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Toll road risk assessments for adaptation planning

We reviewed physical infrastructure data, exposure to various risks, including landslide, sea level rise, extreme heat, rain, wind, flooding and snow and qualitative interviews about historic physical climatic events.


As part of their asset planning internal review, the client initiated a physical climate risk and mitigation project with ClimSystems and SLR Consulting. The challenge for the client was to understand the physical risks from climate change to their infrastructure, which included toll roads and tunnels in Eastern France (including the Alps), near the Baltic coast of the Netherlands and the USA. They also wanted to understand the impacts of climate on the kilometres travelled by toll road users and how this could change over time due to climate-related changes.


We augmented data on the physical infrastructure to be examined with qualitative stakeholder interviews. This approach provided information about historical physical climatic events that had impacted the various road segments.

We then examined the percentage of the three toll road assets exposed to various climate risks. While some variables were consistent across the three assets, some were particular to one asset, such as landslide risk in the Alps and sea level rise for the tunnel in the Netherlands. Other variables examined included heatwaves, extreme rainfall and winds, flooding and snowstorm days, and a specialised heat index for road workers in all three locations.


We presented maps for baseline conditions and future scenarios along with tabular data, which included baseline values and Net Zero but with risk scores by the percentage of road or asset length at risk for the specific climate variable. The results were reviewed with key stakeholders in workshops. These focused on the physical dangers and the predetermined thresholds being considered. In some cases, the thresholds were set qualitatively without any prior weather or climate risk data to inform the process and needed to be reconsidered before moving to the next phase of the project.

Discussion in these workshops also revolved around the secondary impacts of climate change on the potential revenue from the toll roads. In particular, the potential for a lack of snow in the Alps. While this reduced the risk of road closures, revenue losses and maintenance costs, the risk of less winter skiing traffic raised some concerns about the project will include a financial analysis of the risks and adaptation options for reducing risks.

Understand projected impacts of climate change for your assets – and the opportunities.