The plaintiff and the defendant were driving side-by-side in lanes one (kerb-side) and two respectively, travelling 90km/h in a 70km/h speed zone, towards slow-moving council vehicles in lane one. The council vehicles were fitted with bright flashing signs facing to their rear which indicated to faster vehicles to merge into lane two. One of the council vehicles was a street sweeper, travelling at approximately five km/h, and the other was an escort vehicle which travelled a short distance behind the street sweeper.
The plaintiff and defendant both saw the lights on the council vehicles indicating to merge into lane two. The plaintiff, without indicating and without checking her blind spot, merged right into lane two. The defendant swerved right into a right-turn only lane but corrected back into lane two. At this point, the plaintiff and defendant had passed the escort council vehicle and then collided with each other. The collision occurred in the middle of lane two. The collision was found to be ‘minor’ but it caused the plaintiff’s vehicle to ‘bounce’ left into lane one and collide with the street-sweeper.
The Court of Appeal  found the defendant negligent for swerving back into lane two causing the collision with the plaintiff’s vehicle. The Court found that the plaintiff was equally culpable but did not explicitly provide any countervailing reason. However, it may have been the plaintiff’s act of merging without indicating or looking.
The judge at first instance, Ashford ADCJ, concluded a different set of factual circumstances and found the defendant completely to blame for the accident.
The disparity in the factual conclusions of the two tribunals came down to the way each tribunal of fact dealt with conflicting witness accounts. The primary judge, ultimately, accepted the evidence of the plaintiff and the driver of the council escort vehicle and rejected the evidence of other witnesses, who were described as reluctant, difficult and truculent.
The Court of Appeal found that the primary judge’s reasons for rejecting some witness accounts was not justified . Instead, the Court found that this was not a case where any one witness could be accepted as definitively describing what happened. Rather, it was necessary, from the whole of the evidence, to draw such inferences as best synthesise the various observations, taking into account their strengths and weaknesses .
Insurers will often be met with conflicting witness evidence. It is important to always gauge the strength of the various witnesses to best inform the liability decision at the inception of the claim and the resolution strategy (whether or not to take a matter to hearing or compromise by way of settlement).
The Court of Appeal demonstrates in this case that synthesising the various observations in light of their strengths and weaknesses is the best way to deal with the particularly difficult situation where no definitive witness account can be accepted over another.
The Court also highlights what gives weight to a witness account such as: the consistency of the account over time; the accuracy of the observations when compared to the physical evidence; and the consistency of the account when compared to other witnesses.
Claims staff should, when possible, speak with their insureds and any available witnesses before making a liability decision. Witnesses should also be evaluated as claims progress and more evidence comes to light so that the appropriate resolution strategy is implemented.
 Mcfarlan JA and Meagher JA agreeing with the reasons of Simpson AJA
 See paragraphs 121 and 122
 Paragraph 129