A pedestrian movement model that takes into account the capacity drop phenomenon in the motion of crowd

In this paper we propose a CA movement model based on the "Cell Transmission Model" developed by Daganzo. The cell transmission model was developed as a discrete approximation to the hydrodynamic theory of vehicular traffic flow. The proposed movement model refers instead to the motion of crowd and is required to simulate the dynamic of an egress process in tall buildings taking into account not only queue and spillback phenomena but also the capacity drop phenomenon. In fact we performed experiments that show important evidence that, for a given cross section, in presence of jam upstream the section, the pedestrian flow through the section is not always equal to the section capacity but suddenly it can drop (dropped capacity). This finding is coherent with recent empirical studies of pedestrian behavior at an exit and in contrast with many previous works where it is assumed that in presence of jam upstream a cross section, the flow through the section equals its capacity. The movement model has been used for simulating evacuation processes in high rise buildings. The target is to assess to which extend the capacity drop phenomenon affects the building evacuation time.