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Dunedin City Council – Kaunihera-a-rohe o Otepoti
Green pattern.

9.5 Focus on resilience

Issue

Dunedin’s transport infrastructure faces threats from the effects of climate change. In some cases, the existing network also encourages and locks people into unsustainable travel patterns.

Course of action

Promote the integration of land use and transport planning to reduce the demand for vehicle travel, and plan and prioritise to ensure Dunedin’s critical transport infrastructure is resilient in the face of future threats and constraints.

Outcomes

  • Reduced reliance on fossil fuel-based products for transport and transport infrastructure.
  • Increased protection of the transport network from sea level rise and other climate change effects, where appropriate.
  • Reduced need for people to travel, through the integration of land use and transport planning.

Goal

The total amount spent on transport fuel in Dunedin, as a proportion of Dunedin’s GDP, will have decreased by 10% by 2024.

Strategic approach

Dunedin has 1800km of roads plus other transport related assets such as 1000km of kerb and channel, 1000km of footpaths, retaining walls, bridges and culverts, signs and markers, seawalls, drains and traffic signals. In total, these assets are worth $1.3 billion57 and require on-going maintenance to ensure their value is maintained and they continue to provide for the needs of the community and the wider region. It is essential that these assets are utilised as efficiently as possible to maximise the benefits from the investment and their on-going maintenance. The strategic approach will be as follows.

Supporting the Spatial Plan – increased residential density and the transport system

It is more efficient and cost effective to locate new residential development where there is sufficient existing road capacity, in preference to ‘greenfield’ locations which require construction and on-going maintenance of new infrastructure. This aligns with the strategic direction of the Spatial Plan to provide for more medium-density residential development, around centres and public transport routes where optimal use of the existing transport system and other infrastructure can be made.

As this development takes place over time, it will support greater network resilience, less need for new infrastructure and decreased dependence on fossil fuels. This approach is also consistent with central Government direction of maximising efficiency and value for money, by ‘sweating the existing asset’ in preference to constructing new infrastructure. How this will be achieved and supported is discussed in more detail earlier in Section 9.3, the ‘Focus on Centres’.

Explore developing an Economic Network Model

Government funding for maintenance of local roads is decreasing over time, and councils are being asked to look at making efficiencies in this area (see 2.10). One possibility is to explore a model of prioritisation based on economic value or social value (or a combination of factors), where roads that are of higher value are maintained to a higher level of service, and those of lower value may receive a lower level of service or may even be downgraded or, in extreme cases, abandoned over time. This approach (called an Economic Network Model) is being explored by several other councils around the country and the DCC will also explore the value of this option over the short to medium term to see whether this approach would yield benefits for Dunedin.

Explore alternatives to bitumen and the potential to recycle roading waste

Maintenance costs are increasing over time as a result of rising fuel and bitumen prices. This presents a challenge when coupled with constrained funding for local road maintenance. Alternatives to bitumen, such as synthetic or biomass-based agents exist but are not readily available on the New Zealand market and are generally cost-prohibitive in comparison to bitumen. There is also a variety of environmental problems associated with production of biomass-based agents, and bitumen is a by-product of the oil refining process.

Recycling of waste product from road infrastructure maintenance may also provide an opportunity for increased resilience in the future. Old concrete from kerb and channel renewal and asphalt millings left over after re-surfacing of sealed roads are examples of products that may be recycled back into the transport network. However, the roading industry in New Zealand is not yet equipped to recycle these materials, or to do so in a way that achieves a standard equal to new product.

The DCC will stay informed of developments in these areas and will encourage contractors to adopt sustainable practices over time, as environmentally friendly alternatives to bitumen and recycling capability become available and viable. One method of supporting uptake in this area may be through the DCC’s Waste Levy Fund. In the Waste Minimisation Plan, the DCC has committed to make funds available for the purpose of promoting or achieving waste minimisation in accordance with the Plan58. Roading contractors seeking to invest in waste minimisation methods may be eligible to apply for grants from the Waste Levy Fund.

Develop a Preventative Maintenance Strategy

It is anticipated that sea level rise and other hazards will affect some of the city’s transportation infrastructure within the life of this Strategy. The DCC will explore developing a preventative maintenance strategy to identify and develop approaches to ensure Dunedin’s transport infrastructure is appropriately resilient in the event of these effects.

Footnotes

  1. DCC official roading asset evaluation 2012.
  2. A waste levy is collected by central Government at the landfill gate, and a portion of that is returned to the DCC for use in promoting or achieving waste minimisation. The DCC has made some of this money available in the form of a grant scheme. For more information, see the DCC Waste Minimisation Plan.

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