Two into one on toll road as tunnels get a clean-up

Photo / Paul Estcourt

Two-way traffic will be funnelled through each of the twin tunnels on Auckland's Northern Gateway toll road on successive days next week, as the other is closed for maintenance.

The Transport Agency wants drivers to take extra care on Tuesday, when northbound traffic is diverted into the southbound tunnel near Puhoi, sharing it with traffic going to Auckland.

The northbound tunnel will be closed for the day, and probably for some time after dark.

The reverse will apply on Wednesday when the southbound tunnel will close, and two-way traffic will share the northbound structure.

Temporary median barriers will be erected and speed restrictions will be in force.

The agency says drivers should be prepared to be diverted into opposing carriageways at each end of the tunnels.

State highways manager Tommy Parker said last night the closures would be the first since the toll road opened early last year, but the tunnels had been designed to cope with two-way traffic.

The maintenance will include cleaning the tunnels' air-flow fans and walls, and testing their fire safety systems.

Although drivers not wanting to risk delays will be able to use the alternative free coastal route between Silverdale and Puhoi, any disruption will be eclipsed by the closure for 36 hours next month of the southbound lanes of the Newmarket Viaduct, one of the country's busiest motorway sectors.

The agency has chosen Father's Day weekend from 5pm on Saturday, September 4, for the closure, which will extend from Gillies Ave to Greenlane and is needed to prepare for traffic to use a new southbound carriageway from Monday, September 6, as the first stage of its $215 million viaduct replacement project.

Although detours will be signposted, Mr Parker said the agency needed as many as possible of the tens of thousands of people who would normally travel south across the viaduct that weekend to put off their trips, as alternative routes would not be able to cope otherwise.

"We're talking about trying to redirect up to 80,000 vehicles on the Sunday alone," he said. "Even with detours the impact of the closure will be felt well beyond the Southern Motorway."

The agency will suggest that drivers from north of Auckland use parts of the western ring route such as Upper Harbour Highway and State Highway 20 between Mt Roskill and Manukau to bypass the congestion.

Newmarket Business Association chief executive Cameron Brewer said he raised concerns with the agency about closing the viaduct link on Father's Day, which many families celebrated with outings, but was told it was a good weekend for road closures.