The Kenepuru interchange is a partial interchange. From Kenepuru Drive, traffic can use the interchange to head north or south on Transmission Gully. Traffic travelling southbound from the north on Transmission Gully can also access Kenepuru Drive through the interchange.
Traffic travelling north from Wellington won’t be able to get off at the Kenepuru Drive interchange. Instead, traffic will remain on the existing SH1 and use the Mungavin Bridge exit as it currently does.
Originally a full interchange was planned at this location however an independent safety audit highlighted significant safety concerns about the proposed northbound off-ramp. Numerous interchange designs were developed but none could satisfactorily address the safety auditors’ concerns, and with the agreement of the NZ Transport Agency (NZTA) and Porirua City Council, the northbound off-ramp was deleted.
As a part of the interchange there is a new link road that bridges the existing SH1, the North Island main trunk railway and Porirua Stream, connecting the interchange on Transmission Gully with a new roundabout on Kenepuru Drive.
You can check out this NZTA aerial overview (YouTube) of the Kenepuru Interchange, where it fits within Transmission Gully and where the link road joins into Kenepuru Drive.
Traffic modelling undertaken by the NZTA to understand the effects of the change to the Kenepuru interchange predicted only minimal increases in traffic volumes (e.g. 180 extra vehicles at the morning peak) following the opening of Transmission Gully, which will not adversely affect the operation of the Titahi Bay Rd roundabout opposite Kenepuru Drive.
However, given what we now know about the Kenepuru Landing development and the proposed Adventure Park, the Council is undertaking further investigations to see what the impact will be in terms of more traffic, trucks, cyclists and pedestrians, and how to best manage vehicle and people movements in the area.
We are currently working on an Integrated Transport Study for the city which will identify transport issues and how we can address these. It’s not just about traffic numbers, it’s about how people move around and get to the places they want to go to; whether that’s customers visiting businesses, parents dropping off children to school, people commuting to and from work, or trucks accessing the Spicer Landfill or the other commercial and industrial businesses at Kenepuru, Broken Hill and Elsdon.
Council’s District Plan consultation is ongoing. One of the issues being looked at is how the interchange will connect into the existing transport network and how the community will move around, within the context of the projected growth and development of the city. An informal draft District Plan will be released in October 2018 for feedback and comment.