A man and woman killed in a drink-drive crash last year would have died almost instantaneously, a coroner has ruled.
Robert Hilton Scott was convicted of two charges of careless driving causing death earlier this year, for crashing the car that killed his girlfriend Samantha Michelle Bradley, 19, and hisclose friend Jeremy Neil Johnson, 22.
He failed to negotiate a bend in the Hakataramea Highway and rolled down a bank and hit a tree around 11.30pm on August 17, 2013, after the trio and another friend had been drinking at a birthday party in Timaru.
Neither Mr Johnson or Ms Bradley, who were sitting in the back, were wearing seatbelts at the time. They both had alcohol in their system, with Mr Johnson also testing positive for cannabis.
Mr Johnson was thrown out of the Nissan Primera, suffering serious injuries to his head and chest, while Ms Bradley injured her face, head and brain, the coroner's report said.
Scott woke up at the wheel around 8am the next day to find his girlfriend and friend were both dead. He reached a nearby farmhouse and raised the alarm.
Coroner David Crerar, in two decisions released today, said the injuries Ms Bradley and Mr Johnson sustained in the crash were "in the circumstances inevitably lethal, if not instantaneously lethal".
However, Coroner Crerar said the crash investigation report stated that both of the rear seat passengers were not wearing seatbelts and "their deaths can, at least in part, be attributed to them not wearing their seatbelts".
According to court reports Mr Johnson had originally been the driver, but swapped with Scott at some point in the journey.
The fourth friend who had been in the car with them was not named in court reports, but had been in the front passenger seat when the car crashed. He was able to walk away from the scene to the road, where he was picked up and driven back to Timaru, without alerting anyone to the crash.
Scott, who pleaded guilty to both charges, was sentenced in June to 200 hours community work and disqualified from holding or obtaining a driver's licence for 12 months.
He was also ordered to pay reparation of $9000, which was reportedly to be held in a trust for his friend's child.
In court, Scott was reported to be "struggling to cope, and haunted by the crash".