Looking closer at the Harbour Crossing proposal

The most expensive transport project outlined in the Auckland Plan (and that’s quite an achievement in a transport chapter full of incredibly expensive transport projects) is not a rail project, but rather another motorway: the $3.9-$5.3 billion additional harbour crossing project. An NZ Herald article today confirms my understanding from the Auckland Plan, that this won’t even include a rail line initially:

The planners say Auckland is likely to need another Waitemata crossing by 2030 – at an estimated cost of $3.9 billion or $5.3 billion, for either another bridge or a pair of tunnels.

But it will be initially for road traffic only. Rail is factored in at some more distant time, and public transport will have to take the form of dedicated bus lanes until then.

“It is unlikely that any physical work on rail north of the crossing will commence within the period of this plan,” the document concedes.

I’ve discussed this project before, as well as my preferred alternative to it, but it’s something worth having a closer look at – for a number of reasons, but perhaps none greater than its truly enormous cost. How can a project cost so many billions of dollars?

Fortunately, there’s a wealth of information on the project that can be accessed here including a comprehensive business case for the roading elements of the project. Somewhat unsurprisingly, given its huge cost and (in my opinion) rather unproven need, the project’s cost-benefit ratio is extremely low:
Given the low cost-benefit ratio (and remembering that this assessment measurement tends to favour roading projects), it is somewhat surprising to see the report still enthuse to strongly for the project’s need:

The Auckland Harbour Bridge (AHB) represents a critical enabler of urban mobility for people and freight in the Auckland region. At present, the bridge handles approximately168,000 vehicles per day, making it critical to the economic wellbeing of Auckland and New Zealand.

There is a compelling need to consider additional capacity on State Highway 1 (SH1) between the Auckland central business district (CBD) and the North Shore as:

• The route already has a level of service (LOS) during peak times of E/F – the most congested measure.
• Population and travel demand growth is forecast to increase by around 22% (40,000 vehicles per day) by 2041, which will significantly impact on the ability of the route to provide economic benefits to commuters and freight.
• The resilience of the network is an ongoing concern in terms of:

o Managing the future loads on the current AHB and associated maintenance needs
o Providing an ability to manage and recover from significant network disruption, and
o Adequately balancing the needs of CBD-bound commuters, public transport (PT) and port-bound freight, with north-south traffic that does not originate or terminate in the CBD.

The present value of the economic benefits associated with providing additional capacity, over a 30 year analysis period, is approximately:
• $300 million in travel time savings
• $80 million in decongestion benefits, and
• $9 million in travel time reliability benefits.

In addition to the transport benefits list above, present value benefits from agglomeration are around $250 million, and the modelling demonstrates movement in land-use to key growth nodes such as Takapuna, while continuing to grow other nodes such as the CBD.

The critical aspect of these benefits is that they are derived from an increase in capacity and connectivity over a reasonably small stretch of the network. Additional capacity or network optimisation in the CBD (including the ability to take additional traffic from the Northern Busway, Central Motorway Junction (CMJ) and North Shore connections would widen and deepen the economic benefits derived from the additional capacity attributable to an additional crossing.

Perhaps my main question of the project is best illustrated by simply looking at a map of what’s proposed:In effect, the project spends $3.9-5.3 billion in order to add more transport capacity between Takapuna and the city centre. No more lanes are proposed north of the Esmonde Road interchange, no more lanes can fit through spaghetti junction to the south, the project simply looks to increase the number of lanes between the two places – up to around 12-14 lanes (depending on what’s done to the harbour bridge). That leads me to think of cheaper ways providing this additional transport capacity, perhaps in the form of a railway line as I discussed previously here.

The NZTA study looked at two options – a bridge and a tunnel – without identifying a preference for either of those options. The Auckland Plan clearly notes a preference for a tunnel option, which obviously comes with the bigger price tag. Both options included retaining the existing bridge, for the obvious reason that it’s a pretty important piece of infrastructure with quite a lot of life left in it, so it would be not only exceedingly expensive to remove, but also quite illogical.

One of the most interesting parts of the study is looking at the detailed layout of what the project would look like, if built. There are a large series of diagrams found in this document (caution, very large file) of the route, including many engineering drawings of long-sections, as well as aerial diagrams showing exactly where the roads, including the tunnels, would go.

Starting at the northern end of the project, the following diagrams shift southwards across parts of the project that I find to be of interest: This is how the project links in at Esmonde Road. It seems as though one lane has been added to the Northern Motorway in the southbound direction compared to what’s there now. It’s interesting to see that the railway line ends abruptly on the southern side of Esmonde Road – in a rather useless location for a station actually. See the key for what the colours mean, which is consistently applied throughout the diagrams. The image above shows what would happen around the Onewa Road interchange. There’s quite a lot of further reclamation into the sea, much of it necessary for the two-way busway. It is somewhat strange that a full two-way busway is shown in these plans as well as the rail connection. I guess there’s not much faith from NZTA in the rail link going ahead so they feel this is necessary?

Shifting slightly further south, we see the vast array of roads as at the northern portal of the harbour tunnel:It’s quite a challenge to make sense out of the image above, but the main thing which happens is that the “new” lanes from the tunnel (which is in orange for bored and purple for cut and cover) duck underneath the southbound part of the motorway which will go over the harbour bridge. The busway lanes also go all over the place, shown in blue where they are on elevated structures.

Shifting south again, to where the tunnel emerges on the city side of the harbour, things get pretty complicated straight away:This one is particularly challenging to make sense out of, because we don’t actually even yet have the “existing” situation – with the Victoria Park Tunnel (shown in aqua colour) not being complete. Effectively the harbour tunnel skips Fanshawe Street, then ducks under Victoria Park. The lanes coming off the bridge split off at Fanshawe Street but then continue under Victoria Park in another tunnel. The irony of this design is that the extremely expensive Victoria Park Tunnel we’re currently building effectively ends up being a vastly oversize glorified onramp from Cook Street.

As we see in more detail below: It seems as though Cook Street is designed to become the primary entrance and exit to the city for cars, with Fanshawe Street perhaps becoming more the bus connection. I’m not quite sure how this fits in with Auckland Council’s plans for Cook Street in their City Centre Master Plan.

For the bridge option, things are largely similar on the northern side of the harbour, but different in the south: The big blue coloured area shows the alignment of the bridge – which is a pretty massive impact on the Westhaven Marina.

Interestingly, for the bridge option the Victoria Park Tunnel gets used for a bit more than being just a glorified onramp from Cook Street – as shown in more detail below: Under this scheme we still end up with a huge number of tunnels under Victoria Park – somewhat unnecessarily in my opinion as I’m not sure how essential it really is to have a connection to Cook Street as well as Fanshawe Street. At least not for the price of those tunnels, which I imagine is pretty huge.

It’s a bit difficult to appreciate the visual impact of either proposal – though the image below gives us a pretty good indication: I think overall what all these images show is how utterly massive (and therefore expensive and environmentally damaging) this project would be – for either the bridge or tunnel option. We really do need to question whether it’s worth it, whether such a project is really so essential and whether we should look at cheaper and less environmentally damaging options.

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