My wife and I spent Christmas with some family out of Auckland. That saw us travelling and along the way we passed what I thought was an excellent roading project and the type of thing we should be doing a lot more of instead on spending so much money on motorway scale projects, many of which don’t stack up economically. The project is on SH2 and is half way between Waihi and Katikati and is known by the NZTA as the Ardern Cottage Curves Realignment. The curves being realigned are a series of tight bends that apparently have a poor safety record (and it’s easy to see why). The image below shows an aerial view of the curves which bulge out from generally sweeping nature of the roads that surround them. The realignment cuts that bulge out.

Ardern Cottage Curves Aerial

Here is what the curves look like from the road. As you can see there are quite narrow lanes with no shoulder (so quite dangerous for any cyclists) and there is poor visibility around the curve. Before this project there a permanently installed electronic sign not far behind here reminding people to slow down for the curves. It’s not hard to see why this was a safety issue and on average just over 8,100 vehicles travel this road daily.

Ardern Cottage Curves Streetview

Here’s what the NZTA say about the project which is costing $5.1 million

Project purpose

The key purpose of this project is to improve safety along this corridor, however travel time and efficiency will also improve as a result of these works.


The Arden Cottage Curves Realignment project will help to improve safety along a high accident area and efficiency through this corridor of State Highway 2.


Features of the project include realigning a series of curves on State Highway 2.

Other facts

The project is to be split into 2 stages:

  • Stage 1 works will focus on drainage and moving services in the disused railway corridor, lying adjacent to the existing State Highway. This work will be carried out March 2013 and May 2013.
  • Stage 2 works will start after the 2013 winter season, and will tie the newly built road into the existing highway. These works are expected to be completed in May 2014.

When we travelled through the realignment on Christmas Eve it was already open to traffic and despite not being due for full completion till May and there being a temporary speed limit of 70km/h the benefits of the project were immediately clear. Not only did the realignment shave off that bulge but it was easy to see it would be much safer for all road users as a result of having a straighter road, better sight lines and wide shoulders. I also think it is a wise use bit of use for that old rail corridor – which even if we had the most rail fanatic government has almost a 0% chance of ever being needed again.

So as I said it is a good project from the NZTA and at $5 million is tiny compared to some of the spending going towards the Roads of National Significance. For the same price as Transmission Gully we could get about 200 projects like this all over the country. I wonder what that could do to our road toll?

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  1. A similar project in this vain that I’d like to see to rerouting SH27 away from the curvy section about 10km past the SH2 junction. Looking on Google maps the road can easily be rerouted along the plain about 1km east. I have no idea why when the road was created, this was the chosen route.

    1. Probably depends a bit on when the road was first built. in the early days roads were built by local roads boards and perhaps one of the land owners at the time didn’t want his farm being cut in half by a road so it was forced to go the route it does now to avoid that. Since then it’s probably been too expensive to do anything other than upgrade the existing route.

      Edit: just had a quick look. The NZTA have a permanent telemetry site just south of those curves so pretty reliable data and it shows only about 4200 vehicles per day using that stretch of road.

      1. Interesting that the vehicle volume is so low. I drive the route frequently and have often thought that that twisty bit up and over a line of hills (which as Frank E says can easily be bypassed by a lazy curve to the east) is a large piece of low-hanging fruit for through traffic in the north and east Waikato. The section at the top of the hill often suffers slips and washouts so the maintenance cost must be high, surely the cost-benefit ratio (to use the NZTA’s favourite tool 😉 ) must good…?

        And IIRC the NZTA has designated the SH2 – SH27 – SH29 corridor as the main future access route from Auckland to Tauranga, so maybe we’ll see some movement on this bypass in the near future.

        FWIW the other low-hanging fruit is of course the remaining nasty bits of SH2 between the SH1-SH2 junction and the SH2-SH25 junction (yes, I know the NZTA has a plan to sort those bits out too but I haven’t seen much movement for a couple of years). I guess the SH1 Waikato RONS has sucked up all the funding available, so holidaying Aucklanders and truckies on SH2 and SH27 will have to wait…

        To get back on topic, this is definitely a worthwhile project. Totally agree with the sentiment about more little improvements like this nationwide going a long way…

        1. Once the Waikato Expressway is finished the primary route will be SH1 – SH29. Government has already labelled Cambridge – Tauranga as a future RoNS. That route currently isn’t that busy at about 9k per day so my guess is we would start seeing some Mangatawhiri Bypass type projects i.e. deviations off the existing route to make it straighter and limited access but primarily single lane with a few passing lanes along the route but all designed so that it can be easily expanded to four lanes in the future. A lot depends on what they do with the Kaimais and the road lobby are pushing for a $2b+ tunnel under them.

        2. I stand corrected… but the thought of more RONS madness is… ugh. A tunnel is madness, there’s no way it can be justified… rationally at least.

          The Mangatawhiri Bypass-type projects you mentioned (especially on the Tauranga side of the hill) would be more than enough to increase speeds and capacity.

  2. SH2 between Athenree and Waihi “Athenree gorge” has had a number of bits realigned in the last 20? years IIRC. The Ardern curves were just the final un-reconstructed bit. I hope the intersection at the top will get some improvement too, since the through traffic is going to be faster now.

  3. ” I also think it is a wise use bit of use for that old rail corridor “.
    Careful Matt. Rail corridors – even those we think have a 0% chance of ever being needed again – are valuable assets often procured at considerable cost in the past and much more difficult to reinstate in the future once they have been severed. Britain now rues the loss of many rail corridors closed in the Beeching era, despite assurances at the time of a 0% chance of ever being needed again.

    1. Yes I’m well aware that we need to be careful not to just waste rail corridors but if this line was ever needed again then this section of road would be the least of the concerns. Much of the corridor has already been cut up, sold off and developed over. I would suggest that many of the road realignments already through the gorge have already used the rail corridor. The only town that couldn’t be served by this cut would be Waihi. In situations where the corridor is already well beyond a chance of being revived then I think it’s a good idea to use the corridor to improve other transport assets.

  4. I can see a 50 year future where a direct Auckland Tauranga route would be handy. Rail route is indirect, so old Kaimai express took 3.5 hours on that route. A new high speed alignment could get a rail journey of 1.5 hours or less, depends a lot on what happens within Auckland.
    Alignment great for Metroport trains if we wanted to close Ports of Auckland past 2050 too.
    However this of course does not mean that road projects on the old 19th century alignment should be prevented, a new route would need brand new alignment.
    Yes I am dreaming slightly here but am thinking about a changed world.

  5. I think a high speed railway link from Auckland to hamliton would be a start, if we could get from A to B in an hour, than we can build on that, next would be a subway in Auckland and again with the high speed trains, it took me 3 hours to get from north of Auckland to south, makes me think, whats its costing the people of Auckland to get to and from work each day, not just in cost of money, by what time is worth to them, same can be said about any main road in nz, if we can get from Auckland to hams without stopping due to something along the way, save 10, maybe 20 minutes, that’s good, same with hams to tga, or on the way to wellington, if over the next 20 years we turn SH1 into a motorway from Auckland to wellington, than its for the better, and what about the north island to south bridge, motorway all the way to chch, we need to get ahead, if we want to keep up with the world

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