THAPA KAMALA v. TANG WING KIT

HCPI 574/2018

[2021] HKCFI 1292

IN THE HIGH COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

COURT OF FIRST INSTANCE

PERSONAL INJURIES ACTION NO 574 OF 2018

________________________

________________________

________________________

D E C I S I O N

________________________

I. INTRODUCTION

1.  By a summons filed on 1 August 2019 (“Summons”), the plaintiff (“P”) applied under Order 38 rules 4 and 36 of the Rules of High Court (“RHC”) for leave to adduce expert evidence on liability. The defendant (“D”) opposed the Summons. On 16 June 2020, Master Grace Chan (“Master”) by way of paper disposal handed down her reasoned decision (“Master Decision”) to dismiss the Summons with costs (“Master Order”). On 22 June 2020, P filed her Notice of Appeal against the Master Order pursuant to Order 58 rule 1 of the RHC (“Appeal”).

2.  There was no dispute that on 25 April 2016 at/about 7:30pm D was driving a taxi with registration number JZ3714 (“Taxi”) along the northbound lane of Tai Tam Road (“Road”) near the American Club (“Club”) towards Chai Wan, and P was a pedestrian using the Road near the Club. The Road was a 2-way carriageway with 1 lane for southbound traffic (“SLane”) and 1 lane for northbound traffic (“NLane”) divided by solid and broken centrelines with the solid line nearer to the NLane (“CLine”), ie northbound vehicles on the NLane were not permitted to cross the CLine at any time.

3.  P claimed that at the material time she was standing on the eastern pedestrian pavement outside the Club waiting to cross the Road. A southbound taxi stopped in front of her (“Stopped Taxi”), so she walked towards its rear and started to cross the Road from behind it. When P passed the Stopped Taxi and was about to reach the middle of the Road, D without warning caused/allowed the Taxi to cross the CLine and hit P, who thereby suffered personal injuries (“Accident”).

4.  P claimed D as the driver of the Taxi owed a motorist’s duty of care to other road-users (including P), and the Accident was caused by D’s negligence in inter alia (a) driving at a speed in excess of the legal speed limit of 50kph, (b) driving at a speed that was excessive in the circumstances, and (c) crossing the CLine in the middle of the Road.

5.  D denied liability, and in particular denied the allegations in paragraph 4(a)-(c) above. He went on to aver inter alia that at the material time:

(a)	he was driving the Taxi at about 30kph;
(b)	he was driving the Taxi on the NLane and did not cross the CLine;
(c)	when D passed the Stopped Taxi on the SLane, a black shadow (later known to be P) suddenly and without stopping dashed out from the rear of the Stopped Taxi and encroached upon the Taxi’s path without giving D any reasonable opportunity to avoid collision, but D immediately applied brakes in an attempt to avoid collision;
(d)	no reasonable driver would have anticipated a pedestrian would suddenly dash out and cross the Road behind the Stopped Taxi, especially when there was a pedestrian crossing area in the vicinity;
(e)	P should not have crossed the Road where she did, and D had taken appropriate steps to meet such traffic emergency by driving at a speed well within the speed limit and at a pace reasonable for the then road conditions;
(f)	P without good cause encroached upon the Taxi’s path when it was dangerous so to do.

6.  Thus, the primary issues on liability pertinent for the Summons/Appeal would be whether at the material time (a) D was driving the Taxi at a speed in excess of the legal limit of 50kph (“Speed Limit Issue”) and/or at a speed that was excessive in the circumstances (“Excessive Speed Issue”) (collectively, “Speed Issues”) and (b) whether the point of impact between the Taxi and P was at the NLane or the SLane (ie whether the Taxi crossed the CLine) (“Location Issue”).

II.  PROSECUTION AGAINST P

7.  The police investigated the Accident, and prosecuted P for the offence of “being a pedestrian negligently endangering her own safety” under ESS39884/2016 (“Traffic Summons”). After a trial that took almost 90 days (“Trial”), Deputy Special Magistrate Ho Lai Ming (“Magistrate Ho”) returned a verdict of not guilty on 14 October 2019 (“Verdict”). D was not prosecuted in respect of the Accident.

8.  At the Trial, the prosecution (“Prosecution”) adduced expert evidence from a government chemist Dr Tam Cheok-ning (“Dr Tam”). Dr Tam as PW2 gave oral evidence, and his 2 statements dated 31 July 2017 (“Dr Tam’s 1^st Statement”) and 11 September 2017 (“Dr Tam’s 2^nd Statement”)[1] were adduced as exhibits 7(i)-(ii). Dr Tam carried out traffic accident reconstruction exercise at the incident location for taking measurements, and analysed the CCTV footage that captured the Accident (“Footage”) as recorded by a CCTV camera (“CCTV Camera”) mounted on a column at the Club’s premises (“Club Column”). Paragraph 4.2 of Dr Tam’s 1^st Statement stated as follows:

“Using the average rate of 7 frames per second [“fps”] and the measured distance of 7.8 metres travelled by [the Taxi] [“7.8m Road Stretch”] from Frame 31 to Frame 36, the average speed of [the Taxi] between Frames 32 and 36 was determined to be 49±5 km/h.”

The aforesaid frames were part of a series of 40 images/frames (“Frames”) extracted from the Footage between “19:40:31” and “19:41:30” at/about 7 fps with the assumed moment of impact occurring at/about “19:41:13” (Frame 35).[2] In the admitted facts dated 10 January 2018 and adduced as exhibit P(A) at the Trial (“Admitted Facts”), the Prosecution and P agreed that for the purpose of the Traffic Summons the average speed of the Taxi for the section captured by the CCTV Camera, ie the Footage stamped “19:40:31” to “19:41:30”, was found to be 49+/-5kph.

9.  Ir Lo Kok Keung (“Ir Lo”) was a mechanical engineer. He adopted Dr Tam’s findings, conducted further investigative analysis of each 2 consecutive Frames for Frames 32-36 over the 7.8m Road Stretch, and opined in paragraph 4.2 of his unsigned draft expert report (“Ir Lo’s Draft Report”) that the Taxi was travelling at the speed of 59+/-6kph at the beginning of that road segment (Frame 32) but slowed down to about 38+/-4kph at the tail-end of that road segment (Frame 36). But the Prosecution disputed Ir Lo’s qualifications, so after Magistrate Ho ruled there was a prima facie case against P at the Trial, she invited Ir Lo to give evidence on his expertise/qualifications, but eventually declined to allow P to call Ir Lo to give opinion evidence, so Ir Lo’s Draft Report was not adduced as exhibit at the Trial.

10.  P claimed that whether or not the Taxi crossed the CLine could be ascertained from expert analysis of the Footage, so at the Trial she called a consulting traffic reconstruction engineer Mr Grant Lee Johnston of Grant Johnston Consulting Engineers (“Mr Johnston”) as DW5 to give oral evidence, and to produce his expert report dated 9 June 2019 (“Dr Johnston’s 1^st Report”) as exhibit D7 and his letter dated 20 June 2019 with photographs as exhibit D7A-D. According to the admitted facts dated 14 June 2019 adduced as exhibit P(B) at the Trial, the Prosecution and P agreed that Mr Johnston’s expertise was in the area of traffic accident reconstruction. P also called a land surveyor Dr Tang Hong Wai (“Dr Tang”) as defence witness to give oral evidence at the Trial, and to produce his expert report dated 3 June 2019 (“Dr Tang’s Report”) as exhibit D6.

11.  As noted in the Master Decision, Magistrate Ho by her oral reasons for the Verdict (“Oral Reasons”) stated she did not accept either P or D to be honest/reliable witness, and there was a lurking doubt as to whether the Taxi crossed the CLine, so she gave the benefit of such doubt to P, and returned the Verdict to acquit her of the Traffic Summons.

12.  In the affirmation of D’s solicitor Wu Yaqing (“Wu”) filed on 9 March 2020 to oppose the Summons (“Wu Aff”), reference was made to Magistrate Ho’s concern over P copying her statement given to the police from a paper provided to her by her solicitor at the police station. This elicited P’s response in her 2^nd affidavit filed on 9 March 2020 in reply to the Wu Aff (“P 2^nd Aff”) that (a) such paper was the English version of P’s written instructions to her solicitors over which she had no issue,[3] and (b) Magistrate Ho’s criticism against P’s veracity stemmed from her apparent bias against P since early on at the Trial such that P had to apply for her recusal on the 4^th day of the Trial but she refused P’s application. In relation to (b) above, P’s 2^nd Aff went on at length about Magistrate Ho (i) imposing on P what P perceived to be an unwarranted bail condition,[4] (ii) refusing to allow Ir Lo to give opinion evidence for P for reasons that were plainly wrong,[5] (iii) causing difficulty to P’s witness DW6,[6] and (iv) unnecessarily prolonging the Trial that consumed scarce judicial resources.[7]

13.  Mr Leung, counsel for P, submitted that such matters in the Wu Aff were unhelpful, especially when Magistrate Ho acted in excess of her powers to cause trouble to P, her legal representatives and her witness, which conduct resulted in 2 successful judicial reviews that quashed her decisions and made an order of mandamus directing her to hear closing submissions and not to further delay the Trial.[8] But Ms Lee, counsel for D, submitted that the Wu Aff helpfully exhibited the used/unused materials for the Traffic Summons to give a complete picture of what materials might be available if expert evidence on liability were disallowed in the present action, and P’s criticisms of the Wu Aff had no bearing on the merits of the Appeal.

14.  Bearing in mind that Mr Leung’s contention that Magistrate Ho’s views on P’s/D’s veracity and her reasons for not believing them would not bind the court in the present action, and further noting that both Mr Leung and Ms Lee did not take any issue on the veracity of such factual witnesses for the Appeal,[9] I do not propose to discuss the aforesaid matters in the affirmation evidence unless necessary. In any event, as noted in the Master Decision, Magistrate Ho in her Oral Reasons did not appear to have made specific findings of facts or to have formed definitive views on what expert evidence she accepted.

III.  PROCEDURAL HISTORY

15.  On 28 May 2018, P commenced the present action against D to claim for loss and damages from personal injuries suffered as a result of the Accident. P’s total claim as pleaded in her Revised Statement of Damages was about $6.08 million.

16.  P’s witness statement dated 19 December 2018 (“P’s 1^st Statement”) reiterated the matters in paragraphs 2-4 above, and described the Accident as follows:

“8. On 25^th April 2016, at about 7:30 p.m., [P] finished work from the [Club]. [P] walked along the footpath to exit the [Club]. When [P] reach the Road, [P] stopped at the edge of the pedestrian pavement and watched the traffic along the Road to see if it was safe to cross the Road to the opposite side. Soon, a [Stopped Taxi] pulled towards the pedestrian pavement on [P’s] side stopped in front of [her]. The nearside of that taxi was about half a metre from the edge of the pedestrian pavement. The [Stopped Taxi] had the left indicator blinking and appeared to stop for a passenger. [P] could not see anyone beside [her] and did not know how long the [Stopped Taxi] would stop and wait for its passenger. So [P] walked towards the rear of that taxi in order to cross the Road.

9. [P] then walked along the pavement, and after [P] passed the rear of the [Stopped Taxi] for about half a metre, [P] stopped at the pedestrian pavement and looked at the traffic from both sides of the Road to see if it was safe to cross the Road. There was then no oncoming southbound traffic and [P] started walking onto the [SLane]. Whilst [P] was walking, [P] looked at both [her] right-hand side and left-hand side for any oncoming traffic. [P] saw no traffic coming from [her] right-hand side. For [her] left-hand side, because [the Stopped Taxi] was still stopping at that location (then on [her] left) [she] could not see clearly whether there was any traffic approaching.

10. [P] continued to walk normally. When [P] was still on the [SLane] and nearly reached the CLine, [P] was suddenly hit by a fast-moving vehicle from [her] left. It was a very strong blow and [she] was thrown towards [her] right-hand side and landed on the [SLane] on the edge of the pedestrian pavement. [She] landed on [her] right side. [Her] head also hit the ground and [she] lost consciousness. [She] then suffered serious personal injuries. It was later known to [her] that the vehicle which hit [her] was the Taxi, driven by [D].

11. [P] say that [D] was negligent in causing or permitting the Taxi to hit [P], in that the Taxi was travelling in excess of the legal speed limit and had crossed the [CLine] to hit [her].”

17.  D’s witness statement dated 3 January 2019 (“D’s Statement”) gave an account of the Accident in line with the matters in paragraph 5 above as follows:

“3. 意外當日，即2016年4月25日，約下午7時43分，[D]駕駛的[Taxi]由赤柱經[Road]往柴灣地鐵站方向行駛。

4. 當晚天氣良好，地面乾爽，而沿[Road]出柴灣方向交通暢順。但因當時光線比較暗，[D]有著的士車頭大燈沿[Road]行車。而當時[D]以時速大約30公里沿途行駛臨發生意外一段之[Road]，[D]前方無尾隨其他車輛。

5. 當[D]架[Taxi]駛到沿[Road]近[Club]出入口時，即距離[Club]出入口大約3 – 4 個的士位時，[P]見到對面行車綫就有另一架[Stopped Taxi]停在近[Club]出入口附近，[D]不知它因何事停低。

6. [D]當時亦有留意住那一架停在對面行車綫嘅[Stopped Taxi]，而[D]一直保持時速30公里左右行車。

7. 當[D]的[Taxi]車頭行駛到同對面綫停定的[Stopped Taxi]車尾接近平排時，[D]見到[D]右車頭旁邊(亦即是[Stopped Taxi]的車尾)突然有一個黑影衝過來[D]右車頭方向。[D]第一眼見到個黑影已經急刹車，但是當時已經發生碰撞。由於當時[D’s Taxi]之車速不快，所以[D]在大半個的士距離左右就已經刹停晒架車。

8. [D]立即落車，就見到被[D’s Taxi]撞到的是一個女士。本人便報警。

9. [Accident]之前，由於對面行車綫有另一架[Stopped Taxi]停在近[Club]出入口附近，而那個黑影突然在對面行車綫[Stopped Taxi]的車尾衝過來[D]右車頭方向，[D]完全無可能在碰撞前見到對方的。而[D]一見到對方就已經有碰撞。[D]根本無時間響咹。

10. 今次意外，[D]的車右邊車頭燈位爆咗。而[Taxi]再無其他損毁。

11. [D]之後知道該受傷女子被警方控告不小心過馬路，而[D]並沒有因[Accident]被檢控。”

18.  Plainly, P and D by their statement evidence advanced her/his respective version of the Accident, but P’s 1^st Statement did not give the speed of the Taxi except it was “fast-moving”. Mr Leung submitted that a pedestrian hit/injured as P described would understandably be unable to tell the exact speed of the colliding vehicle. In my view, whether it was so would be a matter for trial, but it was sufficient for the Appeal to note P did not say more about the speed of the Taxi except it was “fast-moving”.

19.  On 15 November 2018, Master M Lam granted inter alia the following order:

(a)	within 21 days of the conclusion of the Trial, P “do make discovery of the brief facts, witness statements, photographs, sketches and certificate which are in her possession, custody and power”, otherwise she shall file affirmation to verify her discovery;
(b)	the parties were to inform the court within 14 days on whether they would seek leave to adduce expert evidence on liability.

20.  On 19 December 2018, the parties reported to the court the Footage being evidence at the on-going Trial had not been disclosed to D. On 11 January 2019, Master M Lam directed D to make application (if necessary) for leave to adduce expert evidence on liability within 14 days of P’s compliance with paragraph 19(a) above. On 21 June 2019, the parties informed the court P had made partial discovery under paragraph 19(a) above and expected to make further discovery upon agreement with the Prosecution when evidence was concluded at the Trial, and Master M Lam extended time until 19 July 2019 for P to comply with paragraph 19(a) above. On 21 June 2019, the parties informed the court that Dr Tam’s 1^st Statement[10] and the Footage[11] had been disclosed at the Trial. On 19 July 2019, P filed her affidavit to verify that (a) the Prosecution had not consented to disclosure of documents not referred to or communicated in open court, and (b) apart from P’s discovered documents[12] there were no other relevant documents then in her possession, custody or power.

21.  On 1 August 2019, P filed the Summons for inter alia the following reliefs (“Summons”):

(a)	the parties do have leave to adduce expert evidence on liability;
(b)	the experts do give opinion on (i) the speed of the Taxi prior to and during the collision between the Taxi and P (ie the Speed Issues), and (ii) whether the point of impact between the Taxi and P was on the NLane or SLane (ie the Location Issue);
(c)	P’s nominated experts be limited to a land surveyor Dr Tang, a consulting traffic reconstruction engineer Mr Johnston, a mechanical engineer Ir Lo and a government chemist Dr Tam (collectively, “P’s Experts”);
(d)	D do notify the identities of his expert(s) on liability;
(e)	the parties do exchange their expert reports on liability within 42 days from the order to be made.

22.  On the same day, P filed her 1^st affidavit in support of the Summons (“P 1^st Aff”). P intended to adduce expert opinion on liability on the Speed/Location Issues contained in Dr Tam’s 1^st Statement, Ir Lo’s Draft Report, Mr Johnston’s preliminary engineering investigation report dated 31 July 2019 (“Mr Johnston’s 2^nd Report”) and Dr Tang’s Report. For the purpose of the Appeal, D did not intend to challenge the expertise/ qualifications of P’s Experts.[13]

23.  On 20 August 2019, P filed a Notice to Admit Facts, asking D to admit the following facts:

(a)	that shortly before the collision between P and the Taxi, D was driving the Taxi at a speed in excess of the legal speed limit;
(b)	D caused or allowed the taxi to cross the CLine to hit P.

Unsurprisingly, there was no response from D who all along denied liability on the basis of the facts and matters pleaded in his Defence (see paragraph 5 above).

24.  Although Magistrate Ho returned the Verdict to acquit P of the Traffic Summons on 14 October 2019, she adjourned hearing of the issue of costs. On 14 November 2019, the parties reported to the court in the present action the aforesaid developments and P’s difficulty in obtaining the Prosecution’s agreement to make discovery of police investigation documents (eg unused materials) in the present action. On 30 December 2019, the parties further reported disclosure of the unused materials to D on 15 December 2019, but D wanted sight of other documents before he would prepare affirmation evidence to oppose the Summons. On 7 January 2020, the Master inter alia extended time for filing/serving affirmations in opposition and in reply, and adjourned the substantive hearing of the Summons to 30 March 2020.

25.  On 31 January 2020, D obtained from P all 37 exhibits used/ produced at the Trial[14] and also the transcript of the Oral Reasons. D also obtained from P further documents provided by the police.[15] On 9 March 2020, D filed the Wu Aff, and P filed the P 2^nd Aff. The hearing of the Summons on 30 March 2020 was generally adjourned due to public health considerations, and the parties agreed for the Summons to be determined by paper disposal.

26.  On 18 May 2020, the Master raised written requisitions on whether or not P’s Experts had given evidence at the Trial, and invited written submissions on (a) how the parties would deal with police investigation leading to the Traffic Summons and the consequent Trial in the present action, eg whether documents in relation to the Trial such as exhibits and transcript would be adduced in the present action if the Summons were to be dismissed, and (b) whether single joint expert(s) would be appropriate if the Summons were allowed.

27.  On 22 May 2020, the parties jointly reported to the court that (a) at the Trial the Prosecution adduced Dr Tam’s 1^st/2^nd Statements, Dr Tang’s Report and Mr Johnston’s 1^st Report (which was substantially identical to Mr Johnston’s 2^nd Report), so the transcript of the Trial would not refer to Mr Johnston’s 2^nd Report and Ir Lo’s Draft Report, and (b) P would not rely on the transcript of the Trial which she thought was not relevant.

28.  The Master Decision noted the parties had different views as to (a) whether documents relating to police investigation[16] of the Accident should be admitted as evidence for the present action, and (b) how to deal with the expert reports already made exhibits at the Trial with P suggesting they should be admitted as opinion evidence in the present action if the Summons were dismissed and D holding a contrary view. The Master tended to agree that the transcript of the Trial might not be necessary/helpful, but considered it was for the parties (as they saw fit) to make discovery of the above-mentioned documents in the usual way.

29.  Both Mr Leung and Ms Lee confirmed at the hearing of the Appeal on 19 January 2021 (“Hearing”) that the parties in the present action would not rely on or adduce in evidence the transcript of the Trial. Ms Lee’s written submissions suggested that if the Appeal were dismissed, then certain documents/materials relating to police investigation of the Accident[17] should be admitted as hearsay evidence in the present action to assist the court in determining the issues on liability. On the other hand, Mr Leung was concerned that (a) PC4374’s investigation report of 13 June 2017 recorded that when the police contacted D to ask him whether he would testify against P, D replied he did not want to persist with the complaint/prosecution, and (b) PC4374’s statement stated that he had viewed the Footage and found P suddenly dashed to the NLane when in fact the Footage did not show the point of impact between the Taxi and P due to “blockages caused by other objects”,[18] so Mr Leung suggested that the police could not be said to be independent and that the contents of their notebooks, sketches and statements would be prejudicial to P.

30.  I find it strange that, if this court disallowed P from adducing expert evidence on liability on the Location/Speed Issues, the substance of which were set out in Dr Tam’s 1^st Statement, Dr Johnston’s 2^nd Report and Dr Tang’s Report, P could then adduce (a) the very same Dr Tam’s 1^st Statement and Dr Tang’s Report and (b) the substance of Dr Johnston’s 2^nd Report (by way of the largely similar Dr Johnston’s 1^st Report) via the backdoor through discovery of documents. After all, discovery of documents was meant for disclosure of factual documentary evidence, and it would not be a separate avenue for adducing expert reports that had been used at the Trial but disallowed in the present action. I am not persuaded the Master Decision suggested this, but if it were otherwise, I find myself unable to agree.

31.  But happily, Mr Leung and Ms Lee at the Hearing agreed for Dr Tam’s 1^st Statement (except for paragraphs 5.1-5.3 thereof which admissibility Mr Leung disputed and I reject in paragraphs 86-94 below) to be adduced as expert evidence on liability in the present action. Although Ms Lee was prepared for Dr Tam’s 2^nd Statement to be adduced as well (see footnote 17 above), which statement essentially set out Dr Tam’s curriculum vitae and the primary documents upon which he rested his findings/opinion in Dr Tam’s 1^st Statement (see footnote 1 above), I do not propose to deal with Dr Tam’s 2^nd Statement in the Appeal as (a) the Summons when read with the P 1^st Aff did not ask for such statement to be adduced, and (b) Dr Tam’s casefile might include some primary documents for the matters canvassed in paragraphs 5.1-5.3 of Dr Tam’s 1^st Statement which I disallow in paragraphs 88-90 below. That said, Dr Tam’s curriculum vitae, the 36 Frames and some of the working papers in his casefile pertaining to the Speed Issues referred to in Dr Tam’s 2^nd Statement were plainly pertinent to paragraphs 1-4 of Dr Tam’s 1^st Statement that were agreed to be adduced, and the parties should take proactive steps to (i) identify the relevant parts of Dr Tam’s 2^nd Statement and appendices thereto, and (ii) seek leave to adduce the same in the present action.

32.  Further, given the nature of the Appeal, I also confine myself to the issue of expert evidence on liability and not foray into factual documentary evidence, so I will not address the matter of discovery of documents except to observe that discovery (as distinct from admissibility) of documents is guided by the Peruvian Guano threshold rather than by consideration as to whether a document is or is not adverse to a party, which means a party is required to discover documents relating to the matters in question in the action, including document on any pleaded issue as well as documents reasonably supposed to contain information that may – not that must – either directly or indirectly facilitate a chain of enquiry for advancing one’s own case or to damage the adversary’s case.[19]

33.  On 16 June 2020, the Master handed down the Master Decision that granted the Master Order. On 22 June 2020, P filed the Appeal to set aside the Master Order, and to seek an order inter alia that (a) the parties do have leave to adduce expert evidence on liability, (b) the experts shall give opinion on (i) the speed of the Taxi prior to and during the collision between the Taxi and P and (ii) whether the point of impact was on the NLane or SLane, and (c) consequential directions be given. On 5 August 2020, the Master summarily assessed D’s costs in the sum of $167,500.

34.  On 5 January 2021, ie shortly before the Hearing of the Appeal on 19 January 2021, P filed a summons (“Leave Summons”) for leave to file/serve her supplemental witness statement as per the copy attached thereto (“P’s 2^nd Statement”). On 12 January 2021, the parties filed a consent summons (“Consent Summons”) for (a) leave to P to file/ serve P’s 2^nd Statement, and (b) costs of and occasioned by the Leave Summons including costs of the Consent Summons be to D in any event to be taxed if not agreed. As at the date of the Hearing, the Consent Summons was pending disposal by the PI Master.

35.  P’s 2^nd Statement stated as follows:

“2. As stated in [P’s 1^st Statement], at the time of the Accident, [P] was employed as a security guard and was assigned to work at the [Club]. As on the date of the Accident, [P has] been working at the [Club] for over 2 years.

3. [P’s] duty at the [Club] included attending the guard booth at the entrance of the driveway of the main entrance. During the hours of work, [P] had to walk between the guard booth and the inside of the [Club] for various matters. [P] was aware that there was a [CCTV Camera] installed and mounted on a column with a metal bracket and that [CCTV Camera] captured the Accident. After the Accident, [P] visited the Accident scene several times with [her] lawyers (the latest dated on 04.01.2019) and observed that the [CCTV Camera] and the mounting bracket has been all along at the same position on the column. [She] understand that the [CCTV Camera] was fixed on the metal bracket and may shift slightly.

4. It is now produced and shown to [P] a copy of the photo taken on 04.01.2019 of the [CCTV Camera] of the [Club] which captured the Accident marked exhibit TK-1.

5. At the time of signing [P’s 1^st Statement], [P] was not aware that it was necessary for stating the fact that the position of the [CCTV Camera] and the mounting bracket remained unchanged.”

IV.  SUMMARY OF PARTIES’ RESPECTIVE STANCE

(a)  P’s stance

36.  Mr Leung submitted that Dr Tam’s / Ir Lo’s expert findings/ opinion on the Speed Issues were scientific, reasonable, objective and beyond the knowledge of the lay court, and they were necessary and relevant as being helpful to the court when making findings on the Speed Limit Issue. As for the Location Issue, Mr Leung submitted that in the absence of expert analysis/opinion the Footage, albeit a piece of objective evidence, could not assist because (a) a 2-dimensional lay review would not show one way or another whether the Taxi crossed the CLine, especially as the Accident occurred in hours of darkness and the CLine was not evident “due to blockages caused by other objects”,[20] but (b) a 3-dimensional expert analysis of the Footage/Frames in Mr Johnston’s 2^nd Report by application of Dr Tang’s calculations as to the “angle of drop” of the CCTV Camera[21] would reveal that the Taxi did cross the CLine to hit P on the SLane.[22] On such basis, Mr Leung contended the findings/opinion of Mr Johnston and Dr Tang were (i) scientific, reasonable and objective, (ii) relevant in helping the court to find whether or not the Taxi crossed the CLine to hit P, and (iii) necessary as being beyond the experience and knowledge of the lay court.

37.  Mr Leung submitted that whilst the evidence adduced and what happened at the Trial would not bind the court in the present action, Magistrate Ho’s reference to expert evidence adduced by the Prosecution and by P at the Trial in finding there was a lurking doubt in P’s favour (ie “given what had been said by PW2 [Dr Tam]” on the Location Issue) that led to P’s acquittal demonstrated (a) such expert evidence would be relevant, appropriate and necessary for resolving some of the issues on liability in relation to the Accident, and (b) it would be “utterly unjust” for the Prosecution to be allowed to adduce expert evidence at the Trial, but for P to be debarred from adducing expert evidence on liability in her common law claim.

38.  Mr Leung disagreed the trial judge in the present action could have determined the Speed/Location Issues based on “documents in the criminal case and the evidence given at the trial”. It was uncertain what “documents in the criminal case” that Wu referred to and were admissible in the present action. If they were the expert reports adduced at the Trial, Mr Leung argued that leave of the court was required to adduce such expert evidence on liability in the present action. If they were factual documents adduced at the Trial, Mr Leung doubted how they could assist the lay court in deciding the Speed/Location Issues with reasonable reliability.

(b)  D’s stance

39.  Ms Lee submitted that traffic accidents involving collisions between road-users concerned factual matters within the ordinary experience of pedestrians/motorists. Here, P and D would be able to speak about what happened, and police photographs/sketches, Dr Tam’s 1^st Statement (which itself was an accident reconstruction report) and the Footage were available, so there was ample evidence for the trial judge to make findings of fact without need for expert evidence that had been adduced at the Trial (when the Prosecution carried the burden to prove all elements of the offence beyond reasonable doubt, and when P was entitled to adduce evidence to raise doubt) to be adduced as expert evidence on liability in the present action (when a different threshold was applicable for establishing/disputing common law negligence in a running down action).

40.  Ms Lee contended that in simple run-of-the-mill running down cases that happen “almost daily in Hong Kong streets”[23] (of which the present action was one), expert evidence on liability is not normally allowed, and here there were no exceptional circumstances to justify departure from such general rule. The fact P was summonsed for pedestrian negligence and deployed expert evidence at the Trial would not bind this court, and there was nothing unjust to allow the Prosecution to deploy expert evidence at the Trial,[24] but to deny P (and also D) leave to adduce expert evidence on liability in the present action.

41.  In relation to Mr Johnston’s and Dr Tang’s findings/opinion on the Location Issue, Ms Lee submitted these proposed experts arrived at their conclusions from a series of inferences that were not clear on the face of their reports, and it was unlikely the court would prefer such opinion evidence over the live evidence of P and D (who experienced the Accident first-hand) with the aid of photographs/sketches by police officers (who arrived at the scene soon after the Accident). In relation to Dr Tam’s and Ir Lo’s findings/opinion on the Speed Issues, P admitted at the Trial the average speed of the Taxi for the 7.8m Road Stretch was 49+/-5kph, but it now appeared P proposed to engage Ir Lo to give opinion to “contradict” that of Dr Tam who as a government chemist had no interest in the outcome of this litigation. Ms Lee submitted that, in any event, given P’s agreement on the average speed of the Taxi, it was unnecessary/irrelevant to expect the court to make findings on speed at the micro-level of every 1/7 second as Ir Lo proposed.

42.  In all, Wu believed (and Ms Lee submitted) the factual evidence concerning the Accident to be adduced at trial herein[25] would sufficiently assist the trial judge (who would have the added advantage of having conflicting witness evidence tested under cross-examination) to ascertain how the Accident happened and to determine the Speed/ Location Issues, which were no more than “day in and day out” functions of any trial judge, so there was no probative value in adducing expert evidence on liability. In this respect, I also note the Master (whose Master Order D supported in the Appeal) was of the view that:

“17. …… Very often, the speed of the vehicle and/or location of impact are the issues of running down cases, which our Judges need to rule in most if not all running down cases. These are questions of fact which our court does not need the opinion/assistance of an expert in order to form an independent view on the speed of D and/or whether the speed was excessive in the circumstances and/or the location of the impact.

……

22. In my view, the court, having ample experience in trying simple running down cases, would be able to make its own finding of facts on the issues of speed and location of impact upon considering the totality of the evidence, including the [Footage]. There is no need, as suggested by Mr Leung, for the court to be assisted by the experts in analyzing the content of the [Footage].”

V.  AFFIRMATION EVIDENCE

43.  2 points on the affirmation evidence could be dealt with fairly shortly:

(a)

P complained it was inappropriate for Wu to depose on factual matters on D’s behalf when there was no forthcoming explanation from D as to why he could not make the affirmation in opposition himself. In my view, there were no merits to such complaint. First, the Summons did not involve any debate on factual evidence, and the issue was whether expert evidence on liability (in contra-distinction to lay evidence) should be allowed. D would not have meaningful observations on the reports by P’s Experts except as advised by his solicitors. Secondly, factual information in the Wu Aff was largely gleaned from documents in relation to the Traffic Summons / Trial that P disclosed to D’s solicitors rather than from information within D’s personal knowledge.

(b)

P complained it was inappropriate for Wu to repeat facts pleaded in the pleadings or to make submissions in the Wu Aff as “an affidavit should only contain facts”. Again, there were no merits to such complaint. First, Wu did not verify the factual allegations in the pleadings; rather, he set out the pleaded averments in the Wu Aff to put D’s grounds of opposition to the Summons in context. Secondly, since the Summons concerned expert and not lay evidence, I cannot see how Wu could fairly have alerted P as to D’s stance by way of the Wu Aff without going into perceived weaknesses of the findings/opinion of P’s Experts in their reports.

(a)  Wu Aff and Ms Lee’s submissions

44.  On the Location Issue, Wu pointed out that the contents of Mr Johnston’s 2^nd Report were almost identical to those of Mr Johnston’s 1^st Report, and that Magistrate Ho’s Oral Reasons noted Mr Johnston testified “he would not rule out the possibility that the [Taxi] had not crossed and even had not touched the [CLine]”, and Dr Tam “also confirmed repeatedly that he would not rule out the possibility that the [Taxi] had crossed the [CLine] when hitting [P]”.[26] On such basis, Wu believed Mr Johnston’s 2^nd Report could not assist the court in the present action in determining the Location Issue. Further, Wu doubted the relevance of Dr Tang’s Report on the “angle of drop” of the CCTV Camera since (a) Dr Tang did not attend the scene to conduct a land survey at the time of the Accident, and only did so about 2½ years later on 26 October 2018, and (b) there was no information as to the position of the CCTV Camera at the time of the Accident and/or no evidence that its position remained unchanged until Mr Tang’s land survey. Wu suggested there was a “real possibility” that the position of the CCTV Camera had been changed after the Accident, so Dr Tang’s Report was of no probative value.

45.  On the Speed Issues, Wu noted Ir Lo’s Draft Report made several assumptions in calculating the speed of the Taxi for relevant periods, but Ir Lo did not attend the Accident scene or give justification for his calculations, and instead he relied on information/data by Dr Tam without disputing the same. Wu further reminded that by the Admitted Facts P and the Prosecution had agreed that the average speed of the Taxi for the Footage captured by the CCTV Camera from 19:40:31 to 19:41:30 was 49+/-5kph as set out in Dr Tam’s 1^st Statement,[27] so Wu believed Ir Lo’s Draft Report would contribute nothing to the trial in the present action.

(b)  P’s 2^nd Aff and Mr Leung’s submisions

46.  P contended the Oral Reasons[28] would not assist on the issues on liability in the present action because (a) the trial judge herein would not be bound by the same, (b) Magistrate Ho was apparently biased against P such that her Oral Reasons would be of no value, and (c) at the Trial it was for the Prosecution to prove all elements of the offence in the Traffic Summons beyond reasonable doubt and P was entitled to adduce evidence to raise doubt,[29] but a different threshold was applicable for establishing/disputing common law negligence in the present action.

47.  When the Traffic Summons was first heard on 5 June 2017, Magistrate Chan Ping Chau Kenneth adjourned the case for 4 weeks for the Prosecution to take instructions on whether, in view of the seriousness of P’s injuries, prosecution against her would be of public interest. During such adjournment on 19 June 2017, P’s solicitors wrote to the Prosecution to urge withdrawal of the Traffic Summons, but the Prosecution declined to do so and went on to procure Dr Tam to carry out traffic accident reconstruction to determine the average speed of the Taxi, which was why Dr Tam’s 1^st Statement was made after the first mention hearing of the Traffic Summons.

48.  P claimed Magistrate Ho’s observations that Mr Johnston gave evidence that he could not rule out the possibility of the Taxi not touching/crossing the CLine were irrelevant because (a) no reasonable magistrate would have asked a defence expert witness like Mr Johnston (as Magistrate Ho did) whether he could rule out such possibility when the answer one way or another would have no relevance to P’s conviction or acquittal, and (b) it was, in any event, neither here nor there as Mr Johnston did opine there was likelihood that the Taxi crossed the CLine. So P disagreed that Mr Johnston’s findings/opinion could not assist the trial judge on the Location Issue, especially when P carried the burden of proving her pleaded facts on the balance of probabilities.

49.  Further, Mr Leung pointed out Wu did not explain why it was necessary for (a) Dr Tang as land surveying expert who provided measurements of certain points of reference and (b) Ir Lo as mechanical engineer who opined on the Footage to be present at the incident scene on the date of the Accident. Mr Leung noted with interest that D did not criticise the usefulness of Dr Tam’s opinion on the Taxi’s average speed over the 7.8m Road Stretch at the time of the Accident on the basis that Dr Tam did not attend the incident scene at the material time. [30] Mr Leung further submitted the courts recognised that “[almost] invariably, where expert evidence on liability is adduced, the relevant expert was not present at the time of the incident”,[31] but the question still remained whether expert evidence would be probative and required/ useful to assist the court on determining the issues on liability.

50.  P considered Wu’s assertion of “…… a real possibility that the position of the [CCTV Camera] of the [Club] had been changed after the Accident” groundless in the absence of any supporting evidence. At the time of the Accident, P had been working as a security guard at the Club 3 days per week for over 2 years, and she entered/left the Club building many times each working day, so she knew the CCTV Camera that captured the Footage had been permanently installed/mounted on the Club Column. P also visited the Club after the Accident so as to give proper instructions to her solicitors, and she knew the CCTV Camera had not been moved after the Accident at least until her latest visit on 4 January 2019. P claimed she actually gave evidence at the Trial that the CCTV Camera had not been moved since the Accident, and she was asked to and did mark the mounting screws on a photograph being exhibit D2-4a produced at the Trial. P did not mention this in P’s 1^st Statement because at that time it had not been decided to adduce expert evidence on liability, but in the P 2^nd Aff she said she would seek leave to serve P’s 2^nd Statement (see paragraphs 34-35 above).

51.  Mr Leung submitted that whether P’s such evidence would be accepted by the court would be a matter for the trial judge, and he referred to my observations in Li Siu Ping and Li Siu Yu, the co-adminstratrices of the estate of Chan Kwok Hung, deceased v Perfecta Dyeing, Printing & Weaving Works Ltd[32] as follows:

“59. Almost invariably, where expert evidence on liability is adduced, the relevant expert was not present at the time of the incident. But if the subject matter deserves expert opinion under the principles discussed above, the expert opinion is necessarily based on (a) facts observed by the expert and (b) assumed or accepted facts. In respect of (a), the expert’s factual observations must be stated and proved by him. In respect of (b), the assumed or accepted facts must be proved by the party adducing the expert opinion by some other way. Where expert evidence on liability is required, admissibility does not turn on whether the expert can give factual evidence as to what happened at the time of the incident. Rather, the expert should give a proper basis for his opinion by explaining how his special knowledge and expertise in an area of which he is an expert by experience or training applies to the facts in (a) and (b) above.

60. Further, the expert is not required to ignore witnesses’ accounts and limit himself to consideration of the physical evidence (eg the facts observed by him). His opinion should refer to witnesses’ accounts or assumed facts whilst recognising that ultimately it is for the trial judge to make the factual findings or to accept/reject a particular witness’ account. It is open to the expert to explain whether the physical evidence is or is not consistent with the account given by either party, which in my view does not usurp the function of the trial judge. Once the expert opinion is admitted, it is up to the trial judge to consider all the evidence and give such weight as he thinks appropriate to any part of the evidence if at all.”

VI.  LEGAL PRINCIPLES: APPEAL

52.  I have set out the relevant principles in my judgment in Ng Ting Kwok v Ng On Kwok & anor and in Sun Ming Lok, a minor suing by his mother and next friend, Hui Man Chong v Choy Wing Ho & anor, [33] which I adopt but do not repeat here.

VII.  LEGAL PRINCIPLES: EXPERT EVIDENCE

53.  Mr Leung set out some legal principles on expert evidence in paragraphs 30-50 of his written submissions dated 14 January 2021. Ms Lee helpfully informed the court that D had no dispute with the law so set out in Mr Leung’s written submissions. But despite such broad understanding, there were still some differences in their approach to expert evidence on liability.

54.  Ms Lee submitted that apart from showing the proposed expert evidence on liability was admissible, P had to cross other hurdles. She relied on Liddell v Middleton[34] (and subsequent authorities that followed Liddell as discussed below) for the proposition that generally for running down cases (in contra-distinction to clinical negligence or work-accident cases), granting leave to adduce expert evidence on liability/causation is the exception rather than the rule, so (a) P had to first satisfy the court (i) she was able to surpass “the Liddell hurdle” and (ii) use of P’s Experts’ opinion in the present action was not against the CJR spirit, and then (b) she had to demonstrate that such expert evidence on liability was necessary, relevant and of probative value.

55.  But Mr Leung disagreed that just because P and D could speak about what happened and there were photographs, sketches, Dr Tam’s 1^st Statement and the Footage, there was thereby ample/ sufficient evidence for the court to make findings of fact. It was said that, unlike Liddell and/or where expert evidence on liability was based entirely on partisan witness accounts, the analyses performed by P’s Experts here were scientific, objective and outside the knowledge/ experience of the lay court. Mr Leung reminded that P, who was injured, was unable to tell the speed of the Taxi except it was “fast-moving”, and lay review of the Footage not aided by scientific analysis would not have elicited the speed of the Taxi or would not have shown the location of impact between the Taxi and P. Further, it was said D did not explain how the available photographs and sketches would assist in determining the Location/Speed Issues, and Mr Leung submitted they could not assist (and at least they did not lead Magistrate Ho to make findings of fact). All that would be left would be the partisan statement/oral evidence of P and D which, Mr Leung argued, ought to be assessed against the inherent information that was capable of being scientifically extracted from the Footage being “a piece of incontrovertible and admissible evidence” that the court could confidently rely. It was said that absent such expert assistance the trial judge in the present action would not be able to fully/ properly deal with the Location/Speed Issues, so the analyses/ opinion by P’s Experts that rested on the Footage/Frames fell within the ambit of useful admissible expert testimony that would bring it within the exception referred to in Liddell. Mr Leung argued it would be potentially unjust for either P or D (depending on the trial judge’s eventual findings) if expert analysis of the Footage/Frames to support or contradict the claim herein was disallowed.

56.  Given the difference in approach between Ms Lee and Mr Leung as summarised above, I take the opportunity to revisit the law on admissibility of expert evidence on liability, especially in the context of road traffic claims.

57.  The starting point must be section 58(1) of the Evidence Ordinance Cap 8 (“EO”) which provides that:

“Subject to any rules, where a person is called as a witness in any civil proceedings, his opinion on any relevant matter on which he is qualified to give evidence shall be admissible in evidence.”[35]

But Order 38 rules 36-37 of the RHC impose restrictions on adducing expert evidence:

“36 (1) Except with the leave of the Court ……, no expert evidence may be adduced at the trial or hearing of any cause of matter unless the party seeking to adduce the evidence –

(a) has applied to the Court to determine whether a direction should be given under rule 37 or 41 (whichever is appropriate) and has complied with any direction given on the application.

……

37 (1) …… where in any cause or matter an application is made under rule 36(1) in respect of oral expert evidence, then, unless the Court considers that there are special reasons for not doing so, it shall direct that the substance of the evidence be disclosed in the form of a written report or reports to such parties and within such period as the Court may specify.

……”

58.  Given such statutory restrictions, it is clear the court retains complete control over the use of expert evidence, the purpose of which is to limit expert evidence to what is relevant and reasonably necessary for resolving the issues for determination at trial. The exercise of discretion by the court on whether or not to grant leave for expert evidence to be adduced is within the ambit of its case management powers. The burden is on the applicant to show the proposed expert evidence is usefully required for resolving the issues in dispute.[36]

59.  Quite recently in my decision in Sun Ming Lok, a minor suing by his mother and next friend, Hui Man Chong handed down on 31 March 2021,[37] I have set out the broad principles on the court’s approach in determining admissibility of expert evidence as follows:

“67. It was made clear in the pre-CJR authority of Wong Hoi Fung v American International Assurance Co (Bermuda) Ltd & anor that the court has an inherent power to rule on the admissibility of expert evidence at a pre-trial stage:[38]

‘11. Modern judicial authorities recognise that the court has inherent power to rule on the admissibility of expert evidence at a pre-trial stage …… Where the proposed expert evidence is plainly inadmissible or irrelevant, the court ought to exercise its discretion to refuse the admission of such evidence. But where the court cannot form a clear view on the relevance of the proposed expert evidence or where it considers that the proposed evidence is clearly relevant, then it should grant leave for the evidence to be adduced at the trial ……

12. In deciding whether certain proposed expert evidence should be received, the relevant test has been stated to be a two-stage one. Firstly, the evidence has to be admissible as ‘expert evidence’ for the purpose of s.58 of the Evidence Ordinance (Cap.8). Secondly, the evidence must be relevant, in the sense that it is helpful to the court in arriving at its decision on one or more of the issues to be resolved: Barings Plc (in liquidation) & Another v Coopers and Lybrand & Others (unrep., 9 February 2001), Evans-Lombe J at paras.44-45.’ (my emphasis)

68. The Court of Appeal in Shenzhen Futaihong Precision Industry Co Ltd & ors v BYD Co Ltd & ors[39] pointed out that paragraph 596 of the Final Report on CJR identified the following as conditions for admissibility of expert evidence (page 180):

(a)	the subject matter of the opinion must fall within an area in which expert evidence may properly be given;[40]
(b)	the witness must be qualified as an expert to give the evidence of the type in question;
(c)	his evidence must be relevant to the issues being litigated.[41]

69. But the Court of Appeal emphasised that the giving of expert directions is a matter of case management, and pointed out that after the implementation of the CJR, the courts ‘can also take in account of the probative value of an expert report in exercising case management power ……’ (page 180):

‘11. Counsel drew our attention to the observation of Butler-Sloss LJ in Re M and R (minors) [1996] 4 All ER 239 at p 254 to suggest that if the expert evidence is arguably relevant but ultimately unhelpful the court should still admit the same whilst indicating at the same time that the evidence would carry little weight. That observation was made in a case concerning children where there were allegations of sexual abuse.  The judge hearing the application had evidence (without any objection as to admissibility) from two child psychiatrists that sexual abuse had probably occurred. The judge found otherwise. In the appeal the discussion on admission of expert evidence focused on the abandonment of the ultimate issue rule by virtue of s 3 of the Civil Evidence Act 1972.  It was in such context that Her Ladyship made the observations cited by counsel.

12. With respect, we do not regard those observations as militating against the duty of a judge in exercising the case management function when giving expert directions as discussed above.  In other words, the court will not give directions for expert evidence to be adduced (carrying with it the incidence of substantial costs being incurred on its preparation and court time spent on the same) simply on the basis that the court cannot rule out a possibility of such evidence being relevant and helpful in the sense as discussed above.  If the applicant for expert directions fails to persuade the court on relevance and necessity of such evidence, the application should be dismissed.’ (my emphasis) (pages 182-183)

‘40. We cannot find any fault in this analysis by the Judge. In any event, in the absence of concrete evidence from the BYD Parties demonstrating the relevance and necessity of expert evidence to resolve the pleaded issues on those paragraphs, the Judge was entitled to refuse to direct that expert evidence on (ii) to be obtained which would only lead to proliferation of unhelpful expert issues that could lengthen the trial and increase the costs of the litigation.’ (my emphasis) (page 192)

70. In SUNeVision Holdings Ltd v Hong Kong Science and Technology Parks Corporation (Global Switch Hong Kong Limited, interested party),[42] the plaintiff in that case referred to Wong Hoi Fung and submitted that if the court is in doubt as to the relevance of proposed expert evidence, it should grant leave for it to be adduced at the trial. But G Lam J held that insofar as this submission was at variance with the approach recommended by the Court of Appeal in Shenzhen Futaihong Precision Industry Co Ltd set out in the above paragraph, it was the latter that he should (and in my view, as this court should) follow (paragraph 15). The learned judge at paragraph 16 added that ‘[monitoring] attempts to introduce expert evidence is not just a power of the court but its duty in exercising case management functions’.

71. Lam VP also underlined such post-CJR approach in Taching Petroleum Company, Limited v Meyer Aluminium Limited as follows:[43]

‘13. The proper approach for admission of expert evidence in the post-CJR era was discussed by the Court of Appeal in Shenzhen Futaihong Precision Industry Co Ltd v BYD Co Ltd [2018] HKCA 408 at [3] to [13]. The approach adopted by the Deputy President, based on the pre-CJR authority of Wong Hoi Fung v American International Assurance Co [2002] 3 HKLRD 507, was more relaxed towards admission of expert evidence. See in particular [12], [40], [51] of Shenzhen Futaihong Precision Industry Co Ltd v BYD Co Ltd, supra. At [12], the Court said,

‘…… In other words, the court will not give directions for expert evidence to be adduced (carrying with it the incidence of substantial costs being incurred on its preparation and court time spent on the same) simply on the basis that the court cannot rule out a possibility of such evidence being relevant and helpful in the sense as discussed above. If the applicant for expert directions fails to persuade the court on relevance and necessity of such evidence, the application should be dismissed.’’

In that case, the court below regarded relevance as the key consideration in the applications concerning expert evidence, and held that certain proposed expert evidence was outside the scope of or not relevant to the pleaded issues (paragraphs 14-18), and that it was not permissible use of expert evidence to fish for evidence to formulate a case (paragraph 19). On such basis, Lam VP agreed with such case management approach ‘[subject] to our observation above by reference to Shenzhen Futaihong Precision Industry Co Ltd v BYD Co Ltd’ (paragraph 20).

72. Mr Tsoi also referred me to Kennedy v Cordia (Services) LLP [44] where a home carer slipped and fell on an icy path during a home visit and claimed damages against her employer. Whilst this appeared to be an everyday accident, it raised question inter alia as to whether health and safety practice could properly be the subject of expert evidence. The answer was in the affirmative. It was said the evidence of the claimant’s expert on factual matters was admissible as it was necessary, it assisted the judge and the expert had the required qualifications and experience, and it provided a basis for the court to address the legal issues. The UK Supreme Court held at pages 611-614 as follows:

‘44. …… There are in our view four considerations which govern the admissibility of skilled evidence: (i) whether the proposed skilled evidence will assist the court in its task; (ii) whether the witness has the necessary knowledge and experience; (iii) whether the witness is impartial in his or her presentation and assessment of the evidence; and (iv) whether there is a reliable body of knowledge or experience to underpin the expert’s evidence. All four considerations apply to opinion evidence, although, as we state below, when the first consideration is applied to opinion evidence the threshold is the necessity of such evidence ……

45. Assisting the court. It is for the court to decide whether expert evidence is needed, when the admissibility of that evidence is challenged. ……

……

48. An expert must explain the basis of his or her evidence when it is not personal observation or sensation; mere assertion of ‘bare ipse dixit’ carried little weight …… if anything, the suggestion that an unsubstantiated ipse dixit carried little weight is understated; in our view such evidence is worthless.

……

50. The witness’s knowledge and expertise.  The skilled witness must demonstrate to the court that he or she has relevant knowledge and experience to give …… opinion evidence. Where the skilled witness establishes such knowledge and experience, he or she can draw on the general body of knowledge and understanding of the relevant expertise ……

……

54. Reliable body of knowledge or experience.  What amounts to a reliable body of knowledge or experience depends on the subject matter of the proposed skilled evidence ……

55. In many cases where the subject matter of the proposed expert evidence is within a recognised scientific discipline, it will be easy for the court to be satisfied about the reliability of the relevant body of knowledge. There is more difficulty where the science or body of knowledge is not widely recognised. ……

56. We agree with that proposition, which is supported in Scotland and in other jurisdictions by the court’s refusal to accept the evidence of an expert whose methodology is not based on any established body of knowledge. ……’

73. Although less robustly said than the guidance by the Court of Appeal in Shenzhen Futaihong Precision Industry Co Ltd as explained in Taching Petroleum Company, Limited, Kennedy also placed emphasis on the court’s case management powers for ‘policing the performance of an expert’s duties’ (see below) and to encourage economy in litigation (pages 615-616), which in turn suggested that the court can rule on the admissibility of expert evidence at a pre-trial stage as a matter of case management:

‘58. It is not the normal practice of the Scottish courts to hold preliminary hearings or proofs on the admissibility of the evidence of skilled witnesses. Considerations of cost and practicability may often make such a course unattractive. Where the court has significant powers of case management, as in certain actions based on clinical negligence or relating to catastrophic injuries ……, a judge can address concerns about the evidence in respect of a skilled witness at a case management hearing and discuss with counsel how they are to be resolved. Wide opportunities for such case management in personal injury actions are likely to result from the implementation of Lord Gill’s “Scottish Civil Courts Review’. ……

……”

60.  Much was made in Mr Leung’s written submissions as to who would be an expert, what evidence would amount to expert opinion (ie whether a subject is a matter of art, science, learning or knowledge that can become a subject of expertise by study and experience), and whether the witness had been proved or admitted to be an expert on such subject.[45] But D did not dispute the expertise of P’s Experts for the purpose of the Appeal, and did not disagree the reports of P’s Experts expressed expert opinion that the court was not expected to possess. Therefore, there was no need for me to go into these principles in any detail.

61.  The key question was whether or not the court could/should form its own views/findings on the disputed Location/Speed Issues at trial unaided by such expert opinion. As a starting point, the question whether or not the court will be assisted by expert evidence on liability is a case-specific query as succinctly explained by Zervos J (as he then was) in ZN v Secretary for Justice & ors:[46]

“12. There are some subjects upon which the court is generally incapable of forming an opinion unassisted, and others upon which it could come to an independent conclusion, but the assistance of an expert would be useful. The need for expert evidence will very much depend upon the subject matter and the issues and circumstances of the case ……”

But the previously more relaxed approach that expert evidence on liability will be admissible if it can assist the court,[47] or, in the context of personal injury litigation, if it can aid the court to reach a fully informed decision on whether or not there was negligence[48] must now be viewed through the prism of the appellate guidance in Shenzhen Futaihong Precision Industry Co Ltd & ors v BYD Co Ltd & ors[49] and Taching Petroleum Company, Limited v Meyer Aluminium Limited[50] explained in paragraph 59 above.

62.  In applying the above broad principles to road traffic accident claims, it is necessary to start with Liddell. In that case, the plaintiff was waiting with his wife at the centre of the road intending to cross to the other side when the traffic cleared. His wife saw a car approaching in the distance and ran across the road to the pavement. He waited a little longer, then proceeded to cross the road and was hit by the defendant’s vehicle. He sued the defendant for negligence. He did not give evidence, but called an expert even though there were 4 eye-witnesses. The defendant was found to be grossly negligent in failing to observe the plaintiff and his wife, but the plaintiff was found to be 25% contributorily negligent in failing to observe the defendant, or if he did so, in underestimating his speed and moving into the road as he did.

63.  On appeal, the defendant disputed the finding that he was travelling at an excessive speed beyond the 30mph speed limit. Stuart Smith LJ held the judge was entitled to find the defendant was travelling somewhat over 30mph based on eye-witness evidence in the relevant factual context, and he did not disturb the judge’s finding on causation as the defendant accepted he would/should have done something. But on the apportionment of liability, the English Court of Appeal increased the plaintiff’s contributory negligence to 50% since both parties were to blame. The defendant argued inter alia that the judge was over- influenced by the evidence of the plaintiff’s expert, but Stuart Stuart LJ (with whom Gibson and Hutchison LLJ agreed) canvassed the factual circumstances and held it was dangerous for the plaintiff to step out when he did and it gave little opportunity for the defendant to avoid the accident (page P41).

64.  Stuart Smith LJ made some per curiam observations on the employment of expert evidence on liability “in this type of case”. He referred to the English equivalent of section 58(1) of the EO and Order 38 rule 36 of the RHC, and went on to say at pages P42-P43 as follows:

“In this case, as I have already indicated, there were four eyewitnesses of the accident, though, as is almost inevitably the case, each of those witnesses saw only part of the scene that unfolded. From their evidence, the judge had to determine what happened and, based on her findings of fact as to what each of the two parties involved did, decide whether or not their conduct was negligent, and if so whether that negligence caused or contributed to the plaintiff’s injuries. In some cases expert evidence is both necessary and desirable in road traffic cases to assist the judge in reaching his or her primary findings of fact. Examples of such cases include those where there are no witnesses capable of describing what happened, and deductions may have to be made from such circumstantial evidence as they may be at the scene, or where deductions are to be drawn from the position of vehicles after the accident, marks on the road, or damage to the vehicles, as to the speed of a vehicle, or the relative positions of the parties in the moments leading up to the impact.

In such cases the function of the expert is to furnish the judge with the necessary scientific criteria and assistance based upon his special skill and experience not possessed by the ordinary layman to enable the judge to interpret the factual evidence of the marks on the road, the damage or interpret the factual evidence of the marks on the road, the damage or whatever it may be. What he is not entitled to do is to say in effect ‘I have considered the statements and/or evidence of the eyewitnesses in this case and I conclude from their evidence that the defendant was going at a certain speed, or that he could have seen the plaintiff from a certain point’. These are facts for the trial judge to find based on the evidence that he accepts and such inferences as he draws from the primary facts found. Still less is the expert entitled to say that in his opinion the defendant should have sounded his horn, seen the plaintiff before he did or taken avoiding action and that in taking some action or failing to take some other action, a party was guilty of negligence. These are matters for the court, on which the experts’ opinion is wholly irrelevant and therefore inadmissible.” (my emphasis)

In short, Stuart Smith LJ considered expert evidence that was not science beyond lay knowledge and experience[51] and that merely gave opinion on the ultimate issue[52] would not be admissible, and he gave particular examples of situations when expert evidence on liability might be useful in road traffic accident claims.

65.  On the aforesaid basis, Stuart Smith LJ observed at P43-P44 as follows:

“There has been a regrettable tendency in recent years in personal injury cases, both road traffic and industrial accidents, for parties to employ the services of experts whether they are necessary or not. When they are not necessary, they simply add to the already high cost of litigation and the length of the trial. In industrial accidents an expert may well be needed to explain complicated machinery or to give evidence of practice and safety procedure.[53] But in road traffic accidents it is the exception rather than the rule that expert witnesses are required. ……”

Gibson LJ at P44 associated himself with such comments, and suggested in light of the then impending Woolf reforms that the time had come to curtail the licence enjoyed by expert witnesses and counsel in examining them, and that the court should exercise proper control over and management of the litigation before them. Hutchison LJ also agreed (see P44).

66.  Mr Leung submitted that Liddell was decided over 20 years ago when the laws then in force did not provide for sufficient safeguards against misuse of expert evidence, so the English Court of Appeal back in 1990 expressed concern that expert evidence was then too easily deployed, but it did not mean that in order to come within the ambit of the court’s power to grant leave to adduce expert evidence on liability, a party in a road traffic accident claim had to establish any special justification for his application as an “exception” to a rule that discouraged expert evidence on liability in such claims.

67.  On the other hand, Ms Lee submitted the statutory framework for adducing expert evidence in Liddell was similar to that applicable in Hong Kong today, so the observations in Liddell, which had been studiously applied by the courts in this jurisdiction in the authorities discussed below, were still relevant, and indeed echoed by Seagroatt J in Wong Hin Pui v Mok Ying Kit & anor (No 2) (albeit dealing with expert evidence on quantum) as follows:[54]

“…… This aspect of the case is a classic example of what this Court sees as an unrestrained use of resources with little regard for the cost involved. As a consequence a significant amount of time and effort has been wasted. The trial lasted at least two days more than was necessary. If the plaintiff is required to meet any of the costs to which I have referred, out of his damages, then that would be wholly unwarranted. In my view they fall to be paid out of the costs of the legal advisers who failed to exercise that judgment, where they are not met by the unsuccessful party. The time is now ripe for the court to exercise a controlling hand far earlier than I thought was necessary if practitioners are not prepared to look hard and fast at the case of the person they represent and ask themselves – ‘What do we really need in the way of expert evidence, and what can we ask the Defendants to agree at an early stage?’”

On such basis, as explained in paragraph 54 above, Ms Lee argued P would have to first surpass “the Liddell hurdle” (ie the present action fell within an exception outside the usual rule that set its face against expert evidence on liability in road traffic accident claims) and “the spirit of the CJR” that would raise doubt as to “the use of 4 experts in this simple running down case”, and then P would have to overcome “the second hurdle …… to demonstrate to the Court that the expert evidence is necessary, relevant and of probative value”. On this “second hurdle”, Ms Lee submitted the guiding principles have been set out in Fung Chun Man v Hospital Authority & anor as follows:[55]

“9. The enactment of the CJR did not result in a change to O.38, r.36 of the [RHC]. However, after the enactment of the CJR, it is clear that the court’s discretion, whether or not to grant leave to a party to adduce expert evidence, is to be exercised within the ambit of the court’s management powers. Those powers must be exercised in the light of the underlying objectives of the CJR, including the need to ensure the cost effectiveness of the proceedings; to ensure that the case is dealt with expeditiously; to ensure reasonable proportionality having regard to the amount of money involved, the importance of the case, the complexity of the issues, and the financial position of each party; to ensure procedural economy in the conduct of the proceedings; and to ensure fairness between the parties.

10. The courts recognise that the primary aim of its case management powers is to secure the just resolution of the dispute in accordance with the substantive rights of the parties. However, the substantive rights of the parties to a personal injury action do not include a legal right to call experts of their choice.

11. The expert evidence can only be adduced with leave of the court and, in deciding whether or not to grant leave, the court must ensure that such evidence is admitted only if it is likely to be of real assistance to the determination of the issues, and that it is adduced in the most effective and economic way consistent with the objectives of the CJR.”[56]

68.  In my view, neither Mr Leung nor Ms Lee was entirely correct in their propositions. Whilst it is quite correct that the judgment in Liddell pre-dates the Woolf reforms let alone the CJR in Hong Kong, which reforms have brought about a new culture against profligate use of expert evidence, the statutory framework for adducing expert evidence then and now is the same. In my view, restrictions against unrestrained use of expert evidence on liability (which admonition remains relevant today) still stem from the same statutory framework, but must be viewed through modern developments in civil litigation culture as per judicial guidance by the Court of Appeal in paragraphs 59 and 61 above.

69.  But I do not agree with Ms Lee’s 2-hurdle approach to expert evidence on liability in the context of road traffic accident claims. In my view, the criteria for exercise of the court’s case management powers on whether or not to allow expert evidence to be adduced are of general application to all civil claims, be they personal injury claims (or more particularly road traffic accident claims) or otherwise, and there is no additional “exceptional” criterion for adducing expert evidence on liability in road traffic accident claims. Rather, it is the application of the usual threshold discussed above in the particular context of road traffic accident claims that by reason of usual issues of liability and usual evidence available in the context of such claims that expert evidence on liability is, generally speaking, not appropriate/required, so expert evidence on liability has become a context-based exception. In my view, when later authorities concerning road traffic accident claims cited Liddell and concluded they were either the “exception” or the “norm” for allowing or refusing expert evidence on liability, such observations are no more than a short-hand way to explain the approach of the courts as outlined above. In any case, the need or otherwise for expert evidence on liability in any litigation is case-sensitive, and the court will need to apply the usual criteria to the particular context bearing in mind the rationale explained in the authorities as to why the road traffic accident context usually does not attract expert evidence on liability.

70.  With such considerations in mind, I turn to subsequent cases that applied Liddell in Hong Kong. In Tong Ho Wing (an infant) by Chan Ho Mui his mother and next friend v Wong Fuk & anor,[57] a boy was crossing the road when he was knocked down by a lorry. There were allegations of negligence against the driver who gave a statement to the police. Although there were 2 other independent eye-witnesses, the driver sought to introduce an expert report on liability when he appealed against the case management direction that no expert evidence on liability be adduced. Such report purported inter alia to analyse the driver’s sight restriction of boy, the driver’s braking effort and the boy’s speed from site visit observations, tyre marks, scale drawing and deceleration formula to draw conclusion as to the driver’s response time.

71.  Suffiad J referred to Liddell, and said this simple running down case had “eye witnesses to this accident, witnesses apart from the [driver] who can recount the speed and the manner in which the lorry was driven prior to the collision, as well as witnesses apart from the plaintiff himself who can testify as to the movements of the plaintiff before the impact with the lorry” (paragraph 19), so it was not “an exception to the general rule thus necessitating expert evidence” (paragraph 20). Possibly the only true area of expertise in the expert’s report was the equation by which deceleration was calculated, but on this Suffiad J went on to say as follows:

“22. …… However, the issue of liability involving negligence in this case is to be decided by a determination of what were the circumstances immediately prior to collision whereas deceleration, per se, is only pertinent to what happened after the brakes were applied and as such deceleration is of little or no relevance to the question of negligence in this case. Moreover, the four conclusions arrived at by Professor Mackay under the heading of ‘Analysis’ are matters for the trial judge to find based on the evidence which he accepts and such inferences as he draws from the primary facts found.

23. Likewise, the speed that the plaintiff was walking or running and the driver’s response are also matters for the judge to find after hearing the evidence. These are not matters which the trial judge would need expert evidence to assist him on.

24. For these reasons, I am of the view that the expert report prepared by Professor Mackay is wholly irrelevant and therefore inadmissible. Accordingly, the appeal is dismissed and the order of Mr Acting Registrar Chan stands.”

72.  In Chan Chun Kit v Huen Wai Keung,[58] the parties jointly applied for leave to rely on and adduce into evidence a joint traffic accident reconstruction report prepared by their respective experts. In that case, 2 taxis respectively travelling on a southbound lane and a northbound lane on a 2-lane road had a collision at a spot where the 2 lanes were separated by a hatched area. Both drivers lost consciousness after the collision and had no recollection of what occurred, and the passengers were also unable to offer any helpful account. Bharwaney J referred to Liddell, and found the case before him to “fall within the exception to the general rule that traffic reconstruction expert evidence is not admissible” (paragraph 6) because the trial judge was likely to be assisted by such expert evidence to ascertain, from the available evidence, the relative positions of the 2 taxis in the moments leading up to the impact to determine whether the plaintiff’s taxi had crossed over to the defendant’s northbound lane to cause the collision or whether the collision occurred at the hatched area of the carriageway with both taxis having encroached into that area before the collision. In their joint report, both experts professed to be able to reconstruct the relative positions of the 2 taxis immediately before the collision, and they set out detailed reasons for their respective reconstructions (paragraph 5). On such basis, the learned judge granted leave for the parties to rely upon and adduce into evidence the joint report, and to call such experts to give evidence at trial (paragraphs 7-8).

73.  In my view, Tong Ho Wing (an infant) by Chan Ho Mui his mother and next friend and Chan Chun Kit are helpful illustrations of the case-specific factors that go into the determination as to whether expert evidence on liability is appropriate/required in road traffic accident claims.

74.  In light of the above discussions, it is unnecessary for me to say too much about the Master’s views on the law. Insofar the Master considered that the principles enunciated in Liddell as applied in Tong Ho Wing (an infant) by Chan Ho Mui his mother and next friend and Chan Chun Kit (ie that in running down cases it is an exception rather than the rule for leave to adduce expert evidence on liability to be given) are binding on her,[59] that such case law shows expert evidence is necessary and desirable only in cases such as those where there are no witnesses capable of describing what happened (as in the example by Stuart Smith LJ in Liddell – see italicised part of his judgment set out in paragraph 64 above),[60] and that the Australian case of Zraika v Walsh[61] cited by Mr Leung was not binding on her,[62] this must now be read in light of the relevant principles explained above.

75.  I understand Mr Leung cited Zraika as illustration for the proposition that depending on the circumstances of each case, expert evidence may be appropriate even if there were eye-witnesses to the accident. Although I do not find such broad proposition contradictory to the principles explained above, the key is whether the particular circumstances of the case before the court call for expert evidence on liability bearing in mind the presence of eye-witnesses usually militates against such need. That said, Zraika may not be such a useful illustration as Mr Leung only relied on Campbell J’s judgment and did not refer this court to the judgment of the New South Wales Court of Appeal[63] that allowed the appeal against the primary findings made by Campbell J.

76.  In that case, the plaintiff was carried in utero by his mother Mrs Z who was a passenger in a car driven his father Z, which car collided with a car driven by Mrs W at a T-intersection. Mrs W ignored the “turn left only” sign to her left and drove straight across the intersection from a factory driveway towards the terminating road opposite the driveway, and Z ignored the series of left-turn arrows painted on the northbound kerbside lane from which he intended to continue straight on through the intersection. The plaintiff sued Mrs W, her husband as car owner (Mr W), the Roads and Maritime Services (RMS), Bankstown City Council (BCC) and Z. Mrs W admitted breach of motorist duty of care owed to other road users, but disputed the plaintiff’s apparent disabilities were acquired in the collision. The other defendants denied liability and cross-claimed amongst themselves. Orders were made for separate determination of a series of questions resolving most but not all questions of liability. Campbell J found RMS, BCC and Mr/Mrs W to be 25%, 25% and 50% liable, but found Z did not breach his duty of care to the plaintiff.

77.  Mrs W, Z, Mrs Z, a senior constable who attended the scene and 2 other drivers gave factual evidence. Two consultant traffic engineers (one of whom was Mr Johnston) gave evidence about crash dynamics (paragraph 29). Mr Johnston made certain assumptions about the vehicles at rest that accorded with the senior constable’s evidence, and he worked backwards to a point of impact and then calculated a pre-impact speed of about 68kph for Mrs W’s car (paragraph 36). But there was already evidence from the lay witnesses that Mrs W’s car was “flying” (paragraph 49), and Mrs W had already admitted breach of duty. Campbell J noted “[the] experts had precious little objective material to work with. Essentially it comes down to the reliability of [the senior constable’s] record of the rest positions of the vehicles, the post-impact debris, and the intersection geometry. I accept [the senior constable’s] evidence ……” (paragraph 46). Whilst both experts accepted it was possible that Z approached the point of impact from “northbound lane 2” (paragraph 46), Campbell J found on the lay evidence of Mrs W and 2 other drivers that Z approached the point of impact from the northbound kerbside lane at a speed of 65kph on green light (paragraph 52), but there was no allegation that Z travelled at an excessive speed in the circumstances (paragraph 82).

78.  As regards expert evidence, it seemed the only real point Campbell J relied on was Mr Johnston’s evidence in answer to her query to the effect that even if Mrs W had turned left, a collision was potentially still imminent because even though a slower left turning vehicle would require shorter stopping distance and allow more opportunity to respond/ avoid, neither Mrs W nor Z could see the other until immediately prior to impact, so it was improbable to have been sufficient time for Z to perceive, react and then stop prior to impact. Campbell J was not persuaded Z breached his duty of care (paragraphs 35-38, 85, 90 and 92).

79.  After delivery of judgment, the parties resolved the remaining issues, so the plaintiff was out of the picture. On appeal RMS and BCC challenged Campbell J’s findings that (a) Z had not breached his duty of care and (b) any breach by him was not causative of the collision. The New South Wales Court of Appeal allowed the appeals, holding neither RMS nor BCC was liable, and contrary to Campbell J’s findings, Z did breach his duty of care to the plaintiff and causation was made out. Liability was apportioned between Mrs/Mr W and Z at 40% and 60% respectively.

80.  In relation to expert evidence, Gleeson JA noted Campbell J’s reasoning for her “single sentence in the alternative” in paragraph 92 of her judgment was based upon Mr Johnston’s evidence that even had Z been turning left and therefore travelling at 20kph, it was still “improbable that there would have been sufficient time even at the lower speed to still respond, perceive and react and then stop prior to impact” (paragraph 33) (see paragraph 78 above), and took the view that Z’s counsel on the appeal placed too weight on such sentence which might well have been a slip by Campbell J. Gleeson JA said that even if such sentence were not a slip, it could not stand because (a) had Z not breached his duty in entering the intersection with a view to continuing straight on, he would have remained in the middle northbound lane behind the traffic banked up at the intersection waiting for Mrs W to “inch across” rather than to move into the northbound kerbside lane, so there would have been no collision and no damage, and (b) the issue of whether the plaintiff’s injuries were caused by the collision was not one of issues determined by Campbell J, which explained the limited cross-examination of the expert about whether or not Z’s obligation to turn left would have avoided a collision (paragraphs 34-35).

81.  From the above account, the findings of the New South Wales Court of Appeal clearly turned on factual and not expert evidence, which expert evidence did not sit well with the factual context as explained in (a) above, so Gleeson JA was able to infer/find that (i) had Z been travelling at lower speed the collision would have been less powerful, and (ii) had Z been turning left the collision would have been a glancing impact, and to conclude that Campbell J erred over the evidence about the inevitability of a collision (paragraphs 35-36). In short, the expert evidence had not been helpful for the ultimate factual determination.

VIII.  LOCATION ISSUE

82.  On 26 October 2018 (about 2½ years after the Accident), Dr Tang conducted a land survey outside the Club and inspected the CCTV Camera (including its fixed mounting that allowed the camera to swivel).[64] Dr Tang then used an equipment called “Reflectorless Total Station” to measure the horizontal/vertical distances between the CCTV Camera and 2 points of reference on the CLine, ie a light post (CL1) and a mailbox (CL2),[65] and to use such measurements to calculate the “angle of drop” of 10.7080º for CL1 and 10.7407º for CL2 by applying “a trigonometrical formula”.[66] Dr Tang stated “…… the accuracy of the location of Point CL1 or Point CL2 is within 1 cm. The margin of error of the calculated angle of drop is less than 0.1%”.[67]

83.  Mr Johnston’s 2^nd Report sought to give opinion on the location of the impact between the Taxi and P.[68] On 7 June 2019, Mr Johnston carried out aerial survey of the incident location by using a drone (unmanned aerial vehicle), and used specialist survey software known as Pix4D to produce a scaled aerial image (or orthomosaic survey) and a 3D point cloud of the incident location.[69] He noted the NLane deviated to the right a short distance south of the Club driveway immediately after passing through a pedestrian refuge facility, which deviation was seemingly done to accommodate a bus bay adjacent to the western pedestrian kerb of the NLane. Using the Pix4D image and point cloud, he measured such deviation to be between 7º and 8º over a distance of about 10 metres.[70] He also showed the CCTV Camera’s field of view as bounded by pylons on either side of the Club driveway entrance and by vegetation on the lower right hand side, but such field of view was beyond the end of the road deviation so vehicles should be travelling parallel to the straight portion of the CLine through this segment.[71]

84.  Then, Mr Johnston used Adobe Photoshop software and the technique of “masking” Frames 33-36 to trace the path of the Taxi top light box as it passed through the field of view of the CCTV Camera, and he placed the images onto an additional frame that gave a clearer view of the Road and the CLine.[72] The data was input into a CAD programme designed for crash reconstruction known as “CrashZone”, which measured the apparent angle between the projection of the light box that defined the path of the Taxi through the area visible in the CCTV Camera and the “pavement centerline” to be around 1.95º.[73] But this was the perspective angle visible to the CCTV Camera and not the true angle which had to take into account the “angle of drop” of the CCTV Camera relative to the Road.[74] By adopting the “angle of drop” between 10.0708º and 10.7407º as measured by Dr Tang and using an expressed trigonometry formula, Mr Johnston gave the true angle of the Taxi to the CLine in the portion of the Road visible in the field of view of the CCTV Camera as approximately 10º.[75]

85.  Mr Johnston then calculated the path of the Taxi on the basis of the position of the Taxi shown in the enlarged portions of Frame 32 and Frame 35 with approximately 10º alignment of the Taxi to the CLine.[76] On such projection and taking into account the Taxi’s point of impact at its front right headlight, Mr Johnston opined “this would place the pedestrian at point of impact most likely just on the eastern side of the [CLine] as shown in Figure 4.12. Given that the pedestrian [ie P] crossed behind the [Stopped Taxi] it is not possible that her path intercepted the right front headlight of the impacting [Taxi] beyond the [CLine] if the calculated path of the impacting [Taxi] is accepted”.[77] Such conclusion meant the right front of the Taxi (ie the point of impact on the Taxi) crossed the CLine onto the SLane.[78]

86.  Mr Johnston identified the rest position and orientation of the Taxi after the collision from a police photograph.[79] From the time of impact until the Taxi came to rest, there was a public light bus at the bus stop opposite the Club driveway, a van-type vehicle attempting to exit the Club driveway, and the Stopped Taxi parked close to the SLane pedestrian kerb to the north of the Club driveway.[80] Mr Johnston then set out P’s rest position from an unscaled sketch plan drawn by D that indicated P came to rest adjacent to the SLane pedestrian kerb about 1 car length ahead of the “vehicle at rest”, which he said “suggests a pedestrian throw distance in the order of around 26 metres”.[81] He also explained the kinematics of a typical frontal pedestrian impact, and said P’s rest position was suggestive that she was not moving forward when struck and/or the Taxi was at angle clockwise to the CLine at the time of impact so as to project P towards the eastern kerb.[82]

87.  I should start with the matters set out in the above paragraph in Mr Johnston’s 2^nd Report (collectively, “Pedestrian Matters”). The Pedestrian Matters were separate and distinct from the analysis and discussion in relation to Location Issue canvassed in the rest of Mr Johnston’s 2^nd Report (see paragraphs 83-85 above). Importantly, the pedestrian throw distance upon impact between the Taxi and P was not any part of Mr Johnston’s reconstructions, measurements and/or calculations on the Location Issue (ie whether or not the Taxi crossed the CLine to hit P). Instead, Mr Johnston considered P’s pedestrian throw distance and her rest position in light of the kinematics of pedestrian impact to conclude that P was not moving forward at the time of impact. But such analysis had nothing to do with the Location Issue canvassed in other parts of Mr Johnston’s 2^nd Report and did not sit well with paragraph 10 of P’s 1^st Statement which stated that P continued to walk normally and was suddenly hit by the Taxi when she was still on the SLane but nearly reaching the CLine (see paragraphs 16 above).

88.  Possibly, Mr Johnston addressed the Pedestrian Matters in Mr Johnston’s 1^st Report that was adduced as an exhibit at the Trial (and repeated them in Mr Johnston’s 2^nd Report) as a response to paragraphs 5.1-5.3 of Dr Tam’s 1^st Statement (which statement was also adduced as exhibit at the Trial – see paragraph 8 above) that set out Dr Tam’s analysis/findings on the Pedestrian Matters as follows:

(a)	Dr Tam noted the Taxi’s estimated stopping/braking distances when travelling at 49kph were about 26 / 13.5 metres respectively, the latter of which was comparable to the distance of 12.1 metres between the Taxi’s final stopping position and its position in Frame 36 (see paragraph 128 below). This was supported by the Taxi’s braking lights in Frame 37. Taking the reaction time of 0.9 seconds in the Road Users Code (“RUC”), Dr Tam opined D could have perceived danger of hitting P at Frame 31 (37 – (0.9 seconds x 7fps)) when the distance between the front of the Taxi and P would have been about a private-car length (5 metres), ie shorter than the stopping distance for the Taxi travelling at 49kph, so the Accident was unavoidable if the earliest moment D could perceive P was at Frame 31.
(b)	Assuming P walked from a position by the nearside of the Stopped Taxi (Frame 26) to a position by its offside rear where she could have been seen by D (Frame 31), the distance P travelled between Frames 26 and 31 was estimated to be the width of a taxi (1.7 metres), so P’s walking speed was estimated to be 2.4 metres/second, which was double the typical walking speed of 1.2 metres/second.
(c)	Dr Tam opined that if D’s view was blocked by the Stopped Taxi before Frame 31, P’s view of the Taxi would likely be also obstructed by the Stopped Taxi before Frame 31.

89.  At the Hearing, Ms Lee submitted that paragraphs 5.1-5.3 of Dr Tam’s 1^st Statement should also be adduced as opinion evidence in the present action, but Mr Leung disagreed. Indeed, the Master noted Mr Leung’s written submissions adversely commented that Dr Tam’s findings/opinion in paragraphs 5.1-5.3 of Dr Tam’s 1^st Statement were based on “wrong assumption of facts”, but the Master suggested Mr Leung did not offer any insight on how to accommodate the conflict between such objection and P’s intended reliance on Dr Tam’s findings/ opinion on the Speed Issues in Dr Tam’s 1^st Statement.[83]

90.  In my view, Dr Tam’s 1^st Statement was prepared for the Trial with focus on pedestrian negligence, so his findings/opinion covered both the Pedestrian Matters (paragraph 5) and the Speed Issues (paragraphs 1-4). But both Dr Tam’s 1^st Statement and Mr Johnston’s 2^nd Report kept the Speed / Location Issues and the Pedestrian Matters cleanly distinct. The Summons only sought leave to adduce expert opinion on the Location/Speed Issues and not on the Pedestrian Matters. Although Dr Tam’s 1^st Statement and Mr Johnston’s 2^nd Report were exhibited to P’s 1^st Aff, in paragraphs 8 and 11 of P’s 1^st Aff P particularly asked for Mr Johnston’s opinion on the Location Issue and Dr Tam’s opinion on the Speed Issues to be adduced. Further, Mr Leung in paragraph 109 of his written submissions dated 14 January 2021 acknowledged that Mr Johnston’s analysis of the pedestrian throw distance related to “whether P was stationary at the time of the impact, and not on the location of impact”. Neither P nor D made any application by summons or otherwise to seek leave to adduce expert opinion on liability as to the Pedestrian Matters. Neither Mr Leung nor Ms Lee in their written/oral submissions canvassed the relevance, necessity and probative value of Dr Tam’s and Mr Johnston’s findings/opinion on the Pedestrian Matters (except for P’s pedestrian throw distance which I will deal with below). There was, quite simply, no basis for this court to allow adoption of paragraphs 5.1-5.3 of Dr Tam’s 1^st Statement and paragraphs 4.2-4.3 and 4.24-4.31, Figures 4.2 and 4.13 and 1^st Ø on page 34 of Mr Johnston’s 2^nd Report as opinion evidence on the Pedestrian Matters in the present action, and they must be blue-pencilled and disallowed.

91.  In the circumstances, it is unnecessary for me to deal with the Master’s concern[84] and Ms Lee’s complaint over Mr Johnston’s estimate of P’s pedestrian throw distance of about 26 metres based on an unscaled sketch plan drawn by D at the Trial.

92.  The Master queried why Mr Johnston did not rely on the statement of Malla Bikash (who was waiting for transport at the layby on the NLane at the time of the Accident) given to the police on 11 October 2016, which stated P’s “final position” after the Accident was about 6 metres “in front of the [Taxi]”. Actually such statement was not provided to Mr Johnston. The Master thought “it remains unresolved why the sketch plan drawn by D would be more preferred ……” In light of my conclusion in the above paragraph, the Master’s observation could be dealt with very briefly. Neither party indicated Malla Bikash (who was not a witness at the Trial) would be a witness in the present action or Malla Bikash’s statement to the police (which document was not adduced as evidence at the Trial) would be adduced as documentary evidence in the present action, so her assertions would not form any factual assumption for Mr Johnston’s findings/opinion. Secondly, it was unclear how Malla Bikash’s views as expressed in her police statement, ie 6 metres being the distance between P’s final position and the front of the Taxi after the Accident, could be directly compared to Mr Johnston’s estimation of P’s pedestrian throw distance, ie 26 metres being the distance travelled by P as pedestrian from the point of impact through the air to her rest position based on pedestrian wrap trajectory.[85] In any event, taken to the highest, Malla Bikash’s assertion as to the final positions of P and the Taxi would only provide alternative factual assumption to that in D’s unscaled sketch.

93.  Anyway, Ms Lee in her submissions did not rely on the statement of Malla Bikash. Rather, she argued that if the trial judge preferred, say, the unscaled sketch plan drawn by PC58862 who investigated the Accident as more accurately reflecting the situation, then Mr Johnston’s conclusion would have been thrown into disarray and be of no probative value. At this interlocutory stage and in light of my conclusion in paragraph 91 above, Ms Lee’s submissions could also be dealt with shortly. Even assuming PC58862’s unscaled sketch would be adduced as documentary evidence at the trial in the present action, it would only show the police constable’s unscaled assertion as to final rest positions of the Taxi and P, which at best would provide another alternative factual assumption for evaluation, but it could not provide direct comparison with Mr Johnston’s pedestrian throw distance.

94.  There is no need for me to deal with Mr Leung’s further arguments that (a) there was no unfairness to D for P / Mr Johnston to rely on D’s own evidence as to P’s final position as factual assumption for analysis, and (b) Malla Bikash’s statement and/or PC58862’s unscaled sketch could be provided to Mr Johnston as alternative factual assumptions if in due course such statement and/or sketch were adduced as documentary evidence in the present action, or Malla Bikash and/or PC58862 were to be called as witnesses in the eventual trial. In any event, since there was no application for leave to adduce expert evidence on liability in relation to the Pedestrian Matters, discussions on (a)-(b) above would be academic and irrelevant. Further, in view of the legal principles discussed above, the court would be unlikely to smile kindly on expert evidence on liability in relation to the Pedestrian Matters that rely on partisan accounts or unscaled sketches, which the trial judge himself/ herself would be in a position to assess in its usual fact-finding function.

95.  Turning now to the Location Issue, the Master observed (and Ms Lee also submitted) that the photographs/sketches by the police, P’s/D’s statements to the police, their witness statements and the Footage (which the Master viewed) would provide ample evidence for the trial judge to make his/her own findings of fact on the Location Issue in this simple running down case. Ms Lee further noted that both P and D would give evidence and be subject to cross-examination at trial, and much would hinge on witness credibility in resolving factual disputes on the Location Issue. She reminded that the courts had vast experience in fact-finding in traffic accident cases which the courts handled day in and day out, so there was nothing to take the present action outside the general rule against expert evidence on liability in road accident claims as explained in Liddell.

96.  But Ms Lee did not articulate how the police photographs/ sketches made post-impact would assist the court on determining the location of point of impact between the Taxi and P. As for the Footage, the point of impact was blocked by other objects.[86] What Mr Johnston did was to make a scientific attempt to extrapolate from the 2-dimentional Footage/Frames 3-dimensional information as to the location of point of impact between the Taxi and P (which he eventually opined upon analysis was likely to have been in the SLane albeit quite close to the CLine) interposed on roadway geometry with (a) the aid of aerial survey, specialist software, masking technique, specialist CAD programme and trigonometrical analysis, and (b) the use of the “angle of drop” of the CCTV Camera measured by Dr Tang. He did not rely on any partisan accounts/sketches by P and D, rest positions of P and the Taxi and/or other post-impact features.

97.  Mr Leung fairly agreed that had there been no Footage, the trial judge would have to go about his/her fact-finding exercise as best as could be done on available evidence, eg the photographs/sketches and witness evidence. But with the fortuitous availability of the Footage and in face of contrary partisan accounts of the Accident by P and D, Mr Leung submitted there was no good reason for the parties/court not to harness objective evidence from the Footage to test, assess and weigh the veracity of P’s and D’s subjective accounts on the Location Issue. As Mr Leung colourfully submitted, the Footage “will not lie”. But absent scientific analysis, a layman’s eyeball review would not elicit the bird’s eye perception of the projected location of point of impact “hidden” in the recording, which, Mr Leung submitted, was why scientific analysis of the Footage/Frames would helpfully assist the lay court to fathom evidence on the Location Issue from the Footage as justified according to the authorities.

98.  I agree with the submissions in paragraphs 96-97 above, but I still need to go on and consider whether Dr Tang’s and/or Mr Johnston’s findings/opinion were, as Ms Lee suggested, difficult to follow/ understand, unclear, somewhat shaky and appeared to be based on tenuous inferences such that the court should not allow such evidence on liability when the court could assess the live/statement evidence of P and D.

99.  In my view, from summaries of Dr Tang’s Report and Mr Johnston’s 2^nd Report on the Location Issue in paragraphs 82-85 above, it was not easy to understand the complaints in the above paragraph. Dr Tang’s findings/opinion were premised on aerial photograph of the relevant road segment with measurements of the CCTV Camera to CL1/CL2 at the CLine by land surveying equipment and calculation of “angle of drop” by trigonometrical formula rather than on inferences drawn from partisan accounts or post-impact features. Mr Johnston’s opinion on the location of point of impact was premised on scientific techniques in relation the Footage/Frames explained in paragraphs 83-85 and 96 above that extrapolated 3-dimensional analysis from the 2-dimentional Footage/Frames. The aforesaid analyses by Dr Tang and Mr Johnston did not rely on inferences from partisan witness accounts nor from interpretations of post-impact features (such as vehicle/pedestrian final rest positions, skid/brake marks and/or debris/ blood at the scene sometimes seen in other cases), which matters would be well within lay assessment by the trial judge.

100.  Ms Lee referred to a number of measurements/calculations in Mr Johnston’s 2^nd Report, eg (a) the apparent angle between the projection of the light box that defined the path of the Taxi through the area visible in the CCTV Camera and the pavement centerline measured by “CrashZone” (specialised CAD programme specifically designed for crash reconstruction),[87] and (b) the trigonometrical formula for working out the true angle from the perspective angle (ie the “angle of drop”) of the CCTV Camera,[88] but I cannot see why these expert/scientific extrapolations, measurements and/or calculations would give rise to such unreliable uncertainty that would detract from admissibility of Mr Johnston’s 2^nd Report. As Mr Leung submitted, scientific/expert matters might well be outside layman’s knowledge/experience, but technical complexity of itself would not be a sufficient reason to reject expert evidence. Ultimately, the question was whether such evidence would assist the trial judge to utilise objective information from the Footage/Frames to facilitate assessment of partisan accounts and to determine the Location Issue which was a key dispute between P and D.

101.  Turning now to more specific complaints about Dr Tang’s Report, the Master noted Dr Tang’s observation that the CCTV Camera was mounted on a metal bracket fixed by screws to the Club Column, so its position should be permanent “in that the [CCTV Camera] is not designed to be readily moveable from time to time”. But Dr Tang also fairly noted the mounting of the CCTV Camera allowed the camera to swivel. The Master considered it was unclear “if on the date of inspection by Dr Tang, the camera was swiveled at the same degree or angle as on the date of the accident” for the P 2^nd Aff merely asserted P knew the position of the CCTV Camera had not been moved after the Accident or when she visited the scene again at 4 January 2019, so if the angle of the CCTV Camera swiveled after the date of the Accident, Dr Tang’s measurements and resulting opinion on the “angle of drop” would be distorted.[89]

102.  Ms Lee reiterated that Dr Tang only made measurements on 26 October 2018 (ie more than 2 years after the Accident), and although Dr Tang opined the CCTV Camera’s “position should be permanent”, it was not clear whether the “angle of drop” would also be permanent as the camera was designed to be able to “swivel at the mounting point”. Although the P 2^nd Aff claimed P “knows which [CCTV Camera] installed at the [Club] had captured the Accident and [P knows] that it has not been moved after the Accident, at least until [her] latest visit on 04.01.2019”, which point was reinforced in P’s 2^nd Statement that D had agreed to let P serve, there was no information as to how P came by such knowledge other than the fact she used to work at the Club up to the time of the Accident on 25 April 2016 and she visited the Club thereafter in order to give instructions to her solicitors. Ms Lee suggested P’s eyeball inspection from a distance to confirm the metal bracket holding the CCTV Camera had not moved would hardly be reliable evidence to form sound basis that there was no change in the “angle of drop” of the lens since 2016, but Mr Johnston adopted without query Dr Tang’s datum regarding the “angle of drop” to estimate the location of point of impact in Dr Johnston’s 2^nd Report.

103.  In my view, at this interlocutory stage, it would be inappropriate to make a final determination on factual matters. For the purpose of expert evidence, the court at this interlocutory stage would be concerned to see if factual assumptions adopted by an expert had reasonable basis, bearing in mind it would for the relevant party to prove such factual assumptions at trial not on the basis of absolute certainty but on the balance of probabilities.

104.  Here, there was no dispute the CCTV Camera was mounted high on the Club Column by a metal bracket. Given the height and nature of such installation and P’s 2^nd Statement, which D consented for P to serve and which asserted the mounting bracket for the CCTV Camera had not moved until 4 January 2019 (ie after Dr Tang’s inspection on 26 October 2018), there was at least reasonable basis to suggest the CCTV Camera’s position was permanent.

105.  Dr Tang fairly pointed out the camera of the CCTV Camera was designed to be able to swivel on its mounting point. I note here there was scarce evidence to support Wu’s assertion of a “real possibility” that the position of the CCTV Camera had been changed after the Accident. Indeed, Ms Lee in her submissions merely queried what if the CCTV Camera swivelled on its metal bracket between the date of the Accident and Dr Tang’s visit on 26 October 2018, and on such query postulated the possibility of distortion to Dr Tang’s measurements of the “angle of drop” and to Mr Johnston’s estimation of the location of point of impact that relied on Dr Tang’s measurements.

106.  On the available evidence before this court (eg photographs annexed to Dr Tam’s 1^st Statement and in Dr Tang’s Report), the CCTV Camera was installed on robust mounting at height on the Club Column. The camera lens was angled to point in the direction of the driveway entrance of the Club (as also evident from the Footage/Frames), which logically would be for surveillance of ingress into and egress from the Club premises. Mr Leung submitted such objective facts would lend support to the logical view that such surveillance fixture at height would not have been moved unless there were special reasons which neither Wu nor Ms Lee was able to articulate for the Appeal.

107.  Further, by the P 2^nd Aff and P’s 2^nd Statement P also confirmed that the camera and mounting of the CCTV Camera had not moved. Ms Lee contended P did not say how she came by such knowledge. But in fact P already explained she worked as a security guard for the Club and she returned to the Club several times after the Accident, so she had observed the position of the CCTV Camera which was exposed and visible as it was mounted on the outside wall of the Club Column.

108.  In my view, whether P’s evidence would be believed or amounted to adequate proof of the factual assumptions for Dr Tang’s measurements of the “angle of drop” in the context described in paragraph 106 above would be a matter for trial. If P failed to prove such factual assumptions whether by direct evidence or by inference from primary evidence on the balance of probabilities at trial, then Dr Tang’s expert opinion might arguably fall away. But that was not to say that at this interlocutory stage there was no reasonable basis for Dr Tang’s factual assumptions. I also note Dr Tam visited the incident scene on 20 July 2017 to inter alia examine the CCTV system at the Club and found “[the] live view of the CCTV Camera …… consistent with that of the [Footage]” (see paragraph 128 below). In the circumstances, there is no need for me to deal with Mr Leung’s alternative submission that even if there had been any movement of the CCTV Camera, it would have been minimal as the position of the metal bracket was fixed and the logical purpose of the CCTV Camera would be to keep the Club driveway entrance under surveillance, so Dr Tang’s measured “angle of drop” of about 10º would not be materially affected as it was calculated on the basis of substantial vertical distance (6.86 metres or 6.91 metres) and horizontal distance (36.14 metres or 36.55 metres) between the CCTV Camera and the points of reference CL1 and CL2.[90]

109.  Next, the Master was of the view that Dr Tang failed to explain why he picked the light post (CL1) and mailbox (CL2) as the points of reference. This was not a point taken by Ms Lee for the Appeal, and could be dealt with shortly. Dr Tang explained the range from the mailbox to the light post covered the entire roof lamp of the Taxi at Frame 33.[91] This was relevant to the analysis in Mr Johnston’s 2^nd Report. In order to trace the path of the Taxi’s top light box as it passed through the field of view of the CCTV Camera by using Adobe Photoshop software and the technique of “masking” (see paragraph 84 above), Mr Johnston “…… placed all images behind [Frame 33] which is when the light box on the [Taxi] first appears and [he has] painted in the light box in [Frames 34 and 35] and painted in the [Taxi] and light box in [Frame 36] which shows the progression of the light box through this image”, and he input the resulting image in Figure 4.5 of Mr Johnston’s 2^nd Report into the “CrashZone” programme to measure the apparent angle between the projection of the light box which defined the path of the Taxi through the area visible in the CCTV Camera and the pavement centerline.[92] Thus, CL1 and CL2 were selected to cover the range of the path of the Taxi visible at Frames 33-36 as extracted from the Footage recorded by the CCTV Camera, which Mr Johnston used for his measurements.

110.  Ms Lee then complained that Dr Tang used “an unexplained method called “Reflectorless Total Station”” to conclude the “angle of drop” was 10.7407°. It was said that, to the uninitiated, Figures 5-6 of Dr Tang’s Report presented more questions than answers, eg whereas the CCTV Camera’s position was said to be permanent, the height of the camera point in Figure 5 was 6.86 metres while the height of the camera point in Figure 6 was 6.91 metres.

111.  As Dr Tang explained and as noted by the Master, “Reflectorless Total Station” was not a methodology but a piece of land survey equipment that Dr Tang used to measure the horizontal and vertical distances between the CCTV Camera and CL1/CL2. It was the application of trigonometrical formula to these measured distances by the “Reflectorless Total Station” equipment that Dr Tang calculated the “angle of drop”. As for Ms Lee’s query as to why the vertical “height” of the CCTV Camera in Figure 5 was 6.86 metres and that in Figure 6 was 6.91 metres, it should be noted that (a) the measurements were made by the “Reflectorless Total Station” equipment and not manually by Dr Tang, and (b) the measurements of 6.86 metres and 6.91 metres were not the vertical “height” of the CCTV Camera from the ground below it but the vertical distances of the CCTV Camera to CL1 and CL2 being 2 different points of reference on the CLine, so if the CCTV Camera was at a fixed point for both measurements, the variable would arguably be the road level at CL1 and CL2 (eg they might not be on the same level).

112.  Turning now to Dr Johnston’s 2^nd Report, Ms Lee raised a number of specific complaints, which it was said would demonstrate that the probative value of Mr Johnston’s conclusions on the location of point of impact was in doubt. First, she referred to the values of 7.10° and 9.98° in Figure 4.12 of Mr Johnston’s 2^nd Report that gave the estimated point of impact, and complained that Mr Johnston did not explain the basis as to how 7.10° and 9.98° were derived.

113.  I start with the deviation of 7.10º in the NLane opposite the entrance of the Club. In fact, the deviation of 7.10º in the NLane first appeared in Figure 2.5 of Mr Johnston’s 2^nd Report, and he explained in paragraphs 2.4-2.7 therein that with the aid of drone aerial survey he was able to prepare a scaled aerial image (or orthomosaic survey) and a 3D point cloud of the incident location by using specialist survey software, and from such scaled aerial image and 3D point cloud the angle of deviation of the NLane was mathematically measured to be 180º - 172.11º = 7.89º.

114.  There was another figure of 7.10º seen in Figures 2.5, 4.10 and 4.12 of Mr Johnston’s 2^nd Report being the deviation between the edge of the western pedestrian pavement and the broken white line at the western edge of the NLane that accommodated the bus bay adjacent to the western pedestrian kerb.[93] So both values of 7.10º and 7.89º were measurements of the eastward deviation of the NLane at different points at that segment of the Road.

115.  As for the value of 9.98º in Figure 4.12 of Mr Johnston’s 2^nd Report, such value was first seen in Figure 4.10 of Mr Johnston’s 2^nd Report which was described as “[reconstructed] position of [Taxi] consistent with Frame 32 at 10 degrees to the [CLine]”. Paragraph 4.21 of such report explained that “Figure 4.10 shows the estimated position of the [Taxi] from Frame 32 aligned at 10 degrees to the [CLine] as calculated for the path of the [Taxi] through the area of roadway visible on the [CCTV Camera]”. Thus, the value of 9.98º was the angle of the Taxi to the CLine (ie the angle between the green line that ran through the centre of the Taxi and the CLine) at Frame 32 (which was before the assumed point of impact at Frame 35[94]).

116.  The Taxi continued in motion after Frame 32, and the true angle of the Taxi to the CLine in the portion of the Road visible in the field of view of the CCTV Camera (by using Adobe Photoshop software and “masking” technique on Frames 33-36, using “CrashZone” programme to measure the angle between the projection of the light box that defined the path of the Taxi through the area visible in the CCTV Camera to the pavement centerline (1.95º), and applying Dr Tang’s measured “angle of drop” and an expressed trigonometrical formula to work out the true angle of the Taxi to the CLine)[95] was 10.5º and more precisely 10.4º,[96] which Mr Johnston rounded down to “approximately 10 degrees”.[97] This approximation was consistent with the value of 9.98º for Frame 32 shown in Figure 4.10, but whether 9.98º or approximately 10º was adopted as the value of the angle it would less favourable to P’s case than the more precise true angle of 10.4º because an angle at 10.4º (as compared with an angle at 9.98º or approximately 10º) would mean the right front of the Taxi would be marginally more towards the SLane.

117.  Secondly, Ms Lee submitted the suggested point of impact shown in Figure 4.12 of Mr Johnston’s 2^nd Report depicted the Taxi to be at an angle protruding into the SLane “pointing towards the Club”, but photographs of the Stopped Taxi immediately after the collision showed the Taxi to be totally within the NLane and pointing away from the Club towards the western pavement.

118.  In my view, such submissions juxtaposed the evidence for 2 different points in time, ie the time of impact and the time when the Taxi came to a final stop. Figure 4.12 of Mr Johnston’s 2^nd Report showed the Taxi in motion up to the assumed point of impact at Frame 35, when the front of the Taxi had just about reached the rear of the public light bus at the bus bay on the NLane. Figure 4.4 of Mr Johnston’s 2^nd Report showed the position when the Taxi came to rest. Figure 4.4 showed the Taxi at its final position was pointing away from the Club towards the western pavement, but it also showed the Taxi finally stopped at a position some distance ahead of the front of the public light bus, so the Taxi travelled some distance after impact before it came to a stop. Much would turn on the kinematics of impact on the Taxi, road geometry, D’s braking action[98] and D’s steering reaction upon impact at the right front of the Taxi in order to understand its final direction/position, and at this interlocutory stage such variables would not detract from the vitality of Mr Johnston’s 2^nd Report.

119.  The Master also said it was doubtful whether Dr Tang’s opinion on the “angle of drop” reflected actual “angle of drop” as at the date of Accident, and if not, Mr Johnston’s reconstruction of the path of the Taxi that was partly based on Dr Tang’s measured “angle of drop” might not stand.[99] As I have accepted there was reasonable basis at this interlocutory stage for Dr Tang’s factual assumptions, the admissibility of Mr Johnston’s 2^nd Report could not be assailed on such ground. But Ms Lee criticised Mr Johnston for adoption of Dr Tang’s findings/opinion without query. The short answer to such complaint was that Dr Tang and Mr Johnston did not have overlapping expertise; rather, their respective findings/opinion involved 2 different areas of expertise. There was no reason for Mr Johnston as consulting traffic reconstruction engineer to query or doubt the findings/opinion of Dr Tang as land surveyor, which findings/opinion Mr Johnston used for rendering his own findings/ opinion. In much the same way, a surveyor expert carrying out expert survey to determine the cause and pathway of water leakage may have to rely on laboratory technician’s expert analysis of the chemical properties of plaster/concrete samples, or a medical expert rendering expert opinion on medico-legal issues may have to rely on pathological or radiological investigations/reports on investigative findings for him to formulate his clinical views.

120.  By reason of the above matters, I do not accept Ms Lee’s submissions that the opinion evidence in Mr Johnston’s 2^nd Report and Dr Tang’s Report involved a number of steps/inferences that were not explained in detail and/or that contained factual assumptions that were not on their face justified at all such that the court could not derive assistance from such expert evidence.

121.  Ms Lee submitted Mr Johnston’s 2^nd Report and Dr Tang’s Report, if allowed, would inevitably lead to extensive investigations, expert evidence in response and/or cross-examination to understand/ evaluate the experts’ methodologies and/or factual assumptions, which costs/efforts (including flying Mr Johnston from Australia to attend the trial) and delay to litigation would fly against the underlying objectives, especially the need to increase cost-effectiveness, and it would be disproportionate in a simple running down case that happened in April 2016 notwithstanding that the value of P’s pleaded claim exceeded $6,080,000.

122.  Of course, adducing expert evidence on liability by P (and inevitably by D) will add time, effort and costs to the litigation. But the court cannot lose sight of the fact that the Location Issue was a matter in serious dispute between the parties, and apart from the post-impact evidence (photographs and sketches) and the witnesses’ partisan accounts, the available objective evidence would be the Footage/Frames, but useful information therein had to be extracted scientifically by expert evidence. Bearing in mind that the proposed expert evidence on liability would be limited to objective materials rather than partisan accounts, many of the vices of traffic reconstruction evidence, which the courts have set their face against, would be pared away. The use of VCF hearing may also save costs of having Mr Johnston attending court to give evidence at the trial. Case management measures requiring experts to have without prejudice meeting and joint statements would also help narrow disagreements for trial. I therefore disagree with the Master that in the particular circumstances of this case expert evidence on the Location Issue would not be necessary or of any probative value. Rather, I consider expert evidence useful to the trial judge in his/her fact-finding function.

IX.  SPEED ISSUES

123.  On the Speed Issues, P pleaded 2 specific allegations, ie at the material time of the Accident D drove the Taxi (a) at a speed in excess of the legal speed limit of 50kph, and (b) at a speed that was excessive in the circumstances, and D by his Defence denied both allegations and pleaded a positive averment that at the material time the Taxi was travelling at/about 30kph. Thus, P and D by their respective pleadings engaged each other in dispute over the speed of the Taxi on both the Speed Limit Issue and the Excessive Speed Issue. P’s case on the Speed Limit Issue as distinct from the Excessive Speed Issue was not without significance because a person who drives a vehicle on the road in excess of the speed limit commits an offence under section 41(1) of the Road Traffic Ordinance Cap 374 (“RTO”),[100] and is in breach of the RUC[101] which provides that “[you] must obey the speed limits for the road and for your vehicle ……” Section 109(5) of the RTO further provides as follows:[102]

“A failure on the part of any person to observe any provisions of the [RUC] …… shall not of itself render that person liable to criminal proceedings of any kind but any such failure may in any proceedings whether civil or criminal ……be relied upon by any party to the proceedings as tending to establish or negative any liability which is in question in those proceedings.”

Although previous authorities emphasise that mere travelling in excess of the speed limit is not in and of itself negligence,[103] more recent authority suggests that even though it does not necessarily follow that negligence is to be imputed to a driver who breaks the speed limit (ie there is no presumption of negligence or breach of statutory duty), evidence of the speed limit being broken may provide relevant evidence of negligence on the part of the driver.[104]

124.  Here, insofar as statement evidence was concerned, both during the police investigation and in the present action P was able to say D was driving very fast and then the Taxi hit her whereas D was able to say he was travelling at/about 30kph. It was true, as the Master said, that whether P or D would be believed would be a matter of assessment and weight of their statement/oral evidence to be determined at trial in the present action. But at trial, P’s general observation in her statement evidence that the Taxi was “fast-moving” would have to meet D’s positive and specific statement evidence (whether by reference of his own knowledge/experience as a motorist or by having noticed the speed from the speedometer in the Taxi) that the speed of the Taxi was about 30kph.

125.  Whilst P’s aforesaid statement evidence, if believed, might arguably go some way to support P’s case on the Excessive Speed Issue, it might not be sufficient to establish her case on the Speed Limit Issue, which if established might be relevant to the trial judge’s assessment of the degree of culpability for the Accident between D as motorist and P as pedestrian.[105] After all, evaluation of contribution liability requires assessment of the culpability and causative potency of negligence found against each road-user, but bearing in mind that the duty of take reasonable care is not to be viewed with liberal use of hindsight in the leisure of the courtroom,[106] and that a car is “potentially a dangerous weapon” and those driving cars owe clear duties of care to those around them such that compliance with speed limits and proper awareness of potential hazards can often be critical in such circumstances.[107]

126.  The Master then pointed out there were available photographs / sketch plans from the police investigation as well as the Footage,[108] so it could not be said there was no evidence “on the speed and/or excessive speed of D so that the Trial Judge would need to resort to the assistance of an expert” (my emphasis). But apart from the Footage which I will come to in a moment, neither the Master nor Ms Lee articulated how the available photographs / sketch plans from the police investigation would assist the trial judge on the Speed Limit Issue. Turning to the Footage, the speed of the Taxi was not patent from lay review of the Footage itself without scientific analysis. In short, absent expert evidence, P would not be able to clearly show on available factual evidence whether the speed of the Taxi exceeded the speed limit of 50kph at the time of the Accident even though according to P’s 1^st Statement she saw it was “fast-moving”. Mr Leung submitted that in such circumstances it would be unjust to disallow P from adducing positive evidence showing the speed of the Taxi (even though it was derived from expert analysis of the objective evidence of the Footage/Frames) to establish her own positive case on the Speed Limit / Excessive Speed Issues and to rebut D’s assertion that the Taxi was then travelling at/about 30kph.

127.  Happily, at the Hearing, Ms Lee and Mr Leung agreed on the admissibility of Dr Tam’s 1^st Statement (save for paragraphs 5.1-5.3 therein which I have disallowed – see paragraphs 86-94 above) as opinion evidence in the present action. In the circumstances, I need not deal with the Master’s concern (raised by Ms Lee to the Master and reiterated in her written submissions for the Appeal) as to whether Dr Tam being a government chemist “would forgo his independence” and take on private instructions to act as P’s expert on liability in the present action. Any such concern could be addressed by issuance of a subpoena for Dr Tam’s attendance at the trial of the present action (if required) to be examined.

128.  Dr Tam’s 1^st Statement on the Speed Issues showed Dr Tam carried out laboratory analysis of the Footage from which he extracted the Frames, and ascertained (a) the frame rate of the Footage between “19:40:31” and “19:41:30” was 7 fps as subsequently verified by the control footage recorded by the CCTV Camera, (b) the Taxi appeared at “19:41:12” (Frame 31) and disappeared at “19:41:13” (Frame 40), and (c) the Accident occurred at/about “19:41:13” (Frame 35). Dr Tam visited the scene of the Accident on 20 July 2017 and “examined the CCTV system recording the [Footage] ……” and found “[the] live view of the CCTV camera was …… consistent with that of the [Footage]”. Dr Tam drew some landmarks of the live view of the CCTV Camera on a transparency, and later marked the positions of the Taxi and Stopped Taxi at Frame 31 (when the Taxi appeared in the Footage) and Frame 36 (when the Taxi continued on after the Accident). Dr Tam again visited the scene of the Accident on 25 July 2017 to make measurements of the accident speed of the Taxi. By looking at the live view of the CCTV Camera and positioning the Taxi as the Stopped Taxi and then as the Taxi on the Road, Dr Tam reconstructed the positions of the Taxi and the Stopped Taxi in Frames 32 and 36, and measured the distance travelled by the Taxi to be 7.8 metres from Frame 32 to Frame 36 (ie the 7.8m Road Stretch). By referring to a photograph of the final rest position of the Taxi taken by the police on the day of the Accident, Dr Tam measured the distance travelled by the Taxi from its position in Frame 36 to its final rest position to be 12.1 metres. Based on the average frame rate of 7fps and the 7.8 Road Stretch that the Taxi travelled from Frame 32 to Frame 36, Dr Tam was able to work out the Taxi’s average speed between Frame 32 and Frame 36 to be 49+/-5kph.

129.  Ms Lee in her written submissions stated “[there] was no dispute this [ie 49+/-5kph] was the agreed average speed of the Taxi from the Footage” (my emphasis),[109] and suggested Ir Lo’s Draft Report was not required “in light of the agreement by the parties on the average speed of the vehicle at the material time” (my emphasis).[110] As it was D’s case all along that he was travelling at/about 30kph at the time of the Accident and P’s case all along that D exceeded the speed limit of 50kph at the time of the Accident, I find it surprising (a) if D would agree that the Footage (which recorded the very Accident) showed the “agreed” average speed of the Taxi was 49+/-5kph and/or (b) if the parties would have been able to agree on the average speed of the Taxi at the time of the Accident.[111] I assume what Ms Lee actually meant was that the average speed of the Taxi as determined by Dr Tam was (a) an admitted fact at the Trial as agreed by the Prosecution and P (see the Admitted Facts in paragraph 8 above), and (b) agreed by P and D to be admissible opinion evidence for the present action. Mr Leung fairly accepted the Admitted Facts for the Trial would not bind D or the court in the present action.

130.  But Mr Leung submitted that even armed with Dr Tam’s findings/opinion P might still be unable to establish on balance of probabilities that the Taxi exceeded the speed limit of 50kph because an average speed 49+/-5kph arguably suggested the speed could equally be within or beyond the speed limit. Mr Leung submitted that disallowing P from adducing further expert evidence on liability in the shape of Ir Lo’s Draft Report would be “no different from striking out P’s claim based on D’s speed” (at least on the Speed Limit Issue). So the next question was whether expert opinion on liability by way of Ir Lo’s Draft Report would be helpful and necessary for the trial judge on the Speed Issues (especially on the Speed Limit Issue) at the eventual trial.

131.  According to Ir Lo’s Draft Report, Ir Lo relied on Dr Tam’s findings/opinion that (a) the average speed of the Taxi was 49+/-5kph for the 7.8m Road Stretch between Frame 32 and Frame 36 and (b) the average frame rate of the Footage was 7fps, and on such premise Ir Lo further analysed the speed of the Taxi by dividing Frames 32-36 into 4 sub-periods of 2 consecutive frames and 1/7 second per sub-period (ie Frames 32-33, 33-34, 34-45 and 35-36). Ir Lo then measured the image displacement shown on the computer display for the distance travelled by the Taxi (ie the 7.8m Road Stretch as found by Dr Tam) from Frame 32 to Frame 36 by using the right side mirror as a point of reference, which he cross-checked by using the front-most point of the roof light as another point of reference, and arrived at the scale of 1mm displacement on the computer display being equivalent to 0.195 metre actual displacement on the Road. In determining the speed of the Taxi for each of the 4 sub-periods, Ir Lo (i) used the front-most point of the roof light on Frame 32 as datum to calculate the actual distance displaced by the Taxi on the Road for each of Frames 32-36 by working out the distance from datum and the distance displaced from the previous frame on the computer display, (ii) applied the aforesaid scale to the displaced distance on the computer display to work out the equivalent distance displaced by the Taxi on the Road, and (iii) calculated the speed of the Taxi by dividing the distance displaced for each sub-period by time lapsed (1/7 second). This resulted in the following speed for the Taxi: 59kph (Frames 32-33), 46kph (Frames 33-34), 49kph (Frames 34-35), and 38kph (Frames 35-36), which Ir Lo checked against calculations based on linear motion equations that took into account braking distance, initial speed of the Taxi, stopping time, deceleration rate and gravitation effect and which showed the speed of the Taxi at Frame 32 to be about 57.1kph (if D applied brakes at Frame 32) or higher (if D applied brakes later). So Ir Lo concluded that “the Taxi was travelling at the speed of 59+/-6kph along [the Road] when it was at Frame 32. It slowed down gradually to about 38+/-4kph at Frame 36”.

132.  The Master considered Ir Lo’s Draft Report to be “not necessary nor of any probative value”:[112]

(a)	the Master shared Ms Lee’s concern over how P’s proposal to call both Dr Tam and Ir Lo could work in practice because in seeking to adduce Ir Lo’s Draft Report P wished to introduce more “minute/accurate speed estimate of [the Taxi] (ranging from 59 km/h to 38 km/h) which is different from the opinion given by Dr Tam (at an average speed of 49+/-5 km/h). If so, does that mean P may have to cross-examine Dr Tam, her own expert?”;[113]
(b)	the Master said “it was unclear why [Ir Lo] used the “right side mirror” of the [Taxi] as one of the reference point to determine the speed of the [Taxi] in [Ir Lo’s Draft Report]. It was the right front corner of the [Taxi] near the headlamp and indicator that was the point of impact”;
(c)	the Master also agreed with Ms Lee’s submission that the court would not need to make a finding on the speed of the Taxi down to minute accuracy of every 1/7 second.

133.  At the Hearing, Ms Lee reiterated the submissions akin to paragraph 132(a) above that the expert findings/opinion on the Speed Issues expressed in Dr Tam’s 1^st Statement and in Ir Lo’s Draft Report did not sit well together. Ms Lee queried whether P would challenge Dr Tam’s speed estimate of 49±5kph, but Ms Lee acknowledged it appeared unlikely in view of Ir Lo’s comment that Dr Tam’s methodology was “reasonably accurate”. In fact, Ms Lee’s written submissions went further to say Ir Lo’s Draft Report was unnecessary when “an alternative “reasonably accurate” method of estimating the speed [ie methodology Dr Tam adopted in Dr Tam’s 1^st Statement] is accepted and is agreed by the parties” (my emphasis).[114] But Ms Lee also submitted that since P sought “to establish a different and allegedly more accurate estimate via the opinion of Ir Lo, [it] means that Dr Tam’s estimate has to be dealt with”, and as Dr Tam was not invited to comment on Ir Lo’s Draft Report, it was unknown whether Dr Tam would disagree with Ir Lo’s opinion, which uncertainty would raise a nice question as to whether P would have to cross-examine (normally impermissible) Dr Tam who was proposed to be P’s expert.

134.  Ms Lee also made submissions akin to paragraph 132(c) above that it was unwarranted for Ir Lo to work out the speed of the Taxi to the accuracy of 1/7 second because it was never the practice to measure speed “to that degree of detail” in determining liability in a running down claim, and the trial judge in the present action would not have to make any finding of the Taxi’s speed of such minute accuracy, especially when accident reconstruction by its very nature was not an exact science, and Ir Lo himself accepted his speed estimation necessarily had a margin of error.

135.  Although Ms Lee did not seem to rely on the Master’s reasoning in paragraph 132(b) above, she submitted Ir Lo’s findings/ opinion in Ir Lo’s Draft Report appeared to consist of unclear and somewhat shaky conclusions based on tenuous inferences. She referred to the English Court of Appeal’s warning in Clayton v Lambert[115] on the danger of doing injustice if judges make unwarrantedly precise findings of fact where there are inherent uncertainties about the facts:

“39. The only point I wish to make is that there is a danger of doing injustice if judges make unwarranted precise findings of fact. Of course, if the evidence warrants a precise finding of fact (on the balance of probabilities) that makes the judge’s judgment easier. If there are inherent uncertainties about the facts, as there were here, it is dangerous to make precise findings. This may well mean that the party who bears the burden of proof is in difficulties. But that is one of the purposes behind a burden of proof; that if the case cannot be demonstrated on the balance of probabilities, it will fail.

40. I stress that these last observations are entirely obiter as, for the purposes of the appeal, the parties have accepted the judge’s findings of fact and I have done likewise ……”

Ms Lee argued that reliance on “guestimates” to make exact findings not justified on the evidence would not be appropriate, and Ir Lo’s Draft Report was an example of such “guestimate” that was unlikely to assist fact-finding by the court.

136.  Ms Lee added that if leave were granted for P to adduce Ir Lo’s Draft Report, much time/cost would have to be incurred in response when in fact such evidence was not necessary/relevant and not of probative value in view of the parties’ consensus to adduce expert evidence on the Speed Issues by way of Dr Tam’s 1^st Report, and it would fly against the underlying objectives in Order 1A rule 1(a) of the RHC that encouraged inter alia cost-effectiveness. Although the pleaded value of P’s claim was more than $6,080,000 which, Ms Lee acknowledged, on its face might suggest the cost of obtaining expert evidence on liability would not be disproportionate to the claim, Ms Lee suggested such view would be less cogent after taking into account the costs for both parties to commission expert reports and to have such experts testify at the trial, which would add length to such trial and delay to the resolution of this simple running down claim, and which would attract Seagroatt J’s admonitions in Wong Hin Pui. On such basis, it was said there was no convincing reason to depart from the general rule in Liddell and to grant leave for P to adduce Ir Lo’s Draft Report.

137.  Turning first to the contentions in paragraphs 132(a) and 133 above, I am unable to see any inconsistency between the findings/opinion in Dr Tam’s 1^st Statement and Ir Lo’s Draft Report, or see how such findings/opinion in the 2 reports would not sit together. What Ir Lo did was to adopt the findings, measurements and calculations by Dr Tam as basis for his own calculations/opinion.[116] I find it was reasonably clear from the contents of Ir Lo’s Draft Report that Ir Lo adopted Dr Tam’s findings/opinion (see paragraph 131 above), and indeed Ir Lo expressly confirmed “…… [he has] adopted the findings of Dr Tam”.[117] Then Ir Lo sought to extrapolate further data as to the speed of the Taxi at different points within the 7.8 Road Stretch from the Footage/Frames and Dr Tam’s findings, measurements, calculations and opinion on the average speed of the Taxi over that road segment. If different speeds along the 7.8 Road Stretch could be scientifically ascertained from the Footage/Frames and Dr Tam’s findings/opinion, they would be additional or extrapolated details rather than any inconsistent/different findings. It is a matter of commonsense or logic that the average speed of a vehicle (x) travelling over certain distance may be the result of such vehicle travelling (a) at varying higher (y) and lower (z) speeds that would average out to x,[118] or (b) at a flat speed x throughout. Here, according to Dr Tam 1^st Statement, the assumed point of impact was at Frame 35. Commonsense or logic would also suggest that hitting P might slow down the Taxi somewhat in Frames 35-36 from its pre-impact speed, which would in turn suggest it would not be impossible for the Taxi to have different speeds at different points within the 7.8m Road Stretch to result in an average speed of 49+/-5kph.

138.  Anyway, even though Ir Lo relied on Dr Tam’s findings/ opinion, as a professional expert he also reviewed Dr Tam’s accident reconstruction methodology and found “the method applied by Dr Tam in finding the average speed of the Taxi is reasonably accurate, although it carries some margin of error, which Dr Tam suggested to be about +/-10%”, and he saw no reason to disagree with Dr Tam’s margin of error, which he also applied to his own findings that rested on Dr Tam’s findings/opinion.[119]

139.  Plainly, Ir Lo’s Draft Report posed no challenge to Dr Tam’s findings/opinion on the Taxi’s average speed, and I am unable to see any need for P to (and indeed Mr Leung did not suggest P would) cross-examine Dr Tam by reason of the contents of Ir Lo’s Draft Report. The above analysis would sufficiently debunk Ms Lee’s suggestion that P was “proposing to rely on one expert’s (Ir Lo) evidence to contradict that of another expert (Dr Tam), a Government chemist with no interest on the outcome of the litigation” (my emphasis).[120] As Mr Leung submitted, P adopted a pragmatic approach by limiting Ir Lo’s expert opinion since Dr Tam had carried out the primary reconstruction exercise with public resources.

140.  Ms Lee complained that Dr Tam was not invited to comment on Ir Lo’s Draft Report so it was unknown whether or not Dr Tam would disagree with Ir Lo’s measurements/opinion. Whilst I might see a corresponding expert engaged by D (if any) might wish to comment on Ir Lo’s measurements/opinion, I do not see any sufficient reason for Dr Tam to do so when Ir Lo relied on Dr Tam’s findings/opinion to ground his own calculations/opinion. It was not for Dr Tam to review/comment on a subject that he was not called upon to opine, ie what was the speed of the Taxi at different points as it travelled along the 7.8m Road Stretch.

141.  I now deal with Ms Lee’s complaint that it was unnecessary and unhelpful for the court to measure the speed of the Taxi with accuracy up to 1/7 second when there was recognised margin of error. As Mr Leung submitted, the 1/7 second was the time lapsed between 2 consecutive Frames of the Footage (based on Dr Tam’s findings of the Footage’s average frame rate of 7fps), and the analytical exercise by Ir Lo as expert (in contra-distinction to the judicial exercise by the court) was not to find the travelling speed at which the Taxi moved along the NLane prior to the Accident for determining the Speed Limit / Excessive Speed Issues, but to ascertain the speed of the Taxi at different times (ie the 4 sub-periods of 2 consecutive Frames for Frames 32-36) and different positions (ie the 4 positions of the Taxi on the 7.8m Road Stretch at the 4 sub-periods) that were before, at and after the impact. Thus, 1/7 second was merely to identify specific times/positions of the Taxi (on the basis of the average frame rate of 7fps) for Ir Lo to calculate the speed of the Taxi.

142.  Ir Lo’s findings/opinion, if accepted at trial, would tell the trial judge the Taxi’s speed (subject to acknowledged margins of error) at particular points along the 7.8m Road Stretch just before, at and after the assumed point of impact with P. It must be remembered that the Taxi was a moving vehicle, and its speed in motion prior to the collision would be a factual matter for consideration and determination by the trial judge. But Ir Lo’s measurements/findings as to particular speed of the Taxi, say, at certain points on the 7.8m Road Stretch before impact based on the Footage/Frames and on the findings/opinion in paragraphs 1-4 of Dr Tam’s 1^st Statement (now agreed to be admissible) would be opinion based on objective evidence for the trial judge to assess and decide what was the travelling speed of the Taxi prior to collision. Ir Lo’s findings/ opinion were based on expert measurements/calculations that rested on the Footage/Frames and Dr Tam’s 1st Statement on the Speed Issues, and not on any partisan witness account of a rapidly occurring event with risk of distortion due to discrepancies over subjective allegations and risk of query over variables[121] and post-impact features.[122] Ultimately, it would be for the trial judge to decide what weight ought to be placed on Ir Lo’s findings/opinion in light of the evidential matrix in determining the Taxi’s travelling speed prior to impact to resolve the Speed Limit / Excessive Speed Issues, which in turn would be pertinent to evaluating the respective culpability and causative potency of negligence against each party. I do not think P was urging the court to resolve both the Speed Limit / Excessive Speed Issues in her favour merely because Ir Lo calculated the Taxi’s speed was 59+/-6kph at Frame 32 for 1/7 second.

143.  Bearing in mind that the Speed Issues (especially the Speed Limit Issue) were hotly debated between the parties but P was unable to speak to the speed of the Taxi except it was “fast-moving”, that Dr Tam’s 1^st Statement on the Speed Issues was now agreed to be adduced in the present action, and that Ir Lo could form findings/opinion as to speed of the Taxi at particular points of the 7.8m Road Stretch as calculated/ extracted from the Footage/Frames and Dr Tam’s findings/opinion, I find the expert evidence in Ir Lo’s Draft Report relevant, necessary and of probative value to the Speed Issues to be tried and determined in the present action.

144.  Although Ms Lee did not appear to rely on the Master’s concern over why Ir Lo used “right side mirror” of the Taxi as a point of reference to determine the speed of the Taxi when it was the right front corner of the Taxi near the headlamp and indicator that was the point of impact, I shall deal with this briefly. The purpose of having points of reference for viewing Frames 32-36 was to facilitate measurement of the image displacement shown on the computer display, so that the actual displacement on the Road could be calculated when the Taxi covered the 7.8m Road Stretch during the period of Frames 32-36. The key consideration for such exercise would be to find a corresponding point of reference in the image of the Taxi in all of Frames 32-36, and which part of the Taxi was the point of impact was not material to such exercise.

145.  Turning now to Ms Lee’s suggestion that the findings/ opinion in Ir Lo’s Draft Report were unclear, shaky and tenuous, she did not condescend upon particulars of such suggestion vis-à-vis the contents of Ir Lo’s Draft Report. Rather, she sought to criticise Ir Lo’s findings/ opinion by relying on Clayton’s warning against relying on different “guestimates” to make accurate findings and saying Ir Lo’s Draft Report was such “guesstimate”.

146.  To deal with such complaint, one needs to turn to Clayton. In that case, a motorcycle ridden over the brow of the hill at high speed collided with a vehicle turning right into a lane across its path. A speed limit of 60mph was in force. The motorcyclist was killed. There were brake marks showing the driver had braked, but there was no sign the motorcyclist braked at all. At first instance, judgment was entered against the driver with contributory negligence by the motorcyclist assessed at 75%. It was held on appeal that the overwhelming cause of the accident was the motorcyclist’s excessive and dangerous speed as he came over a blind summit, and that one could not infer negligence from the mere fact there was an accident. The English Court of Appeal held that the judge was wrong to find the driver to be negligent as he only had a split second to react, and none of the options available to him were without its disadvantage. If the motorcyclist had been driving at a proper speed and had reacted correctly, the accident could easily have been avoided.

147.  In that case, there was evidence from traffic reconstruction experts who deduced the driver’s actions in turning right into the lane from the speeds of the vehicle/motorcycle and the distances they had to cover, but it was common ground “the real evidence from which deductions could be made was sparse” (pages 19-20). The experts postulated about the speed of vehicle when it approached the turn into the lane, the distance between the vehicle and motorcycle when the driver and motorcyclist would have first been able to see each other, the position of the vehicle at the moment of collision, and the route the vehicle had taken in making the right turn (page 20).

148.  But the English Court of Appeal reserved particular criticism against the trial judge (rather than the experts) for making findings of fact on speed and distance with a degree of precision that was not warranted by the evidence:

(a)

The finding of fact as to the speed of the vehicle was significant because it governed the time needed to cover the distance between the motorcyclist’s appearance at the top of the hill and the collision (which the judge held to be 110 metres). But the evidence relating to the motorcyclist’s speed was very limited; eye-witnesses described him driving very fast, and his friend who was following said he himself was doing 95mph and thought the motorcyclist was doing the same but would have slowed down for the blind summit. Smith LJ held that “[on] such material, a finding of a range of speed would be justified but a specific speed is not”, nevertheless the trial judge plumped for a specific speed, ie the motorcyclist “…… was approaching at 80mph ……”, “…… based on very limited material from which he was able to draw inferences” (page 26). At the speed of 80mph, it would have taken 3.08 seconds for the motorcycle to travel the distance from top of the hill to the collision.

(b)

As for the time the vehicle was in the motorcyclist’s carriageway, the driver said he took the shortest route (12 metres) and the experts suggested figures between 12 and 30 metres, but the trial judge plumped for a precise finding of 20 metres. Smith LJ found “there was no real basis on which the judge could say what the actual distance was”, but at a speed of 15kph the vehicle would have been on the carriageway in the path of the motorcycle for 2.98 seconds, which led the trial judge to his conclusion that the motorcycle came into view at or about the same time as the driver was crossing the white line.

The English Court of Appeal held that if a judge treated “these guesstimates” as secure findings of fact, it could easily lead to an unjust result either way. If the speed of the motorcyclist was slightly higher than as found, it would have distorted the time taken to reach the collision point, which could have made a crucial difference to the judge’s “calculating back” exercise as it would mean the driver was further into the motorcyclist’s carriageway at the moment when the motorcyclist appeared, which in turn would have put a different complexion into the driver’s decision (page 27). But if the motorcyclist’s speed was slightly less than as found, the judge’s “back-calculation” might have put the driver half a second short of crossing the white line in which case he ought to have aborted the turn (page 27). Smith LJ also found the judge’s estimate of the distance covered by the vehicle was significantly inaccurate. If the driver had taken the shortest feasible route, it would have taken him 1.8 seconds to reach the collision point and adding a second for him to complete his manoeuvre he would have been out of the way if the motorcyclist had been coming at 80mph, but not if the motorcyclist had been coming at a slightly faster speed (page 27). This therefore led to the aforesaid observations by Smith LJ in paragraph 135 above against “guesstimates”.

149.  The above showed Clayton to be a reminder to judges to make precise findings of fact only when warranted by the evidence, and not to do so or, to put it in any way, not to take “guesstimates” and treat them as secure findings of fact if there were inherent uncertainties about the facts that would have precluded precise findings. Smith LJ’s observations were not targeted at reconstruction expert evidence. Rather, the traffic reconstruction experts’ evidence in that case was unable to bring sufficient clarity to the overall evidence to justify the trial judge’s precise findings of fact (and the trial judge should have found for a range of speed rather than a precise speed). But such admonitions would not have precluded expert evidence on liability from being relevant, probative and/or necessary in appropriate cases to offer assistance to facilitate the court’s fact-finding function. I am not persuaded that Clayton took Ms Lee’s objection to Ir Lo’s Draft Report any further.

150.  Moreover, traffic reconstruction by the experts in Clayton was built on sparse evidence that postulated speeds and collision dynamics formulated on witnesses’ accounts and road measurements. I agree that if experts on liability in traffic accident claims engage in little more than an advocacy exercise of suggesting elaborate alternative scenarios premised on permutations/adjustments taken from sparse primary forensic evidence with little/no expertise involved and risk of distortion due to variables, and/or that so-called expert analysis is no more than an attempt to interpret the imprecise interplay between witness account[123] and physical evidence[124] with more precision than such exercise deserved, such opinion evidence is likely to fall foul of the general rule mentioned by Stuart Smith LJ in Liddell and unlikely to be of assistance to the court.

151.  Here, there was no dispute as to Ir Lo’s expertise for the purpose of the Appeal, and the findings/opinion in Ir Lo’s Draft Report required Ir Lo to use skill/expertise (his and Dr Tam’s) to extrapolate and interpret the Footage/Frames that objectively recorded the Accident to ascertain the speed of the Taxi at certain points along the 7.8m Road Stretch, which exercise Ir Lo fairly accepted to have margin of error that he took into account. This was a narrow and confined exercise, and I am not persuaded that such exercise suffered from the vices in the above paragraph that would render opinion evidence unhelpful.

152.  Lastly, I would like to refer to Ayre v Swan[125] which showed that ascertaining vehicle speed from subsets of frames extracted from CCTV footage was an expert technique not unknown to the courts. In that case, the accident was captured on CCTV footage, which enabled the parties’ traffic engineering experts on liability to assess the likely speeds of the involved vehicles immediately prior to the collision between right-turning car A and a motorcycle coming from the opposite direction and passing car B in front of him on the inside. The driver’s expert concluded that the motorcyclist was travelling at about 100-120kph as he approached the car A and his speed at the point of impact was 70kph, but the motorcyclist’s expert concluded that the motorcyclist’s speed was considerably less. Both experts agreed that if the motorcyclist had been travelling at the speed limit, he would have been able to avoid a collision.

153.  The driver’s expert recovered 9 consecutive frames from the CCTV footage covering a period of 2.5 seconds (paragraph 31) that allowed him to make calculations based on known distances over a time window from the driver’s right hand turn until the moment of impact (paragraph 32). The driver’s expert then used an aerial photograph of the incident location to prepare a scaled site plan and drew in the 3 vehicles and sight lines from the CCTV camera, and then he worked out the following for car B (paragraphs 8 and 32):

“32. …… In order to assess the speed of the vehicles, distances were calculated by reference to both the full set of frames and subsets. Thus, in the period of 2.25 seconds, the plan indicated that [car B] had travelled a distance of 29.6 metres at an average speed of about 47kph. However, taking only frames 1 and 6,[126] the initial speed of [car B] was about 53kph. [The driver’s expert] allowed for a margin of error for up to one metre in the distance travelled and therefore assessed [car B’s] initial speed at between 50 and 55kph.”

The driver’s expert made similar calculation of the motorcyclist’s speed when approaching car A (ie about 100-120kph) and at the moment of impact (ie 70kph) (paragraph 9):

“33. Between frames 1 and 9, the [motorcyclist] travelled a total distance of 62 metres (twice the distance travelled by [the driver of car B]) at an average speed of about 100kph. Following frame 5, the [motorcyclist] appeared to slow, presumably braking, before the start of the skid mark which was located between the sight lines of frames 6 and 7. [The driver’s expert] calculated that between frames 2 and 5 the plaintiff speed was 111kph, but allowing for a margin of error of up to two metres, the speed was identified as ‘about 100 to 120 km/h (in other words, in excess of 100 km/h).’”

154.  The trial judge did not accept the expert’s evidence, and found that the motorcyclist was travelling somewhere in the vicinity of 82kph. On appeal, although Basten JA dissented, both Macfarlan JA and McCallum JA agreed that “for the reasons given by Basten JA …... the primary judge should have found that the plaintiff was travelling at a speed of at least 100kph rather than “at a speed in the vicinity of 82 k/h”” (paragraphs 56 and 67). Basten JA held that the primary judge erroneously discounted expert evidence (as explained in the above paragraph) which indicated that the motorcyclist was travelling in excess of 100kph at the time of the accident.

155.  Basten JA noted that the motorcyclist caused a “forensic photographer” and the driver caused a “professional surveyor and photogrammetrist” to provide reports with respect of the calculations by the driver’s consultant traffic engineer expert “based on the CCTV footage and known measurements of distance” (paragraph 12). Even though the motorcyclist’s “forensic photographer” raised some general concerns about the methodology of the driver’s expert (paragraph 34), the latter’s calculations as to the speed of the involved vehicles, particularly that of the motorcycle, based on the CCTV footage received support from the opinion evidence of the driver’s “professional surveyor and photogrammetrist” (paragraphs 12-13) who considered the adopted methodology (paragraph 36) and margin of error (paragraphs 37-38) valid, and who sufficiently addressed the general concerns raised by the motorcyclist’s “forensic photographer” (paragraphs 39-45). Basten JA therefore held that “[in] the circumstances, the balance of probabilities weighed heavily in favour of accepting [the driver’s traffic consultant engineer’s] calculations. According, the appropriate finding was that the [motorcyclist] was travelling at a speed not less than 100kph as he passed [the driver of car B]” (paragraph 47).

156.  In that case, even though the drivers of cars A and B and the motorcyclist gave evidence, the driver’s traffic engineer expert made useful calculations / interpretations of extrapolations from the objective evidence of the CCTV footage and the relevant frames extracted therefrom. Not only did he work out the average vehicle speed over a road segment, he considered subsets of frames extracted from the CCTV footage to work out the speed within subsets of frames. Such expert findings/opinion, not accepted at first instance, was found on appeal to be useful for the judicial fact-finding exercise of ascertaining the motorcyclist’s speed, which in turn reflected on his culpability for the accident. The trial judge’s determination of 50% contributory negligence on the part of the motorcyclist was set aside, and a finding of 80% negligence substituted (paragraph 73). Whilst the need for expert evidence in each case is unique, I find Ayre do lend some weight to the suggestion that Ir Lo’s findings/opinion might be useful to the trial judge in the present action.

157.  I am not persuaded Ir Lo’s Draft Report suffered from the vices referred to by Stuart Smith LJ in Liddell in the particular context of the present case given the parties’ dispute over Excessive Speed / Speed Limit Issues, P’s limited ability to speak to the actual speed of the Taxi, and the fortuity of having the objective recording of the Footage that captured the Accident but which required expert help to “unlock” useful information as to the speed of Taxi therein. I find Ir Lo’s Draft Report to be of probative value.

158.  It was said that adducing expert evidence on liability on the Speed Issues would be a costly exercise that flied in the face of the underlying objectives. Now that it had been agreed Dr Tam’s 1^st Statement on the Speed Issues was admissible opinion evidence, and given the limited nature of the 4-page Ir Lo’s Draft Report (exclusive of appendices) as explained above, any expert response should not be elaborate or extensive but should be a focused critique on his methodology and calculations. In my view, differences between experts on these matters (if any) would not take up disproportionate trial time. Bearing in mind that P’s claimed loss and damages were in excess of $6,080,000, and that the exercise of case management powers was for inter alia the just resolution of the Speed Issues in respect of which P needed expert evidence to support her case that was built on speeding and, more significantly, speeding beyond the speed limit, I find such expert evidence in the particular context of the present action to be outside the “general rule” in Liddell.

X.  OTHER MATTERS

159.  Ms Lee further submitted that the Summons was clear breach of the protocol on commissioning expert reports as provided in paragraphs 69-72 of Practice Direction 18.1. I am unable to see any material breach of such provisions which state inter alia that (a) leave of the court is required for expert evidence to be adduced at trial, (b) a party who obtains expert reports before seeking leave of the court does so at his own risk as to costs and/or eventual refusal of leave to adduce such expert evidence, (c) as soon as it is realised there exists a need or anticipated need for adducing expert evidence at trial a party may apply by summons to the PI Master as soon as possible in the course of proceedings for directions on obtaining expert evidence and/or permission to adduce expert evidence, and (d) the applicant party in such application for directions/permission has to give the name and area of expertise of his expert on liability.

160.  Whilst it is true those provisions also urged parties to adopt a consensual approach to expert evidence if possible, this had no material relevance here because D opposed the Summons and the Appeal, and took the stance that if expert evidence on liability were required on the Location/Speed Issues, the parties should be allowed to engage their own respective experts to prepare separate reports before giving consideration to whether the experts should thereafter have a without prejudice meeting and a joint statement to set out their agreements and disagreements.[127]

XI.  CONCLUSION

161.  For all of the above reasons, I find that expert evidence on liability on the Location/Speed Issues would be of assistance to the trial judge. I grant the following orders:

(a)	the Appeal is allowed and the Master Order is set aside;
(b)	leave be granted for the parties respectively to adduce expert evidence on liability on the Location Issue at the trial of this action by traffic accident reconstruction engineer and land surveyor;
(c)	leave be granted for the parties respectively to adduce expert evidence on liability on the Speed Issues at the trial of this action from traffic accident reconstruction engineer and mechanical engineer;
(d)	the experts on liability nominated by P in respect of the Location Issue are Mr Johnston (traffic accident reconstruction engineer) and Dr Tang (land surveyor);
(e)	the experts on liability nominated by P in respect of the Speed Issues are Dr Tam (government chemist acting as traffic accident reconstruction engineer) and Ir Lo (mechanical engineer);
(f)	retrospective leave be granted for P to serve the following expert reports on liability exhibited to the P 1st Aff: (i) Mr Johnston’s 2nd Report with paragraphs 4.2-4.3 and 4.24-4.31, Figures 4.2 and 4.13 and 1st Ø on page 34 thereof redacted, (ii) Dr Tang’s Report, and (iii) Dr Tam’s 1st Statement with paragraphs 5.1-5.3 redacted (“Redacted Dr Tam’s 1st Statement”);
(g)	within 14 days from the date of this order, P shall serve completed and signed Ir Lo’s Draft Report;
(h)	for the avoidance of doubt, no leave is granted for any party to adduce at the trial of this action (i) paragraphs 4.2-4.3 and 4.24-4.31, Figures 4.2 and 4.13 and 1st Ø on page 34 or Mr Johnston’s 2nd Report, and (ii) paragraphs 5.1-5.3 of Dr Tam’s 1st Statement;
(i)	within 21 days from the date of this order, D shall write to P with copy to the court on the following:
	(i)	state whether D would also rely on the Redacted Dr Tam’s 1st Statement or would nominate his own expert;
	(ii)	subject to sub-paragraph (i) above, state D’s nominations for his experts on liability for the Location Issue and the Speed Issues in (b)-(c) above;
	(iii)	state when the expert reports on liability by D’s nominated experts on the Location Issue and the Speed Issues can be compiled;
(j)	within 7 days thereafter, P and D shall jointly write to the court to propose case management directions on:
	(i)	service of D’s expert reports on liability as well as arrangements on without prejudice meeting of the experts and joint statements by the experts;
	(ii)	any other necessary and appropriate case management directions, including matters concerning Dr Tam’s 2nd Statement referred to in paragraph 31(i)-(ii) above.

162.  There is no reason why costs should not follow event. Ms Lee in her written submissions helpfully accepted that should P succeed on the Appeal, P should be awarded her costs here and below with certificate for counsel. In the circumstances, I grant a cost order (which is an absolute order) that D do pay P costs of and occasioned by the Summons (with certificate for counsel) and costs of and occasioned by the Appeal, including all costs reserved if any, to be taxed forthwith if not agreed.

163.  In respect of the Consent Summons, I grant an order in terms of paragraphs 1-2 thereof.

XII.  POSTSCRIPT

164.  I must end this Decision to re-affirm that it forms no precedent, and whether expert evidence on liability is allowed in road traffic accident cases turn on the particular matrix of each case. Here, it is the unusual and peculiar combination of the pleaded issues, the limitations of the factual evidence, and the fortuity of having the objective Footage with the inopportune blockage by objects at certain crucial points of the recording that led to the aforesaid case management result. The result may be quite different if the Footage had a clear field of view, or there was a pedestrian on the western pavement or a passenger in the Taxi who could give clear and cogent evidence. It may also be quite different if the objective recording is not by the CCTV Camera mounted at height at the Club Column but by a camera in the Taxi that gives a clear view of unfolding events view outside the front windscreen. It is, to say the least, not easy to have such synergy of factors to persuade the court to allow expert evidence on liability in road traffic accident claims given the usual nature of issues/evidence in those cases. In most cases, it will be an impressionistic decision by the trial judge involving weighing and balancing a range of different factors/evidence.

165.  More importantly, litigants and practitioners are reminded that the courts have consistently discouraged traffic reconstruction when there is no or sparse forensic materials and when the “expert” is asked to (a) put forward elaborate alternative scenarios, often based on subjective/ partisan accounts of rapidly occurring event that involve estimates of reaction, time, space, speed and distance made by road-users usually unversed in making such estimates, and (b) to speculate on speed and dynamics leading to undesirably prolonged or intensive enquiry (see observations in paragraph 150 above). Such “opinion” rarely has utility and cannot usurp the fact-finding function of the trial judge. The caution raised in Liddell still has resonance now, and litigants and practitioners should note the courts will not smile kindly on any ambitious attempts to introduce such “opinion” under the guise of scientific criteria.