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Most of us are smart enough to know that we shouldn’t get behind a steering wheel if we’ve had a few drinks. But perhaps we give less thought to the risks when accepting a lift from someone else who’s been drinking. In Allen v Chadwick [2015] HCA 47, the High Court of Australia considered the responsibility of a passenger who suffered personal injury in a motor vehicle accident after choosing to travel with a drunk driver. Although the case relates to legislation from South Australia, similar laws apply in other Australian States and Territories.

Some Negligence Basics

Under Australian law, a person may be liable in negligence if:

  • They owe another person a duty of care;
  • They fail to take reasonable care; and
  • That failure causes the other person loss or damage.

However, the law recognises that an injured person may have contributed to their loss by also failing to take reasonable care, known as “contributory negligence”.

Contributory Negligence For Riding With a Drunk Driver and Without a Seatbelt

These days, the law of negligence is largely governed by Acts of Parliament in each State and Territory. In South Australia, as well as other jurisdictions, there is a legislative regime covering contributory negligence in cases involving intoxication.

Under section 47 of the Civil Liability Act 1936 (SA), contributory negligence is presumed if an injured person relies on the care and skill of an intoxicated person. Where contributory negligence is presumed, the court must reduce the assessment of the injured person’s damages by a fixed percentage. In general, this presumption of contributory negligence cannot be rebutted. However, under section 47(2)(b), the presumption can be overturned if the injured person establishes that they could not “reasonably be expected to have avoided the risk”.

Under section 49 of the Civil Liability Act, the court is also required to reduce damages where the injured person was not wearing a seatbelt as required by law.

Facts of the Case

Ms Chadwick was a 21-year-old pregnant woman who was in a relationship with Mr Allen, a 28-year-old man. The pair, along with Ms Chadwick’s daughter, decided to go out of town for the weekend. Along the way, they met up with a friend of Mr Allen and his two children. Mr Allen and his friend drank steadily that day and into the evening.

At some point after the kids had been put to bed, the three adults decided to go for a drive. Ms Chadwick was not drinking and so took responsibility for driving the car. After driving around for about 15 minutes, with loud music playing and both men shouting directions, Ms Chadwick pulled the car over to urinate behind some bushes.

When she returned to the car, Mr Allen was in the driver’s seat. He shouted at Ms Chadwick to get in the car. When she got in the car, Mr Allen sped off. He subsequently lost control of the car, which struck a small tree, causing Ms Chadwick acute spinal injuries.

There was no doubt that Mr Allen’s negligent driving caused Ms Chadwick’s injuries. However, Mr Allen claimed that Ms Chadwick contributed to her injuries by travelling with a drunk driver and not wearing a seatbelt.

The trial judge found that Ms Chadwick could not reasonably have avoided the risk of getting in the car with Mr Allen, and so section 47(2)(b) of the Civil Liability Act applied to rebut the presumption of Ms Chadwick’s contributory negligence. However, the trial judge reduced Ms Chadwick’s damages on the basis that she had failed to wear a seatbelt.

On appeal, a majority of the Full Court of the Supreme Court of South Australia upheld the trial judge’s decision about section 47(2)(b). However, the Full Court unanimously reversed the trial decision about the seatbelt, concluding that Ms Chadwick’s failure to put on her seatbelt was a natural response to Mr Allen’s erratic driving.

Mr Allen appealed to the High Court.


In a unanimous decision, the High Court clarified the correct approach to determining whether the presumption of contributory negligence should be rebutted under section 47(2)(b) of the Civil Liability Act. The High Court emphasised that the provision is directed at an objective evaluation of the risk of travelling with a drunk driver compared to alternative options. Subject characteristics of the plaintiff are not relevant to this evaluation.

Nonetheless, applying this approach, the High Court concluded that Ms Chadwick could not have been expected to avoid the risk of getting into the car with Mr Allen.

On the issue of the seatbelt, the High Court held that there was no reason to alter the trial judge’s findings that Mr Allen’s driving had not actually prevented Ms Chadwick from putting on her seatbelt.

Key Takeaways

The concept of “reasonableness” is central to the law of negligence. The High Court’s decision sheds further light on what is or isn’t reasonable. The High Court made clear that “reasonableness does not require constant vigilance as the possibility of an emergency and a photographic memory of one’s surroundings”.

But on the other hand, if you have a reasonable alternative option and you still choose to ride with a drunk driver, it is likely that you will bear some of the responsibility if you are injured in a car accident.

LegalVision cannot provide legal assistance with this topic. We recommend you contact your local law society.


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