In-depth investigations

Investigations started in 2006 and provided the first real opportunity to conduct on-site, in-depth investigations into the impact of the designated alignment on ground and environmental conditions. Limited knowledge of these effects was available when the alignment was first proposed.

Drilling and seismic survey testing, a road safety audit, traffic modelling, cost, risk and value engineering assessments have been undertaken in order to arrive at an option, for further consultation, that provides the most appropriate environmental, transport and engineering solutions and is value-for-money.

Advantages of preferred route

The preferred route has several advantages, including greater resilience to earthquakes and less impact on waterways, and is cheaper to construct in real terms than the designated alignment. It minimises the impact of geological hazards like fault lines, landslides and soft terrain.

The preferred Transmission Gully route is currently estimated to cost $1.025 billion and should result in a saving of about $275 million on the cost of the originally designated alignment. That is because the previous estimate of $985 million inflation adjusted today would be $1.3 billion, based on Land Transport New Zealand's escalation figures.

The Government is committed to the release of $405 million earmarked for the Western Corridor highway once the Wellington region re-confirms its commitment to the route. The Minister of Transport has said that she hopes by late 2009 the region will be able to confirm how it will fuind projects like Transmission Gully and come to the Government with its funding plan for this project and other strategic priorities.

Consensus

A consensus on the preferred route has been reached by Transit New Zealand and Wellington's regional and territorial councils which have co-operated closely during the preliminary investigations.

The next stage of the project is public engagement which will see all households in the Greater Wellington region receiving a brochure with a feedback form. Submissions close on 20 August 2008. The draft scheme assessment report will be available at the end of July.