The plaintiff, a 16-year-old learner driver, suffered serious injuries when she lost control of the vehicle she was driving through a bend, colliding with a tree. The defendant held an unrestricted driver’s licence and was supervising the plaintiff.

The defendant was held liable and the plaintiff was awarded $5 million. There was no finding of contributory negligence against the plaintiff. 

It was not raining at the time of the collision but the road was damp. The Court found the plaintiff had entered the bend at a speed that was not reasonable or safe, having regard to her level of experience and the wet condition of the roadway. The Court was satisfied that the defendant had breached his duty of care as there was no evidence that the defendant took any steps at all to instruct, direct or guide the plaintiff as to an appropriate speed to enter and negotiate the bend.

The defendant appealed against the judge's findings on liability on the basis that she had failed to correctly identify the scope of the duty which the defendant owed to the plaintiff. The defendant submitted that the primary judge had imposed too high a standard of care and had not taken into account that a different standard is required of a voluntary supervisor than a licensed instructor.

The NSW Court of Appeal found that the trial judge had appreciated the duty required of a supervisor. However, the critical question which the trial judge did not address, was whether a reasonable person in the defendant’s position as a voluntary supervisor would have instructed or guided the plaintiff to enter the bend at a lower speed.

There was no evidence of advisory or warning signs on the road to indicate that the bend should have been approached with particular caution or at a speed below the relevant limit.  Furthermore, a witness had described the bend as 'very deceptive'. On account of these factors, it was held that a reasonable supervisor would not have foreseen the need to instruct or guide the plaintiff to reduce her speed. The Court of Appeal held the defendant did not breach his duty of care.

Thornton v Sweeney [2011] NSWCA 244

A voluntary supervisor, such as a parent or friend of a learner driver, is subject to a different regulatory regime than that applicable to a licensed instructor.  However, such a supervisor will be held liable if, in the circumstances, they should have given directions that would have prevented a collision.​