The High Court has allowed in part an appeal against two decisions of the Full Court of the Supreme Court of South Australia relating to the tort of negligence and statutory reductions for contributory negligence. Chadwick suffered catastrophic injuries after being thrown from a car driven by her partner, Allen, who had a blood alcohol reading of 0.22. The Full Court allowed an appeal against the trial judge’s decision to apply a 25 per cent reduction in damages under s 49 of the Civil Liability Act 1936 (SA), for Chadwick’s failure to wear a seat-belt on the basis that she was unable to do so because of Allen’s reckless driving. A majority of the Court (Kourakis CJ dissenting) agreed with the trial judge’s holding that a 50 per cent reduction for contributory negligence under s 47, applicable where an injured person relies on the care and skill of a person known to be intoxicated, should not be applied here because Chadwick could not reasonably be expected to have avoided the risk of re-entering the vehicle.

The High Court unanimously allowed the appeal in part, upholding the trial judge’s view of the s 49 issue but agreeing with the Court of Appeal’s application of s 47. The Court held that s 47 requires the objective evaluation of relative risks identified using reasonable powers of observation and exercising reasonable choices between alternatives (at [51]):

Inputs into the evaluation contemplated by s 47(2)(b) are those facts, as they may reasonably be perceived, which bear upon the reasonable assessment of the relative risks of alternative courses of action. Those facts may include matters of objective fact personal to the plaintiff as well as aspects of the external environment. But subjective characteristics of the plaintiff which might diminish his or her capacity to make a reasonable evaluation of relative risk in the light of those facts are immaterial to the evaluation which s 47(2)(b) contemplates.

As applied to the present case, Chadwick could not have been expected to have avoided the risk of driving with Allen because of the risks of, among other things, being attacked by a stranger or becoming lost in a dark, unfamiliar area (see at [56]–[61]). On the s 49 issue, the Court held that the correct inquiry was not whether Chadwick’s failure to fasten her seatbelt was an understandable or reasonable response to Allen’s driving, but rather whether Allen’s driving prevented her from doing so (at [66]). The Court accepted the trial judge’s finding that Chadwick was not prevented from fastening her seatbelt (see [68]–[69]). The Court ordered Chadwick’s damages to be reduced in accordance with s 49(3) to approximately $1.2mil.