The preferred site considers a number of factors, including initial technical assessments of stormwater, ecology, archaeology and geotechnical information.
Discussions with affected landowners are continuing, as is the finalisation of the detailed technical assessments required to complete design, the lodgement of the Notice of Requirement and regional consents.
Construction expected to start in 2022, subject to negotiations on property acquisition and RMA proceedings.
Once started, construction is anticipated to take about two years to complete. Replacing the current intersection directly with the roundabout is not practical due to the high traffic volumes, safety considerations and the resulting disruption on SH1, Waka Kotahi says.
The Government recently confirmed the direction and funding commitment for these safety improvements at Piarere through the NZ Upgrade Programme.
When the NZ Upgrade Programme was initiated, a number of projects, including the SH1/29 roundabout, were in their early stages of development, with detailed project information still being established.
Since then, Waka Kotahi has worked to get a better understanding of project risks, scope, costs and timeframes. For the SH1/29 roundabout, this work resulted in an updated cost estimate of $40m to deliver the project. The same scope and transport benefits will be delivered.
The detailed business case for the longer-term Cambridge to Piarere corridor (Waikato Expressway extension) was recently presented to the Waka Kotahi Board and its decision will be available soon, Waka Kotahi says.