Climate change data
Adapting to climate change is now a key challenge for transportation infrastructure. The Alsace region is characterized by significant geographical diversity, ranging from the Rhine plain to dense urban areas and the Vosges Mountains. The road network is particularly vulnerable to a variety of climate-related hazards.
The European Community of Alsace (CeA) operates an extensive network of over 6,400 km of departmental roads, supplemented by nearly 1,000 km of bicycle paths. This dense network plays a key role in territorial continuity and local economic activity.
Against the backdrop of increasingly severe weather events, the issue of the resilience of this infrastructure has become a central concern. To address this issue, the CeA has launched an ambitious initiative to assess the climate resilience of its road network, drawing on a consortium of experts comprising Arcadis, IRIS Conseil and Hydroclimat. This collaboration brings together expertise in infrastructure engineering, urban planning, and climate modeling.
With this in mind, the CeA is aligning itself with the national TRACC trajectory (+4°C by 2100), with the goal of developing a robust, region-specific, and actionable adaptation strategy.
The study aims to conduct an in-depth assessment of the road network’s vulnerability to climate change, combining scientific analysis with operational considerations.
It has three complementary objectives:
The approach is based on the ASAIT methodology developed by Cerema, which integrates the physical, functional, and territorial dimensions of the network.
The first step consists of a detailed analysis of how the Alsatian road network operates. Beyond simple mapping, the objective is to identify the actual role of each road segment within the overall mobility system.
This analysis is based on several dimensions: network hierarchy, traffic intensity, availability of alternative routes, and access to critical infrastructure (emergency services, economic zones, isolated areas).
By combining these elements, we develop a functional understanding of the network and address a key question: which road segments are truly critical for the territory?
This phase provides an essential foundation for prioritizing challenges and avoiding a uniform approach that would overlook structural vulnerabilities.
Once the network is qualified, the analysis focuses on its exposure to climate hazards, incorporating projected changes under a +4°C climate scenario (TRACC).
We rely on reference climate and hydroclimate data to characterize the hazards likely to impact the network:
The objective is to quantify both the intensity and evolution of these hazards over different time horizons. Each road segment is assigned a multi-hazard exposure score, enabling a shift from a global climate perspective to an operational risk assessment.
This phase aims to understand how infrastructure responds to the identified hazards. Not all roads react in the same way: their design, condition, and surrounding environment influence their level of vulnerability.
The analysis covers pavements, structures (bridges and engineering works), drainage systems, and equipment.
For each type of infrastructure, impact scenarios are defined to anticipate potential effects whether gradual degradation, performance loss, or more critical failures.
This approach goes beyond a purely climate-based perspective by integrating the actual capacity of infrastructure to withstand climate stress.
This final step combines hazard exposure, infrastructure sensitivity, and the functional importance of each road segment to produce overall vulnerability indicators.
This cross-analysis makes it possible to build both physical and functional vulnerability indicators, and to prioritize risks at the territorial scale.
This comprehensive view enables risk ranking, identification of critical areas, and prioritization of adaptation actions.
The study delivers an operational diagnosis of the climate resilience of the Alsatian road network, directly usable by technical teams and decision-makers.
Key outputs include:
These results provide a clear view of intervention priorities and enable the full integration of climate risk into infrastructure management and investment strategies.
Cette étude marque une avancée majeure dans la prise en compte du This study represents a major step forward in integrating climate change into transport infrastructure management in Alsace.
By structuring an approach that is both scientific, territorial, and operational, it transforms complex climate data into actionable decision-making tools.
It contributes to strengthening the long-term resilience of the road network, while supporting the European Collectivity of Alsace in building a coherent, forward-looking adaptation strategy aligned with national climate trajectories.
