I suppose that it’s always been the big question for Auckland’s transport system – what happens if/when (although it has usually been considered ‘when’) the current Harbour Bridge no longer has the ability to provide the necessary capacity for Auckland? Over the years this issue has been managed, firstly by tolling, secondly by adding on the clip-ons and thirdly by installing the moveable barrier. There have also been plans, for decades in fact, about where to provide an additional harbour crossing – if/when (although usually presumed when) it is required.

In fact, one of the very first “planning” projects I ever did – for 7th form Geography in 1999 – was to look at the options that were being considered back then for an additional harbour crossing. Of course all the documentation is long gone from anywhere I would be able to find now, but the basic plan then was to duplicate the bridge on its western side and then burrow the new lanes of the motorway in a big long tunnel underneath Ponsonby and Grey Lynn, to emerge near the Western Springs interchange on State Highway 16. From memory, there was no provision for rail in this option – although I guess back in the late 90s nobody caught trains so that’s not particularly surprising.

But anyway, we have come a reasonably long way since that time, and in 2007 three preferred options were provided – narrowed down from a list of 159 long-list options. They are each described below:

option-1option-2 option-3These options are further detailed in the NZTA (then Transit NZ) study that short-listed these three from the previous 159 options. They are also shown below:

all-optionsNow when I first heard about these options, back a couple of years ago, I was initially just very glad that all of them included some form of public transport component. Ideas of a “busway bridge” were fairly quickly disbanded and it became pretty obvious that the passenger transport component of all the options was likely to be a railway tunnel. This would link with the Northern Busway and, with a bit of re-grading, eventually carry on all the way to Albany (or even Orewa) as a railway line.

In terms of the roading components of options two and three, I am not sure whether I really had a preference. Option 3 was certainly the most expensive, because of the length of tunnelling that would be required, but at the same time it also would bypass a lot more of the current central motorway junction – and would have significant traffic benefits as a result of doing that.

I also though that option two would potentially have some problems in how it connected up with the existing motorway system. As you can see on the plan to the left, at this time it seemed as though the link between the Southern Motorway and the Harbour Bridge would be retained, potentially leading to the already complex spaghetti junction getting even messier. Furthermore, feeding more lanes of traffic into this area would have, in my opinion, only shifted the bottleneck slightly southwards from the Harbour Bridge straight into the heart of the motorway system.

Given the enormous cost of option 3, and the potential issues with option 2 regarding traffic effects and also the environmental effects of expanding spaghetti junction, I guess I was immediately drawn to option 1 as the most sensible choice. After all, by building a railway tunnel surely a lot of traffic that current uses the Harbour Bridge – in particular the many buses that go across it – would be removed with the completion of a railway tunnel. With eight lanes of traffic already on the Harbour Bridge, it seemed a bit unnecessary to add another six lanes in a cross-harbour tunnel AND build a railway line too. Talk about a bit of overkill here! Of course, for the rail link to be possible many other projects would also need to occur – like the CBD rail loop, electrification and upgrading the busway to a railway line. But as electrification is already happening, and the CBD rail loop would be necessary anyway, I think it’s only really the cost of upgrading the busway that would essentially need to be added to the cost of the rail tunnel.

Anyway, last year Transit NZ undertook stage two of their study, to come up with a prefered option of the three that had been previously analysed.

This ended up being the following:

The recommended option comprises four tunnels – two for trains and two for the motorway – east of Auckland Harbour Bridge. The Central Motorway Junction on the isthmus would link to the Northern Motorway, while the suburban rail network could in future be extended northward from the Auckland central business district to the North Shore.

Basically, it’s a tunnel version of option 2 above. One area that slightly changed was that the existing Harbour Bridge would not be connected to the Southern Motorway anymore, but rather have all its lanes fed by Wellington Street, Fanshawe Street and Curran Street (northbound). This is further detailed in the image below:

prefered-optionIt certainly seems like a comprehensive solution to the problem of “what to do about the Harbour Bridge issue?” The new roads tunnels would become state highway one, and have three lanes going each way. There would also be two railway tunnels, liking into a newly developed North Shore Line.

Of course, what always comes with a “comprehensive solution” is a very comprehensive price tag – of between $3.7 billion and $4.1 billion. This compared with a price tag of between $1-1.2 billion for a rail tunnel only option. To break it down further – the road tunnel would have a cost of between $2.5 billion and $3.1 billion.

Of course, being individual tunnels you don’t need to build everything at once here – and with such an extremely high price tag I most certainly think that you wouldn’t want to build everything at once. I would, of course, propose building the rail tunnel part of the crossing first and see what effect that has on traffic levels across the harbour bridge. If those levels were sufficiently lowered by the railway tunnel then it may not be necessary to embark on the super-expensive part of the project: the road tunnels.

One other interesting thing that “throws a spanner in the works”, is that the existing harbour bridge has many problems of its own – most particularly with the long-term structural integrity of the clip-ons. A lot of work has gone into these clip-ons over the past few years to make them stronger, but there are certainly some long term issues that cannot be fixed by any method other than removing the existing clip ons completely (presumably it could be done one at a time) and rebuilding them out of stronger and lighter material. It is the structural fragility of the clip-ons that has been NZTA’s justification for not allowing a walking/cycling path across the harbour bridge in the last couple of years, so I don’t doubt that they will need replacing eventually.

I guess the real question that remains for me is whether it will really ever be truly necessary to build the road tunnel component of the proposal shown above. Three billion dollars is an awful lot to sink into a single transportation project – especially when there’s already a road (and potentially a railway line) that serve the connection between the North Shore and the city. Clearly the clip-ons are an issue, although perhaps building the rail tunnel would free up enough capacity on the existing harbour bridge to make it possible for the lanes to be reduced down to 6 while the clip ons are replaced. The other issue would be, over time, whether the eight existing lanes of the harbour bridge plus the railway line would be able to cope with traffic flows.

However, there is a giant assumption that is always being made here – that traffic flows will increase. The data actually seems to show this may not be the case. In 2008 the Harbour Bridge had an AADT (annualised average daily traffic) of 153,324 vehicles. This compared with an AADT of 165,747 in 2007 – a pretty significant decrease. Furthermore, in 2006 the AADT was 166,952 – over 13,000 vehicles per day MORE than what we saw on the Harbour Bridge last year. So, does it really make sense to even consider spending $3 billion on a road tunnel along a corridor with declining traffic flows, when it’s likely you are going to build a much cheaper rail tunnel anyway? I think not – which means Steven Joyce will probably announce it soon.

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7 comments

  1. So what’s the cost turning the current busway into a railway line the cost of both the rail tunnel and rail line would have to be cheaper for you know who to really consider it

  2. Not sure really about a cost of turning the busway into a railway from Esmonde Road to Albany. Probably some mild regrading would suffice until you get north of Tristram Ave, and then I think you might need a tunnel to get underneath the Sunset Road ridge (probably deep enough to go under Constellation Drive too).

    I would say that to hazard a guess you might be looking at about $1 billion to upgrade the busway to a railway line as far as Albany. Which STILL makes it about a billion dollars cheaper than building the road tunnel.

  3. Interesting news. I was hoping (obviously in vain) that once the Waterview connection and Western Ring route were complete, so too would the Auckland motorway network, and Steven Joyce might run out of new roads to build, so money would have to go to public transport. Obviously this, and the northern motorway extension past Warkworth, means we might have to wait a little longer before Steven joyce and the road lobby run out of new roads to build. On the topic of the Western Ring route, once complete it will take further traffic of the harbour bridge reducing the need for this.

    My prefered harbour crossing (asuming Waterview gets built) is to extend the Waterview tunnel through Point Chevalier, and then above ground along a causeway along Meola Reef to Birkenhead, before having the motorway cut through Chelsea, Highbury and Northcote to join up with the Northern motorway near Takapuna.

    This will enhance the Western ring route, by turning it into a true bypass (the SH16/18 route via Te Atatu and Hobsonville is too long), and also quicker provide a North Shore-West Auckland connection. A railway line can then be built over the existing bridge, by turning car lines into railway lines, which will carry less traffic due to the new bridge.

    In this way, we can focus public transport on what it is good at (getting people to the CBD and out of it) and motorways on what they are good at (asuming lots of public transport options, betwen suburbs, as suburb-suburb connections don’t have enough people travelling through them to justify public transport. As my route (bar a short extension of the Waterview tunnel) will be almost full surface (I know you hat demolishing homes and pushing motorways through neighbourhoods) it will be cheaper than any tunnel option.

    I do see the need long term for this (and do see the need for Waterview as well), since even though traffic volumes are declining temporarily population growth over the next 50 years will see traffic grow again, even if we increase public transport use.

    On a second issue, this could make the Victoria park Tunnel redundant. If this is to be best, it could be best to postpone the Victoria Park Tunnel so it can redisinged so the Victoria Park tunnel can be turned into part of this longer tunnel when built.

  4. My prefered harbour crossing (assuming Waterview gets built) is to extend the Waterview tunnel through Point Chevalier, and then above ground along a causeway along Meola Reef to Birkenhead, before having the motorway cut through Chelsea, Highbury and Northcote to join up with the Northern motorway near Takapuna.

    The social and environmental effects of doing that route are so extreme it hasn’t even been contemplated, and for good reason too! It would also be extremely expensive to build that route, as on the North Shore there isn’t a good strategic route to link it into. You’d have to tunnel halfway up the North Shore or something – the costs would run into the tens of billions I imagine.

    A railway line can then be built over the existing bridge, by turning car lines into railway lines, which will carry less traffic due to the new bridge.

    Unfortunately the existing bridge is far too steep for rail. A railway line, quite simply, can never be built on the existing Harbour Bridge. The weight would be too much as well I think.

    The issue with the Victoria Park tunnel is quite interesting – apparently if the proposed harbour road tunnel was built then the VPT would potentially become redundant. Another $430 million about to be wasted on a road? Well, I think not actually, as I can’t see (and I hope not to see) the six lane road tunnel ever built.

    Waterview should most definitely be the last motorway build in the Auckland urban area. Though I still reckon the Waterview Connection is a waste of money that could be spent on the CBD rail loop instead.

  5. “The social and environmental effects of doing that route are so extreme it hasn’t even been contemplated, and for good reason too! It would also be extremely expensive to build that route, as on the North Shore there isn’t a good strategic route to link it into. You’d have to tunnel halfway up the North Shore or something – the costs would run into the tens of billions I imagine.”

    Actually, according to wikipedia, they were going to do it in the 1970s but the NIMBYists got their way. As for the North Shore problem, I do see this as an issue, but houses can be buldoozed down. No need to spend billions on tunnels like Waterview.

    I’m not sure if we need a six lane tunnel (maybe 3-4 lanes) and we definately don’t need one now, but Auckland’s population is growing and could reach 2 million by 2031! (an extra 700 000 in 20 years), which might require this long term.

    I don’t think you, or most Aucklanders have woken up to what this population growth will require. And too little planning has been done on this. I suspect more motorways may still be required, and a lot lot more rail/public transport than we currently have now, perhaps even more than you think of. It is quite easy to imagine the possibility of Auckland region with 2.5 million by 2050 (this is a high estimate but still a possibility), and say Clevedon with 50 000 people e.t.c. Given that people like living a long the coast and near transport links, I consider it likely that much of the new growth will be northwards (up along the coast to orewa, and along the Northern motorway).

    On the growth topic it is vital that Auckland plan ahead for it

    Hopefully the supercity will improve planning for the growth. One important thing is that rail and motorway corriders should be set aside now, based on the needs of the future. Witness the whole area by Howick/flat bush having not only no rail link, but no rail corrider reserved for one. This is what happens when you don’t plan enough for growth. And maybe in 2050 the suburbs might have spread all the way to Clevedon, requiring more transport connections.

    I actually think it is really good how they are planning this, as we will need it someday.

  6. It depends on how Auckland grows in the future. If we grow within particular development nodes then we will certainly be able to provide for movement between those development nodes with public transport. The kind of long-term land-use planning that is coming out of the ARC at the moment is quite good in this respect – limiting greenfields development and general infill development, but instead focusing on significant intensification of town centres and sub-regional centres.

    This will lead to a very differently structured city in the future. One that is far better suited to public transport and does not need such extensive motorway investment.

  7. Why do they need a motorway tunnel when they already have bridge that they can use? Delete the road tunnels project and save money. Including the costs of two motorway tunnels is a “poison pill” that only served to make the costs unpalatable for the package as a whole.

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