We investigate the dynamics of the evacuation process with multiple bottlenecks using the floor field model. To deal with this problem, we first focus on a part of the system and report its microscopic behavior. The system is controlled by parameters of inflow and the competitiveness of the pedestrians, and large inflow leads to a congested situation. Through simulations, the metastable state induced by conflicts of pedestrians is observed. The metastability is related to the phase transition from free flow to congestion. The critical condition of the transition is theoretically derived. In addition, we give simulation results of situations with multiple bottlenecks. They imply that local improvement of pedestrian flow sometimes adversely affects the total evacuation time, and that the total optimization of the system is not straightforward.
We propose a simple microscopic model for arching phenomena at bottlenecks. The dynamics of particles in front of a bottleneck is described by a one-dimensional stochastic cellular automaton on a semicircular geometry. The model reproduces oscillation phenomena due to the formation and collapsing of arches. It predicts the existence of a critical bottleneck size for continuous particle flows. The dependence of the jamming probability on the system size is approximated by the Gompertz function. The analytical results are in good agreement with simulations.
18 January 2024 in Journal of Retailing and Consumer Services