$2b-plus for widening work

Widening Auckland's Northwestern Motorway as an upgrade to the western ring route between Manukau and Albany is expected to cost as much again as the controversial $1 billion-plus Waterview link.

The Transport Agency has disclosed that the total cost of widening the motorway between St Lukes and Westgate, and building a combined surface-tunnel link through Waterview, is likely to reach $2.2 billion in "escalated dollars".

Northern state highways manager Tommy Parker acknowledged last night that a widening project planned for the next 10 years would rival a cost of about $1.15 million for the 4.5km Waterview link between the Southwestern and Northwestern motorways.

The agency's official cost of the Waterview project of $1.4 billion includes $242 million for widening the Northwestern as far as Patiki Rd at the end of Rosebank Peninsula, and raising its causeway to prevent inundation from Waitemata Harbour.

That initial widening is deemed necessary to cope with extra traffic flows to and from the Waterview link, which is due to be completed by 2015.

But Mr Parker said public consultations were due to start before the end of the year on widening the Northwestern all the way to its connection with the new Hobsonville motorway under construction between Westgate and Greenhithe for $210 million.

He defended the agency's description of Waterview as the final link in Auckland's western ring route, saying its completion would allow drivers to cover the 48km distance on a continuous motorway loop.

But the full widening project was not due for completion until 2019.

Mr Parker's advice followed the Herald's identification of $875.5 million of spending on the Northwestern Motorway listed in the agency's three-year national land transport programme, issued last week.

The programme has also earmarked almost $2.3 billion for a 34km four-lane extension from Puhoi to Wellsford of the Northern Gateway toll road, including more than $100 million in investigations and property purchases to start within the three-year term.

Auckland Regional Transport Committee chairwoman Christine Rose described such sums as "incredible" when the region was struggling for Government funds for an adequate electric rail system.

She said it heightened need for a "level playing field" between roading projects and public transport, and she questioned the manner by which the Government had added items to the Waterview project in what she saw as a bid to justify its economic viability.

Ms Rose said when the Auckland Regional Council was involved in a working party on the Waterview project, it was told the link would reach its traffic capacity by 2016.

"So as soon as it was built it would be chocker-block because of the constraints of State Highway 16 [the Northwestern] and also that it wouldn't reach a benefit-cost ratio that would justify its construction."

She regarded a late addition of the Northwestern causeway upgrade to the project as "almost a sleight of hand to justify the cost of the Waterview Connection, given it would have very limited benefits in terms of its capacity".

Waterview residents seeking information from the Transport Agency are frustrated it has been unable to provide a benefit-cost assessment for the link itself, without the addition of the causeway upgrade.

Agency regional director Wayne McDonald told Tunnel or Nothing protest group spokeswoman Margi Watson adding the upgrade would give the project an economic return of $1.70c for every $1 spent building it.