SH1 Tīrau to Waiouru accelerated maintenance project update

The 600T crane gets to work on the Mangatoetoenui Bridge

31 January 2025

NZ's largest mobile crane in action

This week has seen the heavy machinery set up at the Mangatoetoenui Bridge site. The huge 600-tonne crane week was assembled on its temporary pad and has begun the heavy lifting. It took 5 trucks to bring all the components of the 16-wheeled crane onto the site last week! 

While the trucks rolled in and the crane was being assembled, the timber deck of the old bridge was removed. This marks the end of an era, with the Maungatoetoenui Bridge the last timber-decked bridge on SH1 in the Waikato region.  

The crane got straight to work, removing the existing 18-metre-long steel bridge beams which will be replaced with stronger beams to accommodation the concrete bridge deck. The old beams will be stored initially and then re-used on other projects in the future.  

Work is underway to prepare for the installation of the modern bridge deck, which has been pre-manufactured off site to make site-works safer and faster. The new deck will be transported to site in 2 loads – each 68 tonnes - on Monday.

Going full steam on the Desert Road

The Desert Road has been a flurry of activity this week, with largely settled weather allowing crews to get on with repair and rebuilding work across the sites. Those earthquakes may have given the ground a little bit of a shake up, but not the crew! 

There is plenty of shaking going on thanks to the many machines in action - foaming stabilising machines, rollers, graders, and excavators, as well as the trucks and trailers carrying metal and cranes into the worksites.

No access from Desert Road to DOC sites

From next week there will be no access to any Department of Conservation (DOC) sites from SH1 between the Waiouru and the junction with SH46.

This includes campsites and walking tracks in the Tongariro National Park and Kaimanawa Forest Park that are accessed from the Desert Road. 

The relevant sections of the DOC website will be updated so that people heading into the great outdoors can plan and prepare.

We are also looking at putting in additional restrictions for those wanting to turn from SH46 onto SH1 and vice versa – these are now only accessible for the residents, marae and businesses. The amount of traffic using this with the idea it would be quicker – or to check out the work in progress – were not only slowing the progress on the site down, but also affecting those businesses who operate in the soft closure area. The intersection of SH1 and SH46 is within the work zone so there must be limited access.

Traffic on the Desert Road detours

Meanwhile, the detour route around the SH1 closure of SH49/4/47/41 continues to keep traffic flowing through the North Island. Currently, journey times from Waiouru to Turangi are around 1 hour 20 minutes on the detour route, compared to 45 minutes on SH1 through the Desert Road prior to the closure.

There has been some congestion at times, as expected with anniversary weekends for Wellington and Auckland in January. The peak traffic has been on Fridays for the last 2 weeks.  We’ll continue to monitor the detour route and we suggest drivers relax and enjoy the amazing scenery on offer on the western side of Ruapehu. 

We have made some changes to the signage near Ohakea as a result of feedback from businesses in Bulls. It seems that people may have  been electing to miss SH1 as much as possible and taking SH4 to Whanganui. We have made the signage clear that SH1 is closed AFTER WAIOURU in an effort to get people to use the official detours through to Waiouru on SH1 and then off at SH49. While we can't force people to use the offficial detour, it is recommended. We certainly want to avoid any confusion.

Once the kids are back at school and Waitangi weekend has been enjoyed we’re expecting to see a reduction in traffic volumes. 

Detours are generally working well, and no delays have been reported across the route. Here’s some statistics you may find of interest:  

• The traffic count on SH4 Horopito (official detour) shows the number of vehicles (including heavy vehicles) has increased between 2.4 and 3.3 times since the closure of SH1 Desert Road. 
• The average volume (Mon-Fri) the week prior of the closure was 2,647 vehicles. During the first week of the closure was 7,149 and the second week was 7,730 vehicles. 
• During the same time periods shown above (Mon-Fri), there was increase of approx. 1,480 vehicles at SH3 “8-mile Junction”, indicating that traffic numbers heading further north increased, however the majority of traffic is continuing on the official SH detour. Note the data is skewed by the Christmas peak holiday period and public holidays, ie Friday 24 January saw a huge increase due to Auckland Anniversary day and similar on the Friday before (Wellington Anniversary). 
• From 10 February onwards (after Waitangi day) data will provide a truer reflection on how the roading network is behaving. 
• The detour is adding on average 35-40 minutes to the trip. The average journey time on the SH49/4/47/41 detour since  Monday 13 January (when the road was closed and detour installed) is 1 hour 20 mins. The average journey time when the SH1 Desert Road is open between Turangi and Waiouru is approx. 45 mins. 
• On SH32 around Lake Taupo (western access) – this road is actually showing around 330 less vehicles per day since the closure.
• Speeds on the SH49/4/47/41 detour are averaging between 80-85km/h. The congestion on Fridays of the recent long weeks appears to have been the cause of frustration for some.

SH1 Tīrau to Putāruru final surfacing tracking well

This work is being done at night, from 7pm to 6am and is progressing really well.

While the road is closed at nights, there will be a short detour using State Highway 5 and State Highway 28. This only adds an extra 4.6km and approximately 8 minutes to journey times. 

Tonight, both lanes of the passing lane will be paved at the same time – one of the benefits of full road closure is being able to have 2 pavers working in tandem when the site allows. 

We’ve got some great footage of the work being undertaken already – look out for that in the next week on social media and in this newsletter.

Speed Management on SH1

This week the Prime Minister and the Minister of Transport announced there would be changes to speed limits in various areas, and also that we would be going to consultation on speed limits in other areas. 

This includes SH1 Hātepe to Tūrangi.   

We will be consulting with the public to understand if there is community support to retain the lower speed limits on all or part of this route.  The consultation is now open and will run until Wednesay 13 March 2025. Submissions can be made using the short survey which will be on our website, along with information on consultation happening on other sections of state highways throughout NZ.

Future closures of SH1

SH1 Pūtaruau to Tokoroa – 3 March: SH1 will be closed for approximately 4 weeks for road rebuilding from Domain Road to Pinedale Road. There will also be approximately 2 weeks of night closures and/or stop/go traffic management in early April and again in late October for the final surfacing of the road rebuilds completed.  

The appropriate detours are still being worked through with the South Waikato District Council and may look a bit different to the detour used for the first lot of closures, so keep an eye on this newsletter and our website for the latest information. 

We could not do this work during the first closure as we could not get all the work needed in December completed before Christmas, when there was a moratorium on road works. 

Access to the VTNZ and the Timber Museum and cafe will still be available to their customers – both are just within the work zone (500 metres in).  We will be able to accommodate this with careful management.

SH1 Ātiamuri to Wairakei – 3 March: SH1 will be closed for approximately 4 - 5 weeks to rebuild the southern end and finish the safety improvements closer to Ātiamuri. Both Higgins and Downer will be working on their sites within this closure. 

Like our last set of closures, our team are out and about talking to residents and businesses who will be impacted by these closures. You can email the team if you have any specific needs or concerns about the upcoming work and we will be in contact.

More information

This work forms part of the government’s $2.07 billion investment into road and drainage renewal and maintenance across 2024-27 via the State Highway Pothole Prevention fund.
Please pass this on to others who may be using SH1 in the next few months and encourage them to sign up to this newsletter by using the subscribe button below.

For more information or any concerns on the SH1 Tīrau to Waiouru maintenance, please email us.

Visit our website www.nzta.govt.nz/t2w

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