John Tamihere’s 18-lane Auckland Harbour Bridge plan would be 'costly and disruptive'

Saturday, 17 August 2019

A look back at the history of the Auckland Harbour Bridge as it celebrates its 60th anniversary. (First published in May 2019)

Experts are skeptical of mayoral candidate John Tamihere’s proposal to balloon Auckland’s Harbour Bridge to 18 lanes.

The former Labour MP announced this week a new two-level structure carrying cars, rail, pedestrian and cyclists would be on the cards if he was elected.

University of Auckland Civil Engineering senior lecturer Dr Rick Henry said the proposal was theoretically possible, but was likely to cause huge disruption and be very costly.

“Multi-level bridges with both vehicle and trains have been implemented successfully overseas,” he said.

John Tamihere is running for the Auckland mayoralty run with Christine Fletcher as deputy.

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“However, replacing the existing superstructure without causing massive disruption to the daily commuter traffic would be almost impossible.”

Henry said the project would likely involve significant additional costs that are likely to make an entirely new bridge or tunnel a more economical option.

The current plan to eventually take the load off the 60-year-old highway bridge is to build cross-harbour tunnels in several decades' time.

AUT University engineering Professor John Tookey described Tamihere's idea as a “classic silver bullet solution” that was likely to come to nothing.

“This is a huge project from the get go. It would be vastly expensive to do even if the existing bridge structure could be fully incorporated without further enhancement,” he said.

The layout of the two-level harbour crossing proposed by mayoral challenger John Tamihere, would be built on the existing bridge piers.

“The idea is for sure blue sky and imaginative, but realistically I think the technical and logistical challenges are substantial and cannot be assumed away.”

Tookey said the impact on traffic flow of having the bridge out of service for a couple of weeks, let alone months, would be significant.

“This is the beauty of the tunnel solution, as the traffic on the bridge can be sustained throughout the construction process with minimal shutdowns,” he said.

Transport commentator Matt Lowrie, of transport blog Greater Auckland, said adding more traffic undermined goals to reduce traffic in the city and make it pedestrian friendly.

“The bridge itself is not the issue, instead it is the approaches that cause bottlenecks and this project does nothing to solve that,” he said.

“It also doesn't address how all the local roads would deal with the extra traffic. The Transport Agency (NZTA) confirmed last year the best option was for a rail only tunnel.”

Mayor incumbent Phil Goff rubbished Tamihere’s proposal as a “fundamentally dishonest” promise that would bankrupt the city.

'Widening the motorway at either end to match the 18 lanes would see massive demolition of buildings and destruction of homes and neighbourhoods. This will cost further billions of dollars that Auckland doesn't have and the Government won't pay for,' he said.

Tamihere said his campaign was all about big ideas and construction on the bridge could begin as early as next year if he won the mayoral race.

'My mayoralty is bringing solutions to quite significant and at times intractable processes – you've got to start somewhere and head down that track, extra work has to be done,” he said.

The mayoral hopeful’s full policy on roading and public transport will be released this week.

Goff has yet to release his transport policy, other than a commitment to make public transport cheaper for school pupils on weekdays.