Roads and Traffic Authority of NSW v Dederer

The High Court of Australia considered an appeal by the Roads and Traffic Authority of NSW ("RTA") against a decision of the New South Wales Court of Appeal, which had upheld a finding of negligence against the RTA. The dispute arose from injuries sustained by Mr. Dederer, a 14-year-old, who dived from a bridge constructed by the RTA's predecessor into shallow water, striking his head on the estuary bed. Mr. Dederer was aware of the variable depth of the water and the presence of signs prohibiting diving.

The central legal issues before the High Court were whether the scope of the RTA's duty of care extended to preventing harm in the circumstances of Mr. Dederer's injury, and whether the RTA had breached that duty. The Court was required to determine if the lower courts had correctly applied the principles of negligence, particularly the assessment of risk, the probability and gravity of harm, and the practicability of precautions, as established in cases like *Wyong Shire Council v Shirt*. The Court also considered the relevance of Mr. Dederer's voluntary conduct, the obviousness of the risk, and the concept of "allurement" in the context of the bridge's use.

The majority of the High Court reasoned that a duty of care does not impose an obligation to prevent all potentially harmful conduct, but rather to exercise reasonable care. They found that the lower courts had erred in their application of legal principles, particularly in characterising the risk and assessing breach. The Court noted that Mr. Dederer was aware of the risks, and that the RTA had erected "no diving" pictograms, which were considered a reasonable response to the identified risk. The Court also found that proposed further precautions, such as pool-type fencing or modifications to the handrail, were either not supported by evidence as reasonable or were unlikely to deter a determined individual. The Court emphasised that the assessment of breach must be prospective and based on the facts as they were known at the time, not with the benefit of hindsight.

The High Court allowed the appeal, setting aside the orders of the Court of Appeal and ordering judgment for the RTA against Mr. Dederer. Consequently, Mr. Dederer was ordered to pay the RTA's costs at trial and in the Court of Appeal. The application for special leave to cross-appeal was dismissed with costs.