Sh1 safety work update

Engineers John Balcombe and Rob Mackie of Downer, and the NZTA's Nat Larmer oversee the massive earthworks under way at Akerama. Photo / Michael Cunningham

One of Northland's most dangerous stretches of road is being made over and drivers passing through Akerama Curves will be struck by the scale of the works.

The straightening of the stretch of State Highway 1, north of Whangarei, is finally under way after more than 10 years of talk. The Akerama Improvements Project will realign dangerous curves along a 3-kilometre stretch of SH1. It is designed to improve safety and access, with the creation of a new southbound passing lane and the extension of the existing northbound passing lane.

The final result - expected in 2017 - will remove tight corners and steep curves between Barnes Rd and Rusk Rd, about 35 kilometres north of Whangarei.

RoadSafe Northland's Gillian Archer said it was a good to see the work start.

"It's been on the agenda for a long time. There's a sophisticated tool that NZTA has which shows that whole area has a higher rate of serious and fatal crashes than just about anywhere else in Northland," Ms Archer said.

Most of the work going on at the moment is earthmoving to cut through hills to make way for the new alignment. It involved the shifting of 121,000 cubic metres of soft unstable soil - 48 Olympic swimming pools' worth - to be replaced with 145,000 cubic metres of "engineered fill". The unstable soil will be landscaped to look like the surrounding environment.

The New Zealand Transport Agency's Northland highway manager, Brett Gliddon, said earthworks on the hilly terrain were time-consuming and weather-dependent. The embankment had to be built in 2.5cm layers, with each layer dried, compacted and tested as it was laid. Several natural springs in the area also posed challenges in terms of creating a solid foundation for the road.

"We have also started building a temporary road so that we can keep traffic moving while we build the new permanent alignment," Mr Gliddon said.

The $15 million project included a new wetland area, which would be planted in about two months. The Akerama Improvements Project was part of the Government's Regional Accelerated Roading Package.