This post by Nicolas Reid was originally published on Linked In. It is republished here with permission.
In this article, I make an argument not very serious for tearing the crossing of spaghetti in Auckland, replacing it with a highway tunnel and rebuilding new streets and neighborhoods in the city above it.
What is the problem with the central junction of the highway?
The great irony of urban highways is that they use large quantities that they are intended to access: land. This is the case of all surface transport infrastructure, of course, however, the highways are the worst offender. Even a small self -enhanced corridor is at least five times wider than a simple street, while exchanges can be the size of a small town.
Nowhere is this consumption of valuable lands more visible than at the intersection of Spaghetti in the center of Auckland, formally known as Central Righway Junction (CMJ). Here hundreds of houses and neighborhoods of the whole city were demolished and excavated to build it, in addition to the negative effects of noise, emissions and compensation extend far beyond the junction itself. The junction of spaghetti is a bow around the neck of the city center, reducing the values of amenity and land on the properties on both sides. But of course, in the transportation space, everything is an exchange. There are great accessibility benefits when having a spaghetti junction, after all, it has 200,000 vehicles a day. This is many people doing many things.
But despite its high traffic volumes, CMJ is not really a good highway exchange. Ask any traffic engineer and they will say it is an old -fashioned design built for plans and standards of the 1950s … and this is a headache for the 2020s. The ramps are very close, very short mixing, very tight corners. The junction surrounds almost completely the city center, but you cannot use it like a road to avoid driving through the city center. And critically, forces regional traffic for traffic and city to the same ramps and deep tracks. There is almost laughable reason for this in the 1950s, they were concerned about the fact that there are not enough people would use the self -enhanced if they did not lead the city center, so they intentionally combined traffic with traffic to share the same lanes.
A proposal to replace the city center highways
If we were building the highways today, we would adopt a different approach. The regional highways would be designed to completely circumvent the city’s core, connecting very far from the city streets. Meanwhile, the city’s traffic would leave the highway early and continued along arterial roads, while an appropriate road would allow traffic to drive through the city’s core and not through it.
So I wonder, why don’t we do that? What would it be like if we bound the self -enhanced with a deviation tunnel, tear the spaghetti crossing and replace it with surface streets and an ring road? This would mean better state highway traffic on the highways, a highway road for the city center, the best connections in the city of the city and, most importantly, a large part of the city’s land available for reconstruction.
In a nutshell, here is my proposal in three simple steps:
1. Build a new tunnel of crossing highways by Porto/City
- This would start on the north highway of the old toll plaza north of the Harbor Bridge and ran to the South Highway, joining the Newmarket viaduct, and connects to the Northwest Highway in both directions.
- It would be 6.9 km long, six tracks in total, and would have an underground exchange with Northwest near Newton Road, otherwise no other ramp or exchange.
- The Harbor Bridge would become an arterial road only for access to the city center, with four tracks for town traffic, two for buses and two to walk and ride a bike.
2. Replace the junction of spaghetti with an avenue ring road
- Demand the cross of the highway and all the road tracks and ramps through St Marys Bay, Newton Gulley, Grafton Gulley and Khyber Pass.
- This is replaced by a surface arterial avenue around the city center, reconnecting all local roads and streets. In some places, this expands existing roads such as Union Street or Alex Evans Street, in others, is a whole new road.
- Santa Maria Bay becomes an avenue by Beira -mar, Grafton Gulley to Boulevard, Freemans Bay and Newton are full back with new avenues and side streets.
- Victoria Park’s tunnel would be reconfigured for a track in each direction for the new ring road, but Victoria Park’s viaduct would be totally demolished.
3. Build the city on the old highway land
- Allocate an appropriate amount to new parks, public spaces and community facilities and sell all the excess of land on the new streets for reconstruction.
The city’s deviation tunnel, Porto intersection, Busway extension, all-in-one-one bonus jackpot of land development
Easy eh, it’s so simple. This would mean an underground highway deviation from the city center, a new road and a reconnected network of local streets and a large set of development sites.
The people driving on the highway passed through the city, those who drove to the city left the highway at Harbor Bridge, Newton Road or Khyber Pass Road to continue in the new Boulevard ring and on the city streets. The people who drove inside and around the central area drove on the main roads or on the new avenue without finding a self -enhanced.
Following these steps would make Auckland’s map look like this:
And the cost and the benefits?
Ok, cool story bro, but what about the cost of this fantastic scheme?
Of course, this would be a great venture, easily the largest infrastructure project in New Zealand. However, it would be technically viable, there is nothing unusual in the staging of self -enhanced tunnels and the construction of surface streets. Therefore, viability really comes down to cost. Let’s break the elements to get an internship idea of how much.
The core piece is a 6.9 km long six -lane highway tunnel with a large underground exchange. This is a configuration similar to the water vision tunnel design, but about three times more. It is also the same length as the latest proposal of Porto’s cross -cross tunnel. Using the $ 600 million WaterView cost per kilometer as a guide, I will fold it again to consider building cost inflation and the highest risk -risk risk of about $ 8.2 billion for the appropriate tunnel. Add the exchange with the northwest and at each end, and we can call it $ 10 billion to the highway component.
Add to this the demolition cost of the current highway and remodeling and stabilizing the land, say US $ 500 million and the 6.1 km of New Urban Boulevard building, reconfiguring the VPT and 1.1 km building of local street connections for another US $ 500 million. With several other costs, we will call a medium -sized estimate of twelve billion dollars. Very similar to the port proposals of Porto of the same scale.
Okay, and the benefits? As well as observed above, this would provide a port crossing with six extra lanes combined with a highway deviation from the city center, would also separate traffic from the highway traffic from the highway. This would give Northern Busway their own tracks to the city, as well as adding walks and bicycle by the bridge, and delivering a new ring ring around the central city. Undoubtedly, there is a large package of transportation user benefits there. I did not calculate it all, but in simple terms, the gain would need to be $ 480 million each year to justify a $ 12 billion project. This is something like $ 1.3 million in liquid transport benefits every day to come together.
However, there is a large piece of land released without the highway surrounding the city, and that is worth something. At the moment, the central junction of the highway occupies 615,000 m2 of the city’s land, if we subtract the land needed for the new avenue ring and the connection roads, still long leftovers, I estimated 370,000m2. This is approximately the same amount of land as the Wynyard neighborhood, which offers an idea of the development potential. Currently, the development lands on the edge of the city center are worth about $ 10,000 per square meter, so replacing the spaghetti crossing with a ring road would release development sites of about $ 3.7 billion. Put the sale of this land in the book and it effectively drops a third of the cost of capital, which means that the net cost of the project would be about $ 8 billion. So now the value of benefit equilibrium is over $ 880,000 per day.
A rapid rear of the envelope assessment shows that we are dealing with 200,000 vehicle trips per day and around Spaghetti Junction and Harbor Bridge, as well as about 40,000 bus trips per day. Therefore, it is worth this project would need to be worth about $ 3.70 per trip for all affected. NZTA Benefit Manual and Costs Costs The time of passengers’ time at about $ 19 per hour, so we are talking about the equivalent of all people who save twelve minutes on your trip. This is very high for an average on all trips, but not absurdly, suggesting that a closer look may be worth it.
In short, is this a crazy idea?
When I started reflecting on this idea, it was a little fun, an exercise in what you could do to fix the roads around the Auckland Center if the money was not the object. However, elaborating some numbers seems to be not a totally terrible idea with regard to the highway megaprojects at least. The idea of using a port crossing to completely circumvent the city and rebuild the corridors of the surface highway on the city streets and in development sites can really be worth investigating more.
What are your thoughts? Let me know in the comments.
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