Do you know what is the longest bridge on an NZ highway or why our roads are black? Find out this and much more below.
- How many kilometres of state highways are there?
- What is the total number of vehicle kilometres travelled?
- What is the busiest stretch of road in New Zealand?
- How many registered vehicles are there in New Zealand?
- What is the difference between a motorway and an expressway?
- How long are New Zealand's motorways?
- When did New Zealand first have a motorway?
- How much do roads cost?
- What are these taxes and charges?
- What is the difference between Transit New Zealand and Land Transport New Zealand?
- What impact does weather and terrain have in the way Transit designs roads?
- Do trucks wear roads out quicker than cars?
- Why are New Zealand roads black?
- Is New Zealand the only country with our sort of roading?
- Why does Transit build roads where it does?
- What is asphalt?
- What is chip?
- Why is there variation in chip?
- What sort of chip seal does Transit use on the roads?
- Is a road with big chip safer than a smoother road?
- How often does a road get repaired?
- What does Transit do to make sure the road is built and maintained properly?
- How do you accommodate things like fault lines?
- Are our roads built with a speed in mind?
- Who decides what are state highways and what are local roads?
- Why are state highways numbered the way they are?
- What is the longest straight road in New Zealand?
- Which is the highest highway in New Zealand?
- Where can I find out about temporary traffic management?
- What is the longest bridge in New Zealand?
- How many bridges are there on the state highway network?
- How did Transit evolve from the Ministry of Works?
- Why are New Zealand's highways called "state highways"?
- Can I put up an advertising sign alongside a state highway?
The state highway network of 10,894.9 (5973.8 km in North Island and 4921.1 km in South Island - August 2006) kilometres of major roads and motorways provides a strategic link to 82,000kms of local roads managed by territorial authorities. It is a national asset worth $12.511 billion and carries 50% of all New Zealand's traffic. There are 170 kilometres of motorway in the highway network.Back To Top
There are 19 billion vehicle kilometres travelled (VKT) on New Zealand state highways. Auckland state highways carry 21% of the VKT. Auckland has 3% of the state highway network length and 32% of the population of New Zealand which means that this part of the network suffers severe congestion.
State Highway 1 immediately south of Auckland is the busiest road in New Zealand with over 200,000 vehicles a day. The Central Motorway Junction (Spaghetti Junction) in Auckland city is the next busiest with 200,000 vehicles a day. Learn more about state highway traffic volumes.Back To Top
There are 3.8 million registered vehicles in New Zealand as at 30 June 2005. Learn more about Vehicle Registration Statistics at Land Transport New Zealand.
Motorways are highly controlled, high-speed roads which normally have grade-separated intersections. In other words they have things such as flyovers so that motorists don't have to stop at traffic lights.
Expressways are also high speed roads, but they have well spaced at-grade intersections. This means they may have accesses and driveways on to them and traffic lights.Back To Top
New Zealand's motorways make up 3% of the total network length. They carry 9% of New Zealand's traffic.
The first section of motorway opened in December 1950. It ran for 3 miles between Takapu Road and Johnsonville and is part of the main approach to Wellington City.Back To Top
In the year 2000/01 it was expected that about $1.8 billion would be spent on state highway and local road construction and maintenance. Most of this comes from taxes and charges paid by road users.
- Fuel excise (about 26%)
- Vehicle licensing fees (about 25%)
- Local rates (about 17%)
- Other sources, such as the disposal of road properties and interest on funds (about 1%)
- about 30% each for state highways and local roads
- 18% on the New Zealand Road Safety Programme
- 6% on public transport
- 5% on administrative costs of the agencies that collect the funding, ie. Land Transport New Zealand.
Land Transport New Zealand provides the money for the National Roading Programme for the year ahead. The money from Land Transport New Zealand is allocated to local authorities which also contribute some of their own funds from rates. Regional councils are allocated funds for public transport. State highways, managed by Transit, are fully funded by Land Transport New Zealand, but there is no fixed level of funding guaranteed.
Land Transport New Zealand also determines standards of maintenance and construction, undertakes reviews and audits of road controlling authorities, provides advice to local authorities, and develops policies for financial assistance including evaluating projects and establishing competitive pricing procedures.
Since July 1996 Transit New Zealand has not been involved in providing funding to local authorities for roads. Transit operates as a road controlling authority. Transit prepares an annual National State Highway Programme and a 10-year Forecast and puts this to Land Transport New Zealand for approval.
Transit's objective is to operate the state highway system in a way that contributes to an integrated, safe, responsive and sustainable land transport system. This includes maintaining the state highway network, developing standards, providing assistance and advice, and liaison with the New Zealand Police, Land Transport New Zealand and the National Road Safety Committee. Transit also develops major construction programmes for improving existing state highways and building new ones.
The terrain adds hugely to the cost of building roads. Once you have done the expensive earthworks for a road it is very expensive to realign it or try to make it higher or lower.
It's also expensive to cut through hills or build up roads over wet or coastal areas.
Weather makes a big difference to maintenance costs. Hot weather can cause bleeding (this can occur when the road surface gets hot and goes molten), snow and ice can crack the road, and in wet weather water can get under the surface of the road and break it up.
Roads also have a camber (each side of the road slopes away from the centreline at a rate of about 3%) to let stormwater run off as fast as possible.Back To Top
Yes - by the 4th power law. For example, a vehicle weighing 2 tonnes is 16 (24th = 2*2*2*2 = 16) times more damaging to the road than a vehicle weighing 1 tonne (14th = 1*1*1*1 = 1).
Heavier vehicles pay for this extra wear through higher road user charges.
New Zealand roads are made from bitumen, not concrete. Bitumen is flexible, copes with variable temperatures, suits lower volumes of traffic and is cheaper. Our roads have a chip seal, (the coating of stones on top) some with big chips, some with little chips. Some of the roads in South Africa and Australia are like ours.Back To Top
South Africa and Australia have similar roads to those in New Zealand. They all have a thin chip seal surface. In New Zealand this is the case especially on our rural roads. This sort of road is cheaper to build and it suits the lower traffic volumes and less intensive development that South Africa, Australia and New Zealand have in common.
Although these roads are cheaper to build, Transit has to be vigilant in regard to maintenance: these roads are fragile, thin and flexible by international standards. They bend under trucks far more that roads do in Europe or America where they are made out of thicker, stronger layers of asphalt.
New Zealand's roads have mostly developed from original bullock tracks. We assume that the quickest way from A to B is a straight line. But if the line (our road) has to go over swamps, across rivers and over hills it will be very expensive to build. Not only that, our ancestors took the line of least resistance. They went round the swamp, round the hill and sometimes alongside the river till they found a good point to cross because that was easier - even if it took longer.
Our roads started being built many years ago when people wanted to go to and from the ports, the goldfields, their farms and elsewhere.
Today's highways carry heavy, sophisticated and expensive vehicles. But the roads we travel on today might well be laid on the foundation that was a bullock track one hundred and fifty years ago.
We've grown up with a traditional pattern of roads, and in New Zealand especially, it's far from being a straight line. That's a reflection of our topography and of the changing patterns of our economic and social development.
People want roads, but right from the beginning they wanted them built for low costs. So there has to be a balance between what is best for the economy of the country, what will satisfy people's needs, improve their safety, and what we can afford to build.Back To Top
Asphalt is a mixture of stones and bitumen. You take stones and put them into a mixer with bitumen which glues them together, and they finish up like concrete. The road surface is actually called asphaltic concrete, and it is like concrete, just not quite as brittle. Most of the roads in New Zealand have only very thin layers of asphaltic concrete on top. They are built mainly out of gravel, compacted down with rollers.
Bitumen is a residue made out of a distillation of the same oil that is used for fuels. Most of the bitumen Transit uses is produced at the Marsden Point refinery.
The chip is the name for the small sharp edged rock embedded on the top of the road. In the South Island the rock comes from rivers; in the North Island it mostly comes from quarries. You can make chip only out of very good rock - it has to be strong so it doesn't get slippery after it's been on the road surface for a while.Back To Top
New Zealand has a huge variety of rock. The South Island has river gravels or greywackes that have washed off the surfaces of the Southern Alps into the rivers. This makes excellent sealing chip in the South Island. In fact South Island roads are more grey than black because this kind of chip has more quartz in it. Chip used in the North Island uses more pure volcanic materials, such as andocites and basalts so North Island roads are blacker.
If a road is re-sealed with big chips on top of big chips on top of big chips, layer after layer, every 10 to 12 years, then eventually the road becomes a pudding of black bitumen with big stones at the bottom. That kind of road is flexible and gets slippery.
The cure for that is to re-seal with alternate layers of small and big chips which fills the gaps and stops the chips falling to the bottom of the mix. The whole mix is a lot stronger, and the bitumen does not rise to the top (called flushing) and become black and slippery on top.Back To Top
No, not at all. What makes a road safe is how much grip (skid resistance) vehicle tyres have on the road. This is a combination of how big the chips are in terms of whether they stick out of the bitumen, and how the surface of the chip looks.
Some of the chips are very, very small, like the relatively soft volcanic andacites. But even though the chip is small it has a high skid resistance. Transit keeps monitoring skid resistance and uses the standards that are used in the United Kingdom. There's no simple rule that 'big chips give you better grip'.
What does matter is the way the road is built. If you keep building a road out of big chips on top of big chips on top of big chips, layer after layer, every 10 to 12 years, then eventually you will probably get a pudding of black bitumen with big stones in it.
A road gets resurfaced every 10 or 12 years. Transit re-builds a road every 30 to 40 years. If roads are built from asphaltic concrete they only need to be re-furbished every 60 odd years, because all you do is put on a new top. What changes is the amount of traffic on a road, and that's usually always increasing.Back To Top
Transit has specifications and contracts that detail what is required to cope with the topography, the flexibility and the stability of the road. This ensures the roads cope with the traffic volume and are safe for road users.
We can't assume that our roads will stay in place during an earthquake. Transit does pay detailed attention to seismic technology. In fact New Zealand road and bridge builders are world leaders in this area having shared skills in both California and Japan.
The SH73 Otira Viaduct on the West Coast, which was opened at the end of 1999, has been designed for seismic forces 40% higher than the maximum value normally used by Transit.Back To Top
Our roads are not built to accommodate the desire of many people to drive everywhere at high speed, due to topographical, safety, and financial reasons.
A high proportion of crashes on the state highway network are due to excessive speed so please always drive to the conditions.
Transit provides a road with a warning signing system. The yellow curve advisory speed signs are there to give drivers enough information to be able to drive the curve comfortably and safely in all weather conditions.
Transit New Zealand is the Crown Entity that can classify a road as a state highway or a special purpose road. All other roads are local roads controlled by territorial authorities.
Transit assesses proposals for state highways and special purpose roads against specific criteria. Only the Transit New Zealand Authority can declare or revoke the status of a road as a state highway or special purpose road.
A state highway should form part of an integrated national network of roads that:
1 (a) are strategic inter-district routes connecting locations of national economic significance such as:
- significant centres of population
- major ports and airports
- major industrial, forestry and agricultural areas
- major tourist areas
with a minimum number of parallel or alternative routes;
- the most convenient, efficient and safe route for through traffic
- a minimum restraint on traffic capacity and legal weight and dimensional constraints for heavy commercial vehicles
2 (a) in major urban areas, are arterials that:
- carry traffic traversing a significant distance through the urban area
- connect with the existing state highway network
- when integrated with the existing state highway network would significantly improve the overall performance and management of the state highway network.
Special Purpose Roads
To qualify for consideration for declaration as a special purpose road
in terms of Section 104 of the Transit New Zealand Act 1989, a road should:
- cater for a high proportion of tourist traffic
- be of a standard below that currently deemed as being adequate for consideration of state highway status
- pass through an area where the rating potential of the surrounding land is significantly lower than the maintenance costs of the road.
The numbering system on state highways is for internal administrative purposes but it also provides a good way for road users, particularly strangers to an area and tourists, to travel on the state highway system by using route numbers. The numbers are chosen according to what is most suitable and historical precedent.
The more important roads of the state highway network have generally been given single digit numbers while the less important state highways within regional areas are usually given two digit numbers . For example, the Northland and Auckland highways are numbered 10,11 and so on to 19. South of the Auckland Harbour Bridge to Waikato is 20, 21 onwards, and from Waikato to Taupo the numbers are 30, 31 and so on to 39.
When a new state highway is declared Transit looks for the most appropriate number to fit the series. Learn more about the latest (January 2004) state highway numbers and their locations numbers.
The longest section of straight state highway is through Culverden on State Highway 7 in the South Island. It starts just south of the intersection with SH70 to Kaikoura, and is approximately 13.7km long.Back To Top
The highest State Highway in New Zealand (elevation) is SH1 the Desert Road at 1,074 metres. Other high highways are
SH8 Lindis Pass 1,000 metres
SH94 at the Homer Tunnel 945 metres, and
SH60 Takaka Hill Road 791 metres
The highest road (not a state highway) is the road over the Crown Range.
The Code of Practice for Temporary Traffic Management (CoPTTM) is the standard reference for all temporary traffic management on state highways.Back To Top
The longest bridge on the state highway network is the Rakaia River bridge on SH1S at RP 381/18.80, Length = 1,757 metres. [RP means route position]
The next longest bridge is the:
- Auckland Harbour Bridge SH1N at RP 414/9.21, Length - 1,580 metres.
- Thorndon Overbridges on SH1N at RP 987/2.24, Length = 1,335 metres.
- Whirokino Trestle Bridge on SH1N at RP 873/11.72, Length = 1,098 metres.
- Waitaki River Bridge on SH1S at RP 569/0.00, Length = 906 metres.
- Hokitika River Bridge on SH6 at RP 471/0.00, Length = 740 metres.
- Haast River Bridge on SH6 at RP 750/0.00, Length = 737 metres.
The longest state highway structure is the Lyttleton Tunnel on SH74 at RP 22/3.72, length = 1,945 metres.
A bridge is defined as 3.5 metres across, which includes some large culverts. There is a total of 3,983 bridges on the state highway network, accounting for 139 kilometres of the total highway network length of 10,894 kilometres. There are 177 one-lane bridges, 15 timber bridges and speed restrictions on 12. Bridges vary in character from rural single lane bridges, dual mode bridges such as the historic Awatere road and rail bridge, spectacular viaducts such as the Otira Viaduct to multi-lane motorway bridges.Back To Top
Transit New Zealand was formed in 1989 with two responsibilities: a) control and operation of highways and b) administration of the Fund. Learn more about the history of Transit. PDF (3.64MB)
Transit New Zealand uses the term "state highway" to differentiate between local roads which are built and maintained by local authorities and the national state highway network. "State" in the sense used here, is an older term used to mean "government".
The 11,000 kilometres of New Zealand's state highway network make up 12 per cent of the country's roads and carry half of the traffic. Transit New Zealand is responsible for planning and building projects as well maintaining the network.Back To Top
If you are considering putting up an advertising sign or device alongside a state highway there are a number of factors to consider. PDF (1.03MB)