How road asset management can deliver climate resilience

Most countries face multiple challenges with providing road networks at acceptable performance levels. The majority of roads in Asia and the Pacific were constructed during the road boom years of the 1980s, resulting in these assets now being more than 40 years old.

Many of these roads are deteriorating at increased rates due to increases in traffic volumes, higher truck loads and increasing adverse climatic conditions. Road agencies face significant cost increases for constructing and maintaining these roads, often in constraining economic situations. However, none can afford the road networks to lose functionality, which would negatively impact socio-economic growth.

Investment planning for growing travel demand, ageing road infrastructure, climate mitigation and adaptation requires robust and systematic planning processes to balance the investment into priority areas. As a result, most road agencies have established road management systems to assist in their road assets' maintenance and renewal planning.

While some road authorities may consider addressing climate change outside of their traditional asset management practices (often as a result of the different skills required), good practice is that it is far better to integrate climate change into infrastructure asset management, rather than creating a parallel management system.

Integrating planning for climate adaptation into these road management systems is becoming essential and urgent for many. In fact, climate resilience is just another lens looking at the road network needs - alongside viewing the network from a traffic capacity, road condition or safety lens, to name but a few.

Significant efficiency gains are promised through such integration because road improvement work often includes elements of renewals that also require improved resilience considerations. Undertaking maintenance and renewal on the road in isolation while ignoring the need to make it more climate-resilient can only cause significant damage to newly maintained roads.

A two-stage resilience process is needed. Network-level planning includes a full climate risk assessment process considering prevailing hazards from a given geographical area, the exposure of the infrastructure, and fragility (i.e. the ability of the infrastructure to withstand a shock event of a given magnitude).

The climate risk is then overlayed with the network criticality to determine the priority for improving the robustness of specific road links. The priority is used to determine the level of resilience investment and overall priority of the timing for the investment in the context of priorities of other road links identified for upgrading.

A climate risk-based decision-making process that integrates the resilience programme with a road maintenance and renewal programme is needed. The integrated programme typically includes adaptation strategies such as drainage improvements or specific solutions such as climate-resilient surfaces.

"Climate-responsive road asset management will help countries to maximise the outcome of every dollar invested in the road network to benefit communities and reduce the harmful impacts of climate change."

Note that resilience improvement typically involves improving the robustness through constructing erosion and flood control measures. However a significant part of network assessment also highlights areas that require increased focus on routine road maintenance, such as regular drainage cleaning and solid waste removals. Often, well-designed drainage systems are not maintained as intended – resulting in a loss of climate resilience to today's weather events, let alone the more extreme events predicted in the future. Therefore, it is important to provide resilience improvements and ensure it always functions effectively.

The network-level planning may identify significant resilience improvement needs involving detailed project-level planning, including detailed investigations and full options analysis. For example, roads vulnerable to coastal or major flooding hazards may require adaptation strategies well beyond the road reserve. Major flood-prone road sections may require flood mitigation measures upstream in the catchment area.

Likewise, slope improvement strategies may require significant geotechnical investigations and assessment of several slope stability improvement options. Decision-making for this planning level could use techniques such as multi-criteria analysis that aims at maximising several development goals and objectives.

When planning how to invest in making roads more resistant to climate change, it's important to decide where to spend money wisely. Some parts of the road network might not benefit much from improvements because they're rarely affected by severe weather or other hazards. When these rare events do happen, they can cause a lot of damage. More common events, like those happening every 25 years, usually don't cause much harm because the roads are built to withstand them.

In areas where the roads are at high risk of damage, it might be better to move the roads to safer places. In other areas, spending money on making the roads stronger can be a good investment. However, in some parts, using financial strategies like insurance is more cost-effective than physical improvements. Finally, in most parts of the network where the risk is low, it's okay to continue as usual and accept the minor risks that come with climate change.

For extremely constrained environments, it is still important to consider some of the no-regret investments into resilience. Some of these include: undertaking routine maintenance on road networks and drainage; improving emergency and response protocols and resources; post-disaster build-back-better or build-back-different strategies; undertaking a comprehensive climate-responsive road asset management process; and using nature-based solutions as adaptation strategies

Climate-responsive road asset management will help countries to maximise the outcome of every dollar invested in the road network to benefit communities and reduce the harmful impacts of climate change.