Gateway to the North

TPC were commissioned by an alliance of private landowners to develop and test the technical viability of a proposed realignment of State Highway 1 north of Auckland to bypass the Brynderwyn Hills, known as ‘Gateway To The North’ (GTTN). GTTN was proposed as an alternative to two bypass options shortlisted in the NZ Transport Agency’s Programme Business Case (PBC) for State Highway 1 from Whangarei to Te Hana.

The development of GTTN as an alternative option required TPC’s assessment to be aligned with NZTA’s Business Case approach, which was simultaneously progressing through the Detailed Business Case phase, comprising the assessment of the Agency’s own shortlisted bypass options. TPC’s assessment of GTTN adopted the same methodology and multi-criteria assessment as NZTA’s business case.

TPC’s assessment concluded that GTTN was technically feasible and offered the key benefit of a shorter route length than the alternative alignments shortlisted by NZTA, as well as a shorter route length than the existing route of State Highway 1. GTTN additionally made better use of the existing state highway infrastructure and would result in a lesser visual and noise impact than other options being considered by NZTA.

TPC’s assessment included:

• An overview of key planning issues and constraints
• A technical review of the physical route alignment, based on high level concept design in GIS
• A Performance Assessment of GTTN against the investment objectives identified in the NZTA’s PBC, in relation to safety, resilience and reducing the cost of journey times.
• A cost estimate for GTTN

The outcome of presenting TPC’s work to NZTA was that the Agency added GTTN to its two options for further investigation.