The council began by establishing a working party comprising residents, land and business owners, environmental and transport interests and mana whenua, Mr Pannu said.
"We gave them a blank aerial photo and said you tell us what your main issues are.
"We brought technical advisers to that group and asked them to come back to us with options."
He said an initial eight designs were whittled down to four before further consultation and then the creation of the final design.
The working party gave its approval for the proposed route against others because it improved road safety, was better connected to the industrial area, had better benefit to cost ratios, potential for cycle and walkways, was attractive and had clear sight lines.
They made provisos, however, that fertile land loss was minimised, good access to Pakahowhai Country Park was retained and they called for some road design changes.
There was also a strong focus on avoiding Maori land or waahi tapu - this was incorporated into the final design planning and it was found the corridor did not pass through such sites, nor archaeological sites or heritage trees.
A 2014 GHD report on the project said it crossed 14 lots that belonged to private landowners but the rest of the land was owned by HDC, HBRC and the crown. In total 20ha of land was lost.
Such proactive consultation was seen as necessary as there were many interests to consider along the proposed route, from an established residential and rural community to industrial, Maori landowners and prime horticultural landowners.
In finalising the design, Mr Pannu said there were many considerations including being able to prove it met NZTA criteria for funding.
"The cost benefit was rated at 4.5 which is a high score for such a project, and showed it met all its strategic objectives," he said.
He was pleased construction to date had gone without a hitch and was still on track despite wet weather in recent weeks.
Meanwhile the working party was still in operation, meeting once every three months, said group chairman Hastings councillor George Lyons.
"It was a part of the consent to continue to consult with the community regularly through the construction period."
He said the latest meeting of that group was on Tuesday this week, and there were no issues raised.
"The whole process has worked really well," Mr Lyons said.