The inexperience of a Hawke's Bay truck driver on a notorious downhill stretch of a South Island highway, while affected by cannabis, was the likely cause of his death a coroner has found.
Piki Lewis Jones, 34, of Napier died while driving from Christchurch to the West Coast, in thepre-dawn crash, descending the Otira Viaduct. He plummeted 24 metres into a riverbed from a viaduct bend about 6am on June 22, 2011.
An inquest was held in Christchurch on May 19-22, and evidence was given that his truck and trailer crossed the centre line, struck a rock face, crossed back into the correct lane, glanced the rear of another truck also heading downhill, and then crashed through a barrier on the outside of a right-hand bend.
Some evidence given suggested Mr Jones was an inexperienced driver, and was possibly on his first east-west crossing on the highway, and was on his own.
However, an experienced South Island driver said Mr Jones was accompanied by another more experienced, driver several times as he learned the vagaries of the transalpine link.
Mr Jones had stopped at the top of a hill to allow another truck to pass, and then followed the other truck as the vehicles descended the viaduct stretch.
The inquest was conducted by Hastings-based coroner Christopher Devonport, who was told Mr Jones appeared to have smoked some cannabis within the three hours before the 6am crash. He also determined the possibility of a "medical event" could not be discounted as contributing to the crash.
But in a summary he said: "Ultimately, I consider it most likely that lack of experience in driving down the Otira Gorge in the hours of darkness has resulted in driver error by failing to engage the correct gear before the descent."
It was likely brake applications resulted in brake failure, the coroner said.
The state of the wreck meant a full examination of all the braking system was not possible but evidence was that overheating could have caused the failure.
Mr Devonport recommended truck drivers not experienced with the Otira Gorge highway should be accompanied initially by more experienced drivers. He also said certificates of fitness should be issued in a computer-based form.
