At the time of the accident, which occurred just after 6am on July 12 2010, conditions on the open road were icy and hazardous.
An investigation showed Mr Pearson lost control when he drove around a bend on Taylorville Road.
Senior Constable Simon Burbery, who participated in the investigation and gave evidence at the Greymouth inquest in June, was reported in the finding as saying the maximum speed a vehicle should travel around the bend when the road was icy was around 72km/h.
In his finding, Coroner Richard McElrea said reflective posts and better positioned signs should have been in place on the stretch of road where the crash occurred, but Mr Pearson's lack of experience driving on a roads like Taylorville in hazardous and frosty conditions could not be overlooked.
"He was an experienced driver," said Coroner McElrea.
"But he was not experienced in driving in the conditions he was in, namely frost and icy conditions on a South Island road in the middle of winter.
"The speed he was travelling at would have been appropriate in normal conditions, but with local knowledge he would have been travelling at a lesser speed."
Coroner McElrea also said he did not have to make any formal recommendations regarding roadside signage as reflective posts had already been erected and warning signs about hazardous conditions had been repositioned since the accident.
- APNZ