The NZTA has announced its preferred route to build a motorway from Puhoi to Warkworth which is part of the Puhoi to Wellsford Road of National significance. The route makes a few changes to what was announced about a year ago and said to be due to them having refined the engineering and environmental issues along feedback from locals from consultation. Hidden in the information is news that they plan to start building the motorway in 2014 with a completion date for this section of 2019. Reading through the announcement and various bits of information it raised a lot of questions but first, here is the new alignment aldong with the key changes:
We have already seen that the previous alignment would require some absolutely massive earth works along with multiple viaducts and I don’t think that this has changed much. The first question I have comes from the yellow box at the bottom of the image where they quote that Auckland, Hamilton and Tauranga generate 36% of the countries GDP. The problem with that is Auckland alone currently generates 37% of the countries GDP so getting basic facts like that wrong is not a good start. Here is the key part of the media release:
As the main road link for the freight industry, the new route will better connect Northland to the markets of Auckland and the central North Island to stimulate economic growth in Northland and the Upper North Island.
NZTA State Highways Manager for Auckland and Northland, Tommy Parker, says the agency’s traffic modelling shows that the average number of vehicles travelling between Puhoi and Warkworth each day is expected to increase from an average of 19,700 in 2012 to Puhoi and Warkworth to 31,300 per day in 2026.
“Drivers will make significant time savings on an Auckland-Whangarei journey in 2026 when the Puhoi to Warkworth section of the RoNS is operating, and these time savings are expected to be greater for heavy vehicles carrying freight.
“A divided motorway with a central median barrier will also greatly improve safety, eliminating the kind of head-on collisions which have claimed four lives on this stretch of highway since 2006.”
It seems that with this project you really need to read between the lines because what they aren’t saying is often just as important as what they do say. They claim that 31k vehicles will use the route by 2026 but the key thing here is that it is across both routes, not just the motorway. I also wonder if that increase in vehicles is based on the same growth projections used in other projects and still get used despite traffic volumes being static or even reducing over the last 7 years.
They claim that there will be significant time savings for vehicles but the key thing here is that the benefit is only for drivers coming from further north, that is because the only connection to Warkworth will be on the northern side of town. That time saving benefit was estimated in the past to only be about 5 minutes and those that live in the town will have to drive North to get to the motorway before heading South again which means for many that there will be little to no time saving benefits over what they have now.
There are quite a few other things that could have a big impact on this road. The NZTA have said that they haven’t made a decision yet on whether it should be tolled. Their experience with the existing motorway from Orewa to Puhoi is that even though that piece of road has greater time savings than this new section is expected to deliver, about 30% of traffic still uses the old free route. Using that ratio as an example it would mean that we would still see about 10,000 vehicles per day using the existing route and the motorway would carry about the same amount of traffic as the existing road does today. I believe that would mean it is carrying less traffic than any other motorway in Auckland and less than most arterials.
They have also said that at this stage they won’t be building an interchange at Puhoi which would have interesting outcomes.
- The residents on Puhoi and Mahurangi West would no longer have direct access to the motorway. They would instead be forced to use the free road which takes longer and is more dangerous. I wonder if that has been taken into account in the BCR.
- As there is a big impact on vehicle numbers if the road is tolled, no interchange at Puhoi means that the NZTA either have to toll the whole motorway from Orewa to Warkworth or remove the existing toll. If they take the latter option they should include the remaining debt that the toll is currently paying into account as that would still need to be paid and so it should be added to the costs for the project.
- The NZTA is going to get this consented via a board of inquiry like they did with Waterview, and you can be sure that the locals of Puhoi and Mahurangi West will want ramps built. Given the mitigation that was required for that Waterview with things like vent stack locations, I suspect the locals will have a good chance of winning but that raises another question. Part of me thinks that the reason for not including ramps at that location is that the NZTA know their time savings estimates are bogus so are going to try and force as many people as possible to use the motorway as that would make the old route much longer once again.
So what about the financial and economic aspects of the project, this is what the NZTA has to say:
- Estimated costs for the Puhoi-Wellsford project are $760m for Puhoi-Warkworth and in the order of $1b for the Warkworth-Wellsford section
- The Puhoi-Warkworth section has a BCR of 1.5 and the overall Puhoi-Wellsford project has a BCR of 1.0
From memory $760m is a little cheaper than when the route was announced last year but still bloody expensive for how many people will use it daily. The total cost of the project has increased though from $1.65b to 1.76B. The more interesting thing is the Benefit Cost Ratio (BCR), it isn’t clear if this includes things like wider economic benefits or what discount rates have been used, one thing we can be sure of is that they will be the best case scenario. Taking these numbers at face value they suggest the section to Warkworth is marginally ok but that the section from Warkworth to Wellsford has a BCR of only 0.6. This once again highlights one of the biggest problems with the RoNS, to get some of the bad and uneconomic parts built, they are lumping them in with other projects to bring their scores up. The NZTA hasn’t actually released that much information so I think an OIA request will probably be in order to get a copy of the latest business case.
Other than the costs, there also has been no new information the section from Warkworth to Wellsford. The indications are that they still can’t find a workable route through what is one of the most geologically unstable regions in the country. Perhaps the people working on it also know how stupid the project is and are trying to delay it as much as possible because if spending $760m on a road that currently carries only ~20,000 vehicles per day is bad, spending $1b on a road that carries less than 9,000 vehicles per day is just madness.