Waiting game: Auckland not due to get new harbour crossing until mid 2030s

It will be years before Auckland gets a new harbour croossing. Photo / Brett Phibbs

Auckland is not due to get a new harbour crossing until the mid 2030s at the earliest.

Friday's freak 127km/h gust of wind that tipped two trucks on their sides, severely damaging a load-bearing steel strut and causing traffic chaos, is the latest reminder of the fragility of the city's ageing infrastructure.

It is only 12 months since a road-marking truck flipped and burst into flames on the Auckland Harbour Bridge causing mayhem across the motorway system - and a political stoush between the main mayoral contenders, Phil Goff and John Tamihere.

At the time of the local body elections, Tamihere was promising to turn the bridge into a double-decker super structure within six years costing $10 billion.

Goff mocked the idea, saying there was no case for an early start based on advice from the Waka Kotahi NZ Transport Agency and Auckland Transport that a new crossing will be needed after 2030.

Ever since the Auckland Harbour Bridge opened in 1959, a second harbour crossing has been mooted.

There has been talk of a new bridge, tunnels under the Waitematā Harbour, a rail crossing and a radical idea of demolishing the existing bridge for a new arching structure supporting a splay of cables in the shape of a sail.

Firefighters were on the scene to extinguish the blaze after a crash in September last year. Photo / Antony Gray

The 2007 sail design by a team of architects and engineers would carry cars, buses, bicycles, pedestrians and possibly light rail.

After engineers warned in 2007 of a potential for "catastrophic failure" in a worst-case scenario, 920 tonnes of extra steel was bolted and welded on to the clip-ons to extend the life of the bridge.

At the time, restrictions were placed on heavy vehicles using the clip-ons to reduce vibration and help keep the bridge stable during welding of steel inside the box girders.

Today, the clip-on lanes are open to 50-tonne maximum permitted heavy vehicles and heavier vehicles can only use the truss bridge.

Last year, an official report for a new harbour crossing was released by the Transport Agency.

The Auckland Harbour Bridge that had a centre span damaged after a truck crash when a powerful gust of wind tipped it over. Photo / Dean Purcell.

After looking at three different options - a tunnel for light rail, a combined road and light rail tunnel, and doing nothing - the agency said the best option was a combination of a light rail tunnel plus road pricing.

The report said truck restrictions could be needed on the harbour bridge by about 2030, noting 11,000 heavy vehicles travel on the bridge every day, most of them trucks. By 2046, that number is expected to reach 26,000.

The report also said the Northern Busway will hit capacity by 2030.

Transport Minister Phil Twyford told the Herald at the time that the planning and approvals process for the crossing would take "no less than a decade" and construction would take five to seven years.

A business case for the proposal was due to be completed by late last year, but was delayed by six months. The business case has been completed and is now awaiting board approval.