What is the benefit-cost ratio of the Warkworth to Te Hana project, and over what appraisal period, at what discount rate, and using which categories of benefit was the stated return of $1.60 per dollar invested calculated?

Answer

1.6 (including wider economic benefits) over 60 years at 2% discount rate. The key assumptions used in the economic assessment were: • Time Zero: 1-July-2024 • Base date: 1-July-2023 • Discount rate: 2% (2024-53), 1.5% (2054-83) • Period of analysis: 60 years • Construction period: 10 years (2 years pre-implementation and enabling works + 8 years construction) • Traffic Growth Rate: 2% - Used to calculate future crash cost savings. Traffic growth assumptions within the transport model were based on existing travel demand models for Auckland and Whangārei. These models were supplemented with additional data sources, including land use projections, traffic counts, and other relevant inputs to ensure accuracy and alignment with current growth trends.