Project introduction

Safety will be improved at State Highway 1 and State Highway 29 at Piarere with construction of a new roundabout to replace the existing T-intersection.

  • Estimated project dates

    Dec 2023–Dec 2025
  • Estimated project cost

    $40 million
  • Project type

    Road improvements
  • Project status


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Purpose of the project

In January 2020 funding was approved to upgrade the intersection of SH1 and SH29 at Piarere. This will improve efficiency, connectivity and safety on a high-volume traffic route, which is one of New Zealand’s most critical corridors. The new roundabout is designed to allow connection with the future expressway between Cambridge and Piarere. 

SH1 Cambridge to Piarere project

  • Benefits

    Auckland, Waikato and the Bay of Plenty are part of the Upper North Island’s Golden Triangle, home to more than half of New Zealand’s population. The transport corridors in these regions are critical to support the safe travel of a growing number of visitors and residents, and to get goods to market efficiently.

    SH1 between Cambridge and Piarere is part of the key journeys which link Auckland and Hamilton with Tauranga, specifically the Port of Tauranga via SH29, as well as central and lower North Island via SH1. 

    The new intersection roundabout layout will:

    • improve connectivity, reliability and safety for road users
    • accommodate any future extension of the Waikato Expressway from Cambridge to Piarere, and any future walking and cycling connections.
    • improve the network’s resilience .

    The existing T-intersection is high-risk. Between 1 December 2015 and 30 November 2020, there were 21 crashes within 50m of the T-intersection resulting in 2 fatalities, and 12 crashes involving injuries. The high number of crashes reflects risks taken by road users responding to the intersection layout.

  • Key features
    • A 2-lane roundabout with a 60m diameter central island
    • Futureproofed design with a fourth leg to be added for potential expressway extension
    • Improved and safer traffic flows through the intersection
    • Safer connections between SH29 and SH1
    • Median islands on the approaches to encourage reduced speed
    • Underpasses for walking and cycling connections
    • Improved stormwater system
    • Improved street lighting and landscaping
  • Why a roundabout?

    Roundabouts and grade-separated interchanges such as flyovers or slip lanes are valid options for traffic flow and safety but there are important reasons why a roundabout was chosen for this intersection.

    A roundabout in this area is the safer option as everyone, whichever direction they approach from, is in a slower speed environment whatever the time of day or night.

    Good roundabout design provides equal access and manages energy if a collision does occur, therefore minimising severe injury.

    When required, the roundabout will readily connect to the future Cambridge to Piarere expressway.

    Having a roundabout at the end of the expressway will signal to drivers that there’s a significant change in the road environment. It will help travellers slow down, assess directions and traffic conditions and adjust their driving from a high-speed expressway back into a 2-lane rural highway.


Latest news

Construction of the roundabout got underway in January 2024.

Roadworkers have made good progress with much of the main foundation work now complete.

The focus is currently on construction on the southern side (Tīrau approach road). To safely accommodate this work, from Monday 15 April, traffic south of the roundabout has been moved onto a newly constructed section of road adjacent to SH1. 

This is a short bypass road which rejoins SH1 before the intersection, which continues to operate as normal. This arrangement is expected to remain in place until September 2024.

Motorists are asked to drive with extra care through the site, while people adjust to the new road layout. A temporary speed limit of 60km/h will be in place around the project site to protect road workers and ensure the safety of everyone travelling through the area.

Construction is expected to take up to two years to complete.

Get in touch

If you have any questions or comments, please email us at (Please note this email address is only monitored during business hours). 

You can also write to us at:

NZ Transport Agency Waka Kotahi
PO Box 973
Waikato Mail Centre
Hamilton 3240
New Zealand

Get the latest state highway travel information check the Journey Planner website(external link)

Report issues impacting travel call 0800 4 HIGHWAYS (0800 44 44 49).