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Don’t believe the traffic projections

We have frequently raised concerns about projected future traffic growth, given that in recent years there has been an extended flat-lining of traffic growth. What’s perhaps most concerning about these projections is how they ignore what has actually happened in the recent past and how those producing the projections don’t seem to learn from past mistakes.

This isn’t just an Auckland problem. An article I came across recently looks at projections for a bridge across Lake Washington in Seattle highlights how stubborn the projections of growth are despite evidence to the contrary:

traffic-projections-678What’s crazy about this graph is how persistently wrong the projections have been – yet without any change to reflect the reality of declining traffic volumes over a 15 year period between 1996 and 2011.

Yet it’s not just a specific example of a bridge in one American city where we see these persistently wrong projections coming through. Let’s look at a comparison of official traffic projections across the UK over the past 20 years and compare those with what actually happened:

uk-traffic-projectionsIt’s hard to know whether these repeated mistakes are just accidental, ignorant or wilfully neglectful of reality.

Our own local example of this ignorance is in the traffic projections being used for the stupid Additional Harbour Crossing Project, where modelled traffic growth rates completely ignored recent trends and therefore were calculated from a base that was significantly too high:

This graph was from a year ago and in the past when I’ve posed it, there have been some that say “look it’s starting to rise again” but the reality is it isn’t. The most recent monthly data shows traffic have flat-lined and volumes are still less than it was a decade ago (monthly figures only started in late 2007).

AHB Monthly Traffic Sep 13

Similarly another frequent comment we see when this is discussed is to the effect hat the downturn is only due to the current state of the economy. However many economic indicators are pointing to the economy being much healthier today than it was a few years ago. Other indicators highlight that while on a per capita or percentage basis we might not be doing as well as in the past, on a total basis we are doing well. For example despite the percentage of people who are unemployed being higher than it was in 2007/08, in total there are actually significantly more people employed at the moment.

I suspect traffic projections keep making these mistakes because they are calculated using models with fundamental problems in them. They are generally designed to predict the future based on extrapolating our behaviour from some point in the past. That may have worked in the 90′s (and earlier) but it doesn’t work now and one of the key reasons is that we are seeing generational changes occurring with young people choosing not to drive as much as older generations. Yet while road models might be well over estimating vehicle trips, PT models have been doing the opposite. One of the best examples is Britomart where we exceeded the 2021 projected daily patronage in 2011.

Britomart Projection Numbers Graph

And even the Ministry of Transport in their response to the City Centre Future Access Study said that private vehicle trips were probably being overestimated.

MoT OIA docs - Modelling 1

When there are tens of billions of dollars of public money is riding on these faulty projections, it suggests we need a new approach starting with not believing the current projections.

More bore for your buck!

This post was largely written by good friend of the blog Warren S however I have added some parts too.

Seeing the picture recently of the 14.5 diameter tunnel boring machine to be used in the construction of the Waterview motorway connection started me thinking about the cost of infrastructure and the difference regarding tunnelling for road and tunnelling for rail. Actual costs are hard to come by but certain aspects are evident.

The cost of the Waterview TBM is given as $54 million. I suppose this cost is not great in the overall scheme of things, because the overall cost of this project is roughly $1.4 billion according to the NZTA. The original cost of $54 million will have a residual trade-in value of around $10 million when its Waterview work is done. That is a write-off of some $ 44 million.

Oct 2013 Open Day Alice 3

I then thought I would compare this TBM with the ones they are using in London for Crossrail. They are all made by Herrenknecht though the U.K. ones come from Germany while our one was manufactured in China to the German design.

Right now Crossrail are using eight TBM’s all simultaneously boring away somewhere under London. These machines are less than half the size of what is being used at Waterview at 7.1m in diameter. Being smaller they also come in considerably cheaper at about $20 million compared to the $54 million for our monster. And interestingly with Crossrail 85% of excavated material is being moved by rail or barge – not by road – so eliminates messy roads during construction. Combine this with the fact that there is also less spoil to remove and less concrete needed to make up the tunnel lining and the costs for tunnelling are likely to be significantly cheaper.

Crossrail is scheduled for completion in 2018 with a capacity of 24 trains per hour or roughly one every two to three minutes, that’s similar to what we can expect from the City Rail Link. While we could probably debate all day the merits of what train technologies to use, using our new EMUs an example each train could easily accommodate 750 passengers. At 24 trains per hour that is a capacity of 18,000 people per hour per direction through a rail tunnel. By comparison if we’re lucky the Waterview tunnels – at three lanes wide – will be able to carry about 6,000 vehicles per hour per direction or about 8,000 people if vehicles were carrying a high occupancy rate.

So some of the benefits compared to a motorway sized tunnel are:

  1. Smaller and cheaper TBM to do the job
  2. Less excavation required for rail.
  3. Rail will be more efficient – one line equivalent to two and a half motorway lanes or better.
  4. We are not left with a sole reliance on a motorway system can lead to stagnant chaos and long delays when there is an accident as happens frequently. An efficient metro at least gives us a viable alternative.

Being cheaper and having more capacity definitely raises some questions about how we deal with a future Waitemata Harbour crossing. We have seen traffic volumes on the bridge decline over recent years while at the same time more people than ever catch a bus across the harbour. Further once Waterview has been completed it is likely to take even more pressure off the bridge. At the moment the plans are to build a combined road and rail tunnel which might be similar to below however it is expected to cost roughly $5 billion.

With traffic falling – and potentially continuing to do so – it has removed the congestion/traffic growth argument from the debate and the NZTA have now shifted the discussion with them now saying that a new crossing is needed so the clip-ons can eventually be replaced. The problem is they are being hammered at constantly by heavy trucks (although replacement isn’t needed for some time yet). If the main issue is the clip-ons then we need to be asking if the problem is really worth us spending $5 billion just to avoid having to close two lanes while they are replaced. So what’s the alternative?

A rail tunnel under the harbour.

The idea is fairly simple, we build a much cheaper rail tunnel under the harbour to at least Takapuna, if not further up the busway and linking into the Aotea station on the city side. That provides a massive increase in capacity across the harbour and we use that extra capacity along with other tools like road pricing and demand management to encourage as many people as possible to use the rail services. We then close the clip-on lanes (one side at a time) and replace them.  That could leave us with replaced clip-ons and with rail across to the shore without the astronomical price tag currently associated with the harbour crossing project.


The Waterview motorway connection would appear to be a high cost ‘gold-plated’ project but it is the last link in that chain. After that I believe we have a strong chance of achieving long term value for Auckland with the CRL and ultimately a rail tunnel link to the North Shore.

Learning from San Francisco

I was looking at the herald this morning and I came across this piece titled Troubled bridge over San Fran waters by the Herald on Sunday sports editor who is currently in San Francisco covering the America’s Cup.

Take a look at the Auckland Harbour Bridge. Now imagine a part of it gone after an earthquake. Then think about US$6.4 billion and 24 years spent repairing it.

That’s what San Franciscans have endured since the 1989 earthquake when the Bay Bridge (actually two bridges) suffered the collapse of part of the eastern span connecting San Francisco to Oakland.

Now the news has come in that the re-built bridge will open on September 3, Labour Weekend in the US, after being closed for five days to prepare the new bridge for traffic. It’s not clear what sort of traffic chaos will apply during that period – the bridge routinely accommodates 280,000 vehicles a day.

Nor is it clear whether that will have any effect on America’s Cup fans trying to get to the action as the yachts duke it out on San Francisco Bay, near the bridge.

But what is clear is that bridge is finally opening, after 24 years of delays and budget blow-outs, with only a temporary fix. Three independent authorities have certified that the bridge will be safe with a temporary solution to the earthquake safety bolts which cracked as they were being tightened recently.

That was expected to delay the bridge opening even further – even stretching beyond State Senator Mark DeSaulnier’s complaint that the bridge was “10 years late and US$5billion over budget”.

But now permanent repairs – able to be done while the bridge is open and taking until December – will not delay the opening, though there will be more than one motorist wondering just how safe his morning drive to work really is.

This has relevance to Auckland for two reasons: When you drive on the Harbour Bridge, drive softly. No one needs 24 years and US$6.4 billion of frustration. At that rate, Auckland’s rates will be worth more than the houses.

Secondly, memo to Mayor Len Brown or whoever ends up organising a second crossing. Please give us, the ratepayers, an accurate idea of time and cost. Being 10 years late and 500 per cent over budget doesn’t bear thinking about…

Now I agree that single best reason for an additional harbour crossing – remember we already have a second one in the upper harbour – is to provide resilience in the situation where the bridge is damaged or being upgraded. The herald writer makes it appear that the bridge has been out of action for 24 years but that is simply untrue so let’s look at the story in a bit more detail.

The bridge was opened in 1936 and as mentioned is actually two separate bridges. The first from San Francisco to Yerba Buena Island where it tunnels through the hill before continuing across to Oakland. The bridge has two decks for vehicles, one in each direction and is 5 lanes wide – although when originally built the lower deck was for trucks and trains but the tracks were ripped out in the 1960′s. As mentioned in the Herald piece, it carries a lot of traffic and connects right into the heart of San Francisco so like our harbour bridge is a key piece of infrastructure. In the 1989 earthquake it was damaged with one section collapsing however importantly engineers had the bridge fixed working again within a month.

As mentioned the writer makes it sound like the eastern bridge has been under repair for 24 years but this isn’t the case. The bridge is being replaced by a new version that is being built alongside the existing bridge, much like we saw when the Newmarket viaduct was replaced. Sometimes that means the existing bridge needs to be closed to enable the various changes related to construction to happen. We would see the same thing happen if we built a new harbour crossing as we would still need to connect it into the existing system somehow.

But the interesting thing is how the city copes with such a key bridge being out of action for a long period of time. Sure vehicles can divert to one of the other bridges but that introduces a fairly length detour and one that is much longer than equivalent detour in Auckland via the upper harbour. In that situation I also imagine that the other routes become pretty busy so while it might get you to your destination, it might not be fast. So how did the San Fran area cope both immediately after the 1989 quake and during the shut downs for repair and replacement of the existing bridge. Well there was of one mode of transport that was completely unaffected and able to move huge amounts of people, the Bay Area Rapid Transit system, otherwise known as BART.

The system was opened in 1972 and like the Bay bridge connects the suburbs on the eastern side of the bay with San Francisco itself. It does this in a pair of tunnels under the harbour and through the city and actually travels under the western span of the bay bridge. Since it opened it has been extended to the network it is today and which includes a connection into the San Francisco International Airport. Further expansion is already under way or being planned.

Importantly in the aftermath of the quake and during closures of the bay bridge people have flocked to use the network as a means of getting across the bay however perhaps even more importantly while some people would have gone back to driving, a lot of people kept using the system and patronage has continued to expand.

San Fran BART patronage

But perhaps the most important point and the one most relevant to Auckland in all of this is that San Francisco has an alternative. While the closures to the bay bridge have obviously been a pain for residents, there has at least been another option that has the capacity to handle a lot of extra people. Even if there was another road based crossing, if something went wrong it would immediately be clogged up with all of the diverted traffic. Buses would provide no respite as would be stuck along with the rest of the vehicles. If one of the key reasons to create another harbour crossing is to provide resilience to the network in case something goes wrong then the absolute best thing we could do is to build that crossing as a mode that is not affected by the traffic mayhem that would ensue from a problem with the bridge. It would also need to be one that has the capacity to suddenly handle a lot more people.

This is one of the reasons we propose building a rail only crossing as part of the Congestion Free Network. In the future if demand eventually exists we could then look at another road based crossing but for now the focus should be on completing the missing modes and providing some real alternatives.

What else will the Government announce? the Good, the Bad and the Ugly

In announcing that the government was finally going to come to the party and support the CRL, John Key has also made it clear that the project is going to be just one part of an overall package of transport projects in the city. We will have to wait till tomorrow to find out exactly what they are but I thought I would look at some of the most likely candidates.

The Good: 

The best outcome from my perspective would be a package of PT projects perhaps including rail to the airport, rail to the shore and some busways. Perhaps something like below. It might be unlikely but one can dream can’t they?

Possible System

The Bad:

Perhaps the most likely announcement is something to do with the East-West Link. John Key is announcing the transport package at the Auckland Chamber of Commerce and this project has been one of their key ones. The project would see new roads built and existing ones upgraded to create new links between either Onehunga or Mangere and Highbrook.  The option that has been talked about the most in the past has tended to be option 3 which is a brand new road (new roads in black, upgraded roads in red)

East-West Option 3


Personally I think that there is definitely a need to improve transport in this area but most of what is suggested seems like a solution in search of a problem.

The Ugly:

There are two potential projects that would fall into this category.

The Eastern Highway - Gerry Brownlee breathed new life into this project back at the end of April with the way he answered a question from John Campbell. Back then I made this observation:

At first I thought it was really odd the way that Brownlee talked about AMETI and whether that would happen as it is well under way and he has even visited the construction site. Re-watching the video, it then becomes clear that he is talking about a reviving of the eastern motorway. Did Brownlee just let slip that the government is now considering building it? It would certainly fit in with some whispers I have heard.

Bringing back the Eastern Highway would be a massive change in transport policy as it doesn’t exist on any of our current planning documents, although there is still a designation for it.


Additional Waitemata Harbour Crossing (AWHC) – After the East-West Link this is probably the next most likely transport project to get a nod from the government. It would definitely be popular with many people on the North Shore but the reality is it is a really really stupid project. For starters it adds a huge amount of capacity across the harbour making it easier to drive and potentially putting a lot more cars onto our city streets, right at a time when we are trying to reduce the number in the city.


The most recent business case found that a road tunnel under the harbour would cost around $5 billion and have a benefit to cost ratio of 0.2, in other words for every $1 invested we would only get 20c back. What’s more that was on the back of some very dodgy traffic growth figures. The business case assumed growth would continue at the same rate it historically has but didn’t take into account the fact that traffic volumes had fallen substantially in recent years. Even if growth returned to the level it was previously, which is unlikely given the trends we are seeing elsewhere, the need for a new crossing has been pushed back almost indefinitely.


Are there any other projects that you think will be tacked on to the CRL?

How to link North Shore rail into the network?

There seems to be growing interest rail to the North Shore, perhaps mainly driven by the fact that one of the project’s biggest benefits would be putting off spending $5 billion on the stupidest transport project ever, another motorway crossing of the Waitemata Harbour. However there still seems to be relatively little discussion and agreement over how it might link in with the rest of the rail network. The Integrated Transport Programme costed the rail crossing at around $1 billion, but seemed to show it finishing tantalisingly close to the rail network at Wynyard, but not actually linking in (suggesting that NZTA and Auckland Transport have included it for show more than serious consideration) or perhaps it’s just hidden behind the words “city centre”.itp-rail-crossingThe Auckland Plan was a bit more definitive, showing that North Shore rail should link into the rail system at Aotea Station:cityconnection-awhc-aucklandplanPresumably Aotea Station’s is being future-proofed for a connection to a future North Shore Line in its design (something to submit on in regards to the City Rail Link notice of requirement). Previous options of connecting in at Britomart seem to have been abandoned – most probably because Aotea is more central and it’s not possible anyway to hook the North Shore line into the CRL as you’d end up with far too many conflicting train movements. Patrick outlined in a post a few months back how an extended Aotea Station might work to serve both the CRL and the North Shore Line. A further station would obviously be provided at Wynyard Quarter.

But what next? Should the railway line just be an independent line (maybe Vancouver Skytrain style light-metro to keep Peter M happy?) or could it link through to the Southern or Eastern Lines? Exploring each option further highlights advantages and disadvantages for every option, and perhaps not a particularly obvious preferred candidate.

Starting off with linking it through to the Southern Line, which would most easily be done by continuing the tunnel under Wellesley Street, probably bridging over Grafton Gully and then linking in with the Southern Line just north of Parnell. Something like this:northshore-south-closeThe line could then extend to either the Airport or to the Southern Line, or conceivably both (especially if on the North Shore you had one service pattern commencing at Takapuna and another commencing at Albany). The end result of this approach is probably something similar to what Matt and Patrick developed last year – known as “the cross”:Advantages of this approach include the creation of a pretty legible and easily understood network – basically a north-south line and an east-west line, with a few variations and branches further out. You get a direct link from the North Shore to the Airport, you provide a heap of capacity to the city centre by running the two lines completely independent of each other and you remove the need to use that slow bit of the rail network around Vector Arena. Disadvantages perhaps include the enormous strain on Aotea Station as the transfer station between the two main lines, the requirement that North Shore rail be built to heavy rail standard (rather than the likely much cheaper Light Metro). It also effectively requires the construction of a second CRL – this time in an east-west direction. As we’re struggling to find the funding for the first CRL it does appear slightly premature to be planning what’s effectively a second, somewhat similar, tunnel.

The next option is to look at linking the North Shore Line up with the Eastern Line, via a route that takes a little bit of imagination but isn’t too impossible – leading to something like this:northshore-east-close
Once again this option appears to have a number of advantages and disadvantages. Advantages include perhaps a slightly shorter and simpler link with the rail network that doesn’t involve bridging Grafton Gully and perhaps utilises some of the trackwork at the old Auckland Railway Station area to link into the Eastern Line. Trains heading further east could travel on to either Manukau via the existing Eastern Line or to Botany (or beyond?) via a new southeast line (as previously discussed here). Splitting the trains across two destinations in the east would balance well with trains originating at Takapuna and Albany on the North Shore – creating something like this:

  • Albany-Manukau via City Centre, Panmure and Otahuhu
  • Takapuna-Manukau via City Centre, Glen Innes and Highland Park
  • Swanson to Papakura/Pukekohe via CRL, Newmarket and Southern Line
  • Mt Roskill to Airport via CRL, Newmarket and Penrose

Mapped it looks something like this:ns-rail-optionsNow before you go and yell at me for being too city centre focused I’m not necessarily suggesting that what’s shown above is Auckland’s ideal future rail network, but rather that it’s one way of showing how a North Shore Line could be “linked in” with Auckland’s existing rail network.

The big flaw with both “the cross” option and the one shown above is that they leave no role for Grafton Station, other than potentially on some sort of shuttle between Newmarket and Kingsland (would have to be Kingland now the Inner West Interchange station is gone). Both options also require significant expense east of Aotea Station to “link” the tracks coming into the city from the west with either the Southern or Eastern lines at Parnell or a bit north of that at the old railway station. Both options also seem to relegate the role of the City Rail Link by pulling either Southern Line or Eastern Line trains out of the tunnel and effectively giving both lines only one city centre station (plus Wynyard). Finally, both options also require the North Shore Line to be built as heavy rail, which is likely to be quite a bit more expensive than a light-metro option – although still barely half the cost of a road crossing of the Harbour.

The final option is to just terminate the trains at Aotea Station – running trains from both Albany and Takapuna to Aotea and then back again. This option is completely independent of the existing rail network:shore-aoteaAdvantages include relatively low cost (compared to other options), the potential to do driverless light-metro and the fact that the rest of the rail network’s balance isn’t stuffed up in the ways that caused problems with the other options (such as it being difficult to serve Grafton Station). Disadvantages include quite a lot more transfers, creating another independent system and the challenges with where you’d maintain the train fleet.

As I noted at the start of my post, there’s no clear winner when it comes to options to connect North Shore Rail into the existing system – but there sure are a whole heap of interesting options. Which is your favourite? Why? Have I missed another option or two that might work even better?

“Skypath” across harbour to become a reality?

Allowing people to walk or cycle across the harbour bridge is an aspiration that has been a long time coming. When the harbour bridge was originally proposed it included walkways, like Sydney’s harbour bridge, but the government of the time was concerned about ballooning costs and in the end all we ended up with was a four lane traffic bridge. Then when the clip-ons were added in the late 1960s we ended up with an eight lane harbour bridge but once again no ability to walk or cycle across the Waitemata Harbour.

While in recent times there have been concerted efforts to push for a walk/cycle connection across the harbour, I must say that most of the time I thought it was more aspirational than having a real chance. Particularly as NZTA continue to have a measly budget for walking and cycling projects in Auckland. However, a report to Wednesday’s Transport Committee meeting suggests that there’s actually a feasible and viable plan for making this project become a reality – a plan which doesn’t have to cost ratepayers and taxpayers a single cent: it only requires a commitment in terms of taking on revenue risk liability.

The report begins by outlining updates to the project since it was last brought to the Committee’s attention – back in August 2011. The updates are:

  • The AHB Pathway Trust (the Trust) has developed a lighter structure by using aluminium in the central span;
  • Auckland Transport (AT) has undertaken a review of the SkyPath’s business case and referred it back to the Council to consider funding sources;
  • A range of capital costs for the project has been identified between $28 and $41 million.
  • There is still uncertainty about the capital costs, however for the purpose of the financial analysis in this report a cost of $31 million has been assumed (as outlined in paragraph k) in Attachment A);
  • Update of information in the Trust’s business case and public private partnership (PPP) proposal;
  • Comparison of the SkyPath to the rest of the transport and cycling and walking programme;
  • Quantification of the Council’s contribution to the SkyPath; and
  • Initial identification of project risks (outlined below in paragraph 20).

Oh, and the Trust also created a pretty cool image of what the Skypath could look like at Christmas time:skypath-imageAs I understand it, the proposal for constructing the project is through a PPP between the public agencies involved (Auckland Council, Auckland Transport & NZTA) and what’s referred to as the “PIP Fund” – a private company willing to take on the 25% highest level of revenue risk and to fund the project up front. Payments for crossing the bridge – in the form of a HOP Card or cash – would raise the revenue required to cover capital repayments for the project and operating costs.

Here’s the proposed toll levels:ahb-pathway-tollWhile the report goes to painful lengths to note that this is just the beginning of the process for making the project a reality – in terms of getting official Council support and for Council to take on the revenue risk of the project (not to mention the possible long term requirement for maintaining the structure) – this is a really exciting step forward. And while the PPP structure isn’t perfect (why should we pay a toll to walk across the bridge when we don’t have to pay one to drive across it) I think it’s highly likely in the future that things will change and perhaps NZTA will realise it’s a transport agency rather than just a roading agency – and they’ll take on ownership and responsibility for the structure.

Plus the case for the project is pretty compelling – particularly if all logic and sense tells us that an Additional Waitemata Harbour Crossing (in motorway form at least) should be a lot more than 20 years away. In a nutshell, the report makes a really good argument for the suggested approach:reasons-for-pathwayI sincerely hope that at Wednesday’s meeting the Transport Committee at least gives this approach a go. I think that not only would the pathway be a great transport connection and tourist attraction – but I also can think of it as an incredibly fun thing to wander across on a sunny summer’s day.

Here is a Cycling Auckland’s call for support for the project [thanks Max]:

North Shore Rail and the Harbour Crossing

Someone at the Herald must have let John Roughan back at the typewriter because today’s editorial on another harbour crossing appears to have his fingerprints all over it.

No one seems to doubt Auckland will need another harbour crossing to the North Shore within a generation. The chances of it being another bridge are dwindling but plans for a tunnel under the Waitemata are cautiously being progressed. Too cautiously, in the view of former North Shore mayor and current Auckland Council member George Wood. He has half a point.

Mr Wood believes transport planners ought to be engaging now with community groups as they move to protect a likely route for a tunnel or tunnels east of the harbour bridge. The Auckland Council 30-year plan favours the tunnel option with provision for a rail line to future-proof its capacity. Since that plan’s publication, the Transport Agency has said it would base any application to the council next year for route protection on that premise, despite its judgment that no crossing would be required until 2030.

So it starts out innocently enough and was obviously driven by the article last week where the NZTA confirmed there was no immediate need for another crossing. I’ll start by saying that I think a new crossing will be needed at some point, just not one for cars but I will talk more about that shortly. It then goes on to talk for a bit about how Georges fears of the project being left to drift are probably not needed as the NZTA has proven that they are able to get big projects pushed through both consenting and construction phases. But it is after this that things go down hill pretty quickly suggesting that the biggest threat to the project is the talk of future proofing it for a rail line.

The bigger threat to timing or funding for a tunnel might be any requirement that it include rail, even if it is only on paper to “future-proof” the project. The rail option would work only if the tunnel project was preceded by Auckland mayor Len Brown’s push for a CBD rail link, the multi-billion-dollar tunnel pushing through Britomart station and up-town to Mt Eden. In current conditions it is unlikely both can be funded in the next decade or two even if Auckland ratepayers and motorists accept high tolling and regional charges to carry much of the burden themselves.

Aucklanders and their elected leaders need to prioritise these projects and de-couple them so that at least one is digestible. Development and liveability of the North Shore could well be harmed if the second crossing is tied to the more politically controversial CBD rail link and delayed. The National-led Government believes no such rail link is justified for 30 years: the Auckland Council sees it as a cornerstone for the city’s transport, housing and economic progress.

Which is the more efficient and vital recipient of the nation’s economic resources? The case is clear for a harbour crossing, only timing is in dispute. The case for the CBD rail link is persuasive but unconvincing, a costly, nice-to-have project which in theory would relieve traffic congestion and alter residential development.

Does the North Shore want or need rail in any case? The Northern Busway has been a successful public transport option and would presumably be more effective if the harbour bridge is decongested by a parallel road tunnel.

About the only think I agree with is that it is unlikely both can realistically be funded in the next two decades and that we need to prioritise both our funds and focus on the one that will have the most impact. To even suggest that the most important project is another harbour crossing is the most important is laughable. For starters it is a duplication of a route that already exists and who’s only purpose is to increase capacity to allow more people to drive to the city centre, flooding it with cars when we are trying to make it a more pedestrian friendly place. The CCFAS also confirms that it is expected to absolutely destroy patronage on the busway undermining the investment made in it so far. The CRL by comparison provides a new route that speeds up trips to the city centre without putting any extra cars on the road and that helps to maximise the otherwise underutilised rail corridors. At $2.2 billion all up including things like new trains, it is also considerably cheaper than $5.3 billion harbour tunnel which is the one that more and more looks like “a costly, nice to have project”.

Lets also not forget that due to the sheer cost of another crossing both the new and existing routes would need to be tolled with estimations from a few years ago suggesting that $8 per crossing would be needed.

North Shore Tunnel Connection to CRL

On the topic of rail to the North Shore, there was a bit of a discussion last night on how the CRL designation docs don’t make any mention of how a North Shore line integrate with the CRL. A couple of years ago the plan was to also put the trains through Britomart with a junction under the downtown mall however thankfully that has now changed. My understanding is that the more detailed designs for the Aotea station include the provision for a connection to platforms that would be under Wellesley St. As that would be under a road anyway, it would probably only serve to complicate things with the designation so as long as the station is designed and built in a way that enables it to happen in the future, there is likely no point addressing it now (although it would be nice if AT were to officially confirm this).

NZTA confirms that another harbour crossing not needed soon

Over the last few months we have done quite a number of posts looking at the issues of a potential new harbour crossing and I think that it may have started to frustrate some from the North Shore. particularly councillor George Wood. He has became much more vocal on the issue though social media and calling for the bridge to be built as soon as possible. Well it seems that it has attracted the attention of the Herald who ran a piece today about it that has provided some useful information about the need for the project. I did have a little laugh right at the start as one of the things I had questioned earlier in the year was if there would be any North Shore politicians who would actually stand on a platform of not building another road crossing

North Shore leaders will this year ramp up calls for a new Waitemata Harbour traffic crossing, even though the Transport Agency does not believe one will be needed before 2030.

Although the agency expects to update an application to protect a preferred route for tunnels under the harbour towards the end of the year, Auckland Council member and former North Shore mayor George Wood fears complacency setting in.

He says community groups such as the Northcote Residents Association want to be involved in planning for a new crossing but are being kept in the dark about a proposal which follows at least six studies since 1986 and doubt about the longevity of the existing harbour bridge.

Arguing for the bridge on the grounds that it is old and could fall apart seems to have been a mainstay argument for those that want a new road crossing and helpfully the NZTA have addressed this.

Having recently spent $86 million strengthening the bridge’s two clip-on structures, the agency is focused mainly on its ability to cope with increasing freight loads.

Mr Town said that with careful management, there was no reason why the 54-year-old bridge could not last for another 100 years. But he said the “critical path” for bridge loads was heavy vehicles travelling on the northbound clip-on lanes, for which forecasts indicated a new crossing would be needed by 2030.

Even so, the agency did not want to build the new crossing too early, for cost reasons.

“It’s expensive, so getting the timing right is the thing,” he said.

The agency in early 2011 estimated the cost of a pair of road tunnels at $5.3 billion compared with $3.9 billion for a new bridge, and the Auckland Plan cites a figure of $5.8 billion to include future provision for trains.

Mr Town acknowledged that technological advances were likely to reduce tunnelling costs, while those for a new bridge were unlikely to fall markedly.

But he said “one of the big unknowns” was what the completion in 2017 of the western ring route with its connection to the Upper Harbour Bridge at Greenhithe would do for heavy traffic movements.

“It will provide a genuine heavy traffic option – between 2017 and 2021 we will be looking really closely at travel patterns.”

So the bridge is obviously fairly structurally sound and the issue then becomes a question of when the clip-ons need replacing. The NZTA seems to admit that it will depend a lot on what happens after the completion of the Western Ring Route. You may also recall that we found that the traffic predictions that had been used in the previous business case used incorrect data so it is quite possible that combined with the WRR this could see the need for replacing the bridge pushed out a lot longer than 2030.


Traffic volumes predicted in the AWHC business case vs actual

The other major issue with a new crossing would be the impact on the city centre. The current thinking is for the new crossing to link directly into the existing motorway system and to turn the harbour bridge into a kind of big off ramp. By taking the through traffic off the bridge, it would leave a hell of a lot of unused capacity on there which would have the effect of making it easier to drive to the city. That would severely impact not only the performance of the Northern busway but would see potentially thousands more cars per hour dumped into the city centre when all of the councils plans are focused on trying to reduce vehicle numbers that area.

So far everything seems to point to the conclusion that we are both unlikely to need the crossing for at least a few decades and that even then we might not want it due to the impact it would have on the rest of the city. That kind of brings me back to my question from earlier in the year and wonder when will we get a politician who is brave will actually stand up and say this to the residents of the North Shore?

I think the other thing worth pointing out from this article is it confirms that the NZTA are now looking at a combined road and rail tunnel like has been done in some places overseas. In this situation the tunnel diameter is big enough that a train line can be run below the road deck as shown below. If we must have a new road crossing then it does make sense to do it this way and it is interesting to see the NZTA say that the tunnelling costs are likely to reduce as the technology improves. My preference at this stage however would be for a dedicated and much cheaper rail tunnel first and to only build the road crossing if it is still needed after that (the business case costed a rail tunnel at $1.6b vs $5.3b for a road tunnel).

The same tunnel with a Bombardier ART light metro train under the road deck.

CCFAS and the Additional Harbour Crossing

Along with making a fairly compelling case for the City Rail Link project, the City Centre Future Access Study (CCFAS) also provides some interesting information on my least favourite transport project: the Additional Waitemata Harbour Crossing (AWHC). For some unknown reason the AWHC made it into the “balanced reference case” (otherwise known as the “no CRL option”) for 2041, which means that its impact on the transport network made it into the modelling analysis. This provides us with some interesting information.

Firstly, a reminder of what the AWHC project proposes: which is effectively a new tunnel from the Esmonde Road interchange to the city with that new tunnel becoming SH1 and carrying the through traffic. This enables the existing harbour bridge to be dedicated to CBD-bound traffic or traffic using the Ponsonby (Curran & Shelly Beach Road) ramps. This is illustrated in the diagram below:My ultimate criticism of the project (besides it being unnecessary and hugely expensive) is that the only thing it really does is provide more capacity for cars driving to the CBD, when in fact all the plans and strategies for the CBD’s future are dependent upon reducing its car focus and making it a more people-focused place.

Looking at the 2021 modelling results (before AWHC) we can see that quite a bit of the motorway network is near capacity during the peak (orange) but relatively little is beyond capacity. This probably shows the impact of the Waterview Connection project easing some pressure on SH1. Take particular notice of the Harbour Bridge, which is shown in orange in both directions, showing that it’s between 80% and 100% of capacity during the peak – so fairly effectively utilised:2021-trafficNow let’s zip forwards to 2041 with the AWHC in place. You can see that the new crossing basically performs the same in 2041 as the existing harbour bridge does in 2021 – which effectively is to say that for through traffic there’s pretty much no benefit whatsoever from building AWHC. What does clearly change though is the level of utilisation of the existing harbour bri2041-trafficdge for inbound traffic, which is significantly decongested – making it easier for people to drive from the North Shore into the city. How much easier? Well there’s another chart illustrating that it’ll quite a bit faster:car-travel-comparisonCCFAS talks about this outcome as being very good, and an illustration of why the CRL is needed to ‘complement’ the AWHC project, but to be honest the diagram above is a disaster in terms of the kind of city centre we want. At the moment there is a very strong public transport mode share from the North Shore to the city centre at peak times (my estimates are probably around 60-70% of those trips are by PT), because the busway and the ferry system give public transport a comparative advantage over driving that’s relatively unusual throughout Auckland. The AWHC would destroy that advantage, make driving more attractive and as a result likely flood the city with cars while undermining our investment in the Northern Busway (and certainly killing any prospect for future North Shore rail).

So I ask again, why spend $5 billion to flood the city centre with cars?

Why AWHC is the stupidest transport project ever

In the fallout from the release of the City Centre Future Access Study last Thursday and the government’s rather bizarre response to it, for some reason there seems to have been renewed discussion about the Additional Waitemata Harbour Crossing (AWHC) project. It’s a bit odd to think that if Central Government has concerns about contributing to a $2.4 billion project they’d end up looking more kindly on a $5 billion project instead, but I guess as it’s a road rather than a railway line you really never know.

We’ve discussed the AWHC project on this blog many times before, most particularly recently pointing out some incredibly dodgy traffic statistics used by NZTA to help justify the project. In this post I’m not really going to focus on the cost of the project, or the heroic traffic growth assumptions or even why a rail crossing is a much more sensible option. What I’m going to simply look at is the likely traffic effects of the additional crossing – where it does and does not add capacity to the system and what the impacts of that are likely to be. There’s a wealth of information on the project website, which I will draw on to inform this. For a start, let’s just get a rough idea about what the AWHC project is – something that’s reasonably well illustrated in the diagram below:awhc-connectionsIt’s a little complicated with all the different colours, but let’s just think about what happens for southbound traffic:

  • Traffic heading to Shelly Beach Road, Fanshawe Street and Cook Street uses the existing Harbour Bridge
  • Traffic heading to SH16 west and SH16 port exits uses the new tunnel
  • Traffic continuing south on SH1 uses the new tunnel

The same is obviously also true in reverse. Oh an by the way I wouldn’t get too excited about the rail tunnel shown above – the fact that a shuttle line from Gaunt Street to Akoranga is shown, with no connections to the existing or proposed rail network at the city end, just illustrates that it’s only in there as a token gesture.

At the moment in the morning peak there are five lanes southbound coming over the harbour bridge. The Shelly Beach Road offramp peels off but the five lanes remain through St Mary’s Bay. Then one lane drops off at Fanshawe Street and four lanes continue southbound over the Victoria Park viaduct: two of those feeding into Cook Street and the SH16 exits and the other two linking with the Southern Motorway for trips heading further south. Ignoring the city exits (Shelly Beach, Fanshawe and Cook Street) for a minute, it’s clear that there are four lanes that link the Harbour Bridge through to SH16 (for east and west travel) and SH1 for travel further south. Here’s a diagram showing the future layout of the motorway network with the AWHC built:lane-diagram
It’s a bit confusing at first, but once you ignore the local roads it starts to make a little more sense. We can see that southbound in the morning peak there would be three lanes in the new tunnel and four lanes (one of which is a bus lane by the look of it) coming over the harbour bridge. The new tunnel effectively removes ‘through traffic’ from the Harbour Bridge, but doesn’t actually add any capacity over what already exists for that through traffic.

  • There’s still only two lanes which continue right through for southbound traffic.
  • There are only three lanes (compared to the current four) for traffic heading to either SH1 southbound or the SH16 exits.

What the new road does do, of course, is free up huge amounts of new roadspace for vehicles travelling from the North Shore to the CBD. There are now four southbound lanes over the harbour bridge worth of capacity – all of which can only link to Shelly Beach Road, Fanshawe Street or Cook Street. That’s potentially an absolute flood of additional vehicles that could be funneled into central Auckland because they no longer need to ‘compete’ with the through traffic for roadspace over the Harbour Bridge.

This impact is well documented in the project’s Local Roads report:

The main challenge for this assessment relates to the provision of additional capacity across the harbour and the potential flow on effects this may have on the local road network around central Auckland and feeder roads on the North Shore, particularly in the weekday morning peak. In particular it is noted that the new harbour crossing will allow more traffic to enter the CBD. This conflicts with various CBD strategies that encourage the provision of public transport for trips to/from the CBD and not to provide additional capacity for cars.

It fundamentally conflicts with the concept of a liveable city centre.

It is anticipated that space on the existing Harbour Bridge will be allocated to public transport, walking and cycling, if an Additional Waitemata Harbour Crossing is provided. The precise lane configuration on the existing Harbour Bridge will only be determined over time and this will significantly affect the predicted traffic effects of the additional crossing. The scenario agreed for this study (for both bridge and tunnel options) includes the following lane allocation on the existing bridge:

  • One lane for walking and cycling;
  • A bus lane in each direction, but with general traffic heading to the Shelly Beach off ramp sharing the southbound bus lane; and
  • Five general traffic lanes in total, assumed to operate with three southbound and two northbound lanes in the weekday morning peak, with the reverse in the evening peak.

This scenario would provide three southbound lanes for general in the weekday morning peak plus additional capacity, equivalent to around half a lane, for general traffic heading to the Shelly Beach off ramp. This scenario also provides the opportunity for a significant increase in the rate of flow from Esmonde Road (and Akoranga Drive) onto the Northern Motorway, thereby increasing the rate of flow able to cross the Harbour and reaching the Auckland CBD.

It’s hard to know whether to laugh or cry about the fact that even after spending $5 billion NZTA still can’t bring itself to providing a proper dedicated southbound bus lane. The important thing to note from the above paragraphs though is at the very end: the real impact of the project is a massive increase in flows from the North Shore into the CBD. As no additional capacity is provided south of the CBD the are few gains there aside from being able to hit the gridlock through spaghetti junction a bit quicker because vehicles travelling through the tunnel no longer need to compete for roadspace with those heading for the CBD.

It seems as though the report writers began to realise this fundamental flaw with the project and therefore ended up recommending retaining some measures to limit the flow of vehicles onto the motorway from the North Shore:

A range of options could be used to limit the rate of flow able to cross the Harbour, including changes in the lane allocation. However, for the purposes of this assessment it has been agreed that the effects of the additional crossing will be assumed to be restricted by some means and that this should be reflected by modelling ramp signals on the important Esmonde Road southbound on ramp. Capacity constraints are already predicted to exist on the approaches to or on the other on ramps during the morning peak, and providing ramp signals at Esmonde Road will therefore further constrain the rate of flow able to pass across the harbour and into the Auckland CBD.

So we’ll spend $5 billion on adding a huge amount of capacity across the Waitemata Harbour but we’ll still need to use things like ramp signals to limit the flow of vehicles onto the motorway – doesn’t that kind of defeat the purpose of the whole project?

The impact of the project on some city streets is pretty massive in terms of additional vehicles – especially Fanshawe Street and Cook Street (Curran Street and Shelly Beach Road, two residential streets, get slammed as well):local-road-volumesTo cut what is becoming a pretty long story short, it really does seem as though the AWHC project involves spending $5 billion to make it easier to drive your car into the city centre – something we actually don’t want you to do. In other words, it is building the most expensive transport project ever to create more congested inner city streets and a less liveable city centre. It’s a huge amount of money on something that will make Auckland a far far worse city.

For that reason, it is quite simply the stupidest transport project ever.