Wills' defence, presented by lawyer Mike Antunovic, was that he had done what was expected of a reasonably prudent driver. He asked the suppliers of gravel he was carting to load less than he normally picked up, watched the gravel being loaded on to the trailer and relied on the experience of the loader-driver "who was satisfied the load was safe".
At the hearing it was revealed Wills' trailer had been carrying a bundle of 12 posts to which 1550kg of gravel had been added just prior to him heading on to SH2 and over the Waiohine Bridge, heading south.
Judge Hastings said the trailer had a 1.5m long draw bar and a load weight of 2000kg but two experts had been "mistaken about what load weight meant".
The trailer's manufacturer had told the court the 2000kg load weight included the weight of the trailer and Constable Geoffrey Duff gave evidence he had determined the gross weight of the trailer, including the weight of the posts, was 2060kg.
Several eye witnesses to the crash gave evidence and described the trailer starting to wobble as it drove on to the bridge approaches and before hitting the guardrail.
Mr Cobb had been travelling north when Wills' fishtailing vehicle crossed over into the on-coming lane.
Judge Hastings said Wills had made 12 to 20 previous trips with a loaded trailer over the Waiohine Bridge without incident.
"The difference this time was the nature of your load."
"This trip was unique in the sense you were transporting a bundle of 12 posts with gravel poured on top of, and around them," he said.
Wills is now going through the Restorative Justice process which involves meeting the victim's family and a report from Restorative Justice will be available to the court at sentencing.
Under the Land Transport Act 1998, careless driving causing death carries a maximum penalty of three months imprisonment or a fine not exceeding $4500.
There is also mandatory disqualification of licence for 6 months or more.
