Clare SC DCJ
On 18 July 2012, a collision between the appellant’s truck and the first respondent’s prime mover, driven by the second respondent, resulted in significant damage to both vehicles. Neither driver was injured in the collision. The first and second respondents (the respondent) brought an action for negligence against the appellant in the Cairns Magistrates Court. The learned Magistrate gave judgement for the respondents.
Relevantly, the appellant’s appeal concerned the Magistrate’s decision to exclude an expert report provided by the appellant detailing the time and distance each vehicle would require to stop. The Magistrate found that an expert was not required to analyse the evidence and considered himself to be sufficiently qualified to make a determination.
Her Honour stated:
 His Honour identified his awareness that large vehicles needed time to stop, but it is not clear what, if any, special knowledge he applied. A court may take judicial notice of matters that are notorious or common knowledge. Reliance, however, on specialist information from extraneous sources may jeopardise a fair trial. Reliability would be difficult, if not impossible, for the parties to test. In Dasreef (Australia) Pty Ltd v Hawchar, the High Court rejected a trial court’s reliance on its own experience as a specialist tribunal.
Opinion evidence and specialist field
Her Honour stated, of opinion evidence generally:
 The general rule is that opinions are inadmissible. Witnesses may testify about relevant facts that they have observed, but not their opinion of them. The tribunal of fact is presumed to be competent to draw its own appropriate inferences from the evidence. Expert opinion is the exception. It requires an area of specialised knowledge, something that goes beyond general knowledge and common sense and which is credible. Secondly, a witness must have sufficient knowledge or expertise in that field to be held out as a witness who could assist the court. Thirdly, it requires disclosure of the facts on which the opinion is based and the reasoning which underpins the expert’s opinion.
Her Honour explained that the expert’s vast experience, including international recognition and acceptance in the field of ‘accident reconstruction’ sat uncomfortably with the learned Magistrate’s comments in relation to the expert. As to whether ‘accident reconstruction’ was an organised branch of knowledge, her Honour stated:
 Recent decisions of the Court of Appeal have accepted the legitimacy of the science. In R v Mackenzie, a trained forensic crash investigator had formulated an opinion about the point of impact from gouge marks and the final location of the vehicles. There was no challenge to the “field of specialised knowledge with respect to the causes of motor vehicle collisions”. The Court held the evidence had substantial probative value and was properly admitted. In R v Sheldon, a traffic investigation officer from the Queensland Police Service had interpreted road marks at the trial. On appeal, Mr Sheldon sought to introduce new evidence from a “road safety and traffic engineering consultant” about stopping times and distance. The new evidence was rejected for want of an evidentiary basis, but the court did not did not question the field of expertise or the qualification of either witness.
Her Honour went on to evaluate the nature of the expert’s evidence. In this regard, her Honour stated:
 Mr Ruller’s evidence was in the nature of equations based upon his own measurements and other circumstances that do not appear to have been controversial at trial. From those, he calculated time and speed. He referenced published studies and set out the equations he used and the values he applied, with an index of presumed facts. He thereby provided a demonstrable, objective procedure for reaching his conclusions. His work could be tested and reviewed. He provided calculations for the range of variables, but the conclusion was the same. According to his calculations, if Mr Montague had braked when Mr Nash had braked, the prime mover could have stopped before the slip road, thus avoiding collision with the truck. Mr Ruller concluded he would have stopped at least 4 metres from the lane and perhaps as far back as 11.9 metres.
 The respondents pointed out that Mr Ruller’s calculations were premised upon a prime mover with a load totalling 35 to 37 tonnes, whereas the unchallenged evidence was a total mass of 50 tonnes. The accuracy of the factual foundation of the opinion goes to its relevance and weight. That does not mean that the proven facts must exactly match those assumed by the expert. It is a question of fact whether the facts are sufficiently similar for the opinion to have value. “(I)f other admissible evidence establishes that the matters assumed are “sufficiently like” the matters established to “render the opinion of the expert of any value”, even though they may not correspond “with complete precision” , the opinion will be admissible and material.” To have value, the opinion must have some “rational relationship” with the facts proved. The less value an opinion has, the less relevant it will be. An expert opinion without relevance would be inadmissible.
The respondents further asserted that the existence of three eyewitnesses meant that expert opinion was not required to decide the matter. Her Honour concluded:
 … The existence of eyewitnesses does not make expert evidence about relevant matters inadmissible. The test is not the absence of eyewitness evidence, but whether the expert would offer assistance to the court beyond common knowledge. Expert evidence may tend to strengthen, refute or supplement direct testimony.
Her Honour was satisfied that the expert evidence was wrongly excluded and that the appellant was wrongly deprived of the opportunity to lead relevant evidence in its defence. Her Honour remitted the matter to the Magistrates Court for rehearing.
David Cormack – Brisbane Barrister & Mediator