The State Highway 18 Hobsonville Deviation and State Highway 16 Brigham Creek Extension project is part of the new Upper Harbour Motorway. The Upper Harbour Motorway has been under construction since 2006 to replace the current State Highway 18 that runs along Upper Harbour Drive and Hobsonville Road.
State Highway 18 Upper Harbour Motorway extends from the intersection of Upper Harbour Highway and Paul Matthews Road in the east, to the end of the Northwestern Motorway (State Highway 16) at Westgate in the west. It passes through the developing residential areas of Greenhithe and Hobsonville.
The motorway is being built in three sections – Greenhithe Deviation, Upper Harbour Bridge duplication, and Hobsonville Deviation. The last section of the motorway, Hobsonville Deviation, is now under construction and scheduled to be completed in September 2011.
- 6 km, four-lane State Highway 18 motorway through Hobsonville.
- 3 km, four-lane State Highway 16 motorway to Brigham Creek Road.
- Four interchanges at Hobsonville Road, Trig Road, Brigham Creek Road (north and south) and Squadron Drive.
- One flyover at Hobsonville Road to connect State Highway 16 to the new State Highway 18.
- Five bridges at Hobsonville Road, Trig Road, Brigham Creek Road, Squadron Drive and Totara Creek.
- One cable stay pedestrian/cyclist bridge at Clarks Lane.
- Four new roundabouts along Brigham Creek Road.
- Sinton Road extended to a new roundabout with Brigham Creek Road.