A new overbridge is among options being considered by the council as the final part of changes to a series of streets on the harbour side of the railway tracks to create a more viable bypass of the central city.
The two-lane overbridge — if it goes ahead — would link with Hanover St and require an access road to be built over what is now a council carpark.
The options were presented to councillors in a closed-door workshop in October and slides from the presentation have been provided to the Otago Daily Times under the Local Government Official Information and Meetings Act.
The presentation said lower speed limits and traffic calming measures on State Highway 1 to make access to the new hospital safer were expected to drive more traffic on to the harbour arterial route.
The council has already started making improvements to streets in the area, but staff told councillors traffic delays due to passing trains at the St Andrew St crossing and the design of the Ward St overbridge — which means two trucks cannot pass — would limit how effective the streets were as a bypass of the central city.
Councillors were shown a list of different ways these issues could be dealt with.
An option which included the new overbridge, upgrading the Ward St bridge and limiting use of the St Andrew St rail crossing to emergency vehicles, cyclists and pedestrians was favoured as part of a long-listing process.
Other options included just improving the existing Ward St overbridge, building a new three-lane Ward St overbridge and doing nothing.
However, staff said more work, including cost estimations and traffic modelling, needed to be done before a final preferred option was selected.
Infrastructure services committee chairman Cr Jim O’Malley said the big question mark over the work was how much funding the government was willing to provide.
He supported the option that included building a new overbridge, but estimated it would cost at least $75m and should only happen if NZ Transport Agency Waka Kotahi (NZTA) provided enough funding.
The problem was the indications so far were that NZTA’s funding would only cover upgrading the existing Ward St overbridge.
"Our feedback has been pretty clear that’s just not going to work."
He believed the case was strong for the government to stump up more cash.
"It needs to be funded properly. We are having this so-called inter-generational redesign and we are doing it on the cheap."
Because St Andrew St was likely to become one-way to accommodate the new hospital, traffic on the arterial route would need to be sent further north than the current rail crossing, Cr O’Malley said.
The layout and location of the Ward St overbridge worked against this option, which meant a new overbridge which sent east-west traffic along Hanover St was the ideal solution.
"But that’s expensive, because it probably also means buying some properties on the other side of the railway line."
Rather than building a less-than-ideal solution, or the council paying for a large portion of the project, Cr O’Malley believed the final stage of the harbour arterial route should not be done without the required funding from central government.
"We have got to hold out for something, because otherwise it is going to be very expensive for us."
