East-west motorway link to cost over $1.4 billion

One crucial step in solving Auckland's traffic congestion is to complete the western ring route - a new motorway corridor through the narrow Auckland isthmus.

This major investment will cost $1.4 billion to $1.8 billion, depending on the route and design chosen for the Southwestern Motorway route through Avondale.

As well as providing an alternative route through Auckland it will improve access east and west between rapidly developing areas in the North Shore, Waitakere and Rodney. Already the Upper Harbour Drive route across the Upper Harbour Bridge becomes congested at peak times.

The ring route starts as the Southwestern Motorway (SH20) leading from the Southern Motorway at Manukau. It goes through Manukau City towards Mangere, with an exit on to Puhinui Rd leading to the Auckland International Airport, and Onehunga.

From Onehunga it goes through Mt Roskill, then Avondale, connecting with the Northwestern Motorway (SH16).

That will lead in turn to the Upper Harbour Motorway (SH18) at Westgate, which will go across to the existing Upper Harbour Highway, which connects with the Northern Motorway (SH1).

It will also be a link with the length of State Highway 16 that leads on through Helensville in the west and across to Wellsford - an alternative route to Northland.

It will be more than a decade before the western ring route is complete, but most of it will be available before that. Each project involves extensive consultation with local bodies, residents and others affected, as well as Land Transport NZ's (formerly Transfund) agreement on finance.

Among the projects now being built or planned along the ring route are:

Southwestern Motorway

1. Manukau extension

This $174 million extension links the Southern Motorway at Manukau and the Southwestern Expressway at Puhinui. Construction starts next year. It will probably be finished by the end of 2010.

2. Puhinui interchange

The interchange on the expressway leading towards Mangere Bridge takes this route over Puhinui Rd. Now finished and one of Auckland's busiest interchanges, it was the first step linking the Southern and Southwestern motorways. It cost $14.5 million.

3. New Manukau crossing

This is planned next to the existing four-lane bridge (a structure begun in 1972 and opened in 1983 after seemingly endless industrial disputes).

The planned new structure is still being investigated, but bus lanes and a possible rail link to the Auckland International Airport have been mentioned.

Approaches to the two bridges will be widened to six lanes to avoid congestion, including widening Hugh Watt Drive on the Onehunga side.

It will cost $146 million, starting in 2009-10 at the earliest, with an expected 2012-13 finish.

4. Mt Roskill extension

Construction of this 4km extension, costing $169 million, starts soon and will be finished by 2010. This addition will lead to the next stage.

5. Avondale extension

This is planned as the final link in the southwestern connection to the Northwestern Motorway, probably at Waterview, and is perhaps the most complicated part. The route is not yet designated as it is still being investigated and is subject to consultation.

The area is highly developed with housing and businesses and not many parks. The motorway project could cost $600 million to $1 billion, as it may be built below ground level and even put in a tunnel in places. Construction is due to start in 2010-11 with completion another 10 years away.

Northwestern Motorway

(Downtown Auckland to Westgate)

The Northwestern Motorway is the middle and long-established part of the western ring route. Numerous improvements are planned to help reduce congestion.

6. Port and Northern Motorway access

The Northwestern Motorway is already getting direct access to and from the Auckland Harbour Bridge and Northern Motorway as part of the $195.4 million works on Spaghetti Junction in the central city. And it has access to and from the Port of Auckland, through Grafton Gully.

The direct access to and from the Southern to the Northwestern Motorways in the central city is being improved and altered.

7. Newton Rd to Western Springs

A $6 million auxiliary lane will allow traffic from Newton more time to merge as it enters the Northwestern Motorway. Construction starts soon and finishes in 2007.

8. Southwestern to Northwestern interchange

This is still being planned, and the cost is included in the Avondale extension estimate.

9. Te Atatu interchange westbound off-ramp

A $4.8 million project to upgrade this off-ramp should begin in 2009-10 and be finished in 2011.

10. Te Atatu to Royal Rd six-laning

This $22 million project will give another lane each way as far as the Royal Rd interchange.

Due to begin in 2011-12, this work will be needed to cope with extra traffic coming from the Southwestern Motorway through Manukau, Mt Roskill and Avondale.

Upper Harbour Motorway

This new motorway will run from Westgate at the present end of the Northwestern Motorway across to the present Albany Expressway off the Northern Motorway in the east.

Projects on this new route include:

11. Hobsonville deviation

This $141 million project will start in 2005-6 and its 5km route from the Upper Harbour bridges to Westgate should take one to two years to build.

12. New Upper Harbour Bridge

A new, superior, Upper Harbour Bridge is being built alongside the existing one.

The $37 million project, to be finished by the middle of next year will have three uphill lanes with the existing bridge having two downhill lanes. Pedestrians and cyclists are being catered for.

13. Greenhithe deviation

This $94 million, 5km route will run from the Upper Harbour Bridge through to join the Albany Expressway. It is due to be completed by mid-2007.

14. Kumeu-Helensville-Wellsford (SH16)

This state highway route beyond Kumeu is now being pushed as an alternative route to State Highway 1 going north to Wellsford and Northland, especially during holiday weekends.

Upgrading is planned on this route, not least because of expected population increases around Huapai, Kumeu, Helensville and Parakai.

Some projects may be hastened by injections of funding from the new 5.6c a litre petrol tax expected to feed a regional development fund from about April.

Given recent sharp rises in petrol prices a final Government decision is still awaited.