The planned $270 million Petone-Grenada link road is back on the NZTA drawing board after a review suggested it would be prone to landslides, and would cost more than first thought.

The four-lane highway was proposed to significantly reduce congestion on the busiest part of State Highway 1 north of Wellington, between the city and Grenada North, as well as on SH2 to the Hutt Valley.

It was planned to tie in with the completion of both the Kapiti expressway and the Transmission Gully motorway, handling an anticipated 30,000 vehicles a day by 2031.

But the NZ Transport Agency is re-examining its plans after finding the road’s design  would not meet the necessary earthquake resilience standards. It is reviewing whether an “expressway standard” road is needed, reviewing some of the previously discarded options for the project -  which included routing it through the undeveloped Takapu Valley.

Possible changes also include reducing the speed limit on the road, adjusting interchanges, and reconsidering the path through steeper hills along the route.

Written by Geoff Mowday at Whitby Newsbrief