Tīrau to Waiouru is one of the largest and most ambitious maintenance projects in New Zealand. Part of the Government’s $2.07 billion Pothole Prevention fund, the project condenses 4 seasons of maintenance into 2 maintenance seasons, reducing the future disruption on the sections of SH1 treated.
The Tīrau to Waiouru Accelerated Maintenance project goes beyond basic maintenance delivering condensed work, including road rebuilding, to improve the overall condition of the road and reduce the amount of future road works and disruption needed on this section of SH1.
The project uses staged full road closures to:
The work is designed to meet expected traffic growth, and have a long-term life, ensuring the sections of SH1 worked on are resilient into the future.
New Zealanders want a well maintained and reliable transport network. Between SH29 at Piarere and SH49 at Waiouru 5,670 potholes were repaired between July 2022 and April 2024. That meant a lot of road works disrupting traffic.
We have heard how disruptive multiple roadwork sites and traffic delays can be, especially for the freight industry, and we know that having reliable, predictable journey times is important to everyone. Our work will build a stronger road, less prone to potholes and reduce the amount of future disruption needed by road maintenance on this section of SH1.
While sections of SH1 are closed in blocks, we are also bringing forward future work, working with other service providers who might need to carry out maintenance in the road corridor and carrying out other work including vegetation clearance, widening parts of the road, refreshing road markings and fixing drainage.
We recognise and acknowledge there will be inconvenience and disruption to people while this work is carried out, especially locals and businesses on SH1 and the detour routes. Doing the work now and using closures means there will be a considerably longer period when there will be far less roadworks in the future.
We continue to work closely with the local councils, iwi, freight industry, emergency services, bus companies and tourism organisations on planning the staged closures. All closures will have allowances for emergency services, locals and their suppliers to go about their ordinary journeys as much as possible, and access given to towns centres. Work required in any town centres will be done under night closure only, to lessen disruption to the daytime activities.
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View larger map of the accelerated maintenance project [PDF, 288 KB]
For details on the works, see our Works programme page
CloseTīrau to Waiouru is one of the largest and most ambitious maintenance projects undertaken in New Zealand to date.
We’re using full road closures to get the work done in the shortest time possible. If we did the work under traditional traffic management and stop/go it could be up to an additional 4 years of work.
CloseWe return to do the final surface on the sections we have worked on up to about 12 months after the first coat of chipseal is bedded in. The rebuilt road needs time with normal traffic using it in order to settle in. Applying the final asphalt surface too early will result in a poorly finished surface, as the pavement layer may continue to be compacted after the final coat is laid, resulting in an uneven road surface (rutting). The second coat provides a thick, durable layer of chip seal, waterproofing the surface underneath. This process prevents ‘flushing’, which is where the bitumen rises to the surface of the road, making it shiny and slippery.
In some other areas along T2W we have returned to complete works that were stopped to minimise disruption on SH1 during public holiday periods or to minimise disruption during large events.
For example, we returned in early 2025 to complete work from Putāruru to Lichfield, between Domain and Pinedale Roads. This work couldn’t be done during the first closure of this section as we wanted to avoid having major disruption on SH1 during Christmas.
Work on the Ātiamuri to Wairakei section was also reprogrammed to accommodate the busy Christmas holiday period and the large Taupō Ironman 70.3 World Championship event. We also combined our T2W project work between Ātiamuri and Wairakei with a major safety improvement project being delivered by contractor Higgins who started that project in 2022.
CloseWe use summer to resurface and rebuild roads as the weather is warm and dry, which helps ensure quality outcomes and longer-lasting roads. Road maintenance is heavily dependent on the weather and the ground temperature is particularly critical.
In many sections of Tīrau to Waiouru we’re using Foam Bitumen Stabilisation (FBS) to strengthen and repair sections of road where the underlying layers (the pavement) are in poor condition. FBS allows us to work quickly to repair larger sections of road, so they are ready for sealing. FBS uses bitumen, water and air to create a foam which is mixed into the aggregate with cement. When cured it creates a more waterproof and resilient structure when compared to the traditional granular methods of road construction.
For FBS to be effective, we need the ground temperature to remain above 13 degrees, which is why we need to do a lot of work in the peak summer period.
There is also other maintenance work we are carrying out which can still be done when the temperature temperatures do fall below 13 degrees, but we do need to work when the weather is more settled as wind and rain also limits what we can do.
CloseAcross the Tīrau to Waiouru project there have been sites where work has been undertaken both night and day, while in some instances there is either day or night work.
A lot of factors go into our decision. These include coordination of work crews while managing fatigue to ensure everyone is fresh when they turn up to work. We also consider the availability of materials and the logistics of getting those materials to work sites across New Zealand when they’re needed. The overall cost of how we coordinate all these moving parts, risk factors and impact on road users must be considered.
There are also specific work activities we can do at night, while others are best suited during the day. Generally, the Foam Bitumen Stabilisation (FBS) process being undertaken on the Tīrau to Waiouru project cannot be done at night, because of the lower temperatures. On the other hand, asphalt resurfacing, which we are also doing, can be done at night and we’ll do that when we’re able.
In some cases, we must also completely close the road whether we’re working day or night, because of the intensity and pace of work we are doing and the fact the road is often not safe for the public. On the Tīrau to Waiouru project we are doing large areas of road rebuilding, which can mean large sections of the road are uneven, with significant and sudden changes in depth.
The closures do improve productivity, removing the need for traffic management set up and pack down, allowing our teams to work longer hours than usual including both day and night, where we can. So, when you see a state highway closed but crews not working, rest assured there has been a huge amount of planning and logistics work undertaken to ensure the overall work activity is happening in the most efficient way possible.
CloseWe look at a range of factors, including the time a detour will add to people’s journeys, the suitability of the road for the additional volume of traffic, whether all parts of the road and bridges can cope with heavy vehicles, and safety.
We work closely with the freight industry, logging and dairy companies, and local councils to come up with the plan. These discussions will often lead to the detour being tweaked to make sure we minimise the disruption as much as possible.
We also take into account what events or activities may be happening in the area and ensure as much as possible that there is not going to be other work on roads, bridges or nearby potential detours that would result in considerable further disruption. The local council may have a schedule of maintenance and projects that we need to take into consideration. These discussions will often lead to the detour being tweaked to make sure we minimise the disruption as much as possible.
CloseSummer is the season for road maintenance, so you are likely to come across other road works on the detour routes.
The road maintenance work season typically goes from 1 October to the end of March. Generally, the weather is more settled during this period and our work won’t be impacted by rain and cold temperatures.
New Zealand’s state highways are managed and maintained by NZ Transport Agency Waka Kotahi and its contractors. There are also local roads which are managed and maintained by New Zealand’s councils. We are all trying to get our road maintenance done during this period so it’s a busy time.
We do work with local councils to plan when we all do our works to minimise the disruption as much as possible but sometimes there is work both on the state highway and on a local road detour that is critical to complete this season and cannot be avoided.
CloseThere will be businesses alongside areas we are working in who are impacted by this work. For example, road closures and other road works will prevent or impede access to a business, reducing their income over that period.
Compensation for the impact of our works is determined by the Public Works Act 1981 (PWA). Section 68 of the PWA provides that businesses are entitled to compensation for “business loss” only where they are required to relocate because land has been acquired. Therefore, businesses who are impacted by works, but are not required to relocate because we acquired their land, are not entitled to any compensation for their business losses. This important work is very necessary, and we believe this approach will, over time, cause the least inconvenience.
Road closures are temporarily hard on businesses, residents and all the people that have to travel through our detours. For those living in the local areas and traveling through, the businesses near or within the closures are still open and our crews will facilitate access to them, so please continue to support them.
CloseSpeeds cannot be temporarily lowered unless the level of risk meets the threshold for a reduced speed. A detour route must be fit for purpose and enable traffic to continue their journeys safely and efficiently – without undue delays.
We look at a range of factors, including the time a detour will add to people’s journeys, the suitability of the road for the additional volume of traffic, whether all parts of the road and bridges can cope with heavy vehicles, and safety.
Our safety engineers also continue to monitor the detour routes and make any changes, if necessary. We also receive advice from NZ Police on how the detours are performing.
CloseSome locals might know of roads that would short-cut official detours and wonder why we didn’t recommend them. These short-cuts are nicknamed “rat-runs” and are of concern to us, as well as the people living down the local roads with many entrances who suddenly find themselves with noise issues and with concerns for children and stock. Often there are small bridges, narrow sections and overhanging vegetation which may make these roads less suitable for larger vehicles.
In most cases, we can’t prevent people choosing to rat-run down roads they know or following directions from mapping apps. All we can do is suggest the safest and most suitable detour route for people to follow. In some cases, we can make the road open only to residents, but this is only done in exceptional situations.
We do continue to monitor detour routes once they are active and make changes if necessary.
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