Drivers face summer of diversions

Motorists face a summer of road diversions in Manukau City as work starts on a $210 million motorway link and a $14 million regional feeder route to the airport.

As Transit NZ contractors confirm details of a motorway-to-motorway connection between State Highways 1 and 20, Manukau City Council is planning a four-lane regional arterial road to the larger project.

Meanwhile, Government agency Ontrack is working to complete in December a $6 million rail bridge, beneath which the road will pass to directly link Te Irirangi Drive and the new motorway, just south of the Puhinui Rd turnoff to the airport.

Buses are taking train passengers between Papakura and Otahuhu during Labour weekend to allow tracks across a finished section of the bridge to be connected to the main-trunk line.

Subject to the council's acceptance of a roading tender next month, the four-lane road running over the Southern Motorway from Te Irirangi Drive will be extended along two lanes to the west of Cavendish Drive and into Liverpool Ave.

The widened road will join Nesdale Ave through a rail underpass before reaching the new motorway.

It will include cycle lanes and intersection improvements to offer up to 30,000 vehicles a day easier access to the airport.

Manukau City transportation manager Chris Freke said the council had ruled out joining the two ends of Puhinui Rd to improve airport access, as they ran through a residential area.

Australian firm Leighton, which is leading Transit's Manukau motorway contract and has formed a joint venture with local company Works Infrastructure, is preparing for three road deviations this summer at critical points along the 4.5km route between the Southern Motorway and SH20's interchange with Puhinui Rd.

It will create bypasses at the northern end of Roscommon Rd, at Gt South Rd, and at the Southern Motorway's existing Manukau off-ramp.

The four-year project will include the construction of 13 bridges and three motorway interchanges, and a diversion of Puhinui Stream.

But the Transit regional manager, Peter Spies, said it was common to blame delays on roadworks but motorists would soon forget the frequent traffic congestion during peak times on Roscommon Rd.

Apart from the Nesdale interchange and the motorway-to-motorway connection, which will include a 240m north-to-westbound flyover of 10 spans and a west-to-southbound underpass of SH1, a major interchange will be built near the existing intersection of Lambie Drive and Wiri Station Rd.

That will siphon traffic into the motorway network from the Manukau City centre, replacing Redoubt Rd as the main access point.

But Manukau Mayor Sir Barry Curtis is concerned the interchange could become clogged with vehicles using it to gain free access to the 48km western ring route, which Transit wants to toll at seven locations to bridge a $800 million funding gap it says will otherwise prevent its completion by 2015.

Transit intends tolling motorists leaving the route on the southbound underpass to SH1 or joining it in the reverse direction.

It will waive tolls for vehicles joining the western route from southbound lanes of SH1, to discourage trucks from the waterfront or elsewhere from thundering through suburban streets to avoid a toll.

But south-to-westbound motorists will be able to leave the Southern Motorway near the existing Manukau exit, and then join the new road for nothing at Lambie Drive, a prospect which Sir Barry sees as a serious weakness in the tolling scheme.

"If that happens, the result would be appalling congestion, which would defeat the purpose of building the ring route."

Transit consultants will run a mobile centre in Manukau from tomorrow to Saturday to inform local residents about the tolling scheme, which transport planning general manager Wayne McDonald says would be adjusted to minimise "rat-running" through local roads.

Manukau City is spending a further $22 million on other motorway-related activities.

This includes work (which Transit will co-ordinate) on a 1.8km rail spur from the main-trunk line at Wiri and paying for a bridge over the motorway from Barrowcliffe Place, to open about 6ha of council land to development.