Appendix 1: About the state highway network

New Zealand Transport Agency: Information and planning for maintaining and renewing the state highway network.

At 10,908 kilometres, the state highway network (the network) covers the length of New Zealand. The rural part of the network is made up mainly of two-lane sealed highways, with some sections of multi-lane highway and motorway.

The urban network varies. It includes two-lane urban carriageways, multi-lane carriageways, and multi-lane motorway systems in Auckland, Wellington, Christchurch, and Dunedin. Figure 5 (continued overleaf) shows a map of the network.

Figure 5
Map of the state highway network

Figure 5: Map of the state highway network - South Island.


Figure 5: Map of the state highway network - North Island.

The network is made up of a large number of assets. NZTA classes these assets under three broad groupings – structural assets, corridor assets, and land and buildings.

Structural assets are those that are designed using engineering principles to sustain the physical loading imposed by traffic. Corridor assets are needed for the safe operation of the network. The land and buildings grouping includes road reserve land and property held for future capital works. Figure 6 sets out the network asset definitions by group, type, and component.

Figure 6
The state highway network asset groups, types, and components

Asset group Asset type Asset component
Structural assets Pavements Formation (foundation)
Pavement layers
Surfacings Pavement surface
Drainage Culverts (<3.4m2 cross-sectional area)
Surface water channels
Structures Bridges
Culverts (≥3.4m2 cross-sectional area) and underpasses
Other structures (for example, retaining walls, sign gantries, tunnels, and major drainage structures)
Corridor assets Carriageway lighting Lighting
Traffic services Intelligent traffic systems
Traffic signals
Automated traveller information systems
Traffic signs
Guardrails and delineation devices
Road marking
Roadside features (for example, rest areas)
Land and buildings Land
Road reserve (land)
Property (held for future capital works)

In 2009, NZTA estimated the replacement cost of the network at $28.896 billion. Figure 7 outlines, by asset component, details of the replacement cost of the network.

Figure 7
The replacement costs, by asset component, of the state highway network

Component Replacement cost ($million)
Land 8,673
Formation 6,461
Pavement (other) 3,915
Pavement surface 1,044
Drainage 992
Traffic facilities 1,242
Bridges 5,140
Culverts and underpasses 425
Other structures 989
Bailey bridges 15
Total $28,896

Source: NZTA.

In 2009/10, the total cost for maintaining and operating the network was about $514 million.

For 2009/10, the National Land Transport Programme 2009-2012 allocated a total of $527 million for state highway road maintenance, renewal, and operations. This included $15 million allocated from the Government's economic stimulus package to further support an increased pavement renewals programme in 2009/10.

For the next three years, the National Land Transport Programme 2009-2012 reduced expected funding for maintenance and renewal of the network from $527 million in 2009/10 to $502 million in 2011/12.

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