Both he and fellow employee Toby Waitokia, who was a passenger in the truck, suffered fatal injuries and died at the scene.
The first coronial inquiry, completed in July 2015, found the crash was caused by driver error and wrong line at the corner causing rollover; structural failure of the A-frames at the corner causing rollover; and structural failure of the A-frames at the corner with a resulting erroneous driver reaction, the combination causing rollover.
The matter was referred back to the Coroners Court after the families of the deceased expressed their dissatisfaction with the original Coroner's findings and the Police investigation.
A senior crash investigator within New Zealand Police also questioned certain findings contained in the initial Police Serious Crash Unit (SCU) report which the coroner relied upon for his findings.
As a result, the Deputy Solicitor-General directed a second coronial inquiry be opened because new evidence was available which may have a bearing on the findings as to the cause and circumstances of the deaths of Brenssell and Waitokia.
In the Coroners Court at Dunedin, Coroner Peter Ryan, of Wellington, said considerable work was done to further examine the circumstances of the crash in an attempt to determine the most likely cause of the crash.
He said it was possible a combination of factors played a part.
The first was a loss of structural integrity in the support A-frames, and/or possible movement of the concrete panels allowing tie-down chains to slacken under dynamic lateral loading, ''thus enabling the centre of mass of the load to move to the left''.
The laterally unsettling and torsionally distorting effect of the vehicle traversing undulations in the super-elevation in the road just before the crash, also contributed.
The suspension system on the trailer not dealing well with the high centre of mass of the load and the modest overloading, were also possible aggravating effects.
And a ''non-intuitive braking response'' from Brenssell may have resulted from sudden movement of the trailer under dynamic inputs from the road undulations, he said.
''My impression from the evidence is that the crash was the result of a 'perfect storm', in that these four factors all aligned at the same point in time.
Ryan said it was inaccurate and unfair to say Brenssell contributed to the cause of the truck rolling over.
''In that situation, I do not consider that Mr Brenssell could have performed any remedial manoeuvre which may have prevented the crash, once these factors had aligned.''
Ryan recommend that the design and manufacture of all A-frames used for carrying heavy and tall loads on trucks or trailers should be certified.
''This recommendation is addressed to New Zealand Transport Agency and to the Ministry of Transport, together with any other relevant regulatory agency.
''Based on the recommendation provided by the experts, I also make the comment that the design and manufacture of A-frames, together with other risks related to dynamic loading, should be addressed through a consultative process involving all interested parties.''
The New Zealand Transport Agency supported the recommendations.
Detective Senior Sergeant Malcolm Inglis acknowledged the Brenssell and Waitokia families.
''This has been a hard and long road for the families to get to this point.
''They were determined to make sure they got the answers as to what caused this crash and took the lives of their loved ones.
''It is our expectation that any recommendations are met to ensure our roads are a safer place for all.''
