FAQs

This page contains frequently asked questions (FAQs) and answers about Te Aranui o Te Rangihaeata – the Transmission Gully motorway project.

About the project

What is Transmission Gully?

Transmission Gully is a 27-kilometre four-lane motorway north of Wellington that forms part of State Highway 1. It provides important regional resilience and a safe, modern, reliable route to and from Wellington. The motorway has been open to the public since March 2022, however some related construction works are yet to be completed.

It was also New Zealand’s first transport infrastructure project to be delivered under a Public Private Partnership (PPP).

Who was responsible for the construction of Transmission Gully?

Wellington Gateway Partnership (WGP) is the contractor delivering the PPP project for the NZ Transport Agency. CPB Contractors and HEB Construction Joint Venture (CPB HEB JV) was sub-contracted by WGP to design and build the road.

Where did the names for the motorway come from?

The name Transmission Gully came from the 110,000-volt transmission line that used to run through it.

Te Aranui o Te Rangihaeata refers to the route to Kāpiti taken by the great Ngāti Toa Chief Te Rangihaeata, after his stand against Crown forces at Battle Hill. This name was gifted by Ngāti Toa.

What are the key benefits of Transmission Gully?

Transmission Gully provides:

A safer road with central median barriers, a four-lane route and additional crawler lanes on the steeper sections.
Better resilience to landslides, floods and damage to the motorway from a major storm or earthquake.
Quicker reinstatement than the alternative State Highway 59 (former State Highway 1) in the event of a major earthquake.
Peak period travel time savings estimated at around 10 minutes per vehicle for Kāpiti to/from Wellington, 15 minutes Kāpiti to/from the Hutt Valley and five to seven minutes quicker from Porirua to/from the Hutt Valley.
Improved access from State Highway 1 to Porirua and the Hutt Valley with shorter and more efficient freight movements to and from Seaview/Gracefield, Wingate and the Wairarapa.
Important arterial connections for residential and light commercial areas in eastern Porirua to the State Highway network through two new link roads.
An alternative strategic link for the Wellington region, which has improved regional road network security.

Where does Transmission Gully start and finish?

Transmission Gully is an important part of State Highway 1 and the Wellington Northern Corridor. The 27km long motorway connects the Kāpiti Expressway at Mackays Crossing in the north with the Porirua-Johnsonville Motorway near Kenepuru in the south.

It features five interchanges at Mackays Crossing, Paekākāriki, State Highway 58 near Pāuatahanui, Waitangirua and Kenepuru.

If you are unfamiliar with Transmission Gully, make sure you plan your journey and check out our website.

How to drive Transmission Gully

How do get on to Transmission Gully from the north (eg from Kāpiti)?

State Highway 1 connects directly to Transmission Gully just north of the Mackays Crossing Interchange.

If you’re travelling south from Kāpiti, and don’t want to continue on Transmission Gully, you’ll need to exit at either the Mackays Crossing or Paekākāriki interchanges. This will connect you with State Highway 59. This is the best route if your destination is Wellington.

Note: If you miss the southbound exit at Paekākāriki, the next opportunity to turn off the motorway is 15kilometres away, at the State Highway 58 Interchange at Pāuatahanui.

How do I get on to Transmission Gully from the south (eg from Wellington)?

State Highway 1 connects directly to Transmission Gully, south of Porirua near Kenepuru. As you approach the Kenepuru Interchange, stay in the left lanes to continue on State Highway 1 via Transmission Gully. This is the best route if you are travelling to Whitby, Waitangirua, Pāuatahanui, Hutt Valley (via State Highway 58) or Kāpiti.

If you’re travelling to Porirua or further on towards Paremata or Plimmerton, you’ll need to be in the right lanes to continue on State Highway 59.

How long is the motorway?

Transmission Gully is 27 kilometres long and takes about approximately 18 minutes to drive.

What is the speed limit on Transmission Gully?

The speed limit on Transmission Gully is currently 100km/h.

Will the speed limit on Transmission Gully be increased to 110km/h?

We’re currently analysing the consultation feedback alongside technical information, and plan to submit the proposal to the Director of Land Transport for certification soon. Until then, the speed limit on Transmission Gully remains at 100 km/h.

Delivery

Why did construction of Transmission Gully take so long?

Transmission Gully is one of the more significant and complex roading projects in New Zealand. Spanning 27 kilometres of geologically and geotechnically challenging and steep terrain, the project required innovative environmental and construction techniques, with 25 major structures including the largest bridge, Te Ara a Toa, which is 230 metres long and 60 metres high.

Cuts of up to 70 metres were also made through Pouāwhā - the Wainui Saddle, where the Ohariu fault line crosses the motorway. The saddle was lowered to a final crest height of 253 metres above sea level.

Overall, more than 11 million cubic metres of earth was moved during construction of this motorway.

The project was also impacted by COVID 19 and the associated Alert Level 4 lockdowns.

What work is left to do?

From a physical infrastructure roading point of view, the project is substantially complete.

Remaining work includes achieving compliance with overall consenting and outstanding property agreement requirements and defect remediation and decommissioning site compounds once work is finished.

When will Transmission Gully be completed?

No specific timeframe for project completion can be given at this stage. While the parties continue to work towards the end of construction, it should be noted that the motorway continues to provide good, safe service and important regional resilience.

Is Transmission Gully safe to drive if it isn’t fully completed?

Yes. Transmission Gully has been open to the public since March 2022 and continues to provide good, safe service and important regional resilience.

The NZ Transport Agency continues to work closely with both Ventia (the road operator) and WGP to ensure the highway is maintained and kept safe for road users.

Safety

How can I plan my journey?

To plan your journey and stay informed, please check the NZ Transport Agency’s Journey Planner.

Journey Planner(external link)

Can I walk or cycle on Transmission Gully?

No. Because Transmission Gully is a motorway, walking and cycling is prohibited. All southbound on-road cyclists must take the off-ramp at Mackays Crossing to continue on State Highway 59.

The safest route for people walking and on bikes is via the Te Ara o Whareroa shared path through Queen Elizabeth Park, which connects with the Kāpiti cycle route and further south via State Highway 59 to the Te Ara Harakeke shared path.

Walking and cycling

What should I do if I miss my exit?

If you miss your exit, don't stop and reverse – drive on to the next exit instead. If you are unfamiliar with Transmission Gully, make sure you plan your journey before setting off and check out our website.

How to drive Transmission Gully

Please remember to:

drive to the speed limit (remember, the faster you go, the more likely you are to be killed or seriously injured if you crash).
merge like a zip when joining the motorway.
drive to the conditions and turn your headlights on if visibility is poor.
pay attention to any VMS signs, which may advise of incidents ahead or advice for drivers.
do not stop on the motorway unless it is an emergency.
drive without distractions (eg do not use your phone while driving).

What weather conditions can I expect when driving?

Parts of the motorway are located high in the hills and can be affected by strong winds, fog, among other elements. It’s important that you drive to the conditions and adjust your speed and driving accordingly – this includes increasing your following distance.

The variable messaging signs will warn you if there is low visibility, high winds, or other hazards and remind you if the conditions require reduced speed.

What happens if an accident closes the road?

If a crash or other incident, such as a car fire, medical event or severe weather, happens, the motorway may need to be closed to allow emergency services to respond. Variable message signs will be used to advise of incidents ahead and/or advice for drivers, and a detour may also be put in place.

You can also follow NZ Transport Agency Waka Kotahi on Facebook (external link)or Twitter(external link) for the latest traffic.

In the event of a major crash or incident, emergency services manage the response and complete their investigations; Ventia co-ordinates the clean-up, repairs to barriers, etc, and under guidance from NZ Transport Agency or emergency services will reopen the road.

What should I do if my vehicle breaks down or I have an accident?

Transmission Gully uses an Intelligent Transport Systems (ITS) to provide accurate, real-time incident detection and prompt response, as well as the collection of travel data.
The ITS detects changes in the traffic flow using radars along the motorway.

Ventia then directs their on-road Incident Response Service (IRS) team to where it is needed on the motorway, whether it’s for a breakdown or other incident.

Please call 0800 TG INFO to report someone that is broken down or stopped on the motorway. If an emergency, call 111 first.

Is there mobile phone coverage?

As with many roads through rural areas, there have been sections of Transmission Gully where road users experienced issues with mobile phone coverage. These sections vary by mobile provider.

New cell phone towers have been installed by the Rural Connectivity Group (RCG).Regardless of any coverage issues experienced, in an emergency, all cell phone providers reroute 111 calls to the nearest available mobile network.

Are there any service centres or fuel stations along Transmission Gully?

There are no service centres along Transmission Gully.

We advise motorists to use State Highway 59 if they are low on charge/fuel.

You can plan your journey using the NZTA Journey Planner.