Consultants will be asked by the NZ Transport Agency Waka Kotahi (NZTA) to build an investment case for improvements at key intersections in the short to medium term.
This is expected to concentrate on the turnoff from State Highway1 on to SH87 through to the intersection with Hagart-Alexander Dr and the SH1 intersection with Riccarton Rd.
Further interventions could be required longer term, the agency signalled.
Consideration of transport constraints comes as the town anticipates future growth pressures.
"Major developments are now progressing through consenting and fast-track approval processes which are likely to put further pressure on the key access points into the township," an NZTA draft strategic case said.
"This includes a 260-unit Summerset retirement village, the Universal Developments subdivision with 650 residential lots and the proposed 40ha Southern Links freight hub."
The pace of growth, combined with existing network constraints, was placing increasing pressure on the transport system.
NZTA issued a request for tenders, which said a contract would include traffic modelling and an investment case to determine the preferred option for improvements at and between key intersections.
The focus of the project was to "optimise" existing assets, the draft strategic case said.
The agency also specifically mentioned looking into potential feasible long-term solutions, identifying the emerging preferred option and determining triggers for when investment may be required.
Its work sits alongside a Mosgiel transport study being carried out by the Dunedin City Council.
Mosgiel-Taieri Community Board chairwoman Rebecca Shepherd said the town had serious traffic and safety issues.
The board supported the proposed intersections work as an interim measure, she said.
"While the NZTA’s optimisation strategies may provide temporary relief, the community board is wary of these short-term fixes delaying long-term solutions."
Mrs Shepherd said the primary concern was congestion at the SH87 intersections with Hagart-Alexander Dr and Gladstone Rd and railway-related traffic backing up.
The community board emphasised the importance of continued development of long-term measures, using the Mosgiel transport study and other investigations to back this up, she said.
Robust long-term planning was needed to support predicted population growth and planned commercial developments.
City councillor and former Mosgiel-Taieri Community Board chairman Andrew Simms said roading was a key piece of infrastructure that had not kept pace with development on the Taieri.
"The road network is, for all intents and purposes, the same as it was 23 years ago."
Mr Simms said the need for a heavy traffic bypass was identified in 2003 and included in a council transport plan back in 2013.
"Here we are, a decade or so later, and still waiting for some concrete mitigations of the transport problem."
He was encouraged by recent movement from both the council and the transport agency.
The agency’s draft strategic case said there were 53 crashes at the SH87 intersections with Gladstone Rd and Hagart-Alexander Dr and Burns St from 2014 to 2024.
Right turning and rear-end crash types were the most common.
Safety concerns had also been raised about the SH1 off-ramp and roundabout at Quarry Rd.
The main issue
Growth in traffic volumes, combined with network constraints within Mosgiel, is leading to congestion, unreliable travel times and safety concerns at key SH1 and SH87 intersections during peak periods.
Also:
Significant future residential and industrial developments, including the new inland port, are expected to reduce travel time reliability and increase delays along SH1 and SH87 across peak periods.
Population growth:
Rapid housing growth occurred in the past decade — the number of residents increased by 19% to 14,489 between 2013 and 2023.
Growth prospects:
Development of Summerset retirement village. Subdivision with 650 lots. Freight hub (inland port).
Source:
Draft strategic case for improvements to SH1 and SH87 at Mosgiel.
