"Construction of these elements will be highly visible to all road users," Wilton said.
"The underpass' central section, comprised of a 60m open-air trench, will connect the two completed underpass entrances, which got under way in May. The next stage of the Bayfair flyover will see two more piers constructed; one located next to the underpass' central trench and the other near to the existing pier, which is located in the centre of the Bayfair roundabout."
Wilton said a major traffic switch of this kind typically took up to two weeks to complete.
"While the specific dates for the change in road layout will be shared closer to the time, there will be a series of night works ahead of time to complete the necessary preparation, as well as for the switch itself and the required follow-up work.
"This includes completing the new road area, barrier realignment, new line-marking and the removal of old line-marking."
Lane closures will be necessary during night works. Where possible, two lanes of traffic will be maintained in each direction until the switch is complete. The traffic switch was not expected to have an impact on the existing pedestrian and cycling route throughout the site.
In the event of unsuitable weather or other unforeseen circumstances, work may be postponed.
Waka Kotahi acknowledged Bayfair Shopping Centre and Golf 360, and thanked local businesses, residents and motorists for their patience while this work was under way.
The Bayfair flyover and the pedestrian and cyclist underpass are expected to open to the public on completion of the project.
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