Who was to blame for a drunken motorcycle collision? Which case won?

The Facts

Intoxicated friends ride trail bikes on public road and crash into each other

At 5:15 in the morning following a night of heavy drinking, the plaintiff and defendant (who were friends) each rode unregistered off-road motorcycles (trail bikes) on a public road in New South Wales. Neither motorcycle was fitted with a headlight.

While travelling in opposite directions along the road, the two trail bikes were involved in what was effectively a head-on collision.

The collision occurred on the plaintiff's side of the road, about 1.5 metres from the centre line on the road. The bikes collided both on their left sides, which meant that the defendant's bike had to have crossed the path of the plaintiff's bike before they collided.