Effect of dangerous source on evacuation dynamics in pedestrian counter flow

The modeling of evacuation dynamics under a sudden dangerous source is an important and interesting topic in pedestrian counter flow. In this paper, an extended cellular automata model is proposed to simulate pedestrian evacuation in a channel by considering the sudden dangerous source effect, in which the concept of core radius and edge radius of dangerous source are introduced to quantitatively reflect the magnitude of the dangerous source. The parameter of influence power of pedestrian is firstly used to describe the propagation of danger information, and a new algorithm of calculating the optimal directions is presented to reflect the decisions-making behavior of pedestrian. The influences of the position, magnitude of the dangerous source and the influence power of pedestrian on evacuation process in the channel are investigated. And the spatiotemporal dynamic characteristic during the evacuation process is also discussed. The simulation results show that considering the propagation of danger information will reduce the total evacuation time considerably. Without the propagation of danger information, at the medium density, the evacuation efficiency is higher when the dangerous source is located at the side of the channel. However, at the high density, the shortest evacuation time appears when the dangerous source is located in the central partition line of the channel. Furthermore, the strength of influence power among pedestrians plays an important role on evacuation efficiency. In particular, there are important differences in the jamming mechanisms under different positions and magnitude of dangerous source.