This is a guest post from Nick R

The great irony of urban motorways is that they use up huge amounts of the very thing they are intended to access: land.

All surface transport infrastructure naturally consumes land. However, while a street, busway or railway fits in a corridor 10 to 20m wide, even a small motorway corridor is at least five times as wide. And motorways can easily stretch to 200m wide across at interchanges. In addition to using up land, the negative effects of noise and severance extend well beyond the corridor itself. This obviously affects properties that are adjacent to main roads and railways, but with the scale of motorways they keep lowering amenity and land values for hundreds of metres either side. The only way to really avoid this sort of impact is to go underground, a very expensive proposition for any transport and especially expensive for large scale motorways and interchanges.

Nowhere is this consumption of valuable land more visible than at Spaghetti Junction in central Auckland, where hundreds of homes and entire neighborhoods were demolished and excavated to build the central motorway junction (CMJ). This impact is so visible and obvious its not surprising that Greater Auckland and its predecessors have covered the topic many times.

Time for a quick trip into history. Early motorway plans actually avoided the city and focused on the northwestern corridor as the main state highway running northward around the upper harbour.  But there were a few main reasons that the network was quickly changed to run right through town and carve up the inner suburbs:

  • Harbour bridge tolls. Initially the harbour bridge was only conceived as an arterial between the North Shore and central Auckland, analogous to the widening of Great South Road in the other direction that was happening at the time. However in the late 50s there was very real concern that the planned motorway via Hobsonville and Paremoremo would take all the traffic off the brand new harbour bridge, killing off the toll revenue that was needed to pay for the thing. So the decision was made to delay the upper harbour route by decades and make the harbour bridge the main regional motorway north, which required a big motorway interchange nearby. Obviously the traffic generating effects of motorway building and related sprawl development wasn’t well understood at the time.
  • Slum clearances. At the time the demolition of old housing stock in the then undesirable city fringe was seen as a good thing. In hindsight this goal has failed twofold: in the short term this depressed land values even further around Newtown, Grafton and Freemans Bay and converting Karangahape Road, practically overnight, from a prestigious uptown shopping strip lined with department stores and fashion boutiques to a sleezy red light district. In the long term we’ve seen the remaining slum suburbs around the city fringe rocket to the most valuable land in the country, and people re-realised the value of walkable griddy neighborhoods of compact housing in close proximity to the city.
  • Motorway access to revive the city. Somewhat paradoxically, bringing the motorways into the central city were thought essential to revive it, once the suburbanizing dispersal pressure of the motorways themselves and the related building demolitions to widen city centre streets and create more parking took hold. It’s debatable whether motorway access to downtown helped mitigate these impacts, or if it made them worse.
  • And finally something I call the Brave New World factor, a sort of optimism bias that big new revolutionary plans must be good because they are big, new and revolutionary. How could the plan fail if it was so magnificent?

With decades of retrospect, this all looks decidedly fishy, sociopathic even. You can look with bewilderment at the ‘what might have been’ plans for motorways pushed through central London, Paris and Manhattan… but then realise we actually did this in our city.

So what to do about it? Well the answer that tends to come up is to deck over the junction to effectively bury it, and build in the city back on top. This has an obvious appeal, there are plenty of underground motorways and railways around the world. They’re pretty normal even. One interesting thing is that motorways tend to be built as tunnels to begin with and not covered over, while rail yards seem to get decked over quite frequently, for example Federation Square in Melbourne, the downtown yards in Chicago, or indeed parts of our own Britomart.

I used to think that the motorways were threaded through the gullies around central Auckland because they were convenient depressions below road level to route them through. However, apart from some parts of Grafton Gully around the bridge this wasn’t actually the case. The main Spaghetti Junction and the route under Symonds, Queen and Karangahape was excavated, creating a trench for the noodles to tangle in. So covering it over would be more like cut and cover tunneling, with fifty years between the cut and the cover. So this is the approach I’m suggesting, encase the road links in concrete culverts to turn them into tunnels, effectively building structural walls either side, bridging over, then filling in to restore something close to the natural landform. This is more or less the same process they used to cut and cover the CRL tunnel in lower Albert Street, without having to do the excavation first, and now working inches from the foundations of skyscrapers and sewer pipes.

Now there are some obvious fishhooks in this approach. One is working in, around and over a live motorway which is difficult, although certainly not impossible as we seem to have done it constantly for years in various widening, raising and realigning projects across the Auckland motorway network. Waterview interchange is an obvious tunnel. Secondly, this would make open motorways into tunnels, which would need all the requisite exhaust stacks, fire control systems and emergency evacuation routes. Again a large cost but taking the Waterview tunnel as an example, its clearly feasible. Thirdly, management, maintenance and operations. Complex structures are expensive to run and look after. I’m sure Waka Kotahi’s highway network team’s first response to this sort of idea would be laughter, followed by stone faced resistance.

Let’s wave those away as surmountable issues and look at what might be. But first let’s deal with the issue of why this, and why now? Why might a megaproject like this be a good idea and what has changed since the last time it was proposed. The answer to that is the City Rail Link, specifically Karangahape Station. As you can see in this map of walkable streets and building footprints, there is an almighty motorway shaped empty hole making up a huge proportion of the area that should be in close walking distance to the station. Not only that, the lack of walking paths across the junction means that you can’t actually get a lot of buildings to the south and west of the station that you would be able to get to with a normal street network. Some of this sits under a viewshaft, but some sits under unconstrained city centre zoning.

So how could a masterplan look? Well if we use the rest of the City Centre as a guide, we’d want to cover about 20% of the area with roads, streets and lanes, connecting in all the severed streets. Then we’d want about 15% for parks, plazas or public open space. This leaves about 65% of the area for building footprints. Something like this would fill in all that city again, with everything being only a couple of minutes’ walk from the new underground rail station.

I’ve taken the approach of applying these different uses where they can fit easiest. In the following renders the red links shows what a 6m high enclosure of all the single level road lanes, where there is space either side and sometimes between each piece to support these boxing-in structure from below. In the red areas you could create street, lane or plaza above, or build buildings of 2 or 3 stories on raft foundations that don’t need to penetrate the road links below.

The orange parts show areas where you have multiple levels of road structure or high bridge areas, so where you’d need to have some long spans or cantilevers or something else just to cap over. So I’m assuming the orange sites are where you’d probably have to keep as open space or parkland with some street crossings, perhaps with the odd single level building like the podium shops over Britomart station.

Here is where things get really interesting though. Once you’ve mapped that all out there are actually quite a lot of large islands in between of bare land (and a few redundant paved areas), where you would be able to drive foundation piles down to bedrock for large tower buildings. These renders show sites that are affected by viewshaft height controls in purple, and the corner that isn’t limited in height in blue. I was really surprised how much open area there is in between the noodles of Spaghetti Junction.

Wow gee that’s amazing I hear you say. Pretty pictures, but dreams are free and this thing sure isn’t. How much would it cost to build this? To be frank I have completely no idea on how to even start estimating the cost. But we can make a decent stab at estimating the value, which will tell us how much it would have to cost to be worthwhile.

Starting with land value, this varies a lot across the City Centre but a good estimate of the value of a unencumbered, serviced, viable development site near Karangahape Road is $10,000 per square metre. It can less than half that in the crappy parts of the city centre, and several times that on prime downtown waterfront zones, so I’d call $10k a metre quite conservative. The overall area here is 127,000sqm, if we take off the 35% we’re going to use for streets and parks, that leaves the land value of the developable sites at around $850 million.

So, is $850 million dollars enough to enclose all the roadways of the CMJ and fit the systems to make them tunnels, then fill in above, and build all the streets and services and stormwater and everything else required? My gut feeling is it is not enough, but in the right order of magnitude. If the value of the land was $85m you’d say no way, if it was $8.5b you’d do it in a heartbeat. There’s no slam dunk case here, but something along these line might be worth looking into to reap the connectivity-land value uplift benefits of the CRL and help stitch the city centre back to its suburbs.

Looking at those renders, I can’t help but notice all the development site is clustered at the Newton Road end, and all the difficult infrastructure is at the other. That makes me think there is probably a way to do this with a better return on investment. Perhaps something like this, focus on the bit to the southwest of the tall viaducts, which is less constrained and where there are more pockets of open land. This would let you only build the culvert structures (green) over the single level motorway links, and fill in the ground level more easily as they are mostly in cuttings already. Build three fairly conventional bridges (yellow) to provide access to the site and undo the worst of the severance. Then build in between or over the green caps and add other linkages through the site.

This doesn’t cover over the junction entirely, but it does reduce the severance, open up development sites within walking distance of Karangahape Station, and build back in a lot of the missing city fabric. A quick estimate shows around 20 building sites on terrafirma with this smaller option, worth perhaps $700m if brought to market. This is perhaps a more viable proposition.

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96 comments

  1. This is a great concept, I’d like to see it happen. A couple of points:

    – The new development area should be made more permeable to pedestrians/cyclists than it is to cars (in keeping with A4E principles). Specifically this section of Ian McKinnon Dr has no vehicle entranceways or intersections. It would be preferable to keep it that way so as not to impede the existing protected cycleway or future light rail. In fact there’s no reason this bit of road needs to be open to cars at all, just make it a PT / active modes boulevard and fill the rest of the space with trees.

    – This is the sort of project that could only happen with the full support of local and central government. It would need significant funding and regulatory approvals. However if you could get that level of support then surely removing the viewshaft(s) hindering development would be a trivial step in the process.

    – The value of this project shouldn’t be limited to just the newly unlocked land area. There would be huge redevelopment opportunities (and thus value uplift) in the existing built areas adjacent to it, particularly on Eden Terrace.

    1. The government will take away almost all council planning controls very soon I imagine. That the council thinks views of a mountain are more important than affordable housing says it all really…

      1. I heard that the viewshafts are now considered protected under the treaty of waitangi. Which would be unfortunate, no govt, especially the current one would want to be seen removing those, especially for the lowly goal (apparently in their eyes) of providing housing.

        1. Appalling, how?

          I suppose there is also an argument from the Maori side of things about local iwi having cultural links to various maunga. Rivers, mountains and seas could be viewed as members of the family. Being able to see them from public spaces could be taonga, protected under the ToW. Heck, most ToW complaints are about water pollution (poisoning a family member) and Mt Taranki was given the same legal rights as a person because of how important it was to the local iwi. However, most people probably don’t care about a Maori perspective. Especially the more affluent, fairer folk who populate this blog.

          We have lost too many of Auckland’s volcanic cones to building roads already. They are iconic and unique to this city and the viewshafts are a public asset. They are probably worth billions in terms of potential impacts on land value. Scrapping the viewshafts would effectively be handing a public asset over to private developers for free. With a lasting impact to the public forever.

          The huge tax-free capital gains for affected landowners would be enormous.

          I totally support protecting public views of the cones from public spaces. Also, protecting the views from those mountains to other places in Auckland. Though I suppose you could argue for removing a few.

          I suppose if you want to remove the viewshafts, then you should be consistent and remove all height restrictions everywhere. And quarry all the mountains while you’re at it. Make some nice flat land to build some more houses.

          Besides, there is plenty of land in Auckland where we could easily build 4 story apartment housing without the need to touch the viewshafts.

        2. There is a world of difference between blocking the view of a maunga and quarrying it out of existence!

        3. I have a view of Mt Eden from my house. I am totally willing to give that up so that denser housing can be built in Mt Eden to relieve the housing crisis. To argue that my view of Mt Eden is more important than housing families would be morally appalling. I will still be able to enjoy Mt Eden by walking and running up it.

        4. “ I suppose if you want to remove the viewshafts, then you should be consistent and remove all height restrictions everywhere. ”

          Sounds like you’re threatening me with a good time!

        5. What a strawman argument Ari.
          There’s a big difference between building in a view shaft and building on or destroying a volcanic cone.

          As for passing on public rights to private developers, there is nothing to stop council imposing a levy or other charge on properties that would benefit from the changes. Of course in this case the land is owned by the government so selling the land to developers would be benefiting the entire country from the proceeds, while benefiting Auckland itself with an improved city centre.

        6. I’m not going to pass judgement on the idea of viewshafts in general, but the one that affects this site is particularly egregious for the city.

          It’s a view plane to Mt Eden from the toll plaza of the harbour bridge, so that people queuing in their cars on the motorway to pay at the toll booths have something nice to look at. We haven’t actually had a toll plaza since 1984. You cannot access this sight line any other way, not on foot, not from the street, not from parks, not from peoples houses even. It’s a glimpse through the window at best.

          It is particularly impactful because it extends across the western half of the city centre, which is otherwise zoned and appropriate for towers. The current council building has a corner cut off because of this. The skytower had to be moved from where the wanted to put it to not block this view. And all the buildings west of about Hobson street are stunted by it.

          Someone was complaining about a ‘tax free windfall’ if it the constraint was removed. The better question is why we are supressing the value and usefulness of the land in the first place.

          Note that this is a separate and different view protection from the one that extends from the harbour bridge to Mt Eden. I’m not convinced we should have even one protected sightline from a motorway, let alone two next to each other.

    1. It’s not so bad here as the view shafts are a plane that project across the top rather than being a height limit. In this location you can go as high as the buildings on the K Rd ridgeline, but starting from lower down.

      1. They’re still limiting the potential of this city. We shouldn’t be wasting inner city land with low rise buildings. It should be for high rises.

  2. With such proximity to town, surely streets being included (at least in conventional sense) should be subterranean to allow for deliveries making all surface travel active or PT.

    Would be interesting to know if this could also help provide space for light rail over the motorway to access Queen street (assuming will still be plan).

    Ultimately though if involving significant housing this could meet many government priorities, potentially with minimal additional cost too taxpayers.

    1. I imagine it wouldn’t be a good spot for apartments due to the fumes and noise, otherwise the government could build a ton of apartments there, the land is free to them.

      1. That’s the point of enclosing the lanes and filling over of course. It wouldn’t be any worse than the current apartment buildings that surround the motorway junction.

        1. “Does Waterview use state of the art treatment of the air emitted from the vents?”

          Nope. No real treatment. Just high stacks.

          In a more positive sense, that is an issue that will progressively go away with more and more electric vehicles. Venting will still be needed for some decades, but again, if designed in, the air pollution for this new suburb would need be no worse than for someone living on K Road, and as noted, it would diminish to (likely) near-nothing within the lifetime of these buildings.

  3. Great opportunity to chuck a new school for the city centre in as well. The classrooms can still be in a tower but it would be cool to have some good open space

    1. Excellent idea to simultaneously promote higher density living closer to the city centre and reduce the pressure on some of the nearby school rolls.

  4. If nothing else those three pedestrian and cycle bridges marked in yellow on the last two renders would be a great start at overcoming the isolating moat-like nature of the CMJ.

  5. Maybe we could get a licence to occupy from NZTA, show these renders to prospective investors so we can soak up some of the cheap money out there. Then we use new deposits to pay high returns to previous investors for a couple of years while we clip the ticket, then get out before the whole scheme collapses. Does anyone know a Covid free country without an extradition agreement?

    1. Your scheme will only collapse if the asset price falls but this is preventable. If you can get enough older New Zealanders to invest in it then all institutions and branches of government will work to protect it. Council will change their rules to prevent competition. Even governments elected on the promise of making the the asset price fall will change their tune to “Oh New Zealanders expect the price to rise so we can’t do anything about it.” The NZ Herald might even produce a segment specifically to spruik the asset, make early investors feel better about themselves and create FOMO in those who haven’t invested yet.

      1. I was seeing this as a bit like John Law’s Mississippi Company. You wouldn’t actually build anything. Take some really shitty land and spruik it and hope the investors never go and have a look.

  6. There were early plans to sink the SH16/SH1 in Grafton into a trench and cut-and-cover it a few years ago. They never went anywhere, even though it’s the most concentrated for heavy trucks.

    The best NZ example of city-integrated cut-and-cover is the Wellington Memorial Park SH1 project – but none of the new buildings spanned the motorway corridor itself. The MIT project spans the much narrower rail line, and has a full town centre and PT centre to integrate within.

    The real question is: what would any major tenant in their right mind move there? Obviously there’s no car access, no pedestrian access, no public transport access, and no cycle access. Wasn’t this the point?

    This site is so highly polluted that the air conditioning costs would be immense, it’s next to nothing, has no view, and both fabric and foundations would be subject to very high wear and tear so it would have both high operational costs and the buildings would have a shorter lifespan.

    Forget it.

    1. Sh16 is already in a trench in Grafton Gully, if you are meaning the point between Wellesley and Grafton Rd. It was in the old City Centre Masterplan.

      Clearly to make it work you need to introduce that car, pedestrian, cycle, PT access. That’s what make spaghetti junction an interesting case with the CRL station right there.

      1. There was a moment when the old Urban Design Office got enthusiastic and did a few sketches with some blocks of colour. No one bought it at the time. The bit that NZTA did some work on was the Grafton-Stanley St-Port corridor.

        The UDO is long disbanded, Auckland Council has a decade of work just helping the Queen Street recover from near-death, and NZTA is very much in stick-to-knitting mode. Not even Kainga Ora would take this one on.

        1. Oh right Grafton Gully stage 3. If I remember correctly it was all open trench without and thought of cover.

  7. This would indeed be a great engineering feet, however I’d say the cost of putting that area in a bunch of complex tunnel structures would be in the range of $5-10billion.

    Certain areas would likely be extremely hard to get a large building built above the tunnel and so much of it may need to be a nice park.

    1. I haven’t shown any large buildings built over tunnels is the sketches above, they’re all in the gaps between the roadways. The surprising thing is just how much empty land there is in those islands between the motorway links. If anything is vaguely realistic I think it’s the last picture which skips the most challenging parts entirely.

      1. There certainly is plenty of spare space around the CMJ, however I rather like the spare land around the CMJ and other parts of our motorways. It serves a valuable function in the biodiversity of our city which is something most cities have far too little of.

        1. NZTA’s claims about biodiversity were a laugh a few years ago. Such creative greenwash, given NZTA are one of the biggest forces behind greenfields development, which is ruining biodiversity at pace. Biodiversity in the city centre would be far better served by shrinking the motorway system, replacing lanes with plantings.

        2. Caitlin W
          Can you name a single Waka Kotahi project that has destroyed biodiversity in recent year?

          Also, the post is about converting the large planted areas into buildings, not covering the motorway so these planted areas can be made bigger.

        3. ‘There certainly is plenty of spare space around the CMJ, however I rather like the spare land around the CMJ and other parts of our motorways. It serves a valuable function in the biodiversity of our city which is something most cities have far too little of.’

          LOL. Comment of the week

        4. Richard how about we start with Puhoi to Warkworth which plows right through a stand of ancient Kauri forrest, severing it in two

        5. Waka Kotahi have paved over green space with numerous projects in the last 10 years and will continue to do so. Much of it is grass but some of it is bush, but it is safe to say it all has higher levels of biodiversity than the patches of vegetation within the CMJ.

        6. Good Lord, Richard.

          “Can you name a single Waka Kotahi project that has destroyed biodiversity in recent year?”

          That’s got to be the most ignorant comment I’ve seen on GA ever.

          You’re either fooling, or you are a complete fool.

          How about looking at some of WK’s flyover videos during construction? Total annihilation. Do you know nothing about what Transmission Gully did to the waterways and harbour?

        7. Caitlin
          Thanks for resorting to abuse as opposed to providing some examples. Transmission Gully is a project that is under construction, hence not finished, so its a bit hard to claim its long term affects are a net loss for biodiversity. Essentially its final result will be similar to that of the Huntley Bypass what in the long term will have a net benefit to biodiversity due to the off-set mitigation being provided.

          The vast majority of Waka Kotahi projects leave the area better than before as this is the modern way of doing things.

          Heidi.
          Those links you have provided appear to have completely ignored the huge amounts of mitigation works done as part of the Waterview Project and focused on two small sections of bush that likely had limited value due to their small size and nondiverse nature. They are also shown directly after construction ignoring the fact that plants take time to grow.

          Matt L
          Puhoi to Warkworth actually completely avoids the Kauri forrest, at least it was required to when I worked on the Tender. So not too sure what you’re on about there.

          Jezza
          So a grass paddock that occasional features some cows has more biodiversity than new native bush that’s protected from predators and humans and is home to all sorts of birds and lizards?

        8. ‘The vast majority of Waka Kotahi projects leave the area better than before’

          double LOL. Second best comment of the week. Keep trolling, this is great!

        9. Joe
          Can you provide some examples to justify your disagreement or are you just here to abuse people?

          What recently completed Waka Kotahi project has left the area worse off from a biodiversity perspective?

        10. A motorway by definition reduces biodiversity because it is a barrier that is nigh-uncrossable by any animal but a bird (well, maybe a rabbit could survive crossing, if it does so at 3am).

          Thus cutting apart a previously connected ecosphere.

          By all means argue that some ecological sacrifices are acceptable – but please don’t claim nonsense like a big honking piece of asphalt rolled out across the land filled with high-speed metal boxes “improves” the local ecology because NZTA built a few flax-covered stormwater ponds (only needed in turn because the run-off is so toxic it has to be filtered).

        11. Damian
          Can you please point out the part where I claimed the actual carriageway of a motorway is what increases biodiversity? I don’t recall ever making such a claim but rather that is a strawman argument of your own creation.

        12. So the projects only measure up because of the mitigation they do?

          Which is stuff we could afford to be doing anyway, if we weren’t wasting so much money on the road building.

        13. Heidi
          The entire point of things like the RMA is to protect things like the environment. If projects like the Huntley Bypass weren’t built and paid for by road users who would be removing contaminants from old shooting ranges and dumps, would would be doing large amounts of river restoration, who would be eliminating wild goats so native wildlife has a better chance, who would be converting unproductive farmland into native bush?

          Can you name any cycleway, rail or low traffic neighborhood or apartment building projects that have done this sort of work?

        14. And one of the goals of transport planning transformation will be to reallocate funding from destructive projects that induce emissions to healing projects that reduce emissions, like cycle paths.

          It is not necessary to destroy biodiversity at huge cost during road building, in order to do be forced to mitigate with good biodiversity work. We can just do the good stuff. And save loads of money in the process.

        15. Heidi
          I’ll ask again
          “Can you name any cycleway, rail or low traffic neighborhood or apartment building projects that have done this sort of work?”

          Also, what biodiversity is generally lost in the road projects we build these days? Grass fields and old industrial land don’t rate highly when it comes to biodiversity.

        16. While I don’t agree with Richard’s comments, the responses haven’t been too dignified. He made some points which it would be good to see actually addressed by people in the know on here..

        17. The way people got so upset and abusive because I said I like the way we landscape around our motorways certainly spoke volumes for their blind hatred of cars.

        18. This trolling and abuse on here is impressive. You guys sure are valuable contributors to society.

        19. Richard, inherently destructive motorway projects need to be stopped, not justified because their builders are forced to also include biodiversity work on the side. Inherently sustainable transport development like cycleways need to be ramped up with more funding, not criticised because their meagre and pilfered funding doesn’t stretch to doing biodiversity work on the side, work that isn’t required to mitigate destruction as per a motorway.

          What you have written here is value-loaded trolling rubbish. It isn’t worth debating because it’s stupid. Choosing to write it in this forum is looking for kickback. You got it. Stop whingeing about the kickback. If you can’t take it, go away.

        20. Wow, that was a real display of hate and division right there. Thanks for displaying your intolerance of others so clearly.

        21. Joe
          Did you not read her post? I simply said I liked the native bush around the CMJ which has resulted in abuse from all directions including that of the moderator who showed herself to be one of the most intolerant people I’ve ever heard.

          I’m yet to advocate for a motorway here in recent history, however it seems the blind hatred of cars has made pretty much everyone excluding me to claim replacing native bush with concrete roads and buildings will somehow improve biodiversity.

        22. It’s truly remarkable that every single troll that comes here makes some outrageous claim then gets upset that they get called out on it.

          Richard, by your own admission the Huntly bypass was bad for biodiversity and Waka Kotahi had to buy out large amounts of productive farm land to partially offset all of the damage that they were doing.

          And if you think that the Puhoi to Warkworth motorway avoids all Kauri, you should probably let the Waka Kotahi spokesperson quoted in this article know….

          https://www.stuff.co.nz/motoring/102395780/warkworth-residents-fed-up-with-phoi-to-warkworth-motorway-build

        23. Sailorboy
          By “troll” and “outrageous claim” you mean someone who says they like the native bush in the CMJ. It is truly amazing that someone expressing an appreciation for native bush is classed as trolling here and warranted for abuse. It seems this place has turned into an even worse echo chamber than it used to be taking scorn and hate to new levels.

          For the Huntley Bypass, just like any other road project, isn’t just a carriageway. It is obvious to everyone that you would be hard pressed to say the carriageway of the road is a benefit to biodiversity, hence why the project isn’t just a carriageway but is multifaceted. It beggars belief that people find this such an impossible concept to grasp.

          As for P2B avoiding all kauri trees, I never made such a claim. I simply stated that it was required to avoid the Kauri Forrest when I worked on the tender. Feel free to show a map of the motorway showing that it “plows right through a stand of ancient Kauri forrest” as per the actual “outrageous claim”. From what I can see in google earth the road is still avoiding the actual Kauri forrest, and they are building an eco-viaduct to avoid severing the existing ecosystem.

          Also, a single kauri tree isn’t ‘biodiversity’, nobody has ever claimed a road project has zero impact on the existing environment.

      2. You’re joking if you think I’m going to do a detailed cost estimate on this, it’s purely a gut feel based on 20 years of experience working on these sort of things (hence a 100% contingency).

  8. Given this bit of the motorway is usually crawling anyway, I see no problem with expanding the City itself to reclaim some of it as lower-speed, 50kmh roads. It would also let us rethink the Western branch of light rail by building up a new corridor for it to connect with the top of Queen St/K Road, instead of meandering through the inner-West.

    It’s not totally without precedent – look at the city just ends at Hobson St and the motor way starts. Seems no less arbitrary than this, does it?

      1. It would just be a Google satellite image with narrowed lanes, buildings in the non-road bits, light rail from Upper Queen St up the middle of SH16 in the room you’d freed up with lower-speed, smaller lanes and a 50kmh zone out to St Lukes. You’re lucky to do 50km along there West-bound at rush-hour anyway.

  9. I’d say that you’d want to explore every other infrastructure and public transport option around before sinking any public money into this baby. Payback and risk for the ratepayer/taxpayer unlikely to be worth it and certainly other things rank ahead of it on the ‘problem to be solved’ list. The CBD fringe has a lot of underutilised land. But if the private sector wants to do it without taxpayer support, then that is a different story.

    1. QGIS and Google Earth Pro.

      Both are actually free and powerful. QGIS has a big learning curve but you can do a lot in Google Earth by drawing polygons and setting their height.

  10. Taking this at face value – of “creating land” in the centre of Auckland – as unfeasible it may be for various structural / buildability reasons – this proposal is a lot more sensible to me than what Auckland is actually proposing to do: to build over the rich arable land of Pukekohe.

    The land at Pukekohe produces something like 26% of New Zealand’s fresh food, and being next to the biggest city, has immense value for the future food security of Tamaki Makau Rau. It is so vital to Auckland’s future that it should be immediately protected – but instead it is being sold off bit by bit.
    https://www.nzherald.co.nz/property/atlas-change-of-plan-creates-development-opportunities/7RO3P6EDTPFIKKSDQ3I7C5PISU/

    Wake up Auckland !

  11. I like this idea and I’ve often wondered the same thing myself when walking / cycling through the area.
    But as much as I like the idea of repairing the scar in the landscape, I’m aware that an idea like this goes to a lot of effort to preserve the existing throughput and footprint of the motorway junction. Rather, by spending the money on improving active / public transport networks across the city, we would hopefully find that the largesse of the motorway junction itself is unnecessary.
    I would like to get to the point where we start ripping up misplaced motorways like this, rather than spending billions to bridge over them, only to find that the demand falls anyway.
    Until then though, I agree that something like the yellow bridges should just be built.

  12. It really is a very cool concept.

    But I can’t fathom the construction methodology that would accommodate an operational motorway below, though. Anyone? Can we close the CMJ for 2 years with nobody noticing?

    Still, pretty neat vision.

    1. I wondered the same, but in retrospect they kept the causeway of the western motorway open while doubling it’s width and raising it 5m in the air. They built the Waterview interchange in, around and over the live motorway, they added the Victoria Park tunnel, they’re widening a live motorway at Takanini and Albany. About 20 years ago they built all those extra links through spaghetti junction without wholesale closing it down for years.

      It’s feasible, just a question of time, cost and disruption.

  13. I said it a few years ago, perfect place to put that stadium, rather than down on the port.

    Get Watties to sponsor it. Watties Spaghetti Junction Stadium…

  14. So… what happens to the LightPath cycleway? I’m trying to picture this as some funky coloured tunnel instead… Curiously, your Google renders don’t actually show any evidence of its existence (despite being 5 years old now). Or would we simply scrap it as an interesting transitional project and go to an “above-ground” cycle route instead?

    1. That part could stay where it is, or be raised, or relocated. It’s only a small section in there area anyway.

      Yes unfortunately the google 3D renders are quite old, but there’s no other easily available (or free) 3D model of Auckland.

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