Separation at Willis would need either significant widening to cater for slip lanes or a major change in traffic management for the whole southern central city. Go under Willis and you probably have to go under Victoria St as they are so close which, with the loss of Tory St access, would make Taranaki St almost all that’s left.

Ps nick leggett is probably keen on grade separation because he has seen how effective it is in Porirua. Anyone want to go back to an at grade Mungavin Ave?

It would be an easy enough diversion to make, even at this stage of the game, but would involve tens of millions, and probably about 2 years of traffic diversions, to lower Karo Drive so that it zips under Victoria and Willis. I wonder if NZTA will ever have the urge to do it?

But the similarities with the Basin Reserve are strong. At neither place is there a huge problem, just traffic grinding to a halt at peak hour, as local traffic wanting to get home clashes with motorway bound traffic wanting to get out. And in Wellington, peak hour barely lasts an hour, unlike Auckland, where it lasts for three hours. A lot of work for such a short time saving.

An underground option would have been much much better, and still would in my view – and yes that question has been raised several times and continues to be a live issue. In my view also Memorial Park undergrounding should be built wide enough to accommodate 4 lanes should that be required in the future – a lot lot cheaper and less disruptive than building a second tunnel.

In terms of history remember that funding when the existing bypass was built was much more limited. Remember that the money available for transport projects (and I mean national level funding) was really constrained until the Government agreed to ‘full hypothecation’ in late 2007. In simple terms that means that something like half (from memory) of the money from petrol taxes, RUC etc went directly into the Government Consolidated Fund – ie not to transport. Obviously that meant that the scale of projects being constructed now was simply impossible then (and that would lie behind periodic observations about historic underfunding of transport infrastructure). Undergrounding was certainly discussed but from a funding point of view was simply not on the table. If I can end with a quote from the Environment Court considering the matter, I think (stand to be corrected on the exact context) it was in the context of declining the retention of designations to allow future undergrounding ‘There is an air of unreality about it (undergrounding)’