I requested, on behalf of the Campaign for Better Transport:
1. A statement defining the land transport problem or issue that the proposed AWHC solution is attempting to address.
2. The studies and comparative assessments of alternative solutions that the NZTA has conducted, including, but not restricted to, an electrified rail only crossing of the Waitemata Harbour between the Auckland isthmus and the North Shore.
The NZTA responded with the following PDF documents:
- Attachment A: Additional Waitemata Harbour Crossing Preliminary Business Case, January 2011. The business case includes a statement outlining the problem which the Additional Waitemata Harbour Crossing project is attempting to address (refer to ‘Description of Service Need’ on page 9)
- Attachment B: Waitemata Harbour Crossing Study Phase 1: summary report option short listing, November 2007
- Attachment C: Waitemata Harbour Crossing Study 2008: Study Summary Report, April 2008
Question 1: What Problem Are We Trying to Solve?
The Description of Service Need is this:
What stands out here is the statement that the “AHB currently provides the only direct, cross-harbour vehicle link between the CBD and the North Shore.” Resiliency seems to be a major driver behind a solution which supports six lanes of general traffic in a tunnel, with the possibility of rail at some indeterminate point in the future. What is odd is that there is no mention in any of the supplied documents of the Western Ring Route, a $2bn project adding resiliency and reducing demand on the existing Harbour Bridge which, in the NZTA’s own words, will “create a seamless motorway between Manukau and Albany”. This is due for completion in phases in the next few years.
There are also the usual predictions of increasing traffic volumes, which threaten to “adversely impact on the length and reliability of travel times”. Quite why it is vital to minimise the travel times of single occupant cars isn’t explained. Regardless, the Business Case uses traffic volumes in 2008 as the basis of forecasting, before the Northern Busway had a chance to make much of an impact.
However, as Matt pointed out in this post, traffic volumes across the bridge have stubbornly stayed at 2008 levels, at least up until 2014.
And that pretty much sums up the statement of need. As far as analysis of the need for mass rapid transit goes, there’s this analysis of the Busway:
Forecast demand for the Busway indicates that the morning peak hour flows into the CBD could increase to 250 buses per hour in 2041, representing a 138% increase over the 2009 volumes. This figure is the recommended target capacity for the Busway system, representing 12,000 passenger movements per hour6. However, achieving the target capacity is currently hindered by capacity constraints close to the CBD where the provision of dedicated bus facilities is more expensive and bus volumes are at their highest. One of the advantages of a new crossing would be the ability to have dedicated bus lanes across the AHB which would maintain a high level of trip reliability for passenger transport users.
On rail, the Business Case assumes a rail link between Gaunt Street Station in the Wynyard Quarter (underground) and Akoranga Station (at grade). The basis for modelling the tunnel is this diagram:
Construction cost alone of the combined tunnel is $4.6bn in 2010 dollars, with a total nominal cost over a 30 year period calculated as $12bn for the tunnel, including all capital expenditure and operating costs, with a risk factor as well:
The Business Case document comes up with a BCR of 0.4 for the combined tunnel option, including wider economic benefits and not including tolling. Not so much a Business Case for the proposed AWHC then, but more a massive red flag suggesting that not building the proposed tunnel is actually more economically beneficial for Auckland. Even more worryingly, even though there is an assumption that the motorway will be widened to four lanes between Esmonde and Northcote road, there doesn’t seem to be any explanation of how the capacity of the Central Motorway Junction will be increased to cope with the additional three lanes of traffic each way that a new tunnel crossing will provide for.
Incidentally, transport modelling and the Cost Benefit Analysis excluded rail (p.25)
A parallel work stream to this study — The Network Plan — undertook an assessment of the longterm capacity of the existing Busway and concluded that a rail crossing was not required within the timeframes considered for the CBA. As such, the transport modelling excluded the modelling of rail, and the CBA includes costs for the roading component of the crossings only (i.e. the cost for the rail tunnel is excluded).
There is an interesting discussion on tolling (up to $8 each way modelled), but perhaps that is best left for another post.
Question 2: What alternatives have been evaluated?
The Business Case takes it as a given that capacity for additional vehicles is required. This stems from the earlier options papers, which do indeed include an examination of a rail only crossing, which is the second question of the OIA request. Attachment C covers three short-listed options, with variations for each:
The study concludes (p.43) that a combined road / rail tunnel option is best – Option 2C.
So although a rail tunnel was the best passenger transport option, the study recommends a combined road / rail tunnel. The option evaluation process appears not to have used a CBA / Economic Evaluation Manual approach, and it is difficult to tell exactly why option 2C is favoured over a rail only crossing. There is no comparison of BCRs between the rail only and combined tunnel options. Presumably there is a strong weighting for resilience, but again discussion about the Western Ring Route is non-existent. However, the study also carries this warning on p.45:
Limited spare capacity on the strategic and regional arterial networks on both sides of the Harbour, together with the need to move towards a more sustainable transport system, mean it will be neither practical nor desirable to provide sufficient cross harbour road capacity to match demand. Any additional connectivity should therefore be provided to the best practicable standard, that is, in balance with the remainder of the Auckland road network, and in a cost effective manner.
And cost should probably be one of the most important factors. Page 36 has a table of costs for the different options.
A rail only tunnel was costed at about a quarter of the cost of a road / rail tunnel.
In summary, I don’t really think NZTA’s solution is going to work. By design, it will increase the number of single occupant cars in the CBD and surrounding motorway networks and, according to their own analysis, make the economy of Auckland worse than if the project doesn’t proceed. (And that isn’t even considering the impact of tolls on the economy.)
I don’t accept claims that the tunnel will be “future proofed” for rail either. You only need to look at the history of future-proofing in Auckland (think Te Iririrangi Drive or the Manukau Harbour Crossing) to know that most likely it will never happen.
The taxation and expenditure of over $4bn dollars could make a real difference to Auckland if it was spent on the right things. I think Aucklanders should get a say on this. Allowing the AWHC route protection to proceed in its current form, at a cost of tens of millions, is the thin edge of the wedge. If planning starts for a tunnel for single occupant cars, then that is what we’ll end up with.
This isn’t urgent. We’ve got time to get it right.