How will climate change impact on SA's transport systems? Helping to create resilient communities

Most people think of climate change as being something that might affect our natural environment at some point in the future. The TREND Human Dimensions Group is investigating some of the more immediate effects that climatic change is having on the way we live our lives and looking for ways that we can adapt to these challenges.

With our heavy reliance on roads and other infrastructure, disruptions to our transport system can be widespread and catastrophic. For this reason, maintaining a functional and resilient transport network is critical to our economy. In a recent research paper, TREND Human Dimensions have looked at the effects of climatic changes on our transport systems and travel behaviour and advised some immediate steps we can take to help us develop a more robust transport network. The Group looked at the physical, behavioural and economic implications of climate change on transport systems, as well as challenges to planning, insurance, vehicle and road network function, and emergency evacuations. A brief summary of some of the impacts studied is below.

The full paper was presented at the 33rd Australasian Transport Research Forum held in Canberra, October 2010 and published in the journal Road & Transport Research.

Implications for transport infrastructure


Temperature

Temperature extremes increase the expansion, stress and movement experienced by structural materials used in transport systems. Higher temperatures combined with increased solar radiation can reduce the life span of road surfaces, potentially effecting more than 90% of Australia rural roads. Increased maintenance activities will be required to manage these stresses but may be limited by extreme temperatures reducing the ability of workers to withstand the heat. ↑ BACK TO LIST

Rainfall

South Australia is likely to experience a reduction in rainfall which can lead to increased ground movement, changes in the watertable and increased soil salinity. These factors can cause material degradation, reduce the lifespan of transport systems, increase maintenance costs and cause eventual structural failure. Despite an overall reduction in rain, climate models predict an increase in extreme rainfall events. High rainfall can lead to flooding, which will cause significant damage to transport systems. In order to adapt in the short term, we need to focus on drainage design and maintenance schemes. In the longer term we need to optimise culvert design and paving materials. ↑ BACK TO LIST

Sea Level

With expected sea level rises there is an increased chance of storm surges into coastal areas. Infrastructure is at risk from higher tides, salinity levels and ground water pressure. In order to adapt in the short term we need to adjust bridge height design in vulnerable areas and in the long term we need to set more rigorous design and material standards. ↑ BACK TO LIST

Wind

Increased costal winds will affect bridges in coastal areas requiring updated design and improved testing of new structures under more turbulent conditions. In the long-term, materials used for bridges may need to be stronger and more robust. Increased wind combined with high temperatures will also increase the chances of dust storms resulting in decreased road usability, smothering of vegetation and dust infiltration into residential properties. ↑ BACK TO LIST

Behavioural

Changes in climate are likely to affect how people use transport systems. Areas that are densely populated could become less desirable and vice versa, changing the demands on regional transport systems. Travel behaviour will also likely change, for example extreme rainfall events discourage people from driving making them more likely to use public transport. Adverse weather conditions result in longer travel times, slower traffic speeds and higher road fatalities. Smoke from bush fires caused by extremely hot weather can impede driver visibility. Public education and use of advisory systems are our best strategies for helping people adapt their travel behaviour according to changed conditions. ↑ BACK TO LIST

Economic

The direct economic costs are mostly related to repairing or rebuilding damaged transport infrastructure and we can see these rising already. Annual losses directly resulting from significant natural catastrophes has increased over 10 times from the 1950s to 1990s globally and in Australia losses doubled between 1999 and 2008. The greatest public costs are related to disaster assistance, and road maintenance, relocation and repair. Indirect costs are also large, caused by delays, losses from toll roads, freight supply interruption, detours and trip cancellations. ↑ BACK TO LIST

Urban Planning

Planning principals and practice are integral to our adaptation to climate change. We must reduce vulnerabilities and increase resilience by developing, analysing and revising planning systems and practices. Through efficient planning, impacts can be minimised by separating infrastructure and the associated population and resources in high risk areas. An increase in the threshold for residential developments in flood prone areas is one such way, and has been shown in North America to drastically reduce impacts and damages caused by extreme storm events. ↑ BACK TO LIST

Insurance

Increased extreme weather events cause more accidents involving property damage, injury and fatalities which in turn increases the liabilities and insurance costs associated with transport systems. Climate change poses new challenges for insurance and financial markets by increasing the scope of possible losses and the severity of likely damages and payouts. Many risks are currently covered by existing insurance but it is likely that insurers will act to limit their liability in the future. New insurance products might be more appropriate which use the life insurance model, i.e. life insurance covers the risk of timing of death, although the fact of eventual death is certain. Improved planning should improve insurability; insurers could also provide financial incentives for risk averting behaviours. ↑ BACK TO LIST

Vehicle and Road Network Function

Increased temperatures are predicted to cause more vehicle breakdowns and lead to faster tyre deterioration as well as causing overall reduced engine efficiency and therefore higher fuel consumption, exacerbated by an increased use of air conditioning. A robust transport network is required to offer alternative travel paths to cope with potential disruptions. This is usually not a problem in urban areas but in rural settings there are often sparser networks with fewer alternative good quality roads. The failure of a single link in rural road network can have significant effects on the community function and this should be addressed in network planning. A robust transport network is essential to accommodate emergency services. ↑ BACK TO LIST

Emergency Evacuations

The increasing occurrence and severity of extreme weather events (e.g. cyclones, bush fires, floods) will lead to more large scale evacuations and a robust road network is essential for success. Past and present practice has tended to ignore evacuations in planning, design and analysis. Travel during evacuations is very different to normal travel, with long journey times, extended congestion, and potential destination changes in response to altered conditions. Planning strategies can minimise problems by including measures such as contraflow (where lanes and shoulders are reversed to increase travel flow) which can increase outbound travel volume by around 70%. Coordination of traffic signals and use of public transport systems (especially for those with low mobility), along with limiting any flow limitations (like road works) can also speed up evacuation. Use of intelligent transport systems and supplementary advisory services can help inform drivers of the most efficient evacuation routes as conditions change. ↑ BACK TO LIST

Taylor & Philp (2011) Adapting to climate change – implications for transport infrastructure, transport systems and travel behaviour, Road & Transport Research. (264 KB)

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