A generic and density-sensitive method for multi-scale pedestrian dynamics

The simulation of pedestrian dynamics is required for a wide range of applications, including crowd management, evacuation scenarios, and the design of buildings. Microscopic simulators are based on the simulation of individual agents and their mutual interactions. In comparison to macroscopic simulators that are based on network-flow models, microscopic simulators are capable of resolving movement patterns and potentially risky situations more precisely thanks to the modeling of individual behaviour, however, with the cost of much higher computational effort. Regarding the spatial resolution, microscopic simulators are either based on continuous (SpaceCont) or discrete (SpaceDisc) approaches. Whereas in the former, a pedestrian can take any position in the continuous space, in the latter, space is discretized into cells, thus restricting the possible positions of a person. SpaceDisc approaches are less precise, but computationally more efficient and thus typically applied in scenarios with a large number of persons or expanded simulation areas, respectively. For many applications, the spatial resolution of a discrete model is sufficient for observing the phenomena in question. However, in situations with high densities or small-scale obstacles, a continuous model is necessary to obtain realistic results. To combine the advantages of both approaches, we propose to integrate SpaceCont and SpaceDisc into a hybrid simulation model. Such a hybrid approach allows simulating critical regions with a continuous spatial resolution and uncritical ones with discrete spatial resolution while enabling consistent information exchange between the two simulation models. We introduce a generic approach that provides consistent solutions for the challenges resulting from coupling diverging time steps and spatial resolutions. Furthermore, we introduce a dynamic and density-sensitive approach to detect dense areas during the simulation run. If a critical region is detected, the simulation model used in this area is dynamically switched to a space-continuous one. The correctness of the hybrid model is evaluated by comparison with the simulation results of other, well-established simulation models.