Roads and Traffic Authority of NSW v Turner

The Roads and Traffic Authority of NSW (RTA) appealed to the New South Wales Court of Appeal against a decision of the Supreme Court of NSW concerning a claim brought by Mr. Turner. Mr. Turner had suffered injuries in a motor vehicle accident and sought damages from the RTA, alleging negligence in the design and maintenance of a road. The central dispute revolved around whether the RTA's alleged breaches of duty were causative of Mr. Turner's injuries, particularly in circumstances where other factors may have contributed to the accident.

The Court of Appeal was required to determine whether the primary judge had erred in finding that the RTA's negligence was a cause of Mr. Turner's injuries. Specifically, the court had to consider the appropriate test for causation in a situation involving multiple potential causes, and how to assess the RTA's contribution to the harm suffered by Mr. Turner. This involved an examination of the principles governing the "but for" test of causation and the concept of causative potency in negligence claims.

Hodgson JA, Tobias JA, and Handley AJA allowed the appeal. The court found that the primary judge had misapplied the "but for" test of causation. They reasoned that while the RTA may have been negligent, its negligence was not a necessary condition for Mr. Turner's injuries to occur. The court emphasised that for a defendant's negligence to be causative, it must be a cause without which the accident would not have happened. In this instance, the evidence did not establish that the RTA's breaches of duty were a cause in this sense.

The appeal was allowed, and the orders of the Supreme Court were set aside.