Supporters of a sweeping new "Anzac Centenary" bridge across Waitemata Harbour have won support from Auckland City's transport committee for it to be added to a study of various tunnelling options.
The committee decided yesterday to refer a concept design by a team of architects and engineers for an arching structure 1 1/2 times longer than the existing bridge to a harbour crossing working party to be led by Transit NZ and the Auckland Regional Council.
It would follow a similar route to Transit's preferred $3 billion tunnel proposal between Northcote and the Tank Farm but without retaining the existing bridge, which would be demolished to free up land around St Mary's Bay and Westhaven.
The project was championed by Hobson Community board chairman David Simpson, the brother of city transport chairman Richard Simpson, in a presentation to the committee with the architectural firm Jasmax.
Transit was to seek a route protection designation under the Tank Farm for a post-2020 four-lane tunnel before agreeing to a joint study between now and next March to find alternatives.
These include possible tunnel routes between Northcote and Stanley St and between Bayswater and Mechanics Bay, to reduce traffic through central Auckland.
The highways agency has indicated opposition to building a bridge to the Tank Farm, saying it would be too disruptive to plans by Auckland City and the regional council's property arm to develop that into a prime waterfront precinct.
But David Simpson said demolishing the existing bridge and replacing it with a structure big enough to take similar traffic volumes plus a light-railway system, cyclists and pedestrians would free up far more land than the 35ha Tank Farm development, and 3.3km of coastline.
The land would be so valuable that sales from it would virtually pay for the new bridge, which would gain the potential from light-rail to carry three times as many people as the existing structure but with no increase in motor traffic through the central city.
It could be ready in time to mark the centenary on April 25, 2015, of the ill-fated landing of Anzac troops at Gallipoli.
Dr Simpson said a 700-metre saving in distance travelled over the new bridge, which would be on a more direct route than the existing structure, would amount to 70 million kilometres in avoided travel for every 100 million trips across it.
"You would need to be myopic or blind with arrogance to not consider this new option," he said.
Jasmax director Hamish Boyd said bridges were not necessarily undesirable from an urban design stand-point, compared with the "large slot" in the ground needed for a tunnel portal.
The left-hand motorway bend for northbound traffic coming off the Victoria Park viaduct was always difficult, "so the whole idea of straightening things up, getting the [old] bridge out of everybody's hair and leaving something beautiful seemed like a good idea."
Action Hobson councillor Christine Caughey said a tunnel would mean large above-ground vents for traffic emissions.
City Vision co-leader Richard Northey noted that a bridge would be far cheaper to operate, even if new technology could reduce higher tunnelling costs.