Breaking news courtesy of Stuff.co.nz: the CBD rail tunnel has a positive cost-benefit ratio, ranging from 1.1 at the most stringent criteria, through to an amazing 6.6 when including Wider Economic Benefits and a low discount rate.
It seems that much of these results are in line with what was expected, with large direct benefits plus huge secondary benefits related to land use and development. Also interesting to note the conclusion that without the tunnel the CBD will need multiple bus lanes on most road leading into the city, the same conclusion we reached not long ago.
EDIT: The buisiness case is available here:
Auckland Mayor Len Brown says a report on a proposed $2 billion rail tunnel through central Auckland shows the business case for it is “compelling”.
The tunnel, which would link Britomart with Mt Eden station and create an inner-city rail loop, was one of Mr Brown’s primary election campaigning points and the business case was released today.
The report says that the standard benefit-cost ratio (BCR) for the project is equal or higher than that of two of the Government’s Roads of National Significance.
Mr Brown said the tunnel was vital as it would turn Britomart from a dead-end station to a through station, thus making it possible to run many more trains in Auckland.
“The link would double the number of trains that can go through Britomart, let Aucklanders get around the region more easily, and reduce congestion on our roads. The report can’t be ignored,” Mr Brown said.
“The potential urban redevelopment and additional growth derived from investment in this infrastructure would make the project transformational not just for Auckland, but for New Zealand as a whole.”
The tunnel would include new stations near Aotea Square (which could become busier than Britomart), Karangahape Road and Newton.
Mr Brown said the report suggests there is a strong case for proceeding immediately with protecting the route, funding the protection process and further investigation of funding the tunnel.
The report suggests that without the link, the central business district would require twin or triple bus lanes in both directions on most road corridors, Mr Brown said.
“The rail link is quite possibly the most critical element in Auckland’s transformation into a globally competitive urban centre, and this report confirms that.”
The standard BCR of 1.1, worked out on the 8 percent discount rate, is higher than the 0.8 BCR for the proposed Puhoi-Wellsford motorway and equal to that for the Wellington northern corridor, which includes Transmission Gully.
At the 6 percent discount rate the BCR is 1.6, and at the 4 percent discount rate the BCR is 2.4.
With wider economic transformation benefits, such as improved land use, urban regeneration and transformation and economic development, the BCR at the 8 percent rate is 3.5. It is 4.7 at the 6 percent discount rate and 6.6 at the 4 percent discount rate.