Councillors at this week's infrastructure services committee meeting voted to approve initial work on the project, including a more detailed plan and cost analysis.
If approved, the project would see Aramoana Rd, between Careys Bay and Aramoana, widened by 2.5m, allowing 2m for a walking and cycling track and 0.5m for extra road width for motorists, council projects engineer Evan Matheson said.
The upgrade would cost about $9.6 million and take 15 years to finish, with work likely to start next year and be completed in 2025, he said.
That would be 10 years ahead of the council's earlier plan, which envisaged starting the widening of Aramoana Rd some time between 2020 and 2025 and completing the section by 2035, after road-widening on Otago Peninsula was finished.
The Aramoana Rd project would be a more cost-effective use of council funds, with $450,000 each year already spent maintaining the seawall along the road, he said.
If the road-widening and seawall upgrades were undertaken together, those maintenance costs would cease for between 50 and 100 years once the project was completed, Mr Matheson said.
"We are trying to get the best bang for our buck and good use of ratepayer money . . . it's slightly more expensive, but it's safer for the road user," Mr Matheson said.
Following this week's committee decision, council staff would begin a detailed exercise examining resource consent issues and construction costs, before reporting back to the committee later in the year, he said.
Talks would also be held with stakeholders, including the New Zealand Historic Places Trust Otago-Southland branch, he said.
"If everything stacks up, and I'm reasonably confident it will, then we will make a start . . . this time next year," he said.
Resource consents for the additional work would be required from the Otago Regional Council, but it was not known if consents would be publicly notified, he said.
The completed project would be to a lower standard than that being undertaken on Portobello Rd, but that was appropriate for the lower traffic volumes to Aramoana, Mr Matheson said.
"We are not going to straighten the road out. It's still going to be the similar, torturous, winding road that it is. We just want to make it a little safer for vehicles," he said.
The drive along Portobello Rd, on Otago Peninsula, is about to get a little brighter, with plans to install 30 new street lights at Macandrew Bay and Company Bay.
Mr Matheson said cabling for the lights had been installed, and street light columns would be added in the next three weeks.
