Chance to check out major links

SH20 project manager Simon Paton says the completed Manukau project will provide a seamless motorway-to-motorway link. Photo / Greg Bowker

Roads-obsessed Aucklanders have plenty of walking to do this weekend if they want to get up to date on two key motorway links about to be opened, in Manukau and Newmarket.

Walkers and cyclists will have a chance to inspect a new motorway-to-motorway link between the western ring route and State Highway 1 on Saturday, before the Transport Agency opens its southbound lanes hours later to traffic.

The agency is also organising a mass walk followed by a cycle ride on Sunday across a new 690m southbound carriageway, part of a $215 million project to replace Newmarket Viaduct.

Vehicles will not get to use the new carriageway until after the following weekend - September 4 and 5 - when the agency hopes goodwill curried by the walkover will translate into public tolerance during a closure of the viaduct's southbound lanes for up to 36 hours.

But, weather permitting, the agency wants to open southbound lanes on its new 4.5km link between the Southwestern and Southern motorways on Saturday night with little fuss. The link will allow drivers to travel by motorway from New Windsor at the western end of Mt Roskill to Manukau and beyond without having to stop at any traffic lights.

Until now, they have had to endure 12 sets of lights between where the Southwestern Motorway has ended at Roscommon Rd, and the Redoubt Rd on-ramp to SH1, via Wiri Station Rd.

Traffic heading in the opposite direction will have to wait until next month for the link's westbound lanes to open, and a direct exit from the motorway to the airport will take until December to complete, because that will require a 150m realignment of Puhinui Stream.

That means traffic now turning left from Roscommon Rd to the airport will have to head north until then along the Southwestern Motorway, before looping back along George Bolt Memorial Drive.

The $210 million motorway extension project, which began in 2006, has required the construction of 12 bridges including a 240m flyover of SH1 to be used by north-to-west traffic.

East-to-south traffic will pass under SH1, which faced three temporary realignments while a cut-and-cover trench was dug beneath it in stages.

Although ramp signals will moderate traffic flows off the flyover, vehicles joining SH1 from the Southwestern Motorway will not be held up by any lights until reaching Huntly.

The new motorway link will see substantial reductions in traffic from Wiri Station Rd, which is now used by about 40,000 vehicles a day.

It has four interchanges, including at Lambie Drive and Cavendish Drive, which has been extended to the motorway to form a main arterial feeder link to the airport for traffic travelling from East Tamaki via Te Irirangi Drive.

Transport Agency project manager Simon Paton said a reconfiguration of roads around the western end of the new link would cause temporary inconvenience to some drivers, such as those now using Roscommon Rd to reach the Southwestern Motorway from Manurewa.

But Mr Paton said the completed project would provide a seamless motorway-to-motorway link which will be the southern gateway to the 48km western ring route.

Walking and pedalling the motorways

MANUKAU MOTORWAY - New southbound lanes.

When: Saturday 10am-1pm for walkers; 1pm-2pm for cyclists.

Entry: From Lambie Drive.

Transport: Free buses will pick up and drop off walkers between Cavendish Drive interchange and Davies Ave.

NEWMARKET VIADUCT - New southbound carriageway.

When: Sunday 9am-2pm for walkers; 2.45pm -3.30pm for cyclists.

Entry: From project visitor centre in Mahuru St near south end of viaduct.

Parking: Very limited.