NZTA’s East West Link Might Not Trash Onehunga Foreshore But Does Trash Mangere Inlet UPDATED

Irresponsible program


The NZ Herald dropped a clanger yesterday stating the New Zealand Transport Agency’s (NZTA) East West Link motorway (that runs across the northern Mangere Inlet forshore) would “torpedo” the recently complete Onehunga Foreshore project that opened recently. That piece of news was enough to set a few people off with NZTA replying:

Reports in NZ Herald about East West project are incorrect

1 Aug 2016 02:30 pm | NZ Transport Agency

The NZ Transport Agency says a story published by the NZ Herald earlier today (1 August) about the East West Link project is incorrect. The NZ Herald has since corrected the story.

The Transport Agency has no intention of bulldozing or undoing any of the work it recently completed as part of the regenerated and developed Onehunga Foreshore.

The East West Link will provide a variety of positive outcomes for the environment and local communities and media reports this morning suggesting the waterfront development which was opened in November last year is going to be affected by the East West project are inaccurate.

The Transport Agency’s East West project is to the east of the recently opened foreshore area and the design plans for this project have been and continue to be developed alongside Auckland Council, Panuku Development Auckland, the community and stakeholders.

“As well as transport improvements this project will help enhance important features in the area including the foreshore and help clean up environmental pollution that is a century old,” says Brett Gliddon the Transport Agency’s Auckland Highway Manager.

“The aim of the project is to make this special area more accessible, safer and more pleasant, by moving most truck and other through traffic off the overloaded local streets. The new link road will also significantly improve access to the foreshore through more connections and new walking and cycling paths, and is a major opportunity to improve the quality of run off into the harbour.”

“The East West project will not undo any of the work that the Transport Agency funded and is proud to have helped complete in November last year to reconnect the Onehunga community with the foreshore again.”

“Many of the community facilities that are part of the $30m Onehunga Foreshore development will in fact be replicated further east along the Harbour as part of the East West project,” says Mr Gliddon.

The Transport Agency is working closely with Auckland Council and Panuku Development Auckland to provide improved access to the port area, the project will not block access.

“Rather than hindering any future development, the design of the upgraded interchange at State Highway 20 enables development on the Onehunga Wharf to take place and provide access between the wharf, the town centre and the railway station.”

“Providing this access has always been part of the project plans. We are committed to and will continue to work closely with Panuku Development Auckland to progress a design which enhances access to the wharf, enables future development and considers the physical and visual impacts on the surrounding environment.”



Onehunga Foreshore image gallery Source: Auckland Council
Onehunga Foreshore image gallery
Source: Auckland Council


One small problem. NZTA have not said how their giant interchange at the current Neilson Street interchange would not impact on the Onehunga Foreshore park given how the giant Waterview Interchange on the North Western Motorway affected the causeway along there. With Waterview the North Western has been extended from three to four lanes (if not 5 in some cases) across the causeway with no bus way being built. This expansion is to handle the traffic moving to and from State Highway 20 which will soon join SH16 at Waterview.

The East West Link would follow a similar premise as to Waterview with a four lane highway dumping traffic onto SH20 at Onehunga. The area already gets congested with three lanes each way so you are telling me NZTA won’t build that fourth lane which would cut right into the Foreshore park? Talk about dumping industrial traffic into a parking lot of an existing motorway.

Option F
Option F


In any case while the East West Link interchange might very well not touch the Onehunga Foreshore project it definitely still paves asphalt down the foreshore of the Mangere Inlet.

Given the relative Benefit Cost Ratio of this current proposal of the East West Link is -0.3 (in comparison to Option B) I would like to see NZTA justify an environmentally destructive project that has a BCR showing it would cost and have no technical benefits at all (which is what a negative BCR demonstrates). This is in comparison to to Option B for the East West Link that uses existing infrastructure yet had a BCR of 2.7 (in comparison to Option A) suggesting high benefits to the area in terms to costs experienced.

Transport Blog’s Costs, benefits, and East-West Connections outlines the true suggestive Benefit Cost Ratios of NZTA’s East West Link options.

I’ve ranked the options from least to most expensive:

  • Option A has total costs of $200 million and total benefits of $850 million. Consequently, it has an incremental BCR (relative to spending nothing) of 4.3. In other words, Option A seems like a good project.
  • Option B has total costs of $500m and total benefits of $1650m. This means that it has incremental costs of $300m (i.e. $500m-$200m) and incremental benefits of $800m (i.e. $1650m-$850m). Its incremental BCR, compared to Option A, is therefore 2.7. This suggests that it’s well worth spending the extra money for Option B.
  • Option F has total costs of $800m and total benefits of $1550m. Relative to Option B, its incremental costs are $300m and its incremental benefits are -$100m. Its incremental BCR is therefore -0.3.

In other words, if the NZTA were to follow their own economic evaluation manual it shows that Option F is not great value for money. It costs a lot more while actually delivering fewer economic benefits than Option B. Negative BCRs are generally not a positive sign that a project is a good idea.


Source: Costs, benefits, and East-West Connections


As for the cost of Option B? Calculated at around $240m as of 2013 (so probably $300m today) with that Incremental BCR at 2.7 (compared to Option A) compared to NZTA’s proposal standing at $1.85b (July 2016) with a BCR of -0.3. (December 2015) (compared to Option B).

See An Alternate East-West option


Option B This Should Be the East West Connections
Option B
This Should Be the East West Connections


Any project with a Benefit Cost Ratio below 1.0 should not proceed (the City Rail Link has a BCR of 1.4) while ANY project with a negative BCR should be illegal to do straight off the bat. Yet NZTA decide to project with a motorway project that has a negative BCR rather than upgrades to existing infrastructure that had a high positive BCR rating.


One thought on “NZTA’s East West Link Might Not Trash Onehunga Foreshore But Does Trash Mangere Inlet UPDATED

  1. It would be interesting to find out how much of the Penrose/Onehunga/Southdown production actually travels out of the Auckland Region? Equally, how much of the production inputs are sourced from elsewhere? This then leads to gradually relocating the Light and Heavy Industry from these areas to the outer fringes, say the new park at Drury? Sure would cut back on industrial traffic……

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