A couple of weeks ago I looked at the cost of the the Western Ring Route which when it is all said and done will have cost us over $3b however I did miss out some important details. I forgot about the impact on the connections to State Highway 1 in both the north and the south. Readers may recall than when the connection at Manukau was opened in 2010 there was chaos on the Southern motorway as scores of vehicles joined from SH20 which resulted in considerable congestion and frustrated motorists. As a quick fix the NZTA was forced to install ramp signals on the connection to the South to control the flow but said that the long term solution was to widen the motorway further between Manukau and Papakura to relieve the pressure. They also realised that the same thing might happen on the Northern motorway where SH18 joins SH1 so said they want to widen that part too. But how much will these works cost?
Another of the papers the NZTA released to me was their State Highway strategy from 2010 which sheds some light on the issue. In the South they are only showing the costs of adding a third lane southbound from Hill Rd to Takanini which would cost $40-$80m but they all four stages would likely need to be completed before ramp signalling could be removed from the SH20-SH1 connection. I think we could easily add in an extra couple of hundred million for the other works based on the costs we have seen elsewhere.
In the North it is going to cost even more, the paper says that the desire is to the route fully upgraded to expressway standard which means they would need to grade separate the likes of Paul Matthews Rd as well as installing ramps to allow motorway to motorway connections. Widening would also need to take place at least to Greville Rd which would also need an expensive upgrade.
All up from the listed projects we have additional costs in the range of $565m-$910m not including the projects out south that haven’t been costed. All of this is on top of the other $3 billion we would have already spent on the WRR which means that when all is said and done this one motorway would have cost more than $4b alone.
One of the big complaints about the CRL is the cost and at over $2b it is understandable that people balk at it. The project is actually likely to come down in price as a result of the refinement that is going on behind the scenes and things like staging some of the stations as has been mentioned will also help and may even get the cost down below $2b which should help its image enormously. But how does a project like the CRL compare to something like the Western Ring Route (WRR) that is being built. There have been numerous parts completed for it over the last few years but one thing that has happened is that the costs have been spread out over various projects and so the general public doesn’t really seem to have had as much objection to it. Here is a map of the entire WRR:
Thinking about it a bit further I decided to add up all of the costs for the WRR to see just how much had been spent and how much is predicted to be spent in the next few years. After a bit of searching I managed to find the costs for all the projects bar the Royal Rd interchange which is the NZTA haven’t listed yet.
So all up just over $3b will have been spent on the route over a period of roughly 10 years. That is a huge amount of money and I can only imagine what would have been said if the NZTA or its predecessor had tried to build the whole thing in one go. At $2b over the next 10 or so years, the CRL starts to actually sound a bit more reasonable but then of course is the issue of how much each of these projects would be used. Its pretty hard to directly compare the two as there are so many different variables so I decided just to do a really rough calculation. The best numbers I have for the CRL come from an OIA request our former admin did over a year ago.
That shows that in about 30 years that with the CRL the rail network would have 47.6m trips per year or about 130k per day, this is compared 22.2m per year without the CRL or just under 61k per day. From that we can say that the CRL provides for an additional 69k trips per day. A few quick calculations show that for us to be getting the same number of additional trips, the improvements to the WRR would need to generate roughly an extra 80,000 vehicle movements per day on top of what was using SH16 and SH20 before these improvements were started (accounting for an occupancy of 1.3 people). To put that in perspective, that is only just a little less than the number of vehicles that cross the causeway today.
I guess the one big thing with the CRL is that with the exception of perhaps a few of the stations, there is not much chance to stage things and everything else will have to be be built in one go.