Commentary
For accident reconstruction, emergency medicine and neurosurgery experts, this case illustrates the interdependence of accident reconstruction and medical evidence and the need for the medical experts to have regard to the accident reconstruction evidence.
The case
A preliminary liability and causation trial arising out of a road traffic accident in 2015. The Claimant, Jacqueline Colizzi, then aged 45 years, a pedestrian, was hit by a Ford Fiesta Zetec being driven by the First Defendant and as a consequence of which she then fell, and her head struck a stationary Renault Clio around the rear driver's side wheel/wheel arch, and her head then hit the ground. She suffered two skull fractures and axonal injury. She has been left with severe neurological deficits and has been resident in hospital and rehabilitation units for the more than eight years since the accident. She will never be able to work again and will require 24/7 care for the rest of her life.
Issues
One issue was to do with the threshold of serious injury. Counsel for the claimant said the collision took place at about 20 mph. There was no braking before collision. The mechanism of accident was unusual and unpredictable. The claimant's leading leg struck the bottom right hand side of the Fiesta and she was spun and made contact with the Clio and then the ground. Even if the collision could not have been avoided entirely, the opportunity was there for a reasonable driver to take avoiding action short of a collision; ie, the defendant ought to have collided with the claimant at a slower speed and serious injury would likely not to have occurred. She would not have struck the Clio. It would have been a frontal impact at about 15 mph and not a side impact at 20 mph. On the balance of probabilities, in light of the neurosurgical experts' evidence, serious injury was very unlikely at 15 mph and at 10 mph would have been almost impossible. She would have suffered some injury, but not the catastrophic injury she suffered.
Legal principles
In relation to accident reconstruction, the court referred to Stewart v Glaze [2009] EWHC 704 (QB) and how trial judges must exercise caution in relation to the evidence of accident reconstruction experts. In Stewart, Coulson J warned of the danger of: (i) such experts giving opinions on matters beyond their expertise and acting as advocates seeking to usurp the role of the judge; and (ii) elevating their admissible evidence about reaction times, stopping distances and the like into a, 'fixed framework or formula, against which the defendant's actions are then to be rigidly judged with a mathematical precision.'
Expert medical evidence
In the opinion of Professor Vloeberghs, on a strong balance of probabilities, it was unlikely that such severe cranial injuries would have occurred at a speed below 19 mph. The greater the reduction in speed below this, the less likely it is for such severe injuries to have occurred. In Professor Vloeberghs' opinion, if the Court were to find that the impact speed should have been 15 mph then he regards it as extremely unlikely and, at 10 mph, virtually impossible, that there would have been any enduring traumatic brain injury.
Professor Vloeberghs, referred in his report (which he adopted as his evidence in chief) to the paper by Cuerden and Richards, Pedestrians and their Survivability at Different Impact Speeds. They say (judge’s emphasis, footnotes omitted):
"While speed is certainly a factor directly linked to the severity of injury during pedestrian-vehicle collisions, other factors also come into play, making a pure assessment of the effects of speed very difficult. For example one study has shown that a long bonnet on a car reduces the injury risk of pedestrians in collision with that car. This difficulty is exacerbated by the varied nature of pedestrians, who will be of all ages, and have very different biomechanical tolerances. As people age their biomechanical strength decreases leaving them more vulnerable to injury for a given loading condition.
For several reasons, including those noted above, it is impossible to predict solely from the speed of an accident what the injury outcome of a given pedestrian will be. Fatal accidents have occurred at very low speeds, under 20 kph and as low as 12 kph; and slight injuries have been seen at much higher speeds (above 40 kph)."
Professor Vloeberghs broadly agreed with these paragraphs and acknowledged that a pedestrian's outcome after being hit is a 'multi-factorial issue'. As to the first sentence of the second paragraph he said 'many things can happen', but they become rarer at slower speeds. In his clinical practice he had dealt with cyclists who had suffered brain injury at 15 mph even wearing helmets. He said that the sort of injuries C suffered (including bilateral fractures and axonal injuries), 'you would not expect to see at low speed'. He agreed that fatal injuries could be caused by low velocity impacts, eg, by falling over, but would need to define what sort of injury is involved, eg an extra-dural haematoma. He referred to the exponential curve in the paper showing that the cumulative percentage of non-minor injuries starts to increase significantly above 20 kph (about 12.4 mph). The percentage at 20 mph is about 25%. He agreed (although not in terms) it is unlikely that serious brain injury would be caused in a pedestrian being hit at 20 mph.
Mr Macfarlane, instructed by the Defendant, noted that the accident reconstruction experts offered no evidence in relation to the actual interaction between the claimant and the defendant’s vehicle, other than it would appear to have been a glancing blow which was not sufficient to cause injury to her leg. Mr Macfarlane noted that despite the literature and the opinion of Professor Vloeberghs, it was a matter of fact that, despite it being agreed that the actual impact was no more than 20 mph, nevertheless the claimant still suffered a very severe traumatic brain injury from a combination of two head strikes.
Mr Macfarlane noted that the accident reconstruction experts offered no opinion as to whether Ms Colizzi would have been wrapped onto the front of the car, whether she would have suffered a head strike with the vehicle as well as the road surface and, in the case of the former, whether this would have been with the 'A' pillar, the windscreen or the bonnet. The 'A' pillar is the part of a car's structure located at the front of the car on either side of the windscreen. Neither was any evidence offered as to whether she would have been lofted into the air or the speed below which she is likely to have been thrown down in front of the vehicle.
The judgment includes a colour coded diagram taken from data obtained from a Clio showing the variability in the sequelae to a head strike with different parts of the front of the vehicle, noting, for example, that the consequences of impact with the A pillar [ie the red edges of the windscreen] (measured as head injury criteria HIC scores) are substantially greater than the centre of the windscreen or bonnet, which are more deformable structures.
Mr McFarlane gave evidence. He adopted his report subject to one minor immaterial correction. In cross-examination he accepted some energy had been imparted to the claimant by the Fiesta, but he could not say how much, which caused the claimant to rotate and fall. He thought the right side strike was with the wheel of the Clio and the left strike was with the ground. As a generality, he agreed if the claimant had been hit at a slower speed, less energy would have been imparted to her. He said that he had not considered the question of frontal impact because he had not had both reconstruction experts' reports when he wrote his report. His opinion on this issue is set out in the joint statement with Professor Vloeberghs (see above).
He said, on the hypothesis the claimant would have been hit more 'square on' by the Fiesta at lower speed, he said that predicting outcome would depend on number of factors, including how she interacted with the bonnet, and where her head hit, eg, on the windscreen (which is generally more 'forgiving') or the edge of the bonnet (which is not).
He said this accident occurred at substantially below the speed where one would not have expected a severe brain injury of the type the claimant suffered to have resulted; whether a lower speed would have changed the outcome would depend upon findings of fact, rather than matters of medical opinion.
He said one of the problems with relying upon statistics is the that the type of impact (eg, glancing or frontal) all 'get lumped together'.
The judge found that at a minimum, Cuerden’s and Richards' research did not assist the claimant's case.
The court accepted Mr McFarlane's evidence that the predicted outcome had the claimant been hit at a slower speed depended on a number of variables, as he had already indicated. Having carefully thought about it, I have reached the conclusion that counsel for the defendant was right that there was simply too little objectively certain evidence to allow for these variables to be determined, and hence the outcome predicted. He could only uphold this aspect of the claimant's case on the basis of impermissible speculation.
References
Ashton SJ, Mackay GM. Some characteristics of the population who suffer trauma as pedestrians when hit by cars and some resulting implications. Accident Research Unit, Department of Transportation and Environmental Planning, University of Birmingham; 1979. Available at: https://www.ircobi.org/wordpress/downloads/irc1979/pdf_files/1979_4.pdf
Cuerden RW, Richards DC, Hill J. Pedestrians and their survivability at different impact speeds. Proceedings of the International Technical Conference on the Enhanced Safety of Vehicles (ESV); 2007. Available at: https://www.semanticscholar.org/paper/Pedestrians-and-Their-Survivability-at-Different-Cuerden-Richards/834f40d492140d5028a850d4cc0d0cc78179b219