Auckland now boasts a second motorway through the sprawling metropolis, with the completion of the western ring route from Manukau to SH1 on the North Shore.

Spanning decades of planning and built in stages, including the 2.4km Waterview tunnel, the final 2km connection between SH18 and the Northern Motorway at Constellation Drive is finished.

The off-ramp to the Northern Motorway opened a month ago and the new SH1 to SH18 underpass will open early next week.

The completed underpass for the Western Ring Route. Photo / Jed Bradley

Waka Kotahi NZ Transport Agency general manager transport services Brett Gliddon said the new motorway is key to people deciding whether to travel through the central city on SH1 or use the western ring route.

 “The biggest benefit is resilience. We have got two motorways through Auckland so if one is down and we have an issue with the Auckland Harbour Bridge we have now got a full, complete motorway network that goes down the other side of the city,” Gliddon said.

He said the $1 billion cost of the project - initially budgeted at $700 million - was within the realm of what was expected given cost escalations and Covid-19.

At the opening of the motorway connection today, Transport Minister Michael Wood said the final stage of the 48km western ring route included about 10km of walking and cycling paths, extending the Northern Busway to Albany and upgrading the Constellation bus station to give people more transport choices.

Transport Minister Michael Wood at the completion of the Western Ring Route. Photo / Jed Bradley

“It’s been complex, it’s been monumental and it’s part of a long-term story of building a resilient network,” Wood said.

The project also includes new hockey, BMX and equestrian facilities, and design features.

Eight-metre-high concrete panels weighing about 13 tonnes each line the walls of the underpass. The colours inside the underpass reflect the changing colour of the surrounding landscape from the coastline to the east and the Waitakere Ranges to the west, said Stephen Collett, regional manager transport services at Waka Kotahi.

The walking and cycling paths run parallel to SH1 from Constellation Station to Oteha Valley Rd and will open shortly.

The completion of the western ring route leaves just two big roading projects across Auckland, widening the Southern motorway between Papakura and Drury at a cost of $655m and Penlink, the $830m road connecting the Whangaparaoa Peninsula with SH1 in Auckland.

The $880m Pūhoi-to-Warkworth motorway is finished and just awaiting final sign-off by an independent reviewer before opening around June.

The new Pūhoi-to-Warkworth motorway is due to open around June. Photo / Waka Kotahi

Wood said at this stage, the Government has no plans for further big roading projects in Auckland but is looking at building more resilience into SH1 north, including between Warkworth and Wellsford and alternatives to the Brynderwyns, where slips have closed the road.

In 2021, the Government scrapped plans for four-lane motorways between Whangarei and Marsden Point and Mill Rd in South Auckland and no plans to build the East-West Link through Auckland’s industrial belt for heavy transport.

The Government’s real focus is completing the City Rail Link, which this week rose in cost from $4.4b to $5.5b; a second Waitematā Harbour Crossing and its most cherished project - light rail from the central city to the airport costing $14.6b.

This week, Prime Minister Chris Hipkins announced light rail would be staged with the first stage expected to be delivered by the middle of this year.