KEY POINTS:
Motorists may face extra delays on the Auckland Harbour Bridge today as Transit New Zealand starts re-sealing the elderly structure's two northbound clip-on lanes.
Northbound ramps, to the bridge from Curran St in St Marys Bay and off it to Stafford Rd in Northcote, will close until the lanes reopen on Sunday, January 6 - weather permitting.
Transit NZ says that although three remaining bridge lanes in each direction should cope with most of the lighter post-Christmas traffic, there may be "small" delays.
A similar resealing project caused problems after the bridge's southbound clip-on lanes were closed on Christmas Eve last year.
That led to delays for motorists heading for Christmas lunch gatherings across the bridge the next day, prompting a later start for this summer's programme.
Even yesterday afternoon, traffic was reduced to a crawl on the bridge's northbound approach as families headed across the harbour to visit friends and relatives or to reach holiday spots.
Transit regional manager Peter Spies said the work was scheduled for "the least busy time of year".
Motorists who normally join the bridge from Curran St will be directed by signs to the Fanshawe St on-ramp.
"Provided people are aware of the closures and ensure they leave enough time for their journey, traffic should stay flowing well in both directions," Mr Spies said. "Weather permitting, the bridge will be fully opened before most Aucklanders return from their Christmas break."
He said the smoother surface to be applied to the clip-ons would improve safety and driving comfort over the bridge, which is used by more than 180,000 vehicles on an average week day.
His operations manager, Joseph Flanagan, said the rush would be on to re-open the bridge for the return to work of many Aucklanders in the second week of January.
But the project was weather-sensitive as the polyurethane material used to re-seal the clip-ons, while stronger than the "hot mix" surfacing of the main bridge, needed plenty of preparation and drying time.
Transit is also using the holiday period for maintenance work on the bridge's moveable concrete median barrier, used to keep apart opposing traffic, even though it is to be replaced next summer with a more flexible structure for $9.7 million.
Mr Flanagan said that as well as taking only about 20 minutes to re-align lanes each day - half the existing time - the thinner new structure would allow an extra 75mm to 100mm to be added to the 3.05m width of the bridge's inside lanes.
Transit will open a new bridge on Friday to take traffic on Hillsborough Rd across the $195 million motorway extension it is building through Mt Roskill.
A 130m-diameter temporary roundabout which has kept 40,000 vehicles a day away from the bridge construction site for the past year will be removed on Thursday night.
The western 500m section of Hugh Watt Drive between Hillsborough Rd and Hayr Rd will also close permanently then, to make way for earthworks for the new motorway.
Vehicles using Hillsborough Rd will instead be controlled by two sets of lights at its intersection with ramps to and from the end of the Southwestern Motorway, a main route for airport traffic.
Transit regional capital projects manager Sumi Eratne said that would allow the ground on each side of the new bridge to be cut away to a depth of 6.5m, for the motorway to run beneath it.
That would reduce the existing 5 per cent grade for traffic climbing the hill from Onehunga Bay to a much gentler 2 per cent, once the motorway extension opened in mid-2009.
* ROADWORKS AHEAD
The Auckland Harbour Bridge's two northbound clip-on lanes will close today for resealing.
Hugh Watt Drive west of Hillsborough Rd in Mt Roskill, at the end of the Southwestern Motorway, will close permanently on Thursday night.