Assessing the spatial accessibility of hospitals during flood events considering traffic demand: A case study in the city of Cologne, Germany

Kurzfassung

Adequate medical care as a part of critical infrastructure is essential for the population at all times. In a flood event, the resilience of the healthcare system is of particular importance. However, in such crisis situations hospitals can be impaired in their accessibility due to flooded roads. In addition, floods can lead to changes in traffic demand, which indirectly influences the spatial accessibility of hospitals. The aim of this study is to develop a spatial accessibility index for hospitals in the event of flood hazards that considers the influence of altered traffic demand. The city of Cologne (Germany) serves as a case study under an extreme flood scenario. By conducting a scoping review, relevant criteria that influence the spatial accessibility of hospitals are determined. A model to calculate the accessibility of hospitals is developed in a geographic information system (QGIS). The routing of the emergency vehicles is based on a shortest path analysis, which calculates the fastest routes from specified locations to the nearest hospital. The altered traffic demand during a flood event is simulated with an agent-based traffic simulation software called Simulation of Urban Mobility (SUMO) and implemented in the accessibility model. By weighting the accessibility criteria through expert surveys, a spatial accessibility index for hospitals during floods is elaborated in the final step. Overall, the results show that the altered traffic demand in the event of extreme flooding can increase the travel time of emergency services to the nearest hospital in Cologne by up to approx. 6%. Five of the 18 hospitals in the study area are no longer accessible via the road network in such a scenario. To compensate for this, other hospitals have to expect an increase in patient demand. The results of the analysis show which hospitals should be evacuated in the event of flooding and which hospitals require additional resources to provide efficient medical care to the population. A major limitation of the analysis is the static approach used to calculate hospital accessibility during floods. Future work should therefore investigate how the spatiotemporal progression and the intensity of the flood affect traffic demand and the accessibility of hospitals. The implementation of data on driving behavior of road users can make the traffic simulation more realistic and represents a starting point for future work. Against the background of the increase in natural hazards due to climate change, the topic under investigation will become increasingly relevant in the future and is important for local civil protection, urban planning and relevant stakeholders in healthcare.