46 The circumstances under which Mr Johnston arrived at these conclusions deserve further examination. Mr Johnston was first instructed on 13 October 2003. Over the following months he was provided with further material, including parts of a document compiled by MDK and Associates dated 1 December 2000. The pages with which Mr Johnston was supplied contained photographs and descriptions of the scene of the accident, some of which referred to it as very dark.
47 Ultimately, Mr Johnston produced a report in August 2004 that set out a number of assumptions made for the purposes of the opinions expressed within that report. A number of those assumptions that related to significant physical features of the site were wrong, including the number of northbound and southbound lanes in Argyle Street, the fact that the defendant travelled through a left hand curve approaching the point of impact instead of a right-hand curve, the length of the skid marks from the defendant's vehicle being 13.5m rather than 15.6m, and the ambient lighting conditions along the relevant stretch of Argyle Street. With regard to the latter, it appears that, despite having access to police photographs of the scene of the accident taken on the night in question, Mr Johnston only became aware that the light on pole 121 was not operating until some time after the preparation of his first report.
48 Mr Johnston's first report accepted that the point of impact was between 4m and 14m north of pole 122 and contained the opinion that the impact with the plaintiff occurred around 4 m north of pole 122 (T 511). Moreover, Mr Johnston accepted by the time he came to give evidence that Senior Constable Bain had correctly measured the full length of the skid marks at 15.6m. Notwithstanding these concessions and the erroneous assumptions upon which the conclusions expressed in the first report were based, Mr Johnston maintained that he was always of the view that the point of impact was at the commencement of the breaking of the defendant's vehicle.
49 The defendant's objection to the tender of the first report on the basis that so many of its critical assumptions were demonstrated to be incorrect resulted in the rejection of that report and the allowance of some further time to enable Mr Johnston to furnish an amended report, based upon the correct physical features of the site, and to determine whether his conclusions would be correspondingly affected. In the interim, Senior Constable Bain gave evidence in the proceedings in the terms set out above.
50 The cross-examination of Mr Johnston following the tender of Exhibit M exposed serious flaws in both Mr Johnston's methodology and his conclusions. In July 2006, Mr Johnston noted that "Constable Bain presumably had more contemporaneous and better evidence as part of his original police investigation" when dealing with the point of impact, yet Mr Johnston resolutely refused to accept that Senior Constable Bain's evidence, that the point of impact was in the vicinity of the deviation of the skid marks, should in any way affect the conclusion maintained in Mr Johnston's report of February 2007.
51 Mr Johnston initially said that that was not his understanding of Senior Constable Bain's evidence, based upon a conversation Mr Johnston had with Senior Constable Bain at the conclusion of the latter's evidence in the precincts of the court. Somewhat paradoxically, Mr Johnston was provided with a transcript of Senior Constable Bain's evidence but maintained that he had not read it and in any event he disagreed with it. To the extent that he was provided with a transcript of the evidence in order to make allowances for his earlier erroneous assumptions, Mr Johnston apparently relied exclusively on Ms Sheen's evidence. When it was brought to Mr Johnston's attention that Senior Constable Bain's opinion coincided with that of Mr Keramidas, Mr Johnston's reply was "but that doesn't make it correct. It is not correct. … I don't exclude it as a point of impact but the deviation of the tyre marks are indicative of the point of impact." (T 517)
52 Mr Johnston's reasons for rejecting the deviation of the skid marks as the point of impact were less than coherent. He proffered the opinion that the cross fall in the roadway was a more common explanation for deviation of skid marks, yet nowhere in any of his reports did he advance the opinion that the divergence in the skid marks was caused by the cross fall. Moreover, he acknowledged that deviation of skid marks from cross fall, absent any impact with an object, produces curved skid marks from the rear wheels of the vehicle, as opposed to the straight skid marks seen in this case. Mr Johnston then sought to discount the depiction of the skid marks on Exhibit A as not necessarily accurate, notwithstanding the fact that he had not asked Senior Constable Bain about that feature of the plan.
53 He conceded that he could not say exactly what did cause the deviation, but that he was of the firm view that it was not caused by pedestrian impact. (T 518) The foundation of that opinion was that the impact between the plaintiff and defendant's vehicle was, according to Mr Johnston, a central impact. The only feature of the damage to the defendant's vehicle that supported the conclusion that the impact was a central one was the damage to the number plate.
54 In the absence of any cogent evidence that the number plate was damaged solely as a result of impact with the plaintiff and in the light of the defendant's evidence that the number plate was flimsy and was prone to flexing, I place no reliance upon that aspect of Mr Johnston's opinion. There was overwhelming evidence of substantial damage to the driver's side of the vehicle. Yet, when the remainder of the damage to the defendant's vehicle (offside windscreen and offside headlight) was put to Mr Johnston as consistent with the plaintiff striking that side of the vehicle, Mr Johnston maintained that he was unable to say how the headlight sustained that damage. In short, he selectively relied upon the damage to the number plate and the windscreen to support his opinion that the plaintiff struck the centre of the car and was bounced diagonally over the bonnet.
55 Lastly, possibly the most telling aspect of Mr Johnston's evidence in respect of the point of impact was that the deviation of the skid marks indicated a possible point of impact, but that such a finding depended on other factors, including the pedestrian throw distance. It was apparent from Mr Johnston's calculations set out in Exhibit M that the pedestrian throw distance posits a point of impact. Mr Johnston's argument in this regard was therefore entirely circular.
56 Mr Keramidas acknowledged that it was relatively rare for pedestrian impact to give rise to a deviation in skid marks. By the same token, the physics of the phenomenon are reasonably straightforward. Given that the deviation had occurred, some force must have been applied in order to create it. In the absence of curved tyre marks (both front and rear wheels) and anything on the road surface that might generate a rotation of the vehicle, and given that the wheels were locked and sliding, by a process of elimination the deviation of the rear wheels was caused by impact between the offside of the defendant's vehicle and the plaintiff. (T 858) Whilst Mr Keramidas was cross-examined extensively on this topic, he remained unshaken. His evidence and the contents of his report (Exhibit 6) were internally consistent and withstood searching enquiry.
57 Even in the absence of a contrary expert opinion from Mr Keramidas, I would reject Mr Johnston's opinion as to the point of impact. There is an abundance of reliable evidence, namely from Senior Constable Bain and the defendant, together with objective evidence, that establishes the most likely point of impact as proximate to the deviation of the skid marks left by the defendant's vehicle.
The Visibility of the Plaintiff to the Defendant
58 In Exhibit M, Mr Johnston determined that, taking into account the visibility of a pedestrian under low beam at a distance of 50m, coupled with the likelihood that the plaintiff was silhouetted on the roadway before the defendant's headlights illuminated him, the defendant's reaction time was at least 1.3 to 2.1 seconds later than a reasonably alert driver. Accordingly, Mr Johnston was of the view that the defendant should have been able to stop prior to impact with the plaintiff, if she had been maintaining a proper lookout.
59 Each of these underlying conclusions, namely that a pedestrian would have been visible under low beam at a distance of 50m and the silhouetting of the plaintiff on the roadway, were shown to be tenuous at best.
60 Mr Johnston ultimately accepted that the 50m of visibility to which he referred was only applicable to an object on the near-side of the roadway, as opposed to an object on the off-side of the roadway. In the latter case the visibility was 24.8m. Significantly in the circumstances of this case, the distance from the tangent point on the right-hand bend at Lumsdaine street (the tangent point being the last point on the curve) to pole 122 was approximately 35m. Mr Johnston would not concede that the headlights of a vehicle emerging from the right-hand bend at Lumsdaine Street would not illuminate the road ahead until it reached that tangent point. He maintained that vehicles would substantially straighten before reaching the tangent point.
61 However, given that the near-side of the road is the primary focus of headlights on low beam, a pedestrian standing close to the double centre lines (off-side) would only be illuminated at the very conclusion of the vehicle's emergence from a right-hand bend. In addition, disability glare from the oncoming headlights of an approaching vehicle (Ms Sheen) was a relevant factor, which would have reduced visibility available to the defendant. Mr Johnston agreed that if disability glare was present, it may have reduced visibility of an object in the centre of the road to as little as 20m.
62 Mr Johnston relied upon primary source material on the subject of visibility that dealt with white objects rather than grey or blue objects. He agreed that there was no direct illumination from a street light in the area where the plaintiff stood. He also agreed that the defendant's vision would have necessarily adjusted when passing out of the lit area underneath pole 123 into the unlit area in the vicinity of pole 122 and extending to pole 121.
63 With regard to the silhouetting effect said to be present, Mr Johnston agreed that any silhouetting effect depended on the distance of the light source behind the pedestrian. Most importantly, he had assumed in August 2004 that there was an operative streetlight on pole 121, that is approximately 40m behind the plaintiff as the defendant approached. Notwithstanding this assumption, he had made no mention of silhouetting in his original report. Having acknowledged in his evidence that the only streetlight capable of silhouetting the plaintiff was 90m away (pole 120), it defies explanation how silhouetting could acquire a significance in February 2007 that it did not merit in August 2004. The defendant suggested that was because silhouetting received some attention in Mr Keramidas' report and Mr Johnston sought to respond to it. Whatever the explanation, Mr Johnston's opinion in Exhibit M on this topic has very little credibility.
64 In so far as Mr Johnston attempted to deal further with the subject of silhouetting in his report in reply to Mr Keramidas (Exhibit N), I reject the method adopted by Mr Johnston as a reliable demonstration of the silhouetting of a pedestrian at various distances along the relevant stretch of Argyle Street. Mr Johnston carried out what he described as "further tests" on 28 April 2007 and took a number of photographs which appear as figures 6, 8 and 10 in Exhibit N. The photographs purport to demonstrate how a pedestrian is silhouetted at 40m, 50m and 60m with the light on pole 121 disabled (in an attempt to replicate the lighting conditions on the night of the accident), but in re-examination it became apparent that Mr Johnston took the photographs from a static position on the roadway and caused the pedestrian to move further away from the camera on each occasion. Such a method is not consistent with the conditions that were prevailing at the time of the accident, namely that the defendant's vehicle was moving towards a relatively stationary pedestrian.
65 Mr Keramidas canvassed the subject of visibility in some detail at pages 26 to 30 of Exhibit 6. Of the seven factors capable of affecting "detection distance" from a driver's position to that of a pedestrian at night, all but one were of little or no assistance to the defendant. There was very little ambient light, or artificial light (either as direct illumination or as background light), no detectable motion from the plaintiff (in that he was walking towards the defendant's vehicle), and his clothing, whilst not dark, was not at the lighter end of the spectrum.
66 Mr Keramidas concluded that the primary source of visibility to the plaintiff from the defendant's perspective would have been the headlights of the vehicle. According to the relevant literature, there is a reduction in the recognition distance for right-hand curves of unspecified radius to approximately 22m. The reduction in the detection/recognition distance as a result of the curve arises out of the focus of the headlight beam, being at an angle downwards with a bias towards the nearside in its low-beam operation. Based on the expected headlight throw of the defendant's vehicle, the detection/recognition distance would be somewhere below 40m. (Exhibit 6 , p28)
67 There were, according to Mr Keramidas, two complicating factors, namely the existence of a pool of light at the intersection with Lumsdaine Street and disability glare occasioned to the defendant by the approach of Ms Sheen's vehicle. The former would require the defendant's eyes to readjust to a relatively low lighting level on emergence from the right-hand bend. The latter would have been augmented by the fact that the defendants eye level would have been lower to the ground than a person driving a standard sedan, given that the Mazda is approximately 150 to 200 mm lower than the standard sedan's roof height. These complicating factors, in Mr Keramidas' opinion, potentially reduced the visibility of the plaintiff to a range of between 25 and 35 m.
68 In these circumstances, Mr Keramidas was of the view that the defendant's reaction time and the application of her brakes were within those of a reasonable driver and that there was nothing that the defendant could reasonably be expected to have done in order to avoid impact with the plaintiff. Mr Johnston agreed that the area was not one of high pedestrian activity, particularly after midnight, and that it would be reasonable to expect pedestrians to be on the footpath. He agreed it would be quite unexpected for a driver to see someone standing in front of them or even walking towards them on that stretch of Argyle Street. He conceded that if the point of impact was indeed at the deviation of the skid marks, then he could not disagree with Mr Keramidas' conclusions, in particular that the defendant's reaction time was within or close to the normal reaction time in such circumstances.