Road layout changes as SH1 connection to new motorway progresses


Motorists are advised to watch out for further changes to the temporary road layout on State Highway 1 just north of the Johnstones Hill tunnels.

The northbound lane leaving the tunnel will be realigned to run adjacent to the current southbound lane from Tuesday 23 February 2021. The changes will create a safe working area for construction crews as they progress work to widen SH1 to 4 lanes and connect it to the new Ara Tūhono – Pūhoi to Warkworth motorway.

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The road layout changes will be completed over two nights from Sunday, 21 and Monday, 23 February between 9:00pm and 5:00am. Works will continue for a further three nights from Tuesday, 23 February to Thursday, 25 February to complete the SH1 connection with the Hibiscus Coast Highway.

Traffic management in the form of a stop/go will be in place during this time with a temporary 60kmh speed limit through the construction area. 

“The tunnels area can be a traffic bottleneck, especially on weekends and public holidays so we are making the road layout changes overnight to cause as little disruption as possible to traffic,” says Waka Kotahi NZ Transport Agency National Manager Infrastructure Delivery, Andrew Thackwray.

“We ask that drivers keep to the temporary speed limit for the safety of our work crews and other road users, drive to the conditions and don’t be distracted by work activity.”

The latest road layout changes are part of a staged sequence of work to seamlessly connect SH1 to the new 4 lane motorway under construction.

Once that connection is completed early next year, northbound motorists will be able to drive through the Johnstones Hill tunnel and on to the 330 metre long Ōkahu viaduct (Arawhiti ki Ōkahu). They’ll continue on a short section of the new motorway through a big cut in the hillside before re-joining SH1 at Pūhoi. Southbound motorists will drive the same route in reverse.

“Opening this short section of motorway will give motorists a taste of what’s to come when the motorway is completed. The Ōkahu viaduct is the biggest of seven bridges and the hillside cut is one of many along the alignment, with some rock faces up to 47 metres high.”

The 18.5 km motorway, extending the four-lane Northern Motorway (SH1) from the Johnstones Hill tunnels to just north of Warkworth, is due to open in May 2022.

The new motorway will provide increased safety, more consistent travel times, create a more robust and reliable road between Auckland and Northland, and provide a better freight connection between Northland and the Upper North Island. This is expected to support economic and population growth.

It will also improve connections between the growth areas in the northern Rodney area of Auckland and reduce congestion at Warkworth by providing a bypass for through traffic.

Ara Tūhono -Pūhoi to Warkworth project

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