A high-risk State Highway 1 intersection at Rolleston may not cope with extra traffic from thousands of new homes planned outside the town's boundary.
That is the concern of Waka Kotahi New Zealand Transport Agency, which is among the submitters opposing two rezoning plan change applications before the Selwyn District Council.
Plan change requests could pave way for thousands of new homes. Carter Group has lodged the two applications of Plan Change 81 for 28ha and Plan Change 82 for 110ha, which would together pave the way for 1670 new homes if approved.
Both areas are on Dunns Crossing Rd, and flank a block of land that is part of the Plan Change 73 area, where Carter Group is planning 2100 new homes.
PC73 was recently declined by the council but the company is appealing the decision to the Environment Court.
If PC73 was ultimately allowed to proceed and PC81 and PC82 were approved, this would amount to an estimated 3770 new homes in subdivisions along Dunns Crossing Rd on land currently outside of the Rolleston town boundary.
Waka Kotahi team lead south environmental planning Richard Shaw said in the roading authority's submission to PC82 the Dunns Crossing Rd/Walkers Rd/State Highway 1 intersection had existing safety concerns.
There had been one serious crash and 15 minor/non-injury crashes between 2015 and 2019.
It was scheduled for an upgrade, with a roundabout being the preferred option.
Shaw said while the PC82 developer had proposed to delay the occupation of dwellings until the upgrade was complete, additional traffic from new subdivisions generally would put pressure on the upgraded intersection.
"There is some concern over the capacity of the intersection to accommodate the additional vehicle movements resulting from the development of this plan change site, in addition to the vehicle movements potentially generated across other proposed plan change sites in the wider area," Shaw said.
Consideration should be given to impacts of plan change applications outside of town boundaries, Shaw said.
"Development in these areas has not been anticipated and accounted for in future infrastructure planning."
Waka Kotahi was among a total of 24 submitters to PC81 and PC82. The next step is for the district council to schedule hearings, after which the independent hearing commissioner for each plan change will make a recommendation to the district council on whether it should adopt the plan change.