CHEUNG CHUNG CHUEN v. CHAN-TUNG KEUNG AND ANOTHER

IN THE SUPREME COURT OF HONG KONG

HIGH COURT

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JUDGMENT

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Facts

1. On 12th March 1991, a goods vehicle ("the vehicle") fitted with a concrete mixer was involved in a traffic accident at the junction of Gloucester Road and Fleming Road in Wanchai. The vehicle was loaded with ready-mixed concrete supplied by the Pioneer Concrete and was intended to be used at the construction work of Central Plaza. The vehicle was travelling along the inner lane of Gloucester Road next to the Immigration Tower and the construction site of the Central Plaza. This lane turns left into Fleming Road. However, instead of following the bend, the vehicle mounted the kerb of the safety island at the junction, went through the opening which was used by pedestrians to cross the road, toppled over and continued to skid until it crashed into the railings on the other side of the safety island. The vehicle ended up sideways.

2. The vehicle caused injuries to five pedestrians on the safety island, one of whom was Miss Cheung Suk Yin ("Miss Cheung") who died as a result of the injuries. She was crushed between the front of the vehicle and the railings as the vehicle fell on its side. Her father, the administrator of her estate, now brings this action against the driver and owner-of the vehicle-for damage. The other injured persons have also brought two separate actions against the Defendants. These actions are stayed pending the determination of the liability of the Defendants in this case.

Eve-witnesses

3. The accident was witnessed by a number of persons, two of them gave evidence for the Plaintiff.

Mr Wong Hee

4. Mr Wong Hee ("Mr Wong") was a construction worker at the Central Plaza site. He and his co-workers, including Mr Yip Yun Kwai ("Mr Yip"). were going back to the construction site after they had finished lunch. The safety island has a staircase leading up to a footbridge. Mr Wong stated that he and Mr Yip had gone down the footbridge and were walking towards west. He was about 30 feet behind Mr Yip. There was a girl, i.e. Miss Cheung, also walking side by side with Mr Yip to his left. When Mr Yip and the girl reached the ground level near the western staircase of the footbridge, Mr Wong saw the vehicle approaching at a very high speed along the left lane of the eastbound carriageway of Gloucester Road. He could not ascertain its exact speed as he has no driving experience. Mr Wong thought that the truck would turn left to proceed north along Fleming Road, but the truck continued towards them. It mounted the safety island, hit the guard railing and fell on its side. In front of Mr Wong were two other pedestrians in addition to Mr Yip and Miss Cheung. All four of them bore the brunt of the impact and were knocked down by the truck. After hitting the pedestrians, the truck slid forward pushing Mr Yip and Miss Cheung against the guard railing and then came to a halt. The truck continued to slide forward for about 3 yards after it tipped over. Mr Wong said that the first time he saw the truck was at a distance of 30 yards. The truck driver did not use his horn. Also the truck turned over on its side before it hit the pedestrians. Before the accident, he did not see any pedestrian crossing the road in front of the truck. Mr Wong conceded that he could not ascertain the exact speed of the vehicle as he had no driving experience.

Mr Yip Yun Kwai

5. Mr Yip also gave evidence. He said that he and the other pedestrians in the safety island were standing and waiting to cross the road. He saw a truck coming towards him at approximately 30-40 mph on the left side of Gloucester Road eastbound. It was then about 30 feet from him. The accident happened in a split second. The truck moved towards the kerb on its right at a high speed. It appeared to be unsuccessful in negotiating the bend. The driver lost control. The vehicle swung towards the right side. The truck driver did not sound his horn to warn the pedestrians. Mr Yip screamed and turned around to escape the truck coming in his direction. However, it was already too late for him and the other pedestrians to run away. He felt something hit his buttocks. He fell to the ground and hit a railing. His legs were trapped. He then saw the truck had fallen on its side. His legs were trapped under the door on the driver's seat.

Examination of the vehicle

6. Mr Tsang Man Wai ("Mr Tsang") is an engineer employed in the Electrical and Mechanical Services Department of the Hong Kong Government and seconded to the Transport Department He carried out an examination of the vehicle after the accident. In his Accident Report, Mr Tsang listed a number of damages to the truck. Amongst them, the front axle was misaligned, the front suspension was damaged and the steering drag link was separated from the steering arm.

7. I should at this stage briefly refer to the suspension system and steering system of the vehicle.

The suspension system.

8. The suspension system consists of the leaf-springs, the mounting of the leaf-springs and the shock absorber. The purpose of the leaf-springs is to provide a cushion for the vehicle. The leaf-springs were placed on top of the axle and were held onto the axle by the U-bolts, the leaf-springs were not uniform in length, those closest to the top of the axle were shorter and then the length progressively lengthens so that in terms of shape; they form an inverted pyramid shape without the triangle at the top. For the front axle, there were two sets of leaf-springs, they run parallel to the side of the vehicle. The U-bolts hold the middle part of the leaf-springs to the axle.

The steering system

9. The steering system consists of the steering wheel of the driver which was connected to a steering column. This leads to a steering box which consists of the gears. The steering box is connected to a drop arm which will move up and down when the driver turns the wheel to right or left. Connected to the drop arm is the drag link which is connected to the steering arm ball joint located at the road wheel of the truck. There is also a hydraulic cylinder to assist the steering of the car.

U-bolts

10. This truck had three axles, each connecting a set of wheels. The front axle is connected to the chassis of the truck by means of U-bolts, which fastened the front axle to the leaf-springs on each side of the vehicle. There are two U-bolts on each of the near-side and the off-side making a total of four. During the examination, Mr Tsang saw that all four U-bolts were still on the truck. None of them was missing or broken. One of the U-bolts on the near-side had moved from its proper position and had become distorted in shape. He said one of the off-side U-bolts has also become distorted. Photographs were taken of the vehicle both at the scene and pound. As shown in Photographs 10/4 and 10/6, one of the nuts of the near-side U-bolt was missing. Although Mr Tsang said that the front axle is connected to the chassis by means of U-bolts, this is not strictly correct because the U-bolt only fastened the front axle to the leaf-springs. The leaf-springs are in turn attached to the chassis by means of mounting as illustrated by Diagram No.3, Sketch 1.

Braking tests

11. Mr Tsang caused the front axle to be realigned and reconnected the steering arm. Since the old U-bolts were distorted and could not be used, they were taken out and replaced with new ones. After the drag link was reconnected, a brake roller test of the braking system of the truck was carried out. The brake roller test is based on simulated driving, the truck is put on rollers which will turn and the driver will apply the brake. The result of the testing was recorded in the notes of Mr Tsang. A total of three tests were conducted of the surface braking efficiency. The first test result was 44.6%, the second test was 42.1%, the third test was 40.6%. The average is 42.4%. The note stated that the possible error in the roller brakes machine is 3%.

12. In view of the inconsistency of the test results in that the reading was different in each occasion, Mr Tsang abandoned this test and carried out a Tapley meter test. The meter was put on the cab by a motor examiner in a position behind the driver's seat. The motor examiner drove the vehicle, accelerating to a speed of 30 kmh and braked suddenly, as required by the test, then read out aloud to Mr Tsang the Tapley meter reading which he wrote down. This was repeated three times and Mr Tsang took the average of the three readings. The braking efficiency of surface brake was 45%. Mr Tsang said that the mechanical error of a Tapley meter is 1.5%. The Road Traffic (Construction and Maintenance of Vehicles) Regulation 19(1)(a) requires a total braking efficiency of not less than 50%.

Weight of the vehicle

13. The concrete mixer which was full of dry concrete was put back on the vehicle and the vehicle was weighed on the weight pads. The readings show that the vehicle was 27.45 tons, compared with the permitted gross vehicle weight of 24 tons, an overload of 3.45 tons or 14.375%. The manufacturer's permitted gross weight was 26 tons.

Cause of accident

14. The driver did not give evidence. There is not much dispute concerning how the accident happened, namely, that the vehicle mounted the safety island and crushed into the pedestrians. The issue is on the cause of the accident.

The law

15. The basic propositions are to be found in Charlesworth on Negligence (8th Edition), para.5-112 :

"there are many highway collisions in which the accident itself suggests a reasonable probability of negligence in one of the parties rather than the other."

Para 5-113 reads :

"When a motor vehicle under the control of the defendant or his servant had overturned for no apparent cause while being driven along the highway, that fact alone was held to be evidence of negligence against the defendant. Halliwell v. Venables (1930) 99 LJKB 353."

16. As to the duty of care of highway users, as set out under para 9-190 of Chartesworth,

"both statute and common law have gone a long way to ensure that a very high standard of safety is achieved in the construction, maintenance, repair and use of the motor vehicles on the highway. This is in order to measure up to the sophisticated requirements of modern traffic conditions: Clearly the House of Lords had in mind such stringent considerations when reaching its decision in Henderson v. H.E. Jenkins & Son [1970] AC 282."

In that case, a sudden brake failure occurred, owing to loss of brake-fluid, which had escaped through a corroded hole in the hydraulic system beneath the vehicle, at a place where it was inaccessible to the weekly routine visual inspection. It was held, notwithstanding this fact, that the defendants had failed to discharge. the burden of showing that they had exercised reasonable care and skill in detecting and remedying defects.

17. Para 9-255 reads:

"the driver of a vehicle is bound to use reasonable care to keep the vehicle in a roadworthy condition, so that proper control can be exercised."

Phillips v. Brittania Hygienic Laundry Co. [1923] 1 KB 539 showed that the vehicle must also be of such size and design that it can be safely used on the road.

Defence of latent defect abandoned

18. The Defendants' case is that the accident occurred because of a latent mechanical defect of the vehicle in that the U-bolts suddenly failed and the vehicle lost control. This defence is based on the opinion of Mr Seymour-Hart, a road traffic expert. Dr Mak Kwok-tim ("Dr Mak"). the Plaintiff's expert, described the U-bolt theory advanced by the Defence expert as unrealistic and that the sudden and unexpected failure of the U-bolt on the offside front at the critical moment seems to be a speculation rather than a plausible explanation and should not be given much consideration. I agree with this observation.

19. Mr Lunn Q.C., in his closing address abandoned this defence in the light of the evidence given by Mr Seymour-Hart. The concession is in my view properly made. Mr Seymour-Hart was unable to offer any explanation why the U-bolts would fail. There is no evidence of a metallurgical failure and no metallurgical test was carried out. Although he referred to the failure of the U-bolts, it can be seen from the photographs the U-bolts remained on the axles and only one of the nuts of the bolts were missing. The failure is the failure to clamp the leaf-springs to the axle. In his evidence, he said that the U-bolts may not be tightened properly or that one of the nuts had already been missing at the time of the accident. Under cross-examination he agreed that this would mean that the vehicle had not been properly maintained and this is not a hidden defect. This concession, in effect, completely demolishes the defence of latent defect.

Negligence of the Defendants

20. I am satisfied from the evidence that I have heard that the cause of the accident, namely, the mounting of the vehicle onto the safety island and the collision with the pedestrians was due to the negligence of the Defendants. Although the speed of the vehicle when it entered the bend at the junction of Gloucester Road and Fleming Road was within the speed limit for that location, I am satisfied that the vehicle was not driven in a safe speed in the circumstances because the vehicle was overloaded and had a braking efficiency which is below the statutory requirement. The driver had also not given himself a sufficient distance to make the turn.

Overloading

21. It is clear from the evidence that the vehicle was overloaded. Although the weight of 27.45 tons was probably even lower than the actual weight of the vehicle at the accident because the concrete had since dried and some of the mix had spilled when the vehicle overturned, as can be seen from photographs, I am prepared to accept the weight of 27.45 tons.

22. The 2nd Defendant was the owner of the vehicle. He said that he did not know the weight of the concrete that was loaded onto his vehicle and that Pioneer Concrete refused to tell him of the weight. He had driven the vehicle for many years before he asked the 1st Defendant to drive it. And he continued to drive a similar vehicle for a few months after the accident. He was aware that the 1st Defendant was prosecuted for overloading but he did not try to find out after the accident how much concrete. he was carrying in his own vehicle. I find this surprising I do not accept his evidence that he did not know the weight of concrete that was loaded onto his vehicle. After all there was a weight limit to the vehicle and he must ensure the load is within the limit. He knew if his vehicle was overweight it would travel shower; it was heavier and he would feel it when he applied the brake. The 2nd Defendant said on average the concrete that the vehicle carried was 6 cubic metres. The delivery note for the concrete showed that the load was 6.6 cubic metres. As Mr Sarony Q.C. submitted that he cannot hide behind a facade of ignorance when he is plainly under a duty to ensure that the vehicle was not driven on the public highway overladen.

23. The actual quantity of cement was determined by Pioneer Concrete and there was no weight bridge at the Pioneer Concrete depot so that drivers would not know what their total laden weight was. The weight was given on the delivery note expressed in cubic meters and the driver took this delivery note with him and handed it to the recipient of the load at his destination. The foreman of Pioneer Concrete Maintenance, Mr Tsang Pun Fat, said that the drivers knew the formula for converting cubic metres to tonnes. Even if such evidence is discounted, there is no good reason why the driver of this type of heavy goods vehicle should be able to evade liability for this type of heavy goods vehicle should be able to evade liability for ensuring that the load was within the permitted range.

24. The responsibility for the laden weight of the vehicle rests upon the driver and the owner and they were responsible for the overloading of the vehicle.

Braking Efficiency

Mr Seymour-Hart

25. Mr Seymour-Hart attacked the value of the Tapley meters. He said the accuracy of the reading of the meter is in the order of about plus or minus 10%. The variation depends on how much care the tester takes with the instrument. Although he said in his report that this instrument is no longer acceptable to courts in U.K., he conceded in evidence that this is an overstatement.

26. Mr Seymour-Hart said that the Tapley meter is a mechanical device some 30 years old or more, operating on the principle of a hydraulically damped pendulum which is forced forward on brake testing when located in a vehicle. Being hydraulically damped, the instrument can be used in vehicles which are subject to vibrations and road shocks. Sources of error, apart from the instrument error (normally about plus or minus 1.5-2%) are related to the nature of the instrument, it being of the pendulum type, it must be very carefully zeroed (levelled) whilst the vehicle is located and tested on level ground. The motion of the pendulum is copied by a magnet pivoting about the same point. The magnet rotating (driving) a circular scale by the action of a gear and quadrant. On zeroing the instrument, it must be located firmly on a solid part of the body to ensure no reduction in its accuracy derives from floor insulation or carpet material. Furthermore, driver behaviour in terms of the way the brake pedal is applied and the suspension characteristics of different vehicles have been found to adversely affect the instrument.

Mr Tsang

27. Mr Tsang said that the Tapley meter is an accurate instrument for measuring the braking efficiency of a vehicle.

Dr Mak

28. Dr Mak said that the Tapley meter is a simple mechanical device and if it is used properly and carefully, results should be acceptable and comparable to other acceptable braking efficiency testing devices. He disagreed with Mr Seymour-Hart's view that the Tapley meter is unacceptable and that some courts of law in the United Kingdom do not accept results obtained from using the Tapley meter. His understanding was that the Tapley meter is still acceptable to the courts of law and is being used by the motor vehicle examiner to determine the braking efficiency of the vehicle under dynamic conditions.

Tapley-meter is accurate

29. There is no evidence that Tapley meter readings had been disregarded by the U.K. courts apart from what Mr Seymour-Hart had said in his report. To that he now concedes the statement to be inaccurate. Another road traffic expert Dr Lingard had in High Court Action No.A4522 of 1991 testified to the accuracy of the Tapley meter and I have in that case accepted the finding of a Tapley meter. Nothing I have heard in this case persuaded me that the Tapley meter was inaccurate. Notwithstanding Mr Seymour-Hart's criticism of the use of the Tapley meter, it produced the same result in the three tests carried out by the motor vehicle examiner. The errors referred to by Mr Seymour-Hart are mainly human errors caused by the inappropriate use of the meter. There is no evidence to suggest that vehicle examiners would carry out the Tapley meter tests in an incompetent manner.

Rolling road brake test

30. Mr Seymour-Hart said that a far more accurate and reliable dynamic test would have been to place the vehicle on a rolling road brake tester. This type of machine is available at many Transport Department vehicle examination centres and one is also located at each police accident investigation unit. Such a test was in fact carried out during the examination of the vehicle. The test showed that the braking efficiency is lower that the 45% of the Tapley meter reading. I am satisfied that the braking efficiency of the vehicle is not higher than 45% which is below the statutory requirement.

31. The driver was prosecuted for a number of traffic offences in connection with the accident in the magistrates court and was acquitted. Mr Tsang in the magistrates court had given evidence on the Tapley meter test. He did not refer to the brake roller test he had carried out. He denied that the reason why he did not mention this test was that he did not want the court to know about the error of the test. I do not find his failure to mention the test in his evidence in the magistrates court will affect my assessment of his evidence. I do not find that he intended to mislead the magistrate in any way. Furthermore, the Tapley meter test gives a higher braking efficiency and the driver was not prejudiced in any way by the fact that the brake roller test was not referred to in the evidence.

Effect of overloading and the braking efficiency

32. Mr Tsang said that the overloading had reduced the brake efficiency of the vehicle. Normally the driver did not have to apply full braking effort to reduce the vehicle speed for a turn. Unless travelling at high speed, the 45% braking efficiency would be sufficient to reduce the vehicle speed during a normal cornering. This is an opinion which is unchallenged and is accepted by me.

33. In his report of 21st December 1993, Dr Mak said that it is well known that, other things being equal, the greater the braking efficiency, the lower is the braking distance. The greater braking efficiency would also mean that the kinetic (moving) energy of the vehicle can be dissipated at a higher rate through the friction between the vehicle tyres and the road surface. In the event of insufficient distance being available to stop the vehicle safely (in this accident the truck mounted the pavement), greater braking efficiency may have the overall effect of reducing the kinetic energy of the vehicle more and therefore the damage in the subsequent event, for example, the impact with another vehicle or with a kerb may be significantly less.

Minimum speed of the vehicle

34. Based on mathematical calculation, Dr Mak said that the minimum speed of the truck was 37 kmh (or about 23 mph) when the vehicle was travelling into the turn at Fleming Road. The estimate of the minimum speed of the truck, i.e. 37 kmh is based on a braking efficiency of 45% and the near-side front wheel of the truck left a lock wheel skid mark of 12.2m. This speed would be a minimum speed because the truck did not skid to a halt but overturned to its offside and skidded on that side for some distance. Some speed would have been lost and this had not been taken into account in Dr Mak's speed estimation. The speed before entering the left hand bend is likely to be higher than 37 kmh because the driver stated in his evidence that he braked (although not emergency braking) before entering the left hand bend. The sketch shows that the driver applied emergency braking in the left hand bend. The tyre marks also show that the truck had been braked approximately half the distance on the road surface and the other half on the pavement. Hence, with an estimated braking efficiency of 45%, the speed of the truck when the offside front tyre contacted with the kerb is estimated to be 28 kmh (about 17 mph) and the kinetic energy of the truck had been reduced to 58% of its original. If the braking efficiency was higher, say 75% instead, the speed of the truck when the offside front tyre contacted with the kerb would then be 20 kmh (about 12.5 mph) and the kinetic energy of the truck would have been reduced to only 30% of its original. Hence, the braking efficiency has an important bearing on the cause of the accident. There is a fair chance of the accident being avoided if the braking efficiency of the truck had been significantly higher than 45%.

Safe Speed of the Vehicle

35. Dr Mak was asked to give an opinion as to what should be the safe speed of the vehicle in manoeuvring the bend. He said that the safety speed would depend on a number of factors. On dry level roads, the prime factors are the speed and the radius of the turn. Other factors such as the height of the centre of gravity of the vehicle, its width, rotation of the drum, the suspension and the tyres are also important. His estimate of the radius of the left hand bend is 30 m, a vehicle travelling along such a bend at 37 kmh would be subject to the influence of a lateral acceleration (i.e. the force pulling the object outwards) of 3.52 m/s/s or 0.36g (36% of the acceleration due to gravity) which may be sufficient to trigger rollover (overturn) of the truck. Whether or not rollover would occur depends on the fine balance of the other factors, i.e. other than the speed and the radius and there is no definite answer. Although Dr Mak said that a tilt test of the truck may furnish useful information, it should be pointed out that no such test was carried out.

36. Dr Mak was, however, of the view that the effect of the massive load carried by the truck is that the greater the load, the higher the centre of gravity and the less stable the truck would be with respect to rollover stability Although it is difficult to quantify such effect, it is conceivable that a 10% increase in load to a fully laden cement truck (from 6 cubic metre to 6.6 cubic metre) may be sufficient to exceed the threshold of rollover; particularly at the brink of rollover. Considering the above, Dr Mak was of the view that the safe speed for a fully laden cement truck such as the vehicle in question should be at 30 kmh. At 30 kmh or below, the lateral acceleration (and therefore the later force which is responsible for rollover) would be smaller than the roll stability of the truck would be enhanced. The lower speed would also enhance the chance of the driver avoiding an accident as the braking distance would be accordingly shorter.

37. It is clear from the evidence of Dr Mak, which I accept, that because of the low braking efficiency of the vehicle, it was unable to brake in time before it mounted the kerb The situation is exacerbated by the overloading of the vehicle which further reduced the braking efficiency. The speed which the vehicle was travelling was unsafe in the circumstances of this case.

Defendants agreed on safe speed of 30 kmh

38. Mr Seymour-Hart said that his measurement of the radius of bend is longer than that of Dr Mak. If a shorter radius is used, the lateral acceleration is greater. Since the estimated speed of 37 kmh by Dr Mak is based on the radius of the bend and on the 12.2 metre length of the locked mark of near-side front wheel, the estimated speed would be wrong if the two factors used are incorrect. He said the length of lock wheel mark was not 12.2 metres.

39. In my view it can hardly be disputed that this mark showed a lock wheel mark at least in its initial stage. Even if the estimate speed of 37 kmh is not accurate, Mr Seymour-Hart accepted 30 kmh should be the safe speed.

Driver's speed

40. The driver had not given evidence. But according to the notes of the proceedings in the magistrates court, he said he was travelling initially at 60 kmh; his speed in the inner lane was 50 kmh and when he saw a pedestrian jumped out from the pavement onto the road, his speed was at 40 kmh. The speed he drove still exceeded the safe speed of 30 kmh. His story about the pedestrian could be discounted as an invention: none of the eye witnesses saw such a pedestrian and the driver did not refer to this person in his police statement.

41. It is plain from what he told the magistrate, namely "I couldn't turn to the left because the offside wheel got in touch with the kerb and the tyres skidded." showed that he had not given himself enough distance to make the turn. The tyre marks showed that the vehicle was heading towards the safety island. The angle clearly showed that vehicle could not complete the turn.

Axle moved rearwards

42. After the accident, it was discovered that the axle which remained intact to the two road wheels had moved rearwards. The four U-bolts were also attached to the axle, the effect of the movement of the axle with the U-bolts attached to it is that the U-bolts are no longer holding the leaf-springs in the original position in the middle. The U-bolts were holding less of the leaf-springs because the leaf-springs were not of uniform length. Dr Mak, Mr Tsang and Mr Seymour-Hart all agreed that the backward movement of the axle caused the drag link to be severed from the ball joint, although there was disagreement between the experts as what caused the axle to move rearwards.

Defendants' expert confirmed accident caused by overloading

43. In explaining how the axle was shifted backward which caused the severance of the steering system, Mr Seymour-Hart confirmed the accident was caused by the overloading of the vehicle. When he first explained the cause of the front axle moving backwards, he said it was primarily the overload of the vehicle which was fitted with an oversize drum. The overload was located at the highest and most rearward part of the vehicle. That load would lever onto the front axle. Prior to the braking the major load was on the rear axles. The braking caused the load to shift to the front axle. As the vehicle was commencing the turn, the load was on the outer steering front wheel. Because of the intolerable conditions, the axles started its rearward movements. The U-bolts were under some stress which would tend to pull them back. He said the axle rearward movement can only happen if the U-bolt function is not there to the degree that the overloading could be resisted.

44. Although in Re-Examination, Mr Seymour-Hart said overloading was one of the factors to be taken into account, and that even if a maximum load is reached, a-safety factor to the extent of more than 20% is still available, it is clear from his evidence, overloading is a constant factor in his explanation for the rearward movement of the axle and the cause of the U-bolt failure.

Axle shifted due to impact with the kerb

45. As I have found that the Defendants were negligent, it is not strictly necessary for me to decide whether the impact with the kerb caused the axle to shift backwards. However, as the matter was extensively canvassed, I shall express my view on it.

46. Dr Mak and Mr Tsang were of the view that the axle was forced backwards because of the impact of the front of the side wheel when it hit the kerb in the safety island and the U-bolts were damaged as a consequence of the accident and not the cause of it.

47. I find, on a balance of probability, the axle only shifted backwards and the U-bolts only became damaged as a result of the impact of the vehicle with the kerb. I accept the evidence of Dr Mak and Mr Tsang in this regard. The axle at the offside of vehicle was pushed further back than on the near-side. It is logical that this is caused by the impact with the kerb. The fact that the suspension system and steering system were still intact before the impact of the vehicle on the kerb could be supported by the evidence of the tyre marks on the road. Further, Dr Mak has offered a satisfactory explanation as to the damage of the U-bolts.

The tyre marks

48. Dr Mak said that according to the sketch plan prepared by the police, there were three tyre marks, marked as "A", "B" and "C". Dr Mak was of the view that the "A" tyre mark is caused by the offside rear outer wheel; the "B" mark is caused by the offside rear inner wheel; and the "C" mark is caused by the near-side front wheel. The tyre mark of the near-side front wheel i.e. "C" mark is a lock wheel skid mark under emergency braking. The appearance of this mark shows that the suspension system at the near-side front wheel was still intact. If the U-bolts there were severed, as suggested by Mr Seymour-Hart, then, under the influence of braking force and turning motion, the near-side front wheel skid mark would not be straight but wavy reflecting the slack in the suspension system.

49. Under cross-examination, Dr Mak agreed that the photographs showed the initial length of the skid mark was straight but when it reached the safety island, the mark turned towards right. He agreed that this is consistent with the steering failure at that point. He said that the change in the direction of the skid marks occurred after the impact. He said the initial portion of the skid mark is comparatively straight indicating that the vehicle skidded straight forward. The emergency braking of the vehicle achieved the lock up of the wheel and the vehicle will speed forward towards the angle the vehicle pointed at. It was the impact which caused the axle to move backwards allowing the wheel to turn.

50. As to the suggestion that it would take time for the steering system to break due to the movement of the axle, Dr Mak said that it would depend on the movement of the axle. If the first impact caused sufficient movement of the axle, then it would cause the detachment of the steering system.

51. On the other hand, the marks caused by the offside rear wheels, i.e. marks "A" and "B", lacked the characteristics of lock wheel skid marks and they are not lock wheel skid marks (i.e. the wheels were still rolling even under emergency braking. There is a sharp contrast between the near-side front wheel which achieved wheel locking and the offside rear wheels which failed to lock up. The lack of wheel locking would be attributed to the heavy loading on the rear axles and this is also reflected in the low braking efficiency. The offside rear wheels, when they reached the kerb, impacted with the kerb and the impact caused the vehicle to tilt to its offside and the vehicle eventually toppled over.

52. Dr Mak agreed that one of the fastening nuts of the fore U-bolts in the near-side front axle was missing. However, Photographs 11/15 and 11/20 show that the aft U-bolts on the near-side front and offside front were still in place. Mr Tsang also confirmed that the U-bolts were not missing after the accident. This show that all the U-bolts on the front axle were likely to be intact before the toppling over of the vehicle and the damage to them could well be the consequence of the accident. The damage to the U-bolt is that it was deformed and the fastening nut ripped and gone missing. The damage of the U-bolts were caused by the force of the impact transmitted through the axle after the vehicle's impact with kerb.

Impact with the kerb

53. Dr Mak said that the displacement of the front axle, i.e. being pushed backward due to heavy impact or toppling over is not unusual, bearing in mind in the present case the cement truck was overladen. While turning a left hand bend and probably under emergency braking, a considerable load would have been transferred to the offside front wheel and the vehicle would be tilted to its offside. When the front wheel impacted with the pavement, the front axle could be subject to very high stress due to the inertia of the heavy mass in the cement container and the skid resistance to the wheel surface by the pavement and subsequently the front axle was pushed backwards. The impact could be seen by the black tyre mark on the kerb. The wheels of the vehicle did not simply roll over the kerb at low speed. It was a hard impact when the vehicle hit the kerb at a considerable speed.

54. It is suggested by the Defence that the vehicle had not encountered any obstruction of substance when it mounted the kerb and entered into the opening of the safety island. Dr Mak accepted that the kerb was low, he said the height is about 0.1 meters or about 4" high. In the course of the proceedings, Dr Mak further measured the kerb which he said to be 5 inches in height. One must bear in mind that this is a vehicle weighing over 27 tons carrying a high rotating drum at its back. In fact the weight carried by this truck exceeded. the unleaden weight of the vehicle. The vehicle together with its weight was measured. at 27.45 tons. According to the delivery note, the concrete that it carried was 6.6 cubic metres or 15.675 tons, hence the unleaden weight of the vehicle was 11.775 tons. Furthermore, this is not a vehicle driving over a low kerb but a vehicle manoeuvring a turn and braking under emergency braking. The explanation that the impact with the pavement caused the displacement of the front axle is in my view a plausible explanation. The kerb need not be high to cause an accident.

55. Mr Seymour-Hart suggested if there was an impact with the kerb, one would expect damage marks on the wheel and the wheel might also be deflated. The photographs of the offside front wheel did not show any sigh of damage. Mr Tsang also did not refer to any damaged tyre. It should be pointed out that Dr Mak was not asked about the possibility of a deflated wheel. He said that whilst it may be easy to identify an impact mark on a clean wheel, in the present case, an impact mark may well be obscured by the heavy scruffing of the surface of the tyre due to the toppling of the vehicle and skidding on its side.

56. Mr Seymour-Hart also suggested that if the impact with the kerb caused damage of the U-bolt and pushed back the axle, then the tyre marks should show a change of direction after the vehicle reached the kerb and there was no such indication on the photographs of the tyre marks, The marks were that of a smooth curve. But it is clear from photograph 11/29 that the mark of the nearside front tyre showed that there was indeed a change of direction.

Conclusion

57. Accordingly, I find that the Defendants were responsible for the accident. There shall be judgment entered for the Plaintiff on liability with damages to be assessed. I shall order costs nisi of the action to the Plaintiff.