Submissions on the plan opened this week and will continue until May 23.
Running between the Oval and the Pine Hill Rd-Great King St intersection, SH1 on Cumberland and Castle Sts is a key freight and commuter route linking the north and south sides of the city.
NZTA Otago regional relationships acting director Ian Duncan said in a statement the proposed improvements "are part of a business case which identifies ways to improve accessibility, supports new developments like the new Dunedin hospital, while maintaining efficient traffic flow, and reduces risk for road users and pedestrians".
NZTA particularly wanted to know what people thought of its preferred option for the Pine Hill Rd-Great King St intersection, along with several other proposed safety improvements to the SH1 one-way system.
The Pine Hill Rd intersection is a key part of the SH1 one-way system into and through Dunedin, close to the Dunedin Botanic Garden and the entrance to North East Valley.
Mr Duncan noted the long-standing safety concerns with increased risk of crashes because of limited visibility and heavy vehicles descending a steep hill at the intersection.
"Our preferred option is to realign the SH1 traffic lane.
"This would improve visibility and safety at the intersection and make it safer and more efficient for people heading to North East Valley."
This would involve shifting the existing uphill traffic lane about 10m into an area of the Town Belt, requiring about 1000sqm of this land.
The existing bridge over the Water of Leith would be widened.
NZTA will work with the Dunedin City Council (DCC) on ways to compensate for the loss of public land.
What were the other options for that intersection?
Several options for making the Pine Hill Rd-Great King St intersection safer were investigated and discussed with key stakeholders including the DCC and road freight operators.
These included traffic signals and an overpass to separate SH1 traffic from vehicles using Great King St.
Mr Duncan said the overpass option was not progressed for several reasons, including the cost, construction challenges, proximity to the Water of the Leith and environmental impacts.
The traffic signal option was not taken further given the significant safety concerns if a heavy vehicle lost traction or could not stop on the hill.
"NZTA’s preferred option would also increase the safety of the nearby Duke St (SH1)/Cumberland St intersection.
"There were nine crashes there between 2019 and 2023, two-thirds of them caused by drivers trying to cross two busy lanes of the highway to Duke St’s western side.
"To make this intersection safer, we are proposing to remove the straight-through movement, and only allow left turns out of Duke St on the eastern side to SH1 going south.
"We want to hear what people think of this idea also."
• Full details on all the proposed improvements for this SH1 Dunedin corridor are available on the project website https://www.nzta.govt.nz/projects/sh1-dunedin-improvements/ along with details on how to provide feedback.
More information about NZTA’s proposed improvement plans for SH1 and St Andrew St (SH88) to support transport access to the new Dunedin hospital will be available in the second half of this year.
