Upgrade to SH58 interchange prior to Transmission Gully opening


Work will begin this Friday, 12 February, on a major upgrade of the State Highway 58 (SH58) interchange at Pāuatahanui to allow for more traffic and better flow between SH58 and the new Transmission Gully motorway, scheduled to open in September this year.

The roundabouts, which will function as an interchange between SH58 and Transmission Gully, are being upgraded from one lane in each direction to two lanes in each direction. The roundabouts will connect with the Transmission Gully motorway on and off ramps.

Construction will begin this Friday and will be completed within six months.

“We’re urging motorists to be aware that the layout on SH58 at Pāuatahanui will change during construction, and to take care at all times,” says Waka Kotahi National Maintenance and Operations Manager, Neil Walker.

“The widening of the lanes will initially involve night works under stop-go traffic management, which will be followed by work during the day with a temporary speed limit of 30km/h.”

With the Wellington region exceeding population growth projections, particularly in areas outside of the city, traffic volumes on the state highway network have exceeded original expectations.

“Modelling shows traffic volumes will be much greater than originally forecast, so we are upgrading this key interchange to avoid congestion when the motorway opens.

“Doing this work now will help avoid congestion on the ramps connecting to the Transmission Gully motorway and at the roundabouts on SH58,” Mr Walker says.

Once Transmission Gully opens, the SH58 interchange at Pāuatahanui will connect the motorway with SH58 to the Hutt Valley in the east and Paremata in the west, via Pāuatahanui and Whitby.

An average of 20,000 vehicles per day are expected to use the interchange to travel to and from the Hutt Valley when Transmission Gully opens to traffic later this year. Average daily traffic on this section of SH58 (between Pāuatahanui and the Hutt Valley) is currently around 19,000 vehicles - already higher than the 15,000 that was originally forecast back in 2010.  

Traffic volumes on SH58 west of Transmission Gully (between Pāuatahanui and Paremata) are forecast to drop from 19,000 to 11,000 vehicles per day after Transmission Gully opens.

Plan ahead for a safe, enjoyable journey. Keep up to date with: