New roundabout on SH16

The two-lane roundabout on the Northwestern Motorway extension. Photo / Supplied

Traffic on State Highway 16 north of Auckland will have a large new roundabout to contend with from today to replace a dangerous unregulated intersection with Brigham Creek Rd.

The two-lane roundabout has been built at the head of a 3km extension of the Northwestern Motorway, which is being constructed as part of the $220 million Hobsonville motorway project.

Although the four-lane extension will not open until 2012, at the same time as a 6km motorway section of State Highway 18 between Westgate and the Upper Harbour Bridge at Greenhithe, the roundabout will from this week serve more than 5000 vehicles using Brigham Creek Rd daily.

Instead of having to make right turns directly into SH16 towards Kumeu and Huapai - after waiting for breaks in traffic travelling in an80km/h zone - drivers heading from Hobsonville and the North Shore will find the roundabout levelling their odds against more than 20,000 vehicles using the main road each day.

But the cost to all motorists will be having to comply with a 50km/h speed limit through the roundabout.

The new roundabout will eventually feed traffic directly into the Northwestern Motorway, although motorists heading from the north to Hobsonville will have to keep using Brigham Creek Rd in the short term.

That is because the Transport Agency initially considered there would not be enough traffic to justify a direct motorway-to-motorway link between SH16 and SH18 north of Westgate.