions which caused it, and whether the plaintiff was contributorily negligent.
Legal axle loads
Before dealing with the issues which I have set out, I need to explain a point as to the law which applied at the date of the plaintiff's accident. Maximum wheel and axle loads were then governed by the Traffic (Vehicle Loads and Dimensions) Regulations 1975. Relevantly, the regulations were as amended by Statutory Rule 1986 No 291. Given the axle configurations which I have earlier set out, the following were the applicable axle load limits:
· 6 tonnes on the steer axle — reg7(2)(a)(i).
· 14.3 or 15 tonnes on the drive axles — (depending on whether the air suspension fitted is properly described as a load sharing system or not) — reg7(3)(a)(i) or (ii).
· 17.7 or 20 tonnes on the trailer tri-axle group — (again depending on whether or not that system is properly described as a load sharing system) — reg7(5)(a)(i) or (ii).
In his evidence, the plaintiff said that he was instructed by the defendant to load the truck to the maximum legal limit, including "tolerances". The figures he gave were 23.5 tonnes on the truck and 21 tonnes on the trailer; a total of 44.5 tonnes. The tolerances were amounts of grace given by the transport authority. The tare weight of the prime mover and trailer combination was given as 14 tonnes. In cross-examination it was explained that the permitted gross combined mass ("GCM") was 42.5 tonnes, with the tolerances being one tonne for the prime mover and one tonne for the trailer, giving the total of 44.5 tonnes.
The first of the plaintiff's experts was Mr John Lambert. Three reports were tendered, the first dated February 2006, the second and third both dated February 2007. In his first written report, he says that the "legal limit" on the steer axle was 6 tonnes, with 16.5 tonnes on the drive axle group "plus part of the enforcement tolerance being 0.5 tonnes giving a total of 23 tonnes". He goes on to say that the "legal limit" on the tri-axle group was 20 tonnes "plus part of the enforcement tolerance being 0.5 tonnes giving a total of 20.5 tonnes"; a GCM of 43.5 tonnes. The second of the plaintiff's experts was Dr Arnold McLean. Two reports were tendered, the first dated 24 January 2008, the second 11 March 2008. The issue was not raised in either. However, in his oral evidence, when he was describing the air suspension system, he described the relevant legal axle loads as 6 tonnes, 17 tonnes and 21 tonnes for a single steer axle, dual drive axle and tri-axle trailer respectively; a GCM of 44 tonnes.
The defendant's expert engineer was Dr Hans Prem. In two written reports, one dated August 2006, the other dated July 2008 (both responding to the reports of Mr Lambert) he does not raise any issue as to Mr Lambert's assertions of the legal axle load limits. At the trial he seemed to assume that what Mr Lambert had said was correct. Dr Prem's opinion was based on a configuration of the vehicle in which "the vehicle is both correctly loaded, the axle group loads are at their legal maxima". The loaded weights given were 6 tonnes, 16 tonnes, and 20 tonnes. Accordingly, both parties (including their respective experts) conducted the trial on the basis that the legal axle load limits were the same as, or close to, the figures given by the plaintiff. However, as is apparent, those figures were not the legal axle load limits at the time, but are in accordance with amendments to the regulations effected by Statutory Rule 1996, No 129, which commenced on 1 October 1996, and coincided with the commencement date of the Traffic Amendment (National Road Transport Reform) Act 1996. This was of course only three days after the plaintiff's accident.
I made this discovery after judgment had been reserved. By memorandum, I raised this point, along with some incidental issues, with both parties. Neither sought leave to amend the pleadings nor was there any application to re-open. I have been told by way of written submissions that both the plaintiff and the defendant are content to let the evidence stand as it is. The plaintiff acknowledges that it is not part of his case that the defendant had in place a system which resulted, intentionally or otherwise, in continual overloading above the actual legal axle limits, and is "content to proceed on the basis that the plaintiff and the defendant each thought that the stated limits were the legal limits …". The defendant notes the point as to the nature of the plaintiff's case, and adds that in any event, because of the state of the evidence about the suspension systems, it is not possible to make a finding as to what were the actual limits. All of this means that I am to proceed on the basis that both the plaintiff and the defendant were, at least, acting on a mistaken view of the legal limits, and that the experts, to varying degrees, made the same mistake. It is agreed that I have to approach the expert evidence on the basis that references to the "legal limit" (or similar) should be read as the "assumed legal limit". How all of this came about was not explained.
Heavy vehicle safety and truck rollovers
As a further preliminary matter, it may be of benefit to set out some general aspects of this subject-matter, which have been discussed in many papers and reports. The plaintiff tendered a number of these by consent, included in which were the following:
· An Assessment of Heavy Truck Safety in Tasmania — John de Pont of Transport Engineering Research New Zealand Ltd ("TERNZ") — July 2005.
· Report on Survey of Heavy Vehicle Rollover Stability in Tasmania — John de Pont — October 2006.
A paper of Dr Prem (and others) entitled Performance Characteristics of the Australian Heavy Vehicle Fleet — February 2002 — was also tendered by the plaintiff in Dr Prem's cross-examination.
Although these papers and reports post-dated the accident by quite a few years, it is quite plain that the issues which are discussed have relevance to the question of rollover stability of log trucks, including the type of combination driven by the plaintiff, as things stood in 1996. The TERNZ July 2005 report on heavy truck safety in Tasmania analyses crash data for heavy truck and truck combinations starting in 2002, but the report incorporates a discussion paper on New Zealand log transport safety which has statistics relating to log truck rollover crashes from 1999. The essential characteristics of the vehicles have by and large remained the same, and the relevant laws of physics have not been recently amended. Additionally, Dr Prem in his cross-examination, said that issues of rollover stability, including factors of speed, centre of gravity, and weight of load were well known in the logging industry in 1996.
In his first report, Mr Lambert identified the following factors as determining the limits of vehicle stability in rollover situations at a curve. There seems to be no controversy about the list.
· The height of the centre of mass ("COM") of the vehicle; — the higher the COM, with all other factors constant, the less stable the vehicle.
· The track width — (the width between the centres of the wheels or dual wheels at the end of each axle); — the wider the track with all other factors constant, the more stable the vehicle.
· The stiffness of the tyres and the roll stiffness of each suspension; — the higher the roll stiffness, the less the vehicle leans and the more stable it is.
· The characteristics of the load.
· The vehicle's speed.
· The inverse of radius of the curve the truck is following; — double the radius and the side force is halved.
· The superelevation of the curve (the slope of the road pavement towards the inside of the curve); — the greater the superelevation, the less likely the vehicle is to rollover.
· The dynamics of travel down the road.
A central concept relevant to these issues is what is known as static rollover threshold ("SRT"), which is a measure of rollover stability during steady speed cornering. I have based the following description on material which appears in the two reports of Mr de Pont referred to above. When a vehicle is driven through a curve, it experiences lateral acceleration. The magnitude of this acceleration depends on vehicle speed, curvature and cross-slope (or superelevation) of the curve. SRT is the maximum steady turning acceleration which the vehicle can withstand before the wheels on the inside of the curve lift off the ground. This is the beginning of rollover. SRT is expressed as a fraction of the unit of acceleration due to gravity, the symbol for which is "g". High values of SRT mean a better resistance to rollover. There is a time component involved, in that the force needs to be applied long enough to produce the effect. Research into crashes has demonstrated the obvious implied premise; that is, vehicles with low SRT values have a higher rollover rate than vehicles with high SRT values. Apparently, in 2007, the Australian National Transport Commission in its Performance Based Standards system of heavy vehicle regulation, adopted a minimum value of SRT at 0.35g as acceptable in relation to heavy vehicles.
The TERNZ July 2005 report noted that of the 60 large heavy vehicles included in the study which had a rollover crash, 72 per cent were semi-trailers, with the rollover crash rate for log trucks, woodchip trucks and stock trucks, significantly higher (2.5 times) than the rest of the heavy vehicle fleet. The author observed that poor rollover stability does not mean that a vehicle rollover is inevitable. "Within limits it is possible to drive a vehicle low rollover stability reasonably safely provided the driver adjusts the speed through curves accordingly, although there is a smaller safety margin available in emergency situations." The further TERNZ October 2006 report involved a study of 96 heavy vehicles, 15 of which were of the log jinker semi-trailer type. It was established that the average SRT for those 15 vehicles was 0.32. Accordingly, it was concluded that, "overwhelmingly, the vehicle category that currently does not achieve a 0.35 level of rollover stability is log trucks".
Dr Prem assessed the plaintiff's truck in a "correctly loaded" state as having at best, an SRT of 0.309. The situation of a vehicle in close proximity to rollover throughout a turn was addressed by Dr Prem in his report of 18 July 2008. Although his remarks were directed specifically to the plaintiff's truck, they are of general application. He said that for a vehicle in such close proximity, "it would take very little to precipitate rollover — an imprecise steer correction, a small change in speed, a small load shift, or a slightly different line through the turn and a sequencing of bumps in the road."
The plaintiff's driving
Experience and training
At the time of the accident the plaintiff was an experienced semi-trailer driver. He had worked continuously as a semi-trailer driver for 11 years prior to the accident, having driven heavy rigid trucks before then. He had exclusively driven log trucks since 1987, his employment with the defendant starting in 1992. For the whole of the period he was driving log trucks, he delivered logs to either Boyer or Triabunna. The plaintiff underwent an assessment by the Driver Education Centre of Australia in December 1993. This was required for his employment, and involved an evaluation of two trips on the same day. The plaintiff said that both loads were taken from the far Plenty Valley but that the journey did not involve negotiating the series of bends where the accident occurred. His evidence continued as follows:
"Did it involve going past a speed advisory sign?........Yes.
And what was the speed on that sign?........Sixty five.
Right, and did you take that bend at your usual speed on that day?........Yes.
On both loads?........Yes.
And at what speed did you take it?........Approximately ninety.
Mm, and did the instructor say anything to you about your speed on that bend?........No.
Did he say anything to you about your speed on any bend?........No."
In the DECA driver evaluation report, the instructor gave the plaintiff an "A" for his "speed for environment" on both days of the two day assessment. By ticking a box the instructor endorsed the comment that the plaintiff "has an excellent attitude and is very keen to learn. Applies all he/she has learnt during the course and is considered a good and safe driver". The instructor's handwritten comments are that "Harly [sic] is good to work with and had a good attitude toward training…"
The plaintiff described John Vanderwal as the principal of the defendant company, with Rob Reynolds, the transport manager, as his immediate supervisor. Michael Cox was Mr Reynold's assistant and was employed as "driver evaluator". The plaintiff described one incident of Mr Cox travelling with him at some stage before his accident. He said that there was no advanced warning of the evaluation. They travelled together in the truck from the defendant's yard at New Norfolk to Tarraleah, through the Plenty bends, and back the same way with a load of logs to Boyer. The plaintiff said that they passed numerous speed advisory signs, including the 55km/h one at the Plenty bends, and said that he did not drive any differently in terms of his speed or of the line that he took on the roadway to any other day. (He said later in his evidence that he usually drove past the speed advisory sign and into the first of the Plenty bends at 70km/h). The plaintiff said that Mr Cox did not say anything to him about his speed, and said that given the configuration of the truck cab, Mr Cox was able to see the speedometer from where he was sitting in the passenger seat.
The plaintiff described the operation of the "Tripmaster" system on the truck. Each driver was issued with a plastic ID card about the size of an ordinary credit card. That was put into a slot in the dashboard of the prime mover cabin and was left there for the whole shift. At the end of the shift, the truck would be taken to a diesel bowser where there was a computer connection which was plugged into a USB port or similar, in the cabin, and the information recorded by the system was downloaded to the office computer. The plaintiff said that "they could look at whatever you did in the truck, the gear changes, speed, revs, engine brake usage — ".
A "Tamarack Transport — Company Standards" document is in evidence. Amongst other things set out in that document are "The Professional Drivers Ten Commandments", two of which are as follows:
· "When on the road, observe all state laws and respect the laws of nature to do with forces, momentum, and the centre of gravity of your vehicle."
· "Don't hesitate to slacken your speed and be ready to stop the instant potential danger appears."
The plaintiff was asked whether he was able to comply with the requirements of the document, or whether he had any difficulty with it. He said that his attitude to it was fine and that he had no problem with it.
The plaintiff said that he was under no time pressure in the job. He was asked about his practice in relation to speed advisory signs. I have already noted the situation in relation to the 55km/h sign at the Plenty bends. He was asked questions about other speed advisory signs between the Plenty bends and the Boyer paper mill. By reference to signs shown in photographs, the plaintiff said that he travelled at 70km/h around a bend marked 45km/h, 90km/h around one marked 65km/h, 90km/h around one marked 55km/h. In relation to the final photograph identified, he said that he travelled at 90km/h around a bend marked 85km/h but the reason for that was that it was close to a descent into the town of Bridgewater where there was a 60km/h speed limit sign. His explanation was that he was familiar with the roads and how the truck travelled on that road.
Evidence was given of the plaintiff's driving habits by Malcolm McGregor. Mr McGregor worked for the defendant for about 12 years up until 1998 when he retired. He said that he often travelled in convoy with the plaintiff; over the years probably between 60 and 100 times. He said that the plaintiff knew most of the roads "like the back of his hand" and was able to guide him as to what lay ahead. As to his observations of the plaintiff's driving in general, he said:
"Well I would say Harley was one of the best drivers I ever knew. It's all he ever done. I've never seen him recklessly cut corners or on the wrong side of the road, he always kept - was on his own side of the road. All drivers – when you can see a long way ahead you try and straighten the corners out as much as you can without going into the other lane, but I would say Harley his driving was very confident, he wasn't a reckless driver, he was always on his own side of the road and never saw him have any near misses or anything like that." [Emphasis added]
Negotiating the Plenty bends
The plaintiff said that the defendant operated about 18 trucks in 1996 with around the clock operations; two drivers being allocated for each truck, each driver doing a 12 hour shift. On the day of the accident the plaintiff was carting logs from Tarraleah which was a regular place of origin. In a 12 hour shift he would be able to do three return trips. In his nine or ten years of log truck driving, about 70 per cent of trips had involved negotiating the Plenty bends. The plaintiff said that his driving through the Plenty bends, his speed, selected gear and line taken, were consistent from one occasion to the next. He was taken through the way in which he had normally negotiated the bends prior to the accident. Travelling in a southerly direction, he said that the first bend was a right handed bend. There was "a little left kink" before that bend, which he said, was "hardly really noticed". In the plaintiff's case, the right hand bend was accordingly called the first bend. However, Dr Prem counted this bend as the second corner, and as his numbering ultimately became predominant in the trial, I will use his system. The first right hand bend is therefore bend 2. The plaintiff said that he travelled around that bend at 60km/h. He said that he maintained "roughly about 60, because the exit of that bend where it actually straightens out is the worst part of it, because the road elevates then it — the camber of the road goes the opposite way, so the weight of the vehicle becomes unsettled on that particular part of the road".
From the exit of that bend, the plaintiff said that he gradually increased the speed through the rest of the bends and stayed in the same gear. The next bend is a left hand turn, immediately after which is a right hand turn, at which point he said he would be travelling at about 65km/h. What follows is the first of two left hand bends. He said that approaching the first of these two left hand bends, he "lifted off" the throttle so that the drive was "sort of in a neutral zone, … you haven't got that momentum through but you're still carrying the speed but you're not actually creating momentum …". He said that this was because the camber of the road changed. It went from assisting the vehicle through the right hand bend to assisting the vehicle through the left hand bend. Approaching the sixth and last of the bends (bend 6) — another left hand bend — he said he maintained the same gear and held the speed. He said it was an "excellent" curve to negotiate. "The vehicle flows through the curve well balanced, there's nothing unsettling in that curve, and the camber of the road assists the vehicle through there, it travels through nicely balanced."
The plaintiff was asked about his line through these various corners and said that through each corner the truck was maintained within its lane, and whilst on occasions the right hand wheels would be close to the centre line, it was not necessary to cross over to negotiate any of the bends. Similarly, he said on occasions the left side wheels would be close to the white fog line marked on the left side of the carriageway, but that it was not necessary to cross over that line. In cross-examination, the plaintiff was not challenged on this evidence, nor asked about it all. As will become apparent, the issue has significance in the defendant's case.
The prime mover's suspension system
The system in general
The essential feature of the suspension system is that instead of mechanical springs, it has airbags. On a suspension for a bogie axle configuration there are two airbags on each side, each located immediately behind the axle mounts on the trailing arms. I set out below a sketch taken from the manufacturer's specifications. As fitted, the front of the truck is to the left of the diagram. The attachment point for the axles are on the arms to the left of the upright springs, which are to the left of the airbags.
The airbags are inflated by compressed air sourced from a compressor on the prime mover itself. Each time the rear trailing arms move up or down, a height control valve (one per set of airbags) is activated, moving air into or expelling it from, the airbags. If, for example the vehicle leans to the right, the height control valves will cause the right side airbags to expand, and the left side airbags to deflate, thus "levelling" the prime mover. At least as the manufacturer claims, the height control valves are for "increased roll control". A ride height is pre-set according to the manufacturer's specifications. This ride height can be adjusted. Mr Lambert in his first report described the type of suspension as having "medium roll stiffness". He says that such a suspension system requires the height control valve ("HCV") on each side of the suspension to keep the vehicle upright; "Otherwise the compliant rubber bushes would allow the prime mover to lean to one side or the other in travel. The lean would result from the road camber and/or the fact that the load was slightly off-centre".
Mr Lambert says that in Australia, two-lane two-way roads are mostly built with a high crown in the centre to effect water drainage. In that context, he describes the operation of the suspension system as follows:
"[I]n normal travel the vehicle will lean to the left, and the airbag on the left hand side will be compressed and that on the RHS will extend. The HCV on the left will interpret the compression as indicating the height of the axle is too low and so will pressurise the LHS airbag until the height difference is corrected. And the HCV on the right will interpret the extension as indicating the height of the axle is too high and so will exhaust the RHS airbag until the height difference is corrected … [W]ith twin HCV airbag suspension systems the variation in airbag pressure is much greater than the +- 5% — 10% variation expected. The question is where are the extra airbag forces resisted. Basically the extra forces act to distort the suspension. The trailing arms and their connections to the axle form a large roll resistance bar. The trailing arm of the suspension is forced down on the LHS and the RH arm moves upward. … [T]he RHS of the axle moves up and backwards and LHS [sic] end of the axle moves down and forwards. The axle is now not aligned correctly with the chassis and so wants to steer the vehicle to the right. … As the drive axles will want to steer the combination to the right the driver will need to steer to the left ... But that will tend to cause the vehicle to curve to the left. So in time he will have to steer more to the right. This process may require the driver to undertake continuous steering corrections.
Consequential effects of uneven side – to – side airbag pressure. The rate of transfer of air into and out of the airbags is slowed because the tubes leading into and out of the airbags are small. Hence if the airbags on the left hand side have become pressurised, and those on the right have been partially discharged, in a situation where a vehicle starts to lean to the right the high pressure in LHS airbags will cause the trailing arm on that side to be forced up while the low pressure on the RHS will allow that trailing arm to drop down. This will tend to increase the likelihood of the prime mover rolling over to the right."
The plaintiff tendered the manufacturer's specifications. However, these are dated April 2000. They state: "To achieve exceptional roll control with improved air system response times a High Flow Height Control Valve (HF-HCV) may be fitted. When using two High Flow Height Control Valves, the need for a high volume to supply the air is increased". I would here interpolate Mr Lambert's evidence that the WD2-460 was withdrawn from the market, (I infer sometime in or after 2000), and replaced with a different version in 2003.
In cross-examination, Mr Lambert was not able to offer a flow rate in explanation of his comment that the rate of transfer of air into and out of the airbags was slow. He answered the question by saying that he had conducted a test on the same suspension showing a time taken of 13 seconds for the airbag pressures to equalise on the two drive axles. There was a 10 centimetre lift of one axle. Mr Lambert disagreed that the height control valves had any function to perform in terms of roll control. He said that the valves were not there to assist roll control but to make sure that as the load on the truck was altered, the height was not altered so that "the steering angles and all the other aspects — of alignment aspect of the vehicle are maintained". He said that they were not there to work in travel, but unfortunately many manufacturers positioned the valves in places which made them work in travel, which was not their purpose.
Mr Lambert continued: "[N]ormal height control valves that are fitted have a dead band in the middle where movement of the suspension up and down does not result with any air flow moving into or out of the airbags, but where there are trucks with problem suspensions and as this one — in other words, trucks that wander and dart and are difficult to drive — one of the solutions or part of the solution is … to put high flow, high response height control valves and on some vehicles that improved the way they performed. But the height control valve is not designed to install as part of the suspension to actually act dynamically in travel …".
Mr Lambert accepted that the manufacturer represented that the height control valves were for increased roll control, but maintained that the valves were primarily to set the height of the suspension as loads were put on and off. Mr Lambert explained his point as follows:
"The flow is so low that it doesn't have any meaningful effect on [the suspension and the stability of the vehicle]. Because the time it takes for air to move round is so slow in relation to – if a truck goes over a 50mm bump at 100 kilometres an hour, a second later it's 30 metres down the road. It's passed the bump. In that time there's virtually no - there can't be any meaningful airflow from one airbag to another in that time."
Dr McLean, in his first report, referred to the general deficiencies of heavy vehicle, (particularly prime mover), air suspensions as including:
"· The air spring pressure varies significantly over time dependent on the actual instantaneous suspension displacement, instantaneous loads and system response to previous in-service events.
·The air suspension roll, resistance and spring stiffness varies very significantly over time.
·The suspension characteristics including vehicle dynamic rollover threshold characteristics are strongly non-linear.
·The suspension and hence vehicle and steering handling characteristics are strongly payload extent and centre of gravity location dependent.
·The suspension characteristics differ significantly from those in mechanical systems which are stable and consistent.
·Heavy vehicles installed with air suspensions on both the prime mover and trailer exhibit particularly adverse handling behaviour."
In his second report, Dr Mclean says that the WD2-460 exhibits a high sensitivity to low centre of gravity, and significant roll steer. He identified a number of other design deficiencies of this suspension, amongst which were that the pivoted trailing suspension arms were excessively stiff in comparison to the flexible prime mover chassis, and the system utilised twin ride height control valves — one set per side located remote from the bogie centreline. Additionally, Dr McLean says that the WD2-460 suspension "has application to slow (ie less than 80km/h) heavy, high tare, relatively rigid chassis, essentially off road vehicles".
In the report, the first identified "general deficiency" was further explained as it specifically related to the plaintiff's vehicle negotiating the corner at which the accident occurred. Dr McLean noted that the cornering would have caused the vehicle, "particularly and initially the prime mover", to lean to the offside. This would have caused the near side height control to have vented. He goes on to say:
"It must noted the cornering lean and load transfer action is instantaneous. Whereas the air spring venting action is strongly prime dependent. Due to the aforementioned different actions excessive pressures occurred in the near side air springs. The excessive pressure in the near side air springs generates a catapulting action. This catapulting action is enhanced by the fact exhaust from the furthest connected air spring is slower due to the systems exhaust flow resistant characteristics. The same is further exacerbated by the offside ride height control valve opening to counteract the depressed offside ride height. During this valve operation the pressure differential across the offside ride height valve is adverse. Consequently adverse backflow may occur. This catapulting action would have been exacerbated by the rapid change in the road camber up to and immediately after the corner's apex and the suspension and chassis flex in response to the same".
In his evidence, this first identified deficiency was explored. Dr McLean explained that "actual instantaneous suspension displacement" means that when a vehicle rolls, sufficient resistance air pressure in the airbags has to develop to resist the roll effect, so it instantaneously increases. He continued:
"But if a truck goes through a long sweeping corner, … the rolling action causes the ride heights control valve to make the truck become more level. So that fluid flow is a time dependent variable and it takes times for that actual levelling to occur."
This, Dr McLean said, keeps the pressure the same, but when the vehicle exits the corner there is excess pressure, "so you have this integrated effect of pressure which is the system response to previous in-service events".
Dr McLean went on to explain another factor which caused increase and decrease in the air spring pressures and which affect the roll stability. This was the third identified general deficiency; that of "strongly non-linear suspension characteristics". He described a phenomenon known as "torque rise" or "frame rise" which was the combination of two forces created by the application of power to the drive wheels. Drive torque applied to the drive axles lifts up the frame or chassis of the prime mover in a vertical rearward action. This upward movement causes a decrease in airbag pressure. At the same time, because of the revolutions of the drive line, the torque applied results in high pressure in the airbags (with this truck) on the right hand side. If power is applied, the roll stability on the drive axles is actually reduced, as well as the roll effect of the truck being assisted. Dr McLean described all of this as "a very complex phenomena" with air suspensions on drive axles being vastly different to mechanical suspension.
In his first report, Dr McLean said that he understood the plaintiff's truck had negotiated a succession of corners prior to the rollover, which succession had generated "a magnitude accumulation of pressure deviations and approach through and exiting of the corners". In his evidence he explained this as follows:
"Well as a vehicle in the sequence of corners lead into the subject corner there's a major long – generally long sweeping right hand bend and the vehicle would've leaned to the near side, or to the left, and that would've caused instantaneous increase in pressure on the air bags on the near side, on the drive, and the effect is that because it's a long sweeping bend that the levelling valve's tried to correct it and through flow is a time phenomena and will take time to do it. In a short sequence of bends the air bags don't have enough time to get the truck to stand up perpendicular to the road and so it's a time phenomena, so on a big long sweeping bend, which is the first bend into this sequence of curves, at and about the 55 advisory speed sign there that is termed the long sweeping curve. And also we have the problem that the – if the driver backs off and - the truck speed will suddenly decrease because of rolling resistance, so the fact that he's maintaining constant speed or increasing speed slightly indicates that power is going down the drive line so these air springs are actually subject to the frame rise effect becoming like marshmallows, they're actually pressuring these air springs, they're decreasing, so it's a very highly non-linear complex phenomena, subject to this levelling effect on a long sweeping bend."
It will be recalled that Dr McLean in his first report said that the catapulting action he described would have been exacerbated by the rapid change in the road camber up to and immediately after the corner's apex and suspension of chassis flex. In evidence, he was asked to explain that. He said that due to the fact the vehicle had completed a major sweeping right hand bend, it was expected that the pressure in the left hand side airbags was excessive and "even though the vehicle is travelling light on the bogey because of this disturbance due to this torque being applied to the drive line that the pressures were higher still on the new side and that gets the left hand chassis rail and kicks it up and transfers the load to an increased amount to the steer tyre" [sic].
He went on to elaborate on an additional factor which related to his complaint that the WD2-460 had trailing suspension arms were excessively stiff. In the suspension setup, the trailing arm was fixed to the chassis at its forward-most point. To the rear of that point there is a point on the arm at which the axle is attached, with the airbag being at the rear-most point of the trailing arm. These three points were described as the pivot point, the load point, and the point of effort. As I understand it, Dr McLean's premise was that the pressure in the airbag could reach a stage at which, because of the stiffness of the trailing arm, the axle connection point formed the pivot, with the load being taken up by the airbag. The end result of that was "… very large forces going to the pivot point. It elevates the chassis rail."
In cross-examination Dr McLean said that his evidence as to the characteristics of air suspension systems was based on involvement in a study on vehicles operating with air suspension systems which was initiated by the Federal Office of Road Safety in approximately September 1998. This was a major investigation, a number of vehicles involved in which were equipped with the WD2-460 suspensions. He said he studied those very closely as to why they were causing problems. He agreed that airbag suspension systems were generally still in use, but that some manufacturers, including Hendrickson, since about 2000 have used flexible trailing arms to mitigate the effects of the rigid arms.
Dr Prem did not specifically address the features of the suspension in his two reports, but the issue was taken up with him in his evidence-in-chief. He referred to the two height control valves, one on the left and one on the right, those valves being "… designed to keep the suspension arm, if you like, in the same position relative to the chassis. So, it's designed to reduce the amount that the axle rotates relative to the chassis and that's rotation in roll." He agreed that that is what the phrase "roll control" meant and went on to say that the high flow height control valves were seen as an improvement to the previous version of those valves, and that Hendrickson now have an even higher flow version.
Adjusting the HCVs to increase the ride height
In his first report, Mr Lambert noted the suggestion that someone had adjusted the HCVs to raise the ride height of the suspension "in the belief that it would make the suspension more rigid and hence more stable". He thought that this might have been done on the assumption that forcing more air into the airbags would increase the pressure in them and make them stiffer. Mr Lambert detailed a number of actual effects of carrying out this exercise. It raises the COM at the drive axles and makes the vehicle less stable. The COM will increase by roughly the amount of the rise in suspension height. The pressure in the airbags actually remains about the same, but the height of the airbag will increase and alter its characteristics. Using a graph and assuming a height increase of 70mm, he purported to illustrate that "the changed airbag height results in a softer spring — that is a lower spring rate. Hence for any circumstance where there is a variation in vertical loads on the changed airbag it will deflect further." As a result of the lower spring rate, the HCV will be open for longer, so variations in airbag pressure will increase, and the problems he had previously described in relation to airbag suspensions generally would worsen.
He said that it was possible that if the height of the airbag was increased too much, then the limits to the extension of the shock absorber may be reached. As a result, the suspension would be much stiffer, and in fact for much of the time it would act as though it were rigid. However, based on the description of the vehicle performance at the time, he said that this seems not to have been the case. The description of the vehicle performance he was given is not revealed. The plaintiff's evidence about the behaviour of the truck on the accident was not put to him. He said that in summary "altering the HCV to significantly alter the height setting has many detrimental effects on vehicle handling and stability. As a result this could have significantly reduced the vehicle's stability". (Although in his opening address, the plaintiff's counsel went through the process in some technical detail of how the suspension height might be adjusted, all that is in evidence is the WD2-460 "Technical Bulletin", in which there is direction as to how, in very simple practical terms, to effect an adjustment to the ride height.)
In cross-examination, Mr Lambert accepted that the ride height was intended by the manufacturer to be adjustable but "within a very narrow range for each vehicle …". The WD2-460 Technical Bulletin provides that "a given ride height must be obtained" as shown in a table. For Kenworth, the minimum and maximum ride heights are shown as 430mm and 440mm. It is not clear whether this is the minimum and maximum physically achievable, or whether as Mr Lambert's evidence might suggest, it was the manufacturer's intended, or recommended settings.
In his second report, Dr McLean said that he understood that prior to the accident the ride height had been increased by approximately 38mm "by adjusting the lengths of the feedback linkage between the feedback take off connection and the ride height control valve input arms". No source of this information is revealed, and again, the plaintiff's evidence was not put to him. He went on to say that a 38mm change in the ride height would have severely altered the vital drive line geometry and power transmission efficiency. He continued:
"By increasing the ride height the centre of gravity of the load is higher. In general the lower the centre of gravity the more stable the truck and its load. Accordingly increasing the centre of gravity by approximately 38mm will increase both the static and dynamic rollover risk. Further it will also increase the … height (to the top of the turntable coupler plate between the truck and trailer). This would also reduce the static and dynamic rollover stability of the truck and its load.
Both the adjustment of the ride height and the use of the WD2-460 suspension system would have given a driver false feedback concerning the stability and weight of the load being carried at the time.
With the increase in ride height the suspension would have become 'stiffer' at the bogie. This would give the driver feedback on a straight level section of road of increased stability."
Handling problems with the plaintiff's truck
The plaintiff said that he commenced to drive the Kenworth prime mover in the middle of May 1996. Before that he drove a Freightliner prime mover. He said that this truck was consistent in its road behaviour and feedback, explaining feedback to mean "the feeling of the vehicle as you travel along, you get a feeling of the vehicle, how it behaves, how it's cornering, and you drive within the limitations of the vehicle". There was no need to make continual steering adjustments with this truck, nor did it wander nor veer at all. He was asked as to whether he noticed anything different about driving the Kenworth as distinct from the Freightliner. He replied that he had to continually apply steering input which he did not have to do with the Freightliner. The evidence continued as follows:
"And why was it that you had to continually put, have steering input?.............Um, the truck appeared to veer from side to side in the lane carriageway. So, I'd have to steer – if it veered right I'd have to steer to the left and vice versa to keep the truck under control.
Did you find any problem with the rear of the vehicle?.............Um, yes.
And what was that?.............Oh, the rear of the vehicle would lift up while it was in motion or either lift up as a whole or lift up one side or the other left or right.
HIS HONOUR: Sorry, when you say vehicle do you mean the entirety, truck and trailer?
WITNESS: The, no, the –
HIS HONOUR: Or just the prime mover?
WITNESS: The prime mover, the drive wheels of the prime mover.
MR READ (resuming): Did you find anything unusual about the way it cornered?.............Yes.
And what was that?.............It could do that in a corner or on a straight piece of road and that would require an input from the driver.
Right, now were these problems predictable. In other words you'd know when they were going to happen, happen according to a particular time or place?.............No.
Can you just enlarge on that answer?.............Um, they was predictable as in I expected it, um, be ready for it to happen, um, but exactly – you could say exactly where it was going to do it, you couldn't.
Now, did those problems change at all in the three months that you drove your vehicle up to the time of the accident?.............Yes.
Mm, can you enlarge on that please?.............The night of the accident it didn't give any veering or wandering characteristics.
All right, now back to when the problems were there, did you attribute the problems to anything?.............I, yes.
Mm, and what was that?.............Um attributed it to the overloading on the drive."
He was asked whether he spoke to anyone at Tamarack in relation to these problems. He said that he first spoke to Rob Reynolds and John Granville — (Mr Granville's role was identified in the evidence). He said that he told them that the truck would veer from side to side and he would have to continually correct the steering to keep the truck in the direction of intended travel, and that he believed it to be dangerous. On one occasion he spoke directly to Mr Vanderwal, notwithstanding a company directive that employees not take problems to directors. That one occasion was on Friday 13 September 1996, two weeks before his accident. His complaint to Mr Vanderwal was that the veering problems were caused by the truck being continually overweight "on the drive". (I will return to this particular complaint.) To his knowledge, nothing was done as a result of his complaints, the only change to the being that on the night of the accident "the truck appeared to be more rigid, more like a steel spring suspension without the variations that required the steering input".
It can be seen in that passage of his evidence, the plaintiff seems to have identified two problems. The first was veering from side to side in the carriageway. The second was that the prime mover would lift up at the rear as a whole or on one side or the other. The plaintiff was asked whether there was anything unusual about the way the vehicle cornered. His response that "It could do that in a corner or on a straight piece of road …", in the context of the questions and answers seems to relate to the lifting problem. As can also be seen from the passage set out, the plaintiff was asked whether he had spoken with anybody at Tamarack "in relation to these problems" [my emphasis]. Immediately after the passage I have set out, it was established that the accident occurred at 11.45pm and then attention was refocussed on problems with the truck. Notwithstanding the earlier questions and answers, the following line of questioning, which seems to suggest three separate problems, was pursued by the plaintiff's counsel:
"And did you make any complaint in relation to the bumping that you've described?........Yes.
Who to?...........Both Rob Reynolds and John Granville.
Was that at the same time as you complained about the steering problems or at a different time?............That's at the same time.
Right. And was there any response to that?...........No.
Right. And the cornering problem that you've described, did you make any complaint about that?..............Yes.
And the same or a different time?........The same time.
And any response to that?...........No.
When I asked you about response I'm at least meaning by the question, did anything change in relation to the truck to your knowledge, did Reynolds or Vanderwal give you any answers, say what they'd do?....Yes.
Yes, and what was that?.............Rob Reynolds would say, 'I hear what you say'."
In cross-examination the plaintiff agreed that he first noticed something "unusual" about the handling of the truck on the first trip on the day of the accident. He said that he first experienced the handling differences on the first trip up to Tarraleah unloaded, and that the things he had earlier described about the truck's handling on the particular night were present throughout the whole of the first trip when loaded. He did not do anything when he got to Tarraleah on his first trip, to try to find out what might be different. He said that he did not give any thought to what might be causing the differences in the handling, and that it did not cross his mind to wonder about the cause.
The plaintiff said that the truck seemed to sit up more solidly and not roll about as much, and that this applied to when the truck was both unloaded and loaded. He was then asked whether, when he arrived at Boyer with the first load, he tried to find out what might be different, and inspected the truck. He said that he looked at the rear end of the prime mover and saw that the gap between the drive wheels and the mudguards appeared to be larger than normal. He said that normally the gap was about five inches, and that this was in both loaded and unloaded states because the airbag suspension kept it at a steady state. He said the gap appeared about three inches higher than normal. This did not sound any note of caution in his mind, nor concern him, and he did nothing about it.
The following exchange then occurred:
"The suspension on that truck was adjustable wasn't it?..........I believe it can be yes.
Well Mr Beswick, you knew that it was didn't you?...........No.
You didn't know that the suspension on the truck was adjustable?...........No.
If you didn't know that the suspension on the truck was adjustable, didn't it cross your mind that there was something very unusual going on here if the guards were some three inches higher off the wheels, off the tyres, than normal?..........No.
Didn't occur to you to wonder why that might be so or how it had come about?..........No.
So you just got back in the truck and drove it back up to Tarraleah for another load?.........Yes, yes.
Wouldn't, wouldn't you want to know?........It wasn't unusual when you unload the truck for the actual – in the Boyer yard when I looked at the truck after it was unloaded, for when the loads taken off the airbags get a blast of air and lifts the back of the truck up so it wasn't unusual for me to see the truck actually lifted up higher in the Boyer yard. That was a pretty normal occurrence.
Well I thought you explained that when you got to Boyer you had a look at the truck and found that it was higher, that the guards were higher off the tyres than normal and that was unusual?..........Well it might be just a bit confused with how to answer this but it's unusual, if it stayed like it, it would be unusual.
So what did you do?.........I got in the truck and proceeded to do my job.
Did you have another look when you got back to Boyer after the truck was loaded to see whether that situation had changed?........No.
But you said if it stayed that way when the truck was loaded it'd be unusual so you'd want to know, wouldn't you?........No, the truck was travelling okay, it felt okay."
It was specifically suggested to the plaintiff that he did not notice any difference at all in the handling of the truck that night. He said that he did notice something different, that he disagreed with what was being put, but confirmed that he did nothing about it. He said that the "truck was behaving well on the road, it was actually probably behaving better. I had my shift to do and I proceeded to do my job". It was then clarified that he had looked at the gap between the wheels and the mudguards when the truck was unloaded. The plaintiff went on to say "When he was taking the load off, I noticed that the height was sitting – to me appeared to be sitting quite high, but sometimes the air bags would make it do that with the unloading process". He agreed that the situation was not unusual "in that context".
The plaintiff agreed that the truck was still handling well when being driven back unloaded after the first trip, better than it had previously. "It didn't require the steering input". He thought that the truck was just sitting on the road better, and that in terms of being pleased or concerned, he just did not think about the matter at all. Later, he agreed that after he had noticed the differences in the handling of the truck, he did not alter the way in which he drove. He did not drive more slowly, he did not take a different line through corners but kept driving the way he always had. He said it did not cross his mind that because the truck was handling differently "perhaps under load", he should take a bit more care, and agreed that even when loaded he made no change to the way in which he normally drove the truck, even after he had seen the height difference between the wheels and the mudguards.
The fitting of high flow HCVs to the plaintiff's truck and the alteration of the ride height
In cross-examination the plaintiff was asked whether he had ever had any discussion with Mr Pearton — the day shift driver — about the handling of the truck. He said he did this occasionally, discussing the problems he was having. Mr Pearton told him that he was experiencing similar problems. The plaintiff confirmed that he had complained a number of times about the handling of the truck. He said he told management that he was having veering problems and had to continually use more input into the steering to keep it under control, which he attributed to the vehicle being overweight. The question of the installation of new height control valves for the truck was raised with him. The relevant exchange is as follows:
"At some point prior to the accident it's alleged in your case that new valves, new height control valves were fitted to the truck, fast acting valves?..........Sorry, I've got to take you back to the start.
Yep, that's all right, that's my fault. At some point before your crash I think you're aware now at least that new height control valves were fitted to the truck?.........Yes.
Now, as I understand it your evidence is that you didn't know about that before the crash?...........No.
Are you telling his Honour that you had no knowledge at all that new fast acting valves had been fitted to the truck?.......Yes.
Did you know or understand that any modification had been made to the suspension of that truck?.............Yes.
Now, just to make sure you understand my question, you knew before the crash that some modification had been made?...........No, no, in that – how you put that to me, no.
So, you adhere to your evidence that you knew nothing about any modifications to the suspension before the crash?.............Yes.
Nobody ever told you that new valves had been fitted?.............No.
Nobody ever told you that something had been done to the suspension?.............No.
Didn't you tell the workshop supervisor at Tamarack that the fitting of new valves to the suspension had improved its handling?.............No, I never did, no." [My emphasis]
Having regard to that evidence and the position taken by the plaintiff, it is curious that in the plaintiff's case, directly contradictory evidence was introduced. This was in the form of a letter from the defendant, signed by Mr Vanderwal and dated 4 December 1996. It was addressed to a firm of solicitors which is not presently involved in the litigation. It refers to "PM15" which was the defendant's designation of the Kenworth prime mover driven by the plaintiff. The letter, signed by J R Vanderwal – Director, reads as follows:
"Approximately 3 to 4 months ago, both drivers of PM15 complained about their truck suspension being slow to level out. Upon further investigation it was found that the truck had the old (slow) levelling valves and not the quick levelling valves which the truck was specified.
The new valves were supplied by Kenworth Tasmania under warranty, and were installed by workshop staff.
Both drivers praised the new levelling valves to our workshop supervisor. No further action was taken. …"
The specifications for the prime mover with the date of manufacture of February 2006 are in evidence, but they do not show anything other than that the rear suspension was the WD2-460. As I have noted, the WD2-460 specifications speak of high flow height control valves which may be fitted as an option "to achieve exceptional roll control with improved air system response times". In all of this, it is unclear whether the quick levelling valves referred to in the letter, were the standard valves in the suspension's 2000 specifications, and whether the high flow valves referred to in that document are a further improvement.
Another curious aspect of the plaintiff's case occurred in relation to the alleged alteration of the ride height of the suspension on the day of the accident. It will be recalled that a particular of negligence alleged, is that the defendant allowed Mr Pearton "to interfere with the mechanism of the levelling valves of the suspension system". The plaintiff was asked whether he had met with Mr Vanderwal after the accident. He said he had, and that Mr Vanderwal told him that the ride height of the suspension had been raised on the night of the accident This had been done by the adjustment of the "levelling valve that controls the air flow to the airbags on the drive suspension." The plaintiff said that he had not previously been aware of this. But the issue was more dealt with in far greater detail in re-examination. The passage is as follows:
"You were asked this question Mr Beswick, 'Did you ever have any discussion with Michael Pearson [sic] about the handling of the truck?' You were then asked in relation to discussions before the accident, have you had any discussion with Pearson [sic] about the handling of the truck since the accident?.........Yes.
And the – when was that or when were those discussions?..........He came into the hospital to visit.
Yes………..And I've passed him twice on the footpath, just generally passed him.
Right, and what has he said about the handling of the truck in those discussions or on those occasions rather?.............Could you –
What has he said about the handling of the truck on those occasions?.............It was standing up well.
And did he say why?.............He had a play with the levering valves on the way back on his, previous shift to mine.
Did he explain what play with the levelling valves meant?.............No, but what he said to me 'I had a play with the levelling valves on the way back. She's standing up – I've got her standing up', referring to the truck as her."
It will be remembered that Mr Brazendale said that it was probably seven or eight months after the accident when the plaintiff's truck came back after being repaired. He said, "at the start it was a new truck to me because I'd never driven an airbag truck before, so it was sort of different, but after a while it was – it wasn't the best vehicle I've ever driven. [It]just never seemed to sit up properly on the road – like it wanted to lay over all the time, in the corners". He said that as a consequence he had to change his driving style in that he had to be a little bit more careful and more conscious of what he was doing.
I have already noted the evidence of the plaintiff's experts as to this issue. In his examination-in-chief, Dr Prem was asked about the plaintiff's evidence in relation to the behaviour of the truck on the night of the accident; in particular, his evidence that:
· the truck appeared to be more rigid, more like a steel spring suspension without the variations that require the steering input;
· the prime mover did not display any wandering characteristics or veering;
· it felt a lot more rigid, similar to a steel spring suspension.
Dr Prem's response was as follows:
"You, as I understand it, were asked to assume, at least in part, that a modification may have been made to the suspension on this truck for the crash which involved the fitting of faster acting height control valves. Is that correct?.............That's correct.
Is the description there given by the plaintiff of the behaviour of the truck, consistent with the fitting of faster acting height control valves?.............Yes.
Is it consistent with faster acting height control valves doing their intended job? Performing their intended function?.............Yes, it is."
Findings of fact
There are a number of factual issues which arise from this discussion about the prime mover's suspension and associated matters. The first relates to the Hendrickson WD2-460 suspension itself. I am satisfied that the suspension system had the characteristics, and suffered from the problems, as described by Mr Lambert and Dr McLean and which I have set out. As I have noted, there was no real challenge to this evidence. There was a debate between Mr Lambert and Dr Prem about what the purpose of the system's design was, but in essential terms, Dr Prem's brief evidence did not raise any fundamental contradictions. The point of departure arose in relation to the effect of the fitting of high flow HCVs. Leaving that to one side, in simple terms this means that there was a factor of instability inherent in the suspension system.
The more acute manifestation of that instability was in the way in which it operated when the vehicle negotiated successive opposite corners. In a right hand corner for instance, the system operated to raise the near side chassis height to neutralise the effect of the left hand roll. Depending of course on the distance between corners, that would still be happening when the truck quickly exited that corner and entered a left hand corner. This would exacerbate the right hand roll. All of this was in turn exacerbated by the application of power.
In general terms, whilst the fitting of high-flow HCVs may go some way to alleviate the problem, the essential difficulties would remain. The degree to which they would be manifest would depend upon the actual level of flow achieved, the degree of roll of the truck to which the suspension had to respond and the space in terms of time and distance between corners or other events such as road unevenness, which would trigger the activation of the airbags. For those reasons the airflow may not be quick enough to have any meaningful effect, particularly given the speed at which the truck moves and the suspension needs to respond.
The rate of air flow was not the only problem. Dr McLean described the problems with the point of load bearing which arose because of the rigidity of the trailing arm. From about 2000, flexible trailing arms were introduced on such systems to mitigate the effects of the rigid arms. This itself might suggest that high flow HCVs were not seen as a panacea.
All of that leads to a consideration of what the defendant knew or ought to have known in relation to the inherent characteristics of this suspension system. I leave to one side for the moment, what may arise from the complaints which the plaintiff says he made. The present focus is on whether the defendant was negligent in providing the truck which had this particular suspension system fitted to it. I am not satisfied on the evidence, that in 1996 the level of understanding of the problems to which this type of suspension system might give rise, was such that the defendant knew or ought to have known, that its use on a log truck would give rise to a foreseeable risk of injury. In September 1998, the Federal Office of Road Safety instigated an inquiry involving a number of heavy vehicles, some of which at least, were equipped with WD2-460 suspensions. Dr McLean was involved in the investigation and I infer from his evidence that the need for it arose from reported handling difficulties, if not a number of accidents, which had occurred. The resultant report was not available at the time at which the plaintiff was provided with this truck to drive, or when this accident occurred. Further, these types of suspension systems are still generally in use, although with some modifications.
The next factual issue is the plaintiff's complaints to the defendant, when it was that the high-flow HCVs were fitted to the suspension, and what effect that had. I accept the plaintiff's evidence that he complained to the defendant's management, on more than one occasion, about the handling problems. I am satisfied that the high-flow HCVs were fitted an appreciable amount of time before the accident, and I infer that such fitting was done, at least in part, as a response to those complaints. One of the particulars of negligence alleged is that levelling valves were fitted which "were unsuitable and/or not in accordance with the manufacturer's specifications". There is no evidence at all that the valves were not in accordance with the manufacturer's specifications, and to the extent that the allegation means anything other than the valves were ineffective as a solution to the problem, it is unsustainable in fact.
Questions of precisely when that fitting occurred and what effect it had are inter-related. The letter from Mr Vanderwal, tendered in the plaintiff's case, suggests that the valves were fitted at some time between the first week in August 1996 to the first week in September 1996. At the most that would be about six weeks before the accident; about two weeks at the least. The plaintiff was not challenged in his evidence that he spoke to Mr Vanderwal on 13 September 2006 about handling difficulties with the truck, although the focal point of that discussion seems to have been that it was the load measuring system causing overloading, which in turn caused the handling difficulties. Whether or not he spoke to anyone after that date is not made at all clear by the evidence.
I am not persuaded by the plaintiff's evidence that he knew nothing of the fitting of the new valves. There were two particular aspects of his evidence which cause me to approach his evidence with caution where it is challenged or contradicted. As I will discuss shortly, those aspects are his initial assertion that by taking various weights at the weighbridge at Boyer, he was able to determine the front bunk of the trailer was overloaded, and his explanation when cross-examined about the speed at which he was travelling through the corner, that the recorded speed of 72km/h was because the wheels spun off the ground as the vehicle was tipping over. This suggested to me that he may have been tailoring his evidence to match what he understood to be some of the expert evidence.
I am satisfied though, that the fitting of the high-flow HCVs referred to in the letter (whatever precise specifications they were), did not resolve the handling difficulties, and that they were still being experienced up until the day of the accident. The evidence of Mr Lambert and Dr McLean assists me to that conclusion. Additionally, there is evidence that subsequent improvements to the suspension system were carried out by the manufacturer. These included valves with an even higher flow rate, and the replacement of rigid trailing arms with flexible ones. Further still, for the reasons which follow, I am satisfied of Mr Pearton's intervention on the day of the accident. His raising of the ride height lends supports to the conclusion I have reached. Without him having been called, there is no direct evidence as to what he did, or more particularly perhaps, the reason for it. However, I think a reasonable inference to be drawn is that he adjusted the ride height of the suspension in an attempt to further improve the truck's handling.
The question of the skid mark raises Dr Prem's theory as to the behaviour of the truck in the rollover. In his first report, after analysis of a photograph of the skid mark, he concluded from various distances, that at some stage during the rollover process up until the vehicle came to rest, the pitch angle orientation of the prime mover with respect to the semi-trailer was 90 degrees, which physically lead to separation at the turntable between the two vehicle units. In his evidence he described the process of the front left steer tyre lifting off, at which stage the whole of the vehicle is well into the final stages of the rollover. He said that at that point the vehicle would roll onto its side, and slide down the road on its side but going through a rotational turn as well. "So what I am suggesting is that once the vehicle is on its side it's now rotating and sliding towards that tree … and it impacts with the tree when it's on its side." In his second report, by use of the sketch overlays, Dr Prem demonstrates that the vehicle is relatively upright at the commencement of the skid mark but totally on its side with all components of the truck in line when it has come to rest against the tree. I may be misunderstanding the thrust of his evidence, but doing my best, I am unable to reconcile these aspects of his evidence.
Finally, I note Dr Prem's ultimate conclusions set out in his second report. They are:
· rollover was highly probable for a correctly loaded log truck operating within normal load parameters and proper suspension settings travelling at the speeds recorded.
· it was physically not possible to negotiate the curve in a correctly fully loaded log truck travelling at 72km/h and stay within the designated lane, without precipitating rollover.
· it appears physically possible to negotiate the curve at 72km/h in a correctly loaded vehicle which has an SRT value greater than 0.30g using the entire road space, but this carries an extremely high risk of rollover and very little margin for error.
· the precise location in the turn at which the point of rolling stability was reached is not known, but given the vehicle's proximity to rollover, it would take very little to precipitate it.
· the driver used the entire road space (both lanes of the two lane road) to negotiate the curve and in moving from one lane to the other crossed continuous double white lines.
· the most likely cause of the crash was excessive speed.
The causes of the rollover and whether the defendant was negligent
Discussion
I fear that I have been overly long in my summary of the relevant expert evidence, but I think it was necessary in order to understand the parameters of the debate, and in deference to the arguments which were put. As a starting point for what follows, I find that speed, centre of gravity issues, and the correlation with the risk of a rollover crash were known in the logging industry in 1996. I also find that the low to very low rollover stability of log trucks was a phenomenon familiar to those who operated them in 1996. These statements are supported by Dr Prem and it is of note that respect for the laws of nature to do with forces, momentum and the centre of gravity was set out as a requirement in the defendant's "Ten Commandments" for drivers, to which I have referred. Mr Lambert said, and I accept, that of the factors influencing rollover, the most critical are the centre of mass and the weight of the load. This was particularly so with a product such as logs. At the same time, Mr Lambert accepted that a driver should allow for a proper safety margin when selecting a curve speed.
An issue which is dealt with in the TERNZ July 2005 report is that of curve speed selection. The following observations in the report cover a number of factors relevant both to the cause of the rollover, and the question of the likelihood of a risk of injury materialising:
"The standard method for determining the advisory speed is based on a scale that reflects passenger car comfort, not truck safety. For lower advisory speeds (35km/h and less) this speed can generate lateral accelerations of 0.3g or even higher. Thus, if a truck has relevantly low rollover stability … it may rollover if driven around this curve at the advisory speed. At higher advisory speeds the lateral acceleration is less, but as a general principles trucks with low rollover stability should be driven round curves at speeds well below the advisory speed to maintain an adequate margin of safety … Without an adequate margin of safety, small differences in load distribution, speed selection, line through the curve, road roughness and other factors can combine to take the vehicle from a situation where it can negotiate the curve safely to one where it rolls over. For an individual vehicle this occurs very rarely. It is not uncommon to hear of a driver saying words to the effect of 'I was going through the curve with the same load at the same speed as I always do and it just rolled over'. However, when these additional rare events are accumulated the end result is an increased rollover rate." [My emphasis]
There is a difference of opinion of course, between Mr Lambert and Dr McLean on the one part, and Dr Prem on the other, as to the basic scenario of the accident. The difference more starkly exists between Dr McLean's view of things as a "handling deviation" leading to loss of control in the collision with the tree, and Dr Prem's theory that rollover commenced at the rear of the trailer with the truck ending up on its side sliding towards the tree. Mr Lambert and Dr McLean focus on the suspension and load issues. Mr Lambert addresses speed in response to Dr Prem's opinion but in the context of considering the way in which the corner may have been negotiated by the plaintiff. On the other hand, Dr Prem focuses on the aspect of speed but does so on the assumption of a correctly loaded vehicle, and pays no regard to the suggestion of overloading on the front bunk. It may not be strictly necessary to determine the precise behaviour of the truck, save to the extent that the part of the vehicle from which the rollover is said to have initiated, is relevant to the competing theories.
The issue is whether or not the rollover commenced from the rear of the trailer. I found Dr McLean's analysis of the vehicle data, and his spontaneous rejection of Dr Prem's hypothesis with which he was not familiar, to be persuasive. I have already said that I am not able to gain much assistance from the photographs of the skid mark, nor from Mr Lambert's and Dr Prem's interpretation of them. The point that causes me difficulty with Dr Prem's theory in this respect is the nature of the damage to the Armco railing. I also find Dr McLean's view as to this to be persuasive. If the truck were on, or falling onto its side and veering off the roadway towards the tree, one would expect the railing to be pushed the other way, and indeed, some distance away from where it was. As things are shown in the photographs, most of the railing has been pushed forward and rotated anti-clockwise, as viewed from the direction in which the truck was travelling. There is some ostensible conflict between Dr Mclean's view, and the evidence of the plaintiff as to the position of the prime mover at impact, but the two are not irreconcilable. I accept the evidence of Mr Lambert and Dr Mclean that the initiation of the accident was from the drive axles.
The plaintiff's unchallenged evidence was that he was negotiating the curve at about the same speed and on the same line as he had done on many occasions in the past. In the nine or ten years at the frequency with which he negotiated the Plenty bends, quite a few thousand trips around this corner were involved. In this particular truck, loaded with logs, he would have driven around the bends several hundred times. There is no evidence that any incident occurred other than this one. In those many hundreds of trips, no doubt precisely the same speed, precisely the same load, and precisely the same line were not involved. That increases the probability that something quite untoward was operating on the night of the accident.
Having regard to my basic findings of fact as previously set out, and taking into account the further expert evidence, it is more likely than not that a combination of a number of factors operated to cause the accident. I am unable to say that any one factor on its own was the sole cause. Those factors, which I will examine in turn, are:
· the inherent nature of the suspension system;
· the adjustment of that system by the raising of the ride height on the day of the accident;
· a higher centre of gravity, and hence a lower SRT than might reasonably have been expected, due to disproportionate loading as between the front bunk and the rear bunk, causing excessive loading on the drive axles;
· the plaintiff's speed of driving.
The suspension factors
The first two factors can be dealt with together. The starting point is the air suspension itself. It is clear that even with high flow HCVs, the nature of the system's operation results in instability when negotiating a series of left and right bends. In general travel, the vehicle leans to the left due to road camber, the consequent force operating to rotate the chassis frame in a clockwise direction, (when looking at it from the rear). In this series of bends, there is a slight left, followed by a sharp right, with the successive bends being left, right, left and left. As I have determined, it has not been shown that a reasonable employer in late 1995 ought to have known of the inherent design problems with the suspension. Whether or not the new valves which were fitted were the "high flow" ones referred to in the 2000 specifications, is not capable of being determined. But the evidence satisfies me that even with some form of high flow valves then available, the time delay of operation is such that counterproductive forces would have operated in this scenario. However, this needs to be considered in light of the adjustments to the ride height, to which I will now turn.
First, what I am satisfied of is that the increase in the ride height caused a corresponding increase in the height of the load on the front bunk above the drive axles. That exacerbated any high centre of gravity issue caused by the loading system. Second, the plaintiff's evidence is a little unclear but at the least, as I have found, on the night of the accident the prime mover did not have the veering or wandering characteristic. It was more rigid and did not require the steering input. I have found that the alteration in the ride height led to a greater degree of instability and that the adjustment of the ride height caused a lack of feedback to the plaintiff, to the extent that he was not able to readily discern the effect on the truck's handling, of any disproportionate load on the front bunk.
Thus, the elevation of the ride height of the suspension by Mr Pearton contributed to the increase in the centre of gravity of the load in question, and, looking at it objectively, resulted in a false sense of security. It operated as a disguise, in the sense that the plaintiff was not able to utilise the usual feedback which may well have alerted him to risk factors associated with the load. The alteration was carried out without the plaintiff's knowledge, and without any warning to him before he drove the truck on the night. It was done in the background of handling and stability problems known to Mr Pearton and apparently complained of by him to the defendant's management. In my judgment, in the circumstances the conduct was foolhardy. To make, without warning, such a change to the suspension of the vehicle leading to completely different handling, and to an elevation of the load height at the drive axles, was to create a risk of foreseeable injury. That is, it was foreseeable that such changes may cause an accident of some description, whilst the plaintiff was driving. It follows that Mr Pearton failed to exercise reasonable care in relation to foreseeable injury to the plaintiff. As argued by the plaintiff, the defendant is vicariously liable for Mr Pearton's actions.
Uneven loading
This particular truck, correctly loaded and assuming an average load height of 2.1 metres, was estimated to have an SRT of 0.309, a figure at the upper end of the range for it, but still to be regarded as low. As is apparent, there seemed to be no disagreement with Dr Prem's assessment that the truck's SRT would ordinarily have been in the range of 0.273g to 0.309g. That proposition assumes a correctly loaded truck in the sense of a distribution of the weight of the load proportionate to the maximum legal axle loads. I am satisfied on the evidence, that even though I have not been able to find that the load was greater than 26.2 tonnes, a disproportionate amount of that load was borne on the front bunk. Using the figures which I have previously set out, this extra loading was somewhere in the order of two to four tonnes. This caused excessive load on the drive axles and created an overall higher centre of gravity of the load. In summary, the evidence supporting those conclusions is:
· the evidence of the plaintiff, Mr Gill and Mr Brazendale as to the general operation of the particular load weighing system and the uncertainty of the end result with any particular load;
· the evidence of the plaintiff as to the loading process as to the particular load, and the appearance of the front bunk having too much on it, even though the gauge at that stage read some 10kpa less than the nominated reading, with more logs put on the bunk even after that;
· Mr Lambert's evidence that to get to the correct load, (legal axle loads plus tolerances), a pressure of 55kpa in relation to the front bunk load was the correct figure, and not 60kpa;
· the plaintiff's evidence of his general observations of overloading on the front bunk, leading to his complaints that the veering problem stemmed from that;
· what is evident from the series of photographs of the plaintiff's loaded truck prior to the accident. (Although there are some difficulties with Mr Lambert's analysis which I have pointed out, a simple inspection of these photographs bears out the thrust of all of his evidence as to this aspect. The amount of load in the front bunks can be measured against the height of the bolsters which are of consistent height along the length of the trailer. This evidence is also supported by Dr McLean's spontaneous evidence after inspecting the photographs in the trial);
· Mr Lambert's evidence and calculations as to the range of possible overloading on this truck, arising from the use of the load measuring system.
It should be borne in mind that the trailer above the drive axles is 10 centimetres higher than its rear point. It should also be borne in mind that all of Dr Prem's modelling assumed a correctly loaded truck, implicit in which is a distribution of the load, proportionate with the maximum legal axle loads. Dr Prem also assumed that the centre of gravity of the total load was in the centre of a rectangular prism. A centre of gravity of the entire load is really the product of a combination of the centres of gravity of the loads on the front and rear bunks. An increase in the height of the centre of gravity of the front bunk leads to an increase in the overall centre of gravity. The overturning moment as described by Mr Lambert becomes significantly higher. This illustrated by Dr Prem's figure of 0.273g for a front bunk load height of 2.4 metres, as distinct from 0.309g at 2.1 metres. As Dr McLean pointed out, an increase in the height over the drive axles is an "adverse" situation. For those reasons I am satisfied that the front bunk was overloaded in the sense of that load being disproportionate to the load, and that this factor contributed to the accident.
The loading system on the plaintiff's truck was likely to lead to overloading on the front bunk, causing a higher centre of gravity than would otherwise be reasonably achievable. The risk of a rollover crash was therefore materially heightened. The magnitude of the risk in terms of its consequences was high, and the degree of probability of such an occurrence was also high, given the small margins for safe operations. The plaintiff's truck was the only one in the fleet equipped with the particular device. All others were fitted with the Lodec system. The defendant's reason, at least as given to the plaintiff, was that with the lighter tare weight of the truck, load carrying capacity would be adversely affected. No evidence was given on behalf of the defendant as to why the Lodec system could not reasonably have been fitted to the plaintiff's truck; McLean v Tedman (1984) 155 CLR 306 at 314. The defendant had in place the particular load weighing system which included the instruction as to its use, to load the front bunk until the reading was 60kpa. In my view, by so doing, the defendant failed to exercise reasonable care not to expose the plaintiff to a risk of foreseeable injury. It was in breach of its duty.
The plaintiff's speed
Just as with load, in bare theoretical terms speed will always be a factor in a rollover crash scenario. To state the obvious, a loaded stationary truck will not roll over. The question is whether it was excessive speed which caused or contributed to the accident. I approach this question on the basis that the plaintiff was travelling in the vicinity of 70 to 72km/h. I am satisfied on the evidence that leading up to the accident, the plaintiff was taking the line through the corner which he normally took and which he described in his evidence. His evidence as to this was not challenged and was consistent with the observations of Mr McGregor. It was also consistent with what Dr McLean described of his trips with coal truck drivers and it is supported by Mr Lambert's calculations which show that as a matter of physics, it is possible to negotiate bend 6 in the manner alleged at the relevant speed.
To accept Dr Prem's evidence that as the plaintiff went around the corner, he approached it from a point holding on his incorrect side of the roadway, is to reject the plaintiff's unchallenged evidence, supported as it is. It also means accepting that invariably, a correctly loaded truck would never make it around the corner at 72km/h if it were wholly within its proper lane.
It is neither possible nor necessary to settle on a speed at which the truck on this particular occasion could have safely negotiated the corner. But having said that, I am satisfied that in the circumstances which prevailed, the speed of 70 to 72km/h was excessive and that this excessive speed contributed to the accident. By prevailing circumstances I mean to refer to:
· the plaintiff having been alerted to a potential risk in terms of the centre of gravity of the truck created by an unusual loading issue, and one perhaps even more unusual than previously encountered;
· the fact that without warning to him, the truck suddenly began to sit up more solidly, not roll about as much, and had lost its veering and wandering characteristics;
· the proposition that generally, a speed of 70 to 72km/h with a fully loaded log truck leaves little margin of safety.
The defendant's argument as to liability is that the sole cause of the rollover crash was the plaintiff's excessive speed. No response was made to that part of the plaintiff's case which was based on the assertion that his speed immediately before the crash, was the responsibility of the defendant by failing to train or instruct him having regard to the truck's actual or potential characteristics.
It is convenient to repeat the particular of negligence alleged. It is said that the defendant:
"Failed to train the plaintiff in driving the truck, in particular that by reason of the suspension system and/or overloading and/or unevenly distributed load he should enter corners cautiously at a reduced speed and that the truck may become destabilised after successive corners."
The unchallenged evidence is that the plaintiff, at an unidentified time before the accident, travelled through the Plenty bends with Mr Cox, the assistant transport manager. When loaded, he travelled through the Plenty bends at his usual speed. Mr Cox was sitting in a position where he could observe the speedometer. Mr Cox said nothing about his speed or manner of driving. The defendant was at all times in a position to check the plaintiff's speed and manner of driving, correlated to particular stretches of roadway, by reference to the daily Tripmaster data.
I have already noted the defendant's actual awareness of "the laws of nature to do with forces, momentum, and the centre of gravity". The plaintiff, and it would appear Mr Pearton, complained to the defendant about the truck's handling. The plaintiff blamed the handling difficulties on overloading caused by the loading system adopted. The employer's responsibility is not confined to unexpected and unusual dangers. In appropriate cases it extends to dangers which are obvious. In my view this was not a simple and obvious matter; see Raimondo v State of South Australia (1979) 23 ALR 513 per Mason J at 517. The defendant was aware of handling problems with the truck, at least until shortly before the accident. Some action had been taken, but Mr Pearton's intervention on the day, suggests the problems were continuing. The plaintiff had attributed the handling problems to overloading on the drive axles. The defendant had actual or constructive knowledge of centre of gravity issues correlated with high rollover risk. I have previously noted its attitude to the load measuring system. I think a reasonable employer would have taken steps to obviate or minimise the risk of injury caused by a driver travelling at an excessive speed in all of those circumstances. There is nothing to suggest that such training instruction was unduly onerous or impracticable for any reason. For those reasons, I find the defendant failed to take reasonable care, and was in breach of its duty in this respect also.
Causation
The plaintiff needs to establish that any one of the breaches of duty which I have identified, was a cause of, or materially contributed to his injury in the sense of being a contributing factor: March v E & MH Stramare Pty Ltd (1999) 171 CLR 506 at 514; Bennett v Minister of Community Welfare (1992) 176 CLR 408 at 420; Romeo v Conservation Commission (NT) (1988) 192 CLR 431 at 482 and Shorey v PT Ltd (2003) 77 ALJR 1104 at [41]. A contributing factor is material unless it is negligible: Bendix Mintex Pty Ltd v Barnes (1997) 42 NSWLR 307 at 345 and Western Australia v Watson [1990] WAR 248 at 286.
I have found that the defendant was in breach of its duty by failing to have in place a load measuring system which did not create a risk of injury by causing overloading on the front bunk, and in respect of the act of Mr Pearton in raising the suspension ride height. For the reasons which I have earlier given, I am positively satisfied that these breaches made material contributions to the plaintiff's injury. The only question that arises for discussion in this context is the breach of duty in relation to the failure to provide proper training. The plaintiff needs to establish that such training would have been effective; that is, he would have driven more cautiously and at a reduced speed. In cases involving an employer's duty to a worker, and at least where the issue is the failure to provide a particular piece of equipment or device, the determination of what the worker would have done, based on an assessment of the behaviour of a reasonable worker; McWilliams v Sir William Arrol & Co Ltd [1962] 3 All ER 623 per Lord Reid at 632 and Walfertan Processors Pty Ltd v Dever [2006] NSWCA 289 at [35] – [38].
In the general law of negligence, where questions arise as to the effectiveness of warnings (by sign or advice) the test is a subjective one The inquiry is what a particular plaintiff would have done; Chappel v Hart (1998) 195 CLR 232 at [32], [93]; Rosenberg v Percival (2001) 205 CLR 434 at [24]. In Fox v Leighton Contractors Pty Ltd [2008] NSWCA 23, this subjective test seems to have been adopted in the context of a duty of care alleged to be owed to an employee of an independent contractor; see per Basten JA at [57]. (Giles and McColl JJA agreed. The subsequent appeal to the High Court did not involve this point). In this type of case I would tend to the subjective test, but particularly as it was not argued, I need not decide the point. The end result would be the same. (I note that statute now mandates a subjective test, with evidence from the relevant person as to what they would have done, made inadmissible: Civil Liability Act 2001, s13(3).)
In this case there is no direct evidence, and in the absence of such evidence it is a question of whether I am prepared to draw the inference; RTA v Dederer (2007) 234 CLR 330 per Gummow J at [40], State of Victoria v Subramanian (2008) 19 VR 335 at [57], and Fox v Leighton Contractors Pty Ltd (above) per Basten JA at [58]. Even where there is direct evidence, it is still a matter for the determination of the Court, having regard to the hypothetical nature of the exercise, the dangers of retrospective reasoning, and the use of hindsight: Rosenberg v Percival (2001) 205 CLR 434 per Kirby J at [158], per Callinan J at [214]; Hoyts Pty Ltd v Burns (2003) 201 ALR 470 at [64] Ellis v Wallsend District Hospitals (1989) 17 NSWLR 553 at 560, 581.
The plaintiff said that he had no difficulties with the "Ten Commandments" document and that he was "fine" with it. Precisely what all that meant was not explained. Although oddly enough, the DECA assessment did not contain any adverse comment as to the speed at which the plaintiff negotiated corners, generally it shows a competent driver alert to his responsibilities. From the whole of the evidence, I infer that the plaintiff was fond of his job and took his responsibilities seriously. On several occasions he brought to the attention of management, problems he had with the truck's handling and said what he thought to be the reasons. He obviously felt strongly enough about this to speak directly to Mr Vanderwal on one occasion, notwithstanding a company directive not to raise operational problems with company directors. Although the evidence is meagre as to this point, I am prepared to infer that on the balance of probabilities, had the plaintiff been trained, and warned against excessive speed having regard to actual or potential handling problems with the truck, he would have complied and driven more cautiously. Consequently, speed would not have been a material contributing factor in the accident.
Contributory negligence
Of the nine particulars of contributory negligence alleged, those ultimately pursued related to the failure of the plaintiff to have his load adjusted before he set off on the journey, and his excessive speed through the corner. It is said that he failed to properly check his load and require that it be correct before he left on the journey, and that he failed to drive within the "limitations of his vehicle". The use of those words is linked to the plaintiff's own evidence that he knew to drive within such limitations provided by the feedback from the vehicle.
In my view, the practice of driving at the speeds at which the plaintiff customarily did in excess of the speed advisory sign, was one fraught with danger. The evidence makes it clear, as I have previously mentioned, that the margins of safety, particularly with loaded log trucks, are slim. In this respect I refer to Mr Brazendale's evidence who, when he took over the plaintiff's truck after the accident, drove through the corners at some 10km/h or so less than the plaintiff regularly did. He was not asked about why he did this, nor did he offer any reason. There appears to have been no reason why the plaintiff could not have adopted this practice. On his own admission he was under no time pressures.
In Astley v Austrust Ltd (1999) 197 CLR 1 at [30] Gleeson, McHugh, Gummow and Hayne JJ said (omitting references):
"A finding of contributory negligence turns on a factual investigation of whether the plaintiff contributed to his or her own loss by failing to take reasonable care of his or her person or property. What is reasonable care depends on the circumstances of the case. In many cases, it may be proper for a plaintiff to rely on the defendant to perform its duty. But there is no absolute rule. The duties and responsibilities of the defendant are a variable factor in determining whether contributory negligence exists and, if so, to what degree. In some cases, the nature of the duty owed may exculpate the plaintiff from a claim of contributory negligence; in other cases the nature of that duty may reduce the plaintiff's share of responsibility for the damage suffered; and in yet other cases the nature of the duty may not prevent a finding that the plaintiff failed to take reasonable care for the safety of his or her person or property. Contributory negligence focuses on the conduct of the plaintiff. The duty owed by the defendant, although relevant, is one only of the many factors that must be weighed in determining whether the plaintiff has so conducted itself that it failed to take reasonable care for the safety of its person or property."
In this case, the plaintiff was aware that there was something particularly unusual about the load. Mr Gill had stopped loading the front bunk when the gauge read 50kpa, saying that it was too much. More logs were put on after that. The truck in question had a history of handling problems of various descriptions. I have found that some of these were alleviated to some extent, but were not totally resolved. On the night of the accident, the truck was behaving in a foreign manner. I need not detail that evidence again. This handling behaviour was a matter which ought to have put the plaintiff on notice that care may be required, even though the change was seemingly for the better. On his own evidence, the plaintiff noticed that the gap between the drive wheels and the mudguard was excessive to what was normal.
All of this notwithstanding, the plaintiff did nothing to lessen, or even out the load, as it was within his power to do. He did not moderate the way in which he usually drove the truck through the bends. It is true that he had already negotiated the bends once that night with the same handling challenges apparent, but it was after that first load that he noticed the change in mudguard height, and of course, there is the question of the second load itself. This was not an instance of the plaintiff merely "performing his duties according to his habitual and long-standing practice"; Davies v Adelaide Chemical & Fertilizer Co Ltd (1946) 74 CLR 541 at 551 – 552. Nor do I think that driving into and around the bend at his usual speed in the prevailing circumstances, was something done out of a "misguided, but understandable, endeavour on the part of the worker to fulfil his … employment duties in a reasonable way"; Liftronic Pty Ltd v Unver (2001) 75 ALJR 867 per Kirby J at [89].
In my view the plaintiff failed to take reasonable care for his own safety. The exercise is to assess the degree of departure from the standard of care of the reasonable person and of the relative importance of the acts of the parties in causing the damage. It is the whole conduct of each party in relation to the circumstances of the accident which must be subjected to comparative examination; Podrebersek v Australian Irons and Steel Pty Ltd (1985) 59 ALJR 492 at 494.
Of significance in this exercise is that the defendant provided the plaintiff with a truck fitted with a load measuring system which effectively involved "guesswork". At the same time, it provided erroneous advice as to the pressure which would represent the appropriate load on the drive axles, and instructed him to attempt to achieve the maximum legal load with tolerances. Of particular significance is that I have found that the plaintiff's speed was at least, contributed to by the defendant's negligence in failing to instruct or warn him against that practice in particular circumstances. Those circumstances existed in relation to the load on the night. In my view, it is just as between the parties, that the plaintiff bear responsibility for his injuries to the extent of 20 per cent.
Order
There will be judgment for the plaintiff against the defendant for the agreed amount of damages, subject to a reduction of 20 per cent for the plaintiff's contributory negligence.
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