Supreme Court New South Wales

• Medium Neutral Citation: Curtis v Harden Shire Council [2012] NSWSC 757
• Hearing dates: 13 - 17/02/2012
• Decision date: 09 July 2012
• Before: Fullerton J

Decision

Verdict for the defendant

• Catchwords: NEGLIGENCE - road resurfacing works - driver fatality - whether Council failed to provide adequate signage - duty to exercise reasonable care - breach of duty of care - Traffic Control Plan - statutory defence under s 43A Civil Liability Act - special statutory power of a public authority - Wednesbury unreasonableness - traffic control facility - "but for" test - causation
• Legislation Cited: Civil Liability Act 2002; Roads Act 1993; Road Transport (Safety and Traffic Management) Act 1999; Road Transport (Safety and Traffic Management) (Road Rules) Regulation 1999; Transport Administration Act 1988; Uniform Civil Procedure Rules
• Cases Cited: Adeels Palace Pty Ltd v Moubarak; Adeels Palace Pty Ltd v Bou Najem [2009] HCA 48; 239 CLR 420; Allianz Australia Insurance Ltd v Roads and Traffic Authority of New South Wales; Kelly v Roads and Traffic Authority of New South Wales [2010] NSWCA 328; Associated Provincial Picture Houses Ltd v Wednesbury Corp (Wednesbury case) [1948] 1 KB 223; Brodie v Singleton Shire Council; Ghantous v Hawkesbury Shire Council [2001] HCA 29; 206 CLR 512; Bromley London Borough Council v Greater London Council (1983) 1 AC 768 at 721; Commonwealth v Pharmacy Guild of Australia (1989) 91 ALR 65; Council of Civil Service Unions v Minister for the Civil Service (1985) AC 374 at 410; Curtis v Harden Shire Council [2012] NSWSC 84; Firth v Latham [2007] NSWCA 40; Flounders v Millar [2007] NSWCA 238; Jones v Dunkel (1959) 101 CLR 298; Lukacevic v Coates Hire Operations Pty Ltd [2011] NSWCA 112; Minister for Immigration and Multicultural Affairs v Eshetu [1999] HCA 21; 197 CLR 611; Nguyen v Cosmopolitan Homes (NSW) Pty Ltd [2008] NSWCA 246; State for Education and Science v Tameside Municipal Borough Council (1977) AC 1014; Sydney South West Area Health Service v Stamoulis [2009] NSWCA 153
• Category: Principal judgment
• Parties: John Curtis (Plaintiff); Danielle Paterson (2nd Plaintiff); Harden Shire Council (Defendant)
• Representation: Counsel: H Marshall SC / R Taylor (Plaintiffs); R Sheldon SC (Defendant); Solicitors: McCabe Partners (Plaintiffs); DLA Piper Australia (Defendant)
• File Number(s): 2007/293512; 2007/293513

Judgment

1 HER HONOUR: Just before midday on 20 August 2004 Ms Debbie Anne Paterson was driving her Commodore sedan in a southerly direction on Kingsvale Road at Kingsvale when she lost control of her vehicle and struck a tree. She suffered head injuries from which she later died.

2 Kingsvale Road is a rural highway running generally in a north/south direction between Harden to the south and Young to the north. It has a designated speed limit of 100 km/h. It was common ground that Ms Paterson was travelling at, or perhaps slightly under the speed limit for at least some distance prior to the point of impact. Neither the condition of the vehicle nor the weather had any relevant bearing on the cause of the accident. It was also common ground that Ms Paterson was a careful and experienced driver who was familiar with the road. There were no witnesses to the accident or to any part of the driving sequence that preceded it.

3 The accident occurred on a stretch of Kingsvale Road where the previous day the defendant Council had completed laying bituminous material as part of its road maintenance works program in five discontinuous sections of differing lengths over a distance of about 500 metres. That process involved spraying the bituminous material onto the prepared road surface which was then dressed with loose blue metal gravel (or aggregate). It is an expected incident of that method of resurfacing that an excess of gravel will remain on the road surface while it is progressively embedded in the new surface by passing traffic and before it is swept in the final phase of the resurfacing process.

4 Unworked sections of road under repair, also of differing lengths, separated the resurfaced and surface dressed sections. The point of impact was 210 metres from the commencement of the roadworks at a point adjacent to the start of the third resurfaced section.

5 The roadworks were governed by a Traffic Control Plan ("TCP") which had been adapted by the Works Manager employed by the Council from a generic plan (TCP 56) in the applicable Roads and Traffic Authority's Traffic Control at Worksites Manual ("the Manual"). It was common ground that the Traffic Control Plan (as adapted) was designed to address the risks associated with or likely to arise from the roadworks at Kingsvale Road, including the risks to road users presented by the presence of loose gravel on the road surface. There was no provision made on the adapted TCP for any signage advising of the fact that the road had been resurfaced or imposing any reduction in speed in those circumstances, or any pictorial signage warning specifically of the risk of slippage (or loss of traction) due to the presence of the loose gravel. A sign advising of the presence of (unspecified) roadworks was erected approximately one kilometre in advance of the first section of resurfaced roadway. In addition, within 60 metres of the commencement of the first resealed section and at various intervals thereafter, signage was placed which advised that there were no centre lines marked and that vehicles should not overtake, and pictorial signs indicating the potential for windscreen damage from the presence of stones or gravel. These signs were identified in the evidence as "Chip Hazard" signs.

6 Ms Paterson's surviving partner and children bring proceedings against the Council in negligence. Liability is to be determined as a separate question.

7 It was no part of the plaintiffs' case at trial that the Council breached its duty of care to Ms Paterson by leaving an excess of gravel on the road prior to the sweeping scheduled for the afternoon on the day of the accident, or that an excess of gravel contributed to the accident in any material way. Rather, the plaintiffs' case is that the Council breached its duty to exercise reasonable care to avoid the risk of foreseeable injury to users of Kingsvale Road due to the changed condition of the road surface at the site of the roadworks, by failing to provide for and erect signage warning of the fact that the road had been recently resurfaced and specifically of the risk of slippage (or loss of traction) due to the presence of loose gravel on the road surface, and signage limiting or reducing speed from the signposted speed of 100 km/h in those circumstances (see Brodie v Singleton Shire Council; Ghantous v Hawkesbury Shire Council [2001] HCA 29; 206 CLR 512). Although the particulars of negligence also included what was said to be the Council's failure to inspect the construction and repair of the roadworks in order to ensure that they were left in a state where there was no risk to road users, at the hearing it was the failure to provide adequate signage during the inspection phase that was relied upon as constituting the breach of duty. In essence, it was the plaintiffs' case that the failure to provide adequate signage constituted a breach of the Council's duty of care and it was this breach that caused Ms Paterson to lose control of her vehicle.

8 The provisions relevant to breach of duty and causation are found in Part 1A of the Civil Liability Act 2002:

Division 2 Duty of care

5B General principles

(1) A person is not negligent in failing to take precautions against a risk of harm unless:

(a) the risk was foreseeable (that is, it is a risk of which the person knew or ought to have known), and

(b) the risk was not insignificant, and

(c) in the circumstances, a reasonable person in the person's position would have taken those precautions.

(2) In determining whether a reasonable person would have taken precautions against a risk of harm, the court is to consider the following (amongst other relevant things):

(a) the probability that the harm would occur if care were not taken,

(b) the likely seriousness of the harm,

(c) the burden of taking precautions to avoid the risk of harm,

(d) the social utility of the activity that creates the risk of harm.

...

Division 3 Causation

5D General principles

(1) A determination that negligence caused particular harm comprises the following elements:

(a) that the negligence was a necessary condition of the occurrence of the harm (factual causation), and

(b) that it is appropriate for the scope of the negligent person's liability to extend to the harm so caused (scope of liability).

(2) In determining in an exceptional case, in accordance with established principles, whether negligence that cannot be established as a necessary condition of the occurrence of harm should be accepted as establishing factual causation, the court is to consider (amongst other relevant things) whether or not and why responsibility for the harm should be imposed on the negligent party.

...

9 The Council accepted that it owed Ms Paterson a duty to exercise reasonable care by taking reasonable steps to prevent the risk of a foreseeable risk of harm created by the road maintenance works on Kingsvale Road and their state of repair at the time of the accident. The Council also accepted that in discharge of that duty they were obliged to design and implement a TCP which provided for signage both in advance of the commencement of the roadworks, and at appropriate intervals over the course of the roadworks, warning of the presence of loose gravel and associated changes to the road surface, and to take reasonable care in the choice and placement of signs to address the foreseeable risk of harm to road users created by the state of the road under repair. The Council submitted that the signage which had been provided for in the TCP, and which it had in place at the time of the accident following a final inspection at 8.30 the evening before, was sufficient to discharge its duty to take reasonable care so that Ms Paterson, as a road user, was not exposed to an unnecessary risk of injury. The Council further submitted that it was not obliged to erect signage warning of the specific risk of slippage or signage directing or advising of the need to reduce speed from the designated speed limit. The Council's ultimate position on the issue of breach was that a reasonable person, charged with the responsibility of deciding whether or not to erect additional signage (both in the design of the TCP and its implementation up to and including the final inspection), would not have done more than what the Council did in the circumstances.

10 Even if breach of duty were proved, the Council submitted that the plaintiffs had not proved that the failure to erect additional signage played a factually causative role in Ms Paterson's death as they had not established, as required by s 5D(1) of the Civil Liability Act, that breach was a necessary condition of the accident from which she died. The necessary condition test in s 5D(1), which is a statutory statement of the "but for" test for causation developed at common law (see Adeels Palace Pty Ltd v Moubarak; Adeels Palace Pty Ltd v Bou Najem [2009] HCA 48; 239 CLR 420), imposed on the plaintiffs the onus of establishing that it was more probable that not that "but for" the failure to place a speed limitation sign together with a pictorial "Slippery Road" sign on approach to the commencement of the roadworks, the accident would not have happened.

11 It was accepted that if the plaintiffs proved factual causation the scope of the Council's duty extended to the harm Ms Paterson suffered. No submissions were directed to whether, if factual causation could not be established on a "but for" analysis, s 5D(2) might otherwise permit a finding of causation.

12 Even if the plaintiffs established breach of duty and a casual connection between that breach and the accident that resulted in Ms Paterson's death, the Council submitted that because it is a statutory authority under the Roads Act 1993, exercising a special statutory power (as defined), s 43A of the Civil Liability Act operated to relieve it of liability unless, viewed objectively, no statutory authority having that statutory power could have properly considered it was necessary to provide the additional signage.

13 The Council also relied upon s 44 of the Civil Liability Act. It submitted that since the plaintiffs did not put their case on the basis that there was an excess of gravel on the road (and assuming there was no obligation for it to erect pictorial "Slippery Road" warning signs), the failure to erect signage directing a reduction in the applicable speed limit was the only activity that might be prohibited or regulated as envisaged by s 44 and, since the plaintiffs could not have compelled the Council to lower the speed limit, s 44 of the Act also operated to relieve it of liability.

14 In Allianz Australia Insurance Ltd v Roads and Traffic Authority of New South Wales; Kelly v Roads and Traffic Authority of New South Wales [2010] NSWCA 328 at [39] Giles JA noted that Hoeben J, as the primary judge, approached the operation of s 43A and s 44 on the basis that neither section had any application unless breach of duty has been proved. Although Giles JA did not regard it as necessary to consider whether that approach was mandated by the language of the sections (or either of them) he did not suggest the approach was wrong. Since there was no argument directed to that question before me, I propose to follow Hoeben J's approach. Accordingly, I turn now to consider whether the plaintiffs have proved that the Council were in breach of its duty of care.

Additional facts bearing on the issue of breach - the Traffic Control Plan designed by the Council

15 Mr Stephenson, the Works Manager employed by the Council, was responsible for designing and implementing a Traffic Control Plan appropriate to the resurfacing operation at Kingsvale Road. The generic Traffic Control Plan (TCP 56) specified in the Manual for use for "long-term work on a two lane road where the speed limit is 60 km/h or less" was adapted for that purpose.

16 The generic form of TCP 56 is specified in the accompanying notes in the Manual as:

...most applicable to bituminous surfacing and similar works on lightly trafficked roads. Use TCP 353 where speed limit exceeds 60 km/h and ADT [traffic volume] exceeds 5000 vehicles. (emphasis added)

17 Although the speed limit exceeded 60 km/h, Kingsvale Road is a lightly trafficked rural highway where the traffic volume is well short of 5000 vehicles per day. (The evidence was on average between 300 and 400 vehicles per day used the road.) TCP 56 in its generic form provides for a range of pictorial and directive signage, including signs signalling the presence of loose gravel (an incident of the process of resurfacing), and also including a "Gravel Road" sign, a "Rough Surface" sign and two pictorial signs, a "Chip Hazard" sign and a "Slippery Road" sign. Unlike TCP 353, TCP 56 does not provide for speed reduction signs since, as the accompanying notes make clear, it is designed for use where the applicable speed limit is already 60 km/h or less.

18 TCP 353 is also a generic TCP for use in long-term work on a two lane roadway. The accompanying notes provide for its use where the speed limit exceeds 80 km/h (as was the case here) but where traffic volume exceeds 5000 vehicles per day (which was not the case here). It provides for the same two pictorial signs signalling the presence of loose gravel as does TCP 56 but it also provides for speed reduction signs to 60 km/h.

19 There is no generic TCP for use during bituminous resurfacing and similar works on lightly trafficked roads but where the applicable speed exceeds 80km/h. It was common ground that this necessitated that TCP 56 be modified to reflect the road conditions at Kingsvale Road. Modification of generic or standard form TCPs is expressly provided for in Section 4.4 of the Manual.

20 Mr Coffey, a former employee of the Council who held the position of Director of Technical Services at the time of the accident, and the person to whom Mr Stephenson reported, gave evidence in the plaintiffs' case. He agreed that Mr Stephenson was certified by the RTA to undertake the task of preparing a TCP for the proposed roadworks at Kingsvale Road, and to use his judgment as to the appropriate TCP to be used and the extent to which it should be modified, including which of the various directive or pictorial signs should be used. Although he did not review the form of TCP 56 which had been modified by Mr Stephenson before it was implemented, he did undertake an investigation of its suitability at the direction of the Council after Ms Paterson's accident.

21 In Mr Coffey's view, Mr Stephenson's modifications were seriously deficient in two critical respects. The pictorial "Slippery Road" sign (marked T3-3 on TCP 56), which shows a car sideslipping in an uncontrolled movement, was deleted leaving a "Chip Hazard" sign (marked T3-9), which shows stones thrown up from the wheels of one car damaging the windscreen of another car, as the only pictorial warning of the presence of loose gravel. Although the signs reading "Gravel Road" and "Rough Surface" were also deleted, this was not the subject of any criticism. A "New Work No Lines Marked" sign (marked T3-11) and a "Roadwork Ahead" sign (marked T1-1) were provided for about which there was no controversy.

22 Mr Coffey gave evidence that the use of the "Slippery Road" sign was a standard sign used during road resurfacing operations, and that a speed reduction sign should also have been included even though no express provision is made for it in TCP 56 because the designated speed limit at Kingsvale Road was 100 km/h.

23 As part of his investigation into the accident, Mr Stephenson was formally asked by Mr Coffey to provide a written explanation as to why the "Slippery Road" sign was deleted from TCP 53 and, if the road signs were checked at the completion of the sealing process, whether the absence of a "Slippery Road" sign was noted and why no action taken to remedy it. The first part of that question remained unanswered despite Mr Coffey's follow-up enquiries of Mr Stephenson. With regard to checking the site at the completion of the process of resurfacing and after dressing the road surface, Mr Stephenson informed Mr Coffey that he considered the site to be safe when he checked it at 8.30 the evening before the accident. He did not provide any further explanation or justification for the absence of a "Slippery Road" sign in coming to that view. He was not asked by Mr Coffey to explain or justify the failure to have a speed reduction or speed limit sign positioned.

24 Under cross-examination Mr Coffey agreed that he left the selection of the TCP and the need for any modifications to its generic form to Mr Stephenson's judgment. He also agreed that Note 4 to TCP 56 provides expressly for the use of one or more of the available signs (including a T3-3 - the "Slippery Road" sign and a T3-9 - the "Chip Hazard" sign), "as appropriate". His attention was drawn to Note 9 to the TCP which is in the following terms:

For bituminous surfacing work T3-3 and T3-9 are to remain in place until loose aggregate is removed.

25 He was invited to concede in cross-examination that the requirement in Note 9 that both signs are to remain in place until the road is swept, was subject to the officer responsible for designing or adapting TCP 56 for specific use in the particular roadworks (Mr Stephenson in this case) determining that both signs should be included as distinct from one or the other sign being sufficient. He gave the following evidence:

Q. ... accepting that note 4 does not require the slippery sign, T33, to be mandatorily used, in the event that in the judgment of the operator, T33 is used, it should remain in place until the loose aggregate is removed?

A. That's right, your Honour. Could I clarify?

Q. Yes?

A. Mr Stephenson, who designed this traffic control plan, had done the appropriate training for what sort of traffic control plan is required, depending on the particular work site that it was for. Part of that training would have involved him being aware that the sign T33 has to be in place for bitumen resealing works. It is one of the most important signs there.

Q. Because of the nature of the surface produced?

A. Yes, because of the nature of the work undertaken.

26 Mr Coffey went on to say that because aggregate is spread on the road surface as an integral part of a road resurfacing operation, the "Slippery Road" sign is essential to warn of the risk of a loss of traction, irrespective of a driver being alerted to the presence of roadworks that suggested resurfacing because of the sign advising that there were no centre lane markings. He said the "Slippery Road" sign is designed to alert a driver to a reduction in traction where a driver would otherwise be entitled to expect good traction on a sealed road. He likened the unswept and dressed road surface to "walking on marbles".

27 Mr Coffey said a reduced speed sign is designed to give the motorist the perception that "something is happening ahead", in the sense that they are likely to encounter something different from an ordinary driving environment, and for the need "to reduce speed, to be aware". Mr Coffey was not asked whether in designing the TCP for the roadworks at Kingsvale Road Mr Stephenson should have given consideration to other sections of the Manual, in particular Part 8.2 which deals specifically with roadwork speed zones, and Part 8.2.3b which provides that, as a general guide, speed limits of 60 km/h should be imposed where there is present "a loose surface such as a newly sprayed bitumen seal". This was the subject of some close questioning when the expert traffic engineers gave their evidence in concurrent session. Mr Coffey did, however, give the following evidence:

Q. And as part of a TCP plan, was it within Mr Stephenson's power as an accredited or certified RTA certified by the RTA to do TCPs to put a restricted speed sign up on these works?

A. Yes, he would have used his judgment, being an accredited traffic control plan designer, to know which signs to use for this situation.

Q. Dealing with both a "Restricted" speed sign and the "Slippery Road" sign, can you see any firstly, did you receive any explanation for their non-use in the aftercare of these roadworks?

A. No, I never received a proper explanation of that at all.

Q. From your perspective as his supervisor, can you see any explanation for their non-use?

A. No, it makes no sense to me at all that one wasn't used.

HER HONOUR

Q. One being the "Reduced Speed" sign and/or the "Slippery Road" symbolic picture?

A. Both of them, your Honour, but specifically, the "Slippery Road" sign. It's a standard sign that's used in this situation.

28 Mr Coffey agreed in cross-examination that the number and type of speed signs that were required while the resurfacing works at Kingsvale Road were in progress necessitated that Mr Stephenson undertake an assessment of the safe speed at which the curve in Kingsvale Road in the first section of resurfacing could be negotiated in the presence the loose aggregate.

29 Counsel for the defendant then asked Mr Coffey the following questions:

Q. But you accept, don't you, that the extent to which a given location might be, as you described it, like walking on marbles, in the context of the car driving on a recently resealed road, it is determined by the sharpness of the curve and the amount of aggregate?

A. Yes.

Q. Can I suggest to you that a reason why a reduced speed sign was not, or may not, have been necessary, was that the corner with the loose aggregate on it could be safely negotiated at a speed of at least 145km per hour?

A. Under normal circumstances?

Q. No, with the aggregate on the road?

A. Loose aggregate on the road?

Q. Yes?

A. Definitely not.

Q. Are you disagreeing with the speed calculation?

A. Would you like to repeat the question?

Q. Yes. Firstly I should preface it with this; do you understand that the prevailing speed limit at this location was 100km per hour?

A. Correct.

Q. If the fact is that even with aggregate on the road, following a resealing operation and before sweeping, the corner could be negotiated safely at a speed of 145km an hour, there would be no need for a reduced speed sign?

A. Two parts; I disagree that that could occur, that the corner could be negotiated at that speed with loose aggregate on it. But if it can, as you have assumed for whatever reason a reduced speed sign would not be necessary, but it is a circumstance I don't fathom. The premise of the question is just completely wrong.

30 In their joint report Mr Stuart-Smith, the consulting traffic engineer called by the defendant, and Mr Johnston, the consulting engineer called by the plaintiff, generally agreed that assuming no braking and assuming idealised steering inputs, a driver following the curve to the right on approach to the commencement of the roadworks could, theoretically, safely negotiate the curve at 145 km/h even where loose gravel was present on the road surface. In coming to that view, Mr Johnston made no allowance for the influence of the transition from the unworked road surface to the resurfaced section on Kingsvale Road which occurred part way through the curve. Mr Stuart-Smith did not regard that feature as significant.

The expert evidence relating to the Council's Traffic Control Plan

31 At the time of the preparation of the joint report the experts were aware that TCP 56 had been adapted by the Council for the resurfacing works at Kingsvale Road. They were not made aware, and the evidence did not otherwise establish, the criteria according to which it was modified, or why Mr Stephenson arranged for the placement of only some of the signage the TCP provided for in its generic form. Mr Stephenson did not give evidence. It is not known whether he considered the question whether a speed reduction sign was required and, if he did consider the question, why none was provided for.

32 In their joint report Mr Johnston and Mr Stuart-Smith agreed that TCP 56 was appropriate for the roadworks at Kingsvale Road, being the TCP specified by the selection process in the Manual for resurfacing roadworks incorporating the spraying of the bituminous seal on a two lane roadway where the volume of traffic is less than 5000 vehicles per day. They disagreed however as to whether it was appropriate to use TCP 56 in what Mr Johnston described as the "after care phase" which he associated with the spreading and embedding of the loose aggregate before it is swept. He was of the view that TCP 56 was inappropriate for that phase of the operation and that Clause 9.13 of the Manual, which recognises that there are four stages to be considered when bituminous works are being undertaken, should have been taken into account when selecting or adapting the TCP that would govern the entire operation.

33 Relevantly, Clause 9.13 of the Manual reads as follows:

Bituminous works

...

For signs at sprayed sealing works, the four stages to consider are:-

before sealing begins

during sealing operations

until the last loose stones are removed

until the appropriate line marking and road markings are fully restored.

Where the sealing works are undertaken in areas where the posted speed limit is greater than 60 km/h then a 60 km/h roadwork speed zone shall be installed and shall remain in place until the number of loose aggregate particles remaining in place falls to the specified level.

(emphasis added)

...

34 In so far as the question of speed was concerned, Mr Johnston also drew attention to Clause 8.2 of the Manual which is expressed in the following terms:

8.2 Roadwork speed zones

...

8.2.2 Location

Roadwork speed zones may be used where any of the following situations occur:-

...

(v) loose material or stones are on the road surface (ie during spray sealing works)

...

8.2.3 Speed limit selection

The speed limit selected shall not exceed the maximum safe speed of travel for that work area. This safe speed is dependent on the degree of vehicular and pedestrian conflicts, the type and extent of the work in progress, the characteristics of the road and the proximity of workers to passing traffic. As a general guide it is desirable to reduce the speed of passing traffic to the following speeds using appropriate signs and devices together with, if considered necessary, a roadwork speed limit:

...

b) 60 km/h

...

(v) there is a loose surface such as gravel or a newly sprayed bitumen seal.

...

8.2.4 Guidelines

...

(b) Minimum length of zones

...

40km/h and 60km/h roadwork speed zones are to be located so that the zone commences 100m before the start of the work. In general 40km/h zones are only to be erected over the length where people are working or the other conditions listed in 8.2.3(c) exist. Except that the roadwork zone shall end at least 50m past the site where people are working.

...

35 Mr Johnston was firmly of the view that a 60 km/h speed limit should have been incorporated in the design of the TCP to govern all phases of the resurfacing roadworks at Kingsvale Road, irrespective of whether TCP 56 was otherwise the appropriate TCP for use during the resealing phase of the process. Mr Johnston was also of the opinion that T3-3 (the symbolic "Slippery Road" sign) should have been incorporated in the governing TCP and that there was a breach of standards in failing to provide for it.

36 Mr Stuart-Smith was of the view that the generic TCP 56 incorporated all phases of resurfacing works, including the period between the laying of the aggregate and the sweeping of the residue, and that, in this case, it had been modified by the Council to accommodate each stage of the works including the period referred to by Mr Johnston as the "after-care" phase. He took issue with Mr Johnston's use of the concept of "after care" of resurfaced sites, noting that there was no reference to "stages" in a resealing operation in the preparation of traffic control plans for resurfacing works.

37 Consistent with the views he expressed in his own report, in the joint report Mr Stuart-Smith remained firmly of the view that T3-9 (the windscreen damage or "Chip Hazard" warning sign) and that T3-11 (the "New Works -No Lines Marked" warning sign) and their placement in advance of the road repair work, and at various intervals over the course of the roadworks, were adequate to warn drivers of the prevailing conditions on Kingsvale Road at the accident site.

38 In the course of giving his evidence he departed from this view.

39 In so far as concerned the question whether a speed limit should have been imposed in the post-sealing/pre-sweeping phase, in the joint report Mr Stuart-Smith remained of the view that the Council was not obliged to erect a speed limit sign and that the various clauses to which Mr Johnston referred to in the Manual were general guides only and not mandatory.

40 In the course of giving his evidence, and under close questioning by me, he modified that opinion.

41 Mr Stuart-Smith was asked to explain why he was of the opinion that the "Chip Hazard" sign (T3-9), placed 60 metres in advance of the commencement of the roadworks, was adequate to warn road users of the potential for loss of traction on the gravel dressed surface. He said that sign was not simply to warn drivers that there is a risk of windscreen damage but, because it was associated with the "Roadwork Ahead" sign, a driver would be, or should be, conscious of risks associated with driving on loose stones, in particular the possibility of reduced traction were an unconventional manoeuvre undertaken or were the driver travelling at an unsafe speed.

42 He agreed that the need to slow down to a safe speed in these circumstances would depend upon the hypothetical driver appreciating that the "Chip Hazard" sign indicated the presence of surface gravel in sufficient quantities to reduce traction with an associated risk of slippage. Whilst he agreed that it would have been better (in the sense of more desirable) for the Council to have placed a "Reduce Speed" sign in advance of the roadworks, after being afforded the opportunity to reflect upon the implications of his evidence qualified in that way, he ultimately accepted the proposition that the Council should have provided for additional signage to warn of the reduction in friction on the road surface including a "Slippery Road" sign and either a "Reduce Speed" sign or the imposition of a reduced speed limit from the designated speed of 100 km/h. He accepted that in the absence of either of these signs the signage the Council did have in place was inadequate.

43 He also agreed that the "Chip Hazard" sign placed 60 metres before the commencement of the first resealed section on Kingsvale Road did not provide sufficient time to alert a driver to the approaching risk associated with loose gravel or to reduce speed were a driver travelling at the designated speed of 100 km/h. To the extent that Mr Johnston's opinion as to the necessity for a reduced speed limit was based upon Clauses 8.2 and 8.3 of the Manual, Mr Stuart-Smith maintained the view that they were guides only. I am satisfied that Mr Johnston's opinion as to the need for a speed reduction or speed limitation sign was not based solely upon the nominated clauses in the Manual. He was of the view that because the applicable speed limit was 100 km/h, TCP 56 needed to incorporate a speed limit in the post-sealing phase consistent with what is provided for in TCP 353.

44 Mr Stuart-Smith also maintained the position that in selecting or adapting the TCP that was to be applied to bituminous works because there were two applicable TCPs (56 and 353), one which provided for a speed limit and one which does not, the judgment of the authorised Council officer was determinative as to which one would be used and what, if any, modifications would be made. Mr Coffey's evidence and Clauses 4.4 and 4.5 of the Manual render that observation uncontroversial. The critical question, so far as breach is concerned, is whether Mr Stephenson's judgment was flawed. Mr Coffey's evidence on this question is categorical. In the absence of any evidence from Mr Stephenson which may have explained or justified his decision to delete the "Slippery Road" sign and his failure to make any provision for a "Reduce Speed" sign, I regard Mr Coffey's evidence as compelling. The Jones v Dunkel inference urged upon me by the plaintiffs reinforces that view.

45 Mr Stuart-Smith did, however, acknowledge in cross-examination that applicable Australian standards, incorporated into the Council's safe work procedures, provided that:

...traffic speed should be controlled whilst there is loose aggregate on the surface to less than the speed which would cause stones to fly high enough to strike windscreens.

46 He also agreed that the "Chip Hazard" sign was designed to both protect cars from broken windscreens and to minimise the risk of a loss of control when a vehicle passes from an unworked road surface to a re-sealed section where there are loose stones present and to warn that there was a need to reduce speed in those circumstances. It seems to me to follow from this concession that since "Chip Hazard" signs were erected in accordance with the TCP Mr Stephenson designed, there was an implied acceptance that the loose gravel could "fly high enough to strike windscreens" and, accordingly, there was a need for the Council to effect speed controls to something less than the designated speed of 100 km/h, to both allow a driver time to respond to the warning of the presence of gravel and time to respond appropriately if control is lost or threatened, to avert an accident.

47 Whatever else the questioning in the concurrent session revealed about Mr Stuart-Smith's seemingly limited appreciation of the necessity to comply strictly with the expert witness' obligation of impartiality as expressly provided for in Part 31, rule 23 of the Uniform Civil Procedure Rules and the Code of Conduct in Schedule 7, I am satisfied that his revised opinion on both the necessity for the Council to provide pictorial signage and speed reduction signage at the accident site (which, in the result, is not widely divergent from Mr Johnston's opinion), together with Mr Coffey's evidence concerning these issues (which was essentially unchallenged and, in the absence of Mr Stephenson, unanswered), establish breach of duty in accordance with the statutory test in s 5B of the Civil Liability Act.

48 I am satisfied that a speed reduction sign in combination with and a pictorial "Slippery Road" sign should have been put in place in advance of the commencement of the roadworks (and at appropriate intervals thereafter) to alert road users to the potentially hazardous condition of the road, and that the failure to provide for that signage created a significant and foreseeable risk of harm such that a reasonable person in Mr Stephenson's position would have required that signage to be used. I am further satisfied, there being no evidence to the contrary, that it was neither burdensome nor onerous for the Council to have taken precautions of that kind against the foreseeable risk of serious harm to road users were a vehicle travelling at the designated speed of 100 km/h at some point along the course of the roadworks to lose traction, despite the evidence of the experts that the curve in the first resurfaced section could, theoretically, be safely traversed at 146 km/h.

The statutory defence under s 43A of the Civil Liability Act

49 That section provides as follows:

Proceedings against public or other authorities for the exercise of special statutory powers

(1) This section applies to proceedings for civil liability to which this Part applies to the extent that the liability is based on a public or other authority's exercise of, or failure to exercise, a special statutory power conferred on the authority.

(2) A special statutory power is a power:

(a) that is conferred by or under a statute, and

(b) that is of a kind that persons generally are not authorised to exercise without specific statutory authority.

(3) For the purposes of any such proceedings, any act or omission involving an exercise of, or failure to exercise, a special statutory power does not give rise to civil liability unless the act or omission was in the circumstances so unreasonable that no authority having the special statutory power in question could properly consider the act or omission to be a reasonable exercise of, or failure to exercise, its power.

(4) In the case of a special statutory power of a public or other authority to prohibit or regulate an activity, this section applies in addition to section 44.

50 The exercise of a special statutory power (or in this case the failure to exercise it) upon which the operation of the section depends is satisfied if the power under consideration is conferred by or under a statute, and is of a kind that persons are generally not authorised to exercise without specific statutory authority.

51 The Council submitted that its entitlement to rely on s 43A is best demonstrated by the fact that members of the public are not permitted to erect roadside signs, and it was only by virtue of the authority conferred on it by statute that the Council was authorised to erect the signs that I have found ought to have been erected in discharge of its duty of care to road users.

52 I accept that this analysis properly informs the question whether the Council exercised or failed to exercise "a special statutory power" as provided for in s 43A(1). To the extent that the plaintiffs' counsel submitted that s 43A had no application because at common law the Council owed Ms Paterson a duty to exercise reasonable care for her safety which was, in essence, to be discharged by the exercise of a sound judgment, this must be rejected. That submission ignores the language of s 43A. On its proper construction, the section is concerned with the nature and quality of the act or omission on which a plaintiff relies to prove liability for breach of that duty. Where the nature of that act or omission involves the exercise or failure to exercise a special statutory power (whether or not that involves a question of judgment) the quality of the act or omission must involve negligence in the Wednesbury sense of unreasonableness in order for liability to be imposed.

The source of statutory power for the Council to post signage at the accident site

53 As at the date of the accident s 52 of the Road Transport (Safety and Traffic Management) Act 1999 ("RT(STM) Act") provided:

52 Unauthorised prescribed traffic control devices

(1) A person must not, without appropriate authority:

(a) install or display a prescribed traffic control device on, above or near a road or road related area, or

(b) ...

Maximum penalty: 20 penalty units.

(2) ...

54 Section 50 of the RT(STM) Act provided that a "prescribed traffic control device" means:

... a sign, signal, marking, structure or other device to direct or warn traffic on a road or road related area (or part of a road or road related area) that is prescribed by the regulations for the purposes of this definition.

55 Accordingly, both a "Slippery Road" sign and a "Reduce Speed" or a speed limit sign are traffic control devices within the meaning of s 52 in RT(STM) Act, and persons generally were not permitted to erect either of the two signs unless appropriately authorised.

56 As at 19 August 2004 s 87 of the Roads Act provided:

87 Traffic control facilities

(1) The RTA may carry out traffic control work on all public roads, on all parts of transitways that are not public roads and on all roads or road related areas within the meaning of the Road Transport (General) Act 1999 (other than roads or road related areas that are the subject of any declaration made under section 9 (1) (b) of that Act relating to all of the provisions of that Act).

(2) The appropriate roads authority may carry out traffic control work on any classified road, but only with the consent of the RTA.

(3) The appropriate roads authority may carry out traffic control work on any unclassified road, on any part of a transitway that is not a public road and on any road or road related area within the meaning of the Road Transport (General) Act 1999 (other than a road or road related area that is the subject of any declaration made under section 9 (1) (b) of that Act relating to all of the provisions of that Act) that is not a public road, other than one in respect of which the RTA has notified the authority that the RTA proposes to carry out traffic control work.

(4) However, the construction, erection, installation, maintenance, repair, removal or replacement of a traffic control light may not be carried out otherwise than by or with the consent of the RTA.

57 The Council was constituted an appropriate road authority at Kingsvale Road by operation of s 7(4) of the Roads Act. In addition, since Kingsvale Road was an unclassified road, s 87(3) authorised the Council to carry out "traffic control work" which is defined in the Dictionary to the Roads Act to include carrying out any activity in connection with the construction, erection, installation, maintenance, repair, removal or replacement of a traffic control facility, which has the same meaning as in Part 6 of the Transport Administration Act 1988 ("TAA").

58 Relevantly, s 45E of the TAA defines "a traffic control facility" as:

(a) ...

(b) any sign, marking, structure or device containing or relating to a requirement or direction, contravention of which is an offence arising under:

(i) this Act or the regulations, or

(ii) any other Act, regulation or by-law prescribed for the purposes of this subparagraph, or

(c) any other sign, marking, structure or device that is intended to promote safe or orderly traffic movement on roads or road related areas or to warn, advise or inform the drivers of vehicles, or pedestrians, of any matter or thing in relation to vehicular or pedestrian traffic or road conditions or hazards,

...

59 The Council submitted that a pictorial "Slippery Road" sign or a "Reduce Speed" sign are intended to promote safe traffic movement on the Kingsvale Road, and to warn, advise or inform drivers of the condition of the road and the hazards associated with the resurfacing works, and in that way are comprehended by the definition of "a traffic control facility" in s 45E(c). It also follows from that analysis that for relevant purposes the Council was authorised by s 87(3) of the Roads Act to erect, install, remove or replace both signs as part of carrying out "traffic control work" on Kingsvale Road since they were intended to promote safe traffic movement or to warn or inform drivers.

60 Applying the same analysis, the Council submitted that a speed limit sign is also a "traffic control facility" under s 45E (b) of the TAA. Clause 20 of the applicable Australian Road Rules as at August 2004 made it an offence for a driver to exceed the speed limit. Clause 20 was incorporated into the law of New South Wales pursuant to Clause 6 of the Road Transport (Safety and Traffic Management) (Road Rules) Regulation 1999.

61 It follows that a speed limiting sign was a "traffic control facility" under s 45E of the TAA not only because it was intended to promote safe and orderly travel under s 45E(c), but because a failure to obey it constituted an offence under s 45E(b).

62 The plaintiffs' counsel directed no submissions at the legislative pathway the Council invited me to follow in support of its claimed entitlement to rely upon s 43A in defence of the claim. I am satisfied that the Council has made out the case that its liability in negligence (as determined by me) is based on its failure to exercise a special statutory power as defined in s 43A(2) of the Civil Liability Act. Accordingly, by operation of s 43A(3) the failure to exercise that special statutory power will not give rise to any civil liability unless I am satisfied that the failure to erect a "Slippery Road" sign and a speed reduction or speed limitation sign was so unreasonable that no authority having that special statutory power could properly consider that omission to be a reasonable exercise of the power.

63 The only direct evidence bearing on this issue is from Mr Coffey. I am satisfied that he had a level of experience which was sufficient to support what was implicit in his evidence, namely that in his opinion there was an unacceptable departure from what would be expected of other councils exercising similar areas of responsibility under the Roads Act (see Firth v Latham [2007] NSWCA 40 per Hoeben J (with whom Santow JA and McClellan CJ at CL agreed)).

64 Although Mr Coffey's criticism of Mr Stephenson's decision to adapt TCP 56 by deleting relevant signage and not including other signage was trenchant, it is not determinative of the second limb of the test under s 43A. Whether an authority exercising the special statutory power of the Council in undertaking resurfacing works of the kind undertaken at Kingsvale Road could properly have made no provision for a "Slippery Road" sign and a speed reduction sign, despite the known and foreseeable consequences, must be determined objectively. That said, as Giles JA recognised in Alllianz at [65], the decision maker's subjective processes can, to the extent that they are discernible, inform the objective determination of reasonableness of the Council's conduct required by s 43A(3). In this case there was no evidence from Mr Stephenson as to why he deleted the "Slippery Road" sign in the modified TCP 56 despite it being expressly provided for and, by implication, no evidence as to why he did not see the need for a speed reduction sign given the prevailing speed limit of 100 km/h at the accident site and the presence of loose gravel on the resurfaced sections.

65 I note that he did not respond in any direct way to Mr Coffey's repeated enquiries of him after the accident such as might have explained why he modified TCP 56 in the way he did and the Council did not call evidence such as might have made patent the basis for his decision. Rather, the Council relied upon the form and content of the TCP being a matter for Mr Stephenson's judgment. I have already observed that the Manual expressly provides that if a standard TCP does not exist for the work that is planned (as was the case here given the disconnect between speed limit and volume of traffic in TCP 56 and TCP 353), a decision must be made by the authorised officer, in accordance with listed principles, as to whether a minor modification should be made including "detailing the location of signs required for a posted speed limit in accordance with section 8.2" (set out at [34]).

66 In Allianz at [82] Giles JA reviewed the authorities and noted a number of alternative descriptions of the level of unreasonableness, with what his Honour described as fluctuating levels of stringency, before a decision could be said to be tainted by Wednesbury unreasonableness including:

(i) So devoid of plausible justification that no reasonable body of persons could have reached it (Bromley London Borough Council v Greater London Council (1983) 1 AC 768 at 721);

(ii) So outrageous in its defiance of accepted moral standards that no reasonable person who applied his mind to the question would have arrived at it (Council of Civil Service Unions v Minister for the Civil Service (1985) AC 374 at 410, although in Commonwealth v Pharmacy Guild of Australia (1989) 91 ALR 65 at 87 Sheppard J expressed disagreement with this formulation);

(iii) No authority with due appreciation of its responsibilities would have decided to adopt it (State for Education and Science v Tameside Municipal Borough Council (1977) AC 1014 at 1064); and

(iv) As explained by his Honour's analysis in [85], where the decision under review turns upon questions of fact upon which minds could reasonably differ it is difficult to show that no reasonable decision maker could have arrived at the decision, citing Gummow J in Minister for Immigration and Multicultural Affairs v Eshetu [1999] HCA 21; 197 CLR 611.

67 In the result his Honour said at [87]:

Aronson sums it up in "Government Liability in Negligence" [2008] 32 MULR 44 at 80 that "[o]nly the grossest unreasonableness will invalidate the exercise of a statutory discretion". The learned author suggests that instead of transplanting Wednesbury unreasonableness "[i]t might have been more straightforward to draft the new standard simply as 'gross negligence'". I say nothing of that; in seeking to give content to the language of s 43A, however, a constant is that Wednesbury unreasonableness must be at a high level. The force of s 43A, in its use of language modelled on that of Wednesbury unreasonableness, lies in "could properly consider", with the restraint of "could" moderated by "properly". Necessarily, questions of degree and judgment arise in both reasonableness and properness.

68 In Lukacevic v Coates Hire Operations Pty Ltd [2011] NSWCA 112 Giles JA said that the level of unreasonableness invoked by "Wednesbury unreasonableness" (albeit, in the context of judicial review), involved "something quite overwhelming" and involving a "quite demanding level of unreasonableness" (at [45]).

69 The Council submitted that its failure to provide for the additional signage at the accident site did not satisfy the Wednesbury unreasonableness test for the following reasons:

(a) The Manual makes express allowance for minor modifications to standard TCPs by reference to listed principles which are inherently matters for the exercise of judgment.

In this case, there was a plausible reason for a considered view being taken that a driver would not need to be directed or warned to decrease speed or alerted specifically to the risk of a loss of traction, where the roadworks encompassed a moderate right oriented curve in the first resurfaced section but the roadworks were otherwise on a straight stretch of a rural roadway.

(b) The Manual provides that TCP 56 shall be designed on the basis that road condition signs (which include the "Slippery Road" sign) are to be used where the road surface at the work is area is "sufficiently different" from the approach roads to be hazardous to traffic.

The Council submitted that agreement between the experts to the effect that the slide off speed for the corner was between 145 and 160 km/h raised an issue as to how "different" the resurfaced sections were compared to the road leading up to the site. It was also submitted that where minds could reasonably differ as to the need to provide for any additional signs or to reduce the speed limit from 100 km/h the demanding level of unreasonableness to which s 43A(2) refers was not met.

(c) The Manual provides that the imposition of a speed limit for the type of roadworks undertaken at the accident site was the maximum safe speed for the area.

The Council submitted that since it was agreed that the slide off speed at the moderate right curve was 146 km/h it is open to conclude that a safe speed was 100 km/h. It was also submitted that "safe speed" is not a fixed concept thereby giving rise to legitimate and defensible differences of opinion as to what might constitute a safe speed at Kingsvale Road.

The plaintiffs submitted that while that is so, the Manual provides that:

...safe speed is dependent on the degree of vehicular and pedestrian conflicts, the type and extent of the work in progress, the characteristics of the road and the proximity of workers to passing traffic...

and that 60 km/h is specified as the desirable (or general guide) where "there is a loose surface such as gravel or a newly laid bitumen seal".

(d) To the extent that the selection of one or other TCP (56 or 353) bears on the application of the test of unreasonableness, in order to mandate the use of TCP 353 the Council submitted that it was necessary that there be both more than 5000 cars per day and that the speed limit be above 80 km/h. Accordingly, so it was submitted, there was a defensible and plausible basis for the utilisation of TCP 56 (in its modified form).

The Council also emphasised that TCP 56 envisages the use of as few as one of the pictorial signs signalling the presence of loose gravel and that it is an exercise of judgment as to how many should be used, informed by the particular features of the road under repair.

70 I accept that although other Council officers in Mr Stephenson's position might legitimately have made no provision for the placement of a "Slippery Road" sign or a sign warning or directing of the need for a reduction in speed from 100 km/h, the fact that minds might differ as to the need for that additional signage and that the Manual allows for the exercise of a considered judgment as to the number and type of road condition signs where there is gravel on the road as an incident of road sealing works does not, in my assessment, meet the necessary test for Wednesbury unreasonableness within the meaning of s 43A.

71 The Council also relied upon s 44 of the Civil Liability Act which provides:

When public or other authority not liable for failure to exercise regulatory functions

(1) A public or other authority is not liable in proceedings for civil liability to which this Part applies to the extent that the liability is based on the failure of the authority to exercise or to consider exercising any function of the authority to prohibit or regulate an activity if the authority could not have been required to exercise the function in proceedings instituted by the plaintiff.

(2) Without limiting what constitutes a function to regulate an activity for the purposes of this section, a function to issue a licence, permit or other authority in respect of an activity, or to register or otherwise authorise a person in connection with an activity, constitutes a function to regulate the activity.

72 The application of this section attracted little attention in final submissions and none in the evidence. It was not submitted that the failure to erect signs warning of the presence of gravel constituted an action to "prohibit or regulate" an activity as contemplated by s 44.

73 I am not persuaded that the failure to erect a speed limit sign at Kingsvale Road at the accident site involved the exercise of a function to prohibit or regulate an activity as required by the section. To the extent that the Council might regulate the speed at which motorists might drive within the boundaries of the shire whilst roadworks are underway, it does so incidental to express powers under the Roads Act and related legislation and not because it is a function of the Council to regulate the activity of driving as counsel contended. Accordingly, I am satisfied that s 44 of the Civil Liability Act has no application in this case.

74 In the event that I am in error in the application of s 43A and s 44 of the Civil Liability Act I turn now to consider whether causation has been established.

75 It is not enough that the failure to provide for and position a "Slippery Road" sign in combination with a "Reduced Speed" sign could increase the risk of injury resulting from a loss of traction. The plaintiffs are obliged to prove that "but for" the failure to position adequate signage the accident would be unlikely to have occurred.

Additional evidence bearing upon the question of causation

76 Each of the two resurfaced and gravel dressed sections of Kingsvale Road Ms Paterson passed through prior to the point of impact extended the full width of the road. Those sections were of different lengths and the two unworked sections separating them were also of differing lengths. The first resurfaced section of about 90 metres commenced part of the way into a moderate right curve. It was followed by a section of unworked road of approximately 40 metres length which connected with a second 30 metre section of resurfacing on a straight section of the road. A second unworked section of 54 metres then connected with the third resurfaced section. The point of impact was about 210 metres from the commencement of the first resurfaced section, very close to where the third resurfaced section commenced.

77 It was agreed between the experts that there was no physical evidence which was capable of fixing where Ms Paterson was likely to have first lost control of her vehicle over that 210 metres. (It was agreed that the physical evidence supported a finding that she entered the first resurfaced section with her vehicle under control. Thus the focus was on where on the 210 metre stretch of roadway from the commencement of the roadworks to the point of impact control was first lost.)

78 The experts had access to the same body of physical evidence assembled by police and Council officers on the day of the accident as was tendered at trial. It comprised photographs of the road surface before it was swept clear of the residue of gravel later on the afternoon of the accident; the observations of police and Council workers of the appearance of road surface from varying perspectives (also before the road was swept) and sketches or line drawings of where it was thought Ms Paterson's vehicle travelled from the commencement of the roadworks to the point of impact.

79 The experts disagreed about what that evidence was capable of proving as to the probabilities of where and why control of the vehicle was likely to have been first lost.

80 The experts were agreed, however, that the physical evidence collected at the accident scene did confirm the presence of distinct tyre marks deposited by Ms Paterson's vehicle on the second unworked second section of road. Those marks commenced about 45 metres from the point of impact (that is, about 160 metres from the commencement of the roadworks) and arced across the centre line from left to right. It was common ground between the experts (and adopted by both counsel at the hearing) that the appearance of these tyre marks, and their arrangement relative to each other, was consistent with Ms Paterson's vehicle sideslipping as it yawed out of control from the correct to the incorrect side of the road before rotating in a 180 degree arc towards the tree. It was also generally agreed between the experts that because of the orientation and alignment of a faint mark at the end of the gravel in the second resurfaced section, and the distinct yaw marks on the adjacent unworked section, that the faint mark was probably left by Ms Paterson's vehicle as she approached the end of that 30 metre (second) resurfaced section (on the incorrect side of the road) before the vehicle returned (momentarily) to the correct side of the road on the (second) unworked section before rotating out of control and leaving the road and hitting the tree.

81 In the way the plaintiffs' case on liability was advanced at trial (that is, by alleging a failure to warn of the need to reduce speed from the speed limit of 100 km/h because of the hazardous condition of the road surface, and a failure to provide a specific warning of the risk of slippage because of the presence of loose gravel) it was conceded that the patent evidence of Ms Paterson's yawing out of control 45 metres from the point of impact (160 metres from the commencement of the roadworks), associated with some evidence of a loss of control in the preceding resurfaced second section by reference to the faint mark in the gravel on the incorrect side of the road, would not support a finding of factual causation. It was common ground that the plaintiffs' case depended upon my being satisfied that Ms Paterson probably lost control in the first resurfaced section on encountering the loose gravel while travelling at or near 100 km/h, and that it was this that caused her to veer progressively off to the right before she travelled (probably on the incorrect side of the road) for some distance, before returning to the correct side of the road after her failed efforts to regain control resulted in her careering off (again) on the incorrect side of the road and hitting the tree.

82 The Council submitted that the evidence failed to establish the primary fact essential to a finding of factual causation, namely that control of the vehicle was probably lost on encountering the gravel in the first resurfaced section, or at some point within that section, by reason of a loss of traction. It was also submitted that Mr Johnston's opinion as to where and why control was lost, which relied substantially upon proof of that same primary fact, was not persuasive, and that when his reasoning is critically analysed, it is shown to depend upon a series of unproved assumptions as to the movement of Ms Paterson's vehicle.

83 Although Mr Stuart-Smith conceded that it was possible that control was lost in the first resurfaced section, the absence of physical evidence showing the vehicle's passage from the correct to the incorrect side of the road under a loss of traction on the curve - evidence which he expected would have been clearly visible on the road surface were that to have occurred - did not allow him to conclude that the loss of control was probably due to a loss of available friction when, in his view, other competing hypotheses were open, including momentary inattention, drowsiness or fatigue.

84 The differing views of the expert witnesses as to where control of the vehicle was probably first lost, and why, is not determinative of the issue of causation. In Sydney South West Area Health Service v Stamoulis [2009] NSWCA 153 at [29] - [39] per Giles JA and [123] - [154] per Ipp JA. As Ipp JA noted at [138]:

...The fact that experts do not infer causation on a balance of probabilities does not mean that a court may not: Seltsam Pty Ltd v McGuiness at [143]-[144]. A finding of causal connection may be made even when the expert evidence does not rise above the possible; the question is always whether the evidence as a whole establishes causation on a balance of probabilities: Seltsam Pty Ltd v McGuiness at [89], [94]-[96], [98]-[100], [102], [143], [144] and [153].

85 The ultimate question of factual causation in s 5D of the Civil Liability Act is a legal question to be decided in accordance with the "but for" test, with s 5E imposing on the plaintiffs the burden of proving on the balance of probabilities any fact relevant to the issue of causation.

86 In Nguyen v Cosmopolitan Homes (NSW) Pty Ltd [2008] NSWCA 246 at [44]-[55] McDougall J examined the principles that inform an enquiry into factual findings that might underpin the question whether factual causation has been made out in a particular case. At [55] his Honour summarised the position in the following terms:

(1) A finding that a fact exists (or existed) requires that the evidence induce, in the mind of the fact-finder, an actual persuasion that the fact does (or at the relevant time did) exist;

(2) Where on the whole of the evidence such a feeling of actual persuasion is induced, so that the fact-finder finds that the probabilities of the fact's existence are greater than the possibilities of its non-existence, the burden of proof on the balance of probabilities may be satisfied;

(3) Where circumstantial evidence is relied upon, it is not in general necessary that all reasonable hypotheses consistent with the non-existence of a fact, or inconsistent with its existence, be excluded before the fact can be found; and

(4) A rational choice between competing hypotheses, informed by a sense of actual persuasion in favour of the choice made, will support a finding, on the balance of probabilities, as to the existence of the fact in issue.

The application of these principles were of considerable significance in resolving the difficult question of causation in this case.

Available sources of evidence to support a finding that Ms Paterson lost control of her vehicle in the first resurfaced section of the road under repair

87 Senior Sergeant Brand was called by the Council. Senior Constable Hando's statement was also tendered in its case. Both officers attended the scene within a very short time of the accident.

88 After observing the patent physical evidence of tyre marks leading to the point of impact as Ms Paterson's vehicle yawed out of control on the second unworked section, and the faint tyre mark in the gravel on the incorrect side of the road in the immediately preceding resurfaced section, Sergeant Brand inspected the road surface over approximately 100 metres leading to that point for the express purpose of looking for a reason as to why her vehicle was on the incorrect side of the road, in particular, whether there was anything to indicate an attempt on her part to avoid an obstruction or to deviate around an irregularity in the road surface. He was unable to find anything to suggest or indicate why the vehicle ended up on the wrong side of the road at the end of the second resurfaced section, or any other mark on the road surface or in the gravel that might suggest where it had first deviated onto the incorrect side of the road.

89 Senior Sergeant Brand also made a notebook entry and a sketch of the scene (not drawn to scale) to record his observations and to assist his later recall. His notebook entry recalls as follows:

Several sections of the road surface preceding the accident had been resurfaced within the past 24 hours. Not known if the resealed road surface was contributing factor in accident. There were no obvious signs on road surface prior to skid marks (resealed or otherwise) to indicate how or why the VOI [vehicle of interest] has come to be on the incorrect side of the road.

90 His sketch shows the discontinuous sections of resurfaced roadway, the faint tyre marks on the far right of the second resurfaced section (which he described in his evidence as loose gravel which had been moved on the road surface) and the patent skidmarks in the unworked second section as the vehicle yawed of control. There were no tyre marks or tracks of any kind noted on the preceding unworked section of road. In company with other police he awaited the arrival of Senior Constable Hando who was attached to the Goulburn Crime Scene Unit. He remained with that officer and assisted him with his examination of the accident site.

91 Senior Constable Hando's statement also records there being "no visible marks on the road surface" in the first section. This was consistent with a sketch that he attached to his statement. His statement also stated that:

Upon entering the right-hand bend in the roadway the deceased has lost control of the vehicle, which has slid out of control across the roadway in a southerly direction (before rotating out of control in a clockwise direction to the point of impact...

The precise reasoning by which he reached the conclusion that the vehicle lost control "upon entering" the right hand bend and then "slid out of control" when there were "no visible marks on the road surface" undermines the weight of his opinion. He did not give evidence. The plaintiffs did not invite me to draw a Jones v Dunkel inference.

92 Sergeant Brand's evidence was consistent with his statement and his notebook entry. He also gave evidence that during his inspection of the scene he was able to draw a notional line of alignment between the displaced gravel at the end of the second resurfaced section and the angle of entry of the vehicle back onto the correct side of the roadway before it yawed out of control, but was unable to find any physical evidence indicating how long the vehicle had travelled on the incorrect side of the roadway before displacing the gravel at the very end of the second resurfaced section. He had no independent recall of the amount of gravel that was displaced at that point. He agreed that his attention was drawn "more acutely" to the condition of the surface of the road than might otherwise have been the case at the scene of a motor vehicle accident because of what he had been given to understand was the contribution of roadworks to another (earlier) collision. (It is not clear whether this is a reference to Ms Skorulis' accident 24 hours earlier or some other accident.) Sergeant Brand gave evidence that he walked back from the point of impact to the beginning of the first resealed section of the road and that he saw no delineated path of Ms Paterson's vehicle, whether on the correct side of the road or veering from the correct to the incorrect side of the road in that first section, even though he was specifically looking for marks on the roadway to indicate that very movement.

93 In cross-examination he was shown photographs 19 and 20 upon which Mr Johnston placed very significant reliance as evidencing a loss of control in the first resurfaced section and which Mr Stuart-Smith ultimately accepted were likely to have been left by Ms Paterson as she veered from the correct to the incorrect side of the road. He conceded that he may have missed seeing the vehicle's tracks Mr Johnston identified as Ms Paterson's because of their faintness.

94 Mr Curtis, an engineering assistant employed by the Council, also made a sketch of the scene on the day of the accident. His sketch, which is different from Sergeant Brand's, shows a discontinuous set of parallel tyre tracks indicating a path of travel from the left-hand side of the road as the vehicle entered the first resurfaced section towards, and then across the centre line at the end of that section. The path of travel is then picked up on the far right-hand side of the road towards the end of the second resealed section (that is, on the incorrect side of the road) before the vehicle moves back towards the left (that is, towards the correct side of the road) before again crossing the centre line so as to be in alignment with the yaw marks leading to the point of impact. The sketch indicates nothing of the passage of the vehicle over the first unworked section (it being common ground there were no marks of any kind on that section) and nothing of its passage on the second resurfaced section, such as might suggest how or why she was on the incorrect side of the road at the end of that section, at a point 150 metres from where she entered the curve and within 60 metres (or thereabouts) of the point of impact.

95 Mr Curtis did not give evidence. Photographs of tyre tracks on the first and second resurfaced sections were taken by Mr Curtis on the same day, including photographs 19 and 20. As noted, Sergeant Brand was invited to comment upon them in his evidence. Also as noted, both Mr Johnston and Mr Stuart-Smith considered these same two photographs best supported their differing views on the question of where control of the vehicle was first lost. Both photographs show the road receding along a line of near perfect perspective in a northerly direction from where the first resurfaced section ends and the first unworked section commences. I am satisfied the photographs show tyre marks which Mr Stuart-Smith ultimately conceded were consistent with the "light marks" that Mr Elllis, another Council employee, described in the incident report (which follows) and the path of travel of the vehicle which Mr Crisp drew on his sketch, and that they were probably the tyre marks of Ms Paterson's vehicle as she veered across the road from left to right before tracking into the shoulder on the right-hand side of the road.

96 Mr Elllis reported as follows:

At the time of the accident she was driving in a southerly direction from Kingsvale and had just been around through a short winding section of hilly terrain known as 'Stone Rises' and was just rounding a slight curve in the road when it appears she has crossed to the wrong side of the road and then overcorrected before losing control of the vehicle and it skidding sideways into the tree. Impact being the passenger side door. At the time of the accident it was a bright day with little cloud cover.

It is also apparent that as the vehicle rounded the curve in the road it was at the start of recent Council Roadworks which involved resurfacing of the road pavement (undertaken on Thursday 19th Aug). As the vehicle travelled around the bend commencing on the correct side of the road it appears that at the end of the 1st sealed patch the vehicle was on the wrong side of the road. This being a distance of 90.0 metres. The vehicle has then traveled 38 metres on the wrong side before hitting a second sealed patch of 31.7 metres length.

Towards the end of this second patch is where the vehicle appears to have commenced sliding back across the road (to correct side) for 33.3 metres before completely sliding sideways back (another 54.6 m) to the wrong side of the road, across the road shoulder and hitting the tree some 3.0 metres from the edge of the road.

On inspecting the roadworks it is not evident that the vehicle lost control after hitting the first patch or even the second patch. There is no discernible skid marks through the sealing aggregate on the first patch, only some light marks where it appears the vehicle attempted to correct its path.

(emphasis added)

97 Mr Ellis did not give evidence. The plaintiff submitted that a Jones v Dunkel inference should be drawn due to the Council's failure to call Mr Curtis and Mr Ellis. I am not prepared to draw that inference, there being nothing to suggest their evidence would differ materially from their contemporaneous notes.

98 Even if the light tyre tracks Mr Ellis noted indicated that Ms Paterson's control of the vehicle in the first resurfaced section was compromised as she progressively veered over a distance of 90 metres from the correct to the incorrect side of the road (as distinct from this being a deliberate driving manoeuvre which neither expert suggested was a rational explanation in the circumstances), the experts disagreed as to whether a precipitating cause of that loss of control was a loss of traction due to the presence of the loose gravel, as distinct from control being lost as a result of some other cause, or combination of possible causes.

99 Accepting that the light tyre marks observed by Mr Ellis, and shown in photographs 19 and 20, were probably deposited by Ms Paterson's vehicle, Mr Stuart-Smith noted that she deviated from left to right over the first section of resurfaced roadway in a reasonably straight line without any obvious attempt to correct that course. The photographs objectively support that description. In his view, this was inconsistent with a driver experiencing a loss of traction or recovering or attempting to recover from a loss of traction.

100 He also placed considerable reliance on the absence of any physical evidence indicating the tyres were rotating in a clockwise yaw or sideslip, which might have suggested that the precipitating cause of the deviation to the incorrect side of the road was a result of a loss of traction upon encountering the gravel surface as Ms Paterson continued to negotiate the moderate curve to the right. With no photograph of the road surface where the roadworks commenced or within metres of it (and where, on the plaintiffs' case, traction was lost) and no physical evidence on the road surface of any attempt by Ms Paterson to correct any sideslip or undertake any corrective manoeuvres noted either by the police, Mr Ellis or Mr Curtis, evidence which Mr Stuart-Smith expected would be visible even to an untrained eye, it was his view that it was unlikely that control was lost as a result of a loss of traction upon encountering the gravel at the commencement of the roadworks. He was of the opinion that the probabilities favoured Ms Paterson deviating from her path around the curve in the first resurfaced section for a reason or reasons unconnected with encountering the gravel at an unsafe speed. While he appointed other hypotheses, including drowsiness or inattention, he was not invited to address whether such physical evidence as was apparent at the accident site supported either hypothesis.

101 Mr Stuart-Smith resisted any interpretation of photographs 19 and 20 to suggest a slight loss of traction on encountering the gravel favoured by Mr Johnston. Mr Stuart-Smith gave the following evidence:

So looking at the photograph, that's on the right-hand side of the photograph, in other words, Ms Paterson's left as she's coming towards us, so one would have expected some windrow or some build up of material, or some some shading of the tyre mark to indicate some lateral displacement. But not only that. A vehicle doesn't just sideslip over just sideslip and then continue just travelling in that same sort of general direction. Once it starts to sideslip, it continues to rotate until the steering has twisted in the other direction, in which case, you either correct control is regained or else you end up with an oversteer, and the mark is too long.

It's the photograph is like 80 metres from it's 80 metres from the police car to the end of that tyre, the end of that patch. There's 150 metres from the police car to where the plaintiff's vehicle most likely was on the incorrect side of the road at the end of the second patch. So what we would have to assume for that to have been made by her car out of control, is that she sideslipped been sideslipping for about 150 metres without her car seriously rotating.

It's not really feasible for that to occur over such a long distance without other marks having started to occur, without the car sort of turning around to a greater extent. 150 metres is just too long for some some little bit of sideslip to have been caused at an originating point, and then to have continued at the speed that she was travelling.

102 Mr Johnston disagreed with the last aspect of Mr Stuart-Smith's evidence. He said:

...I agree that she wasn't in complete loss of control when the car started rotating at the start and continued to rotate at 150 metres. There was a loss of traction that has caused her vehicle to orient and travel [on] the incorrect side of the roadway. She has then made a series of manoeuvres that she has presumably tried to correct the vehicle, and stops leaving marks because it's on the wrong side of the road. And then there's a second patch, and then has a catastrophic loss [of control] at the end of that.

103 Mr Johnston considered that photographs 19 and 20 supported his assumptions as to Ms Paterson's driving manoeuvres, but accepted that it was not possible to discern from the physical evidence what corrective manoeuvres she attempted or her input as a driver as she endeavoured (on his analysis) to correct her path of travel to the correct side of the road. Ultimately, he agreed that there was insufficient physical evidence to be definitive about her path of travel or what she did or did not do at any point in the driving sequence. Whilst he could not exclude loss of attention or driver fatigue as an explanation for the deviating tyre tracks in the first resurfaced section, he said that a driver subject to those influences generally fails to steer a corner as opposed to oversteering a corner. He went on to say:

...In this case already part of the right curve is negotiated before reaching the unsealed surface. That suggests vehicle control to that point, then it suggests additional control as opposed to a lack of control which is the normal criteria for fatigue, a vehicle will travel off the outside of a curve or fail to negotiate a curve or simply travel straight ahead.

Q. Unless the driver wakes up, I suppose?

A. Unless the driver wakes up and then you tend to find a sharp steer back to the right. That's why you use that vibra line to wake them up as they cross the edge line and then you see a sharp steer vibra line or the audio tactile line marking to attempt that [sic] to wake them up and they steer back on to the roadway. So it is not certainly a stereo typical fatigue crash to travel to the inside of a a right curve especially when you have already substantially negotiated the part of the curve.

104 Mr Johnston agreed that the photographic evidence of what he believed to be Ms Paterson's tyre tracks in the first resurfaced section was not definitive of her having lost control of her vehicle at that time. He also acknowledged that his opinion that the probabilities favoured a loss of control in the loose gravel in that section was not based upon physical evidence of the kind Mr Stuart-Smith expected would be generated from a loss of traction. Mr Johnston relied instead upon the orientation of the tyre tracks deviating from left to right in photographs 19 and 20, and their consistency with the sketch drawn by Mr Curtis, as supporting his view that Ms Paterson was not controlling the forward movement of the car as she traveled through the first resurfaced section, and in this sense she had lost control of it.

105 Although he agreed that a vehicle which had lost control due to insufficient traction on a curve or bend will yaw or sideslip, Mr Johnston disagreed with Mr Stuart-Smith that definite windrows or furrows would be expected to be created (or visible) under lateral displacement in these circumstances. Mr Stuart-Smith gave the following evidence:

Q. We were then looking at your reasons for concluding Ms Patterson was out of control on the first patch and you are referring to the evidence. In case I have not made this clear, what you see in photograph 19 and 20, does that show lateral displacement of loose material, can you say or not?

A. Yes, because lateral placement of loose material means that the material is deposited out of the wheel path. The reason you can see that is there is less aggregate in that path. It has been displaced out.

Q. Does one need skidding for that to occur?

A. No, I heard that evidence earlier [from Mr Stuart-Smith]. Material is displaced out by tyre forces pushing the material sideways. I don't agree that in a high speed rotating tyre that you get this row of two or three stones right on the lateral edge. The stone is moved with some velocity from under the tyre and is thrown out. That's why you have the warning about windscreens damage, stones are thrown reasonable distances.

...

If the wheel is locked you are getting a ploughing effect. The stone is virtually being displaced around a locked wheel, then you get very definitive windrows or furrows on the edge. A high speed rotating tyre doesn't create that demarcation of a mound of gravel. It is displaced some distance, thrown probably outwards but not just dropped over the edge, so as you get this continuous row of a windrow and a high speed rotating tyre.

106 However, Mr Johnston gave the following evidence under cross-examination:

Q: If you consider that Ms Patterson lost control with a clockwise rotation of the vehicle, you would not expect to see a straight line across to the opposite side of the road as result of that loss of control, would you?

A: Not where that actually occurred. Later on, if that was the path the vehicle took, you might. But where the initial precipitating event was, no, you I would not expect a line there.

Q: But if that is the path the vehicle took later on, wouldn't you have to assume the regaining by the driver of complete control of the vehicle in the absence of marks indicating that the vehicle was in a yaw, as to came down the incorrect side of the road?

A: Certainly not complete control, but I would expect the vehicle was under control and largely corrected. So, it was now heading in the wrong direction, but was no longer continuing to rotate.

Q: Would you expect there to be marks on the road showing the loss of control that precipitated that manoeuvre?

A: Provided the area was not completely contaminated by material, yes. I would expect somewhere up near where the police car is, a trained eye would see, or find, that evidence, potentially.

107 It is clear from this evidence that Mr Johnston's opinion was also informed by his belief (or expectation) that physical evidence on the road surface in the first section where he believed traction was lost would likely have been discernable to "a trained eye", and that neither officers Brand and Hando nor Messrs Ellis and Curtis were sufficiently qualified to discern what Mr Johnston claimed he and Mr Stuart-Smith would have been able to discern and indentify as a tyre mark of a vehicle in a clockwise yaw.

108 Mr Johnston's assumption that the tyre marks were present but not seen could only support a finding that they were probably there if there were some evidence that the marks were there to be seen but overlooked. The obvious flaw in his reasoning is that if there were evidence of a yaw mark or sideslip proximate to where Ms Paterson entered the first resurfaced section (whether or not she regained control of the vehicle thereafter) there would be no need to proceed on the assumption that it was overlooked. To the extent that Mr Johnston's opinion that the probable cause of the accident was a loss of control in the first resurfaced section due to a loss of traction is based on the assumption that there either was physical evidence which was missed by all observers, or there might have been evidence that was missed by those people, the reasoning suffers from circularity in the sense that it is assumed that there were marks on the road because one would expect them to be present if there was a loss of control due to lack of traction. I am not persuaded that the theoretical possibility that the tyre marks were missed by those at the scene (and, in the case of Sergeant Brand, missed despite the fact that he was specifically looking for some evidence of the loss of control) permits an inference to be drawn that the tyre marks were there but missed.

109 The question whether the plaintiffs have proved what it was agreed was a primary fact essential to proving causation for the purposes of the application of s 55D(1) of the Civil Liability Act requires a finding that the probability that control was lost in the first section due to Ms Paterson encountering gravel under speed (and that she did not thereafter regain control sufficiently for her to avoid the accident), is greater than the possibility that she veered progressively onto the incorrect side of the road (as shown in photographs 19 and 20) for reasons unrelated to the condition of the road in combination with the speed at which she was travelling. In Flounders v Millar [2007] NSWCA 238, to which Ipp JA made reference in Sydney South West Area Health Service v Stamoulis, his Honour said at [35]:

It remains necessary for a plaintiff, relying on circumstantial evidence, to prove that the circumstances raise the more probable inference in favour of what is alleged. The circumstances must do more than give rise to conflicting inferences of an equal degree of probability or plausibility. The choice between conflicting inferences must be more than a matter of conjecture. If the court is left to speculate about possibilities as to the cause of the injury, the plaintiff must fail...

110 I accept that the competing hypotheses for Ms Paterson's loss of control, being a lack of concentration, inattention, drowsiness or fatigue, would logically need to subsist at the very point on the road where there was increased risk of a loss of control by reason of excess speed on gravel. While this state of affairs might undermine the likelihood of either of them (or any combination of them) being the explanation for the loss of control, it is necessary for me to be actually persuaded of one scenario over another as the more probable explanation and I am unable to reach that level of satisfaction.

111 In the absence of any physical evidence of sideslipping due to a clockwise rotation of the vehicle in the first resurfaced section in circumstances where it would be expected to be obvious, and where the road surface was examined and none noted; where the photographic evidence favours a finding of a gradual veering from the correct to the incorrect side of the road before a faint but definite mark 150 metres after the gravel is first encountered and after an intervening section of unworked road without tyre marks; and where Mr Curtis' sketch and Mr Ellis' report are open to interpretation, the balance of the evidence, which includes the evidence of another accident on a stretch of road under the same road repair works 24 hours earlier, simply does not induce in my mind an actual persuasion that the precipitating cause of Ms Paterson's accident was her losing control of her vehicle in the first resurfaced section due to the presence of gravel and her unchecked speed.

112 While I was satisfied that Ms Skorulis' evidence and the objective facts bearing upon her accident, were capable of informing in a rational way how and why it was that Ms Paterson was on the incorrect side of the road some 150 metres from the commencement of roadwork (the question at the time of the admission of the evidence to which this evidence was directed: Curtis v Harden Shire Council [2012] NSWSC 84) in the final analysis, that evidence was not sufficiently probative to support the necessary finding that the precipitating cause of both accidents was probably the same. While I accept that there are a constellation of objective features in both accidents that Mr Johnston found compelling, and which prima facie would tend to suggest the accidents shared a common cause, to make the finding that they were both probably the result of encountering the gravel without adequate forewarning and under speed would also require me to be able to comfortably draw the inference (as distinct from simply assuming) that Ms Paterson, being a more experienced driver than Ms Skorulis, had managed to regain some control of her vehicle after a loss of traction (thus explaining the distance of 150 metres or more over which her vehicle travelled before control was ultimately lost) but Ms Skorulis did not. I am unable to draw that inference. Moreover, it was only after the experts gave further evidence that the marked dissimilarities between the known passage of Ms Skorulis' vehicle and the reconstructed passage of Ms Paterson's vehicle were highlighted.

113 Given the way the plaintiffs have put their case, the failure to persuade me that control was probably lost because of a loss of traction at the beginning of the first resurfaced section, a primary fact upon which the further and critical finding of factual causation depends, carries with it the consequence that I am not persuaded that but for the failure to provide for and position appropriate signage the accident would not have occurred.

Orders

114 Verdict for the defendant.

**********

Decision last updated: 08 August 2012