Effects of aggressiveness on pedestrian room evacuation using extended cellular automata model

The effect of aggressiveness on pedestrian dynamics is studied in the context of room evacuation, based on a modified cellular automata model. Inspired by the Stevens law in psychophysics, we introduce aggressiveness as a power function combining the external environment and pedestrians’ perception. The aggressiveness affects both their walking velocity and spatial competitiveness. We further consider the evolution of aggressiveness. Instead of following the common cooperation-defector game framework, pedestrians directly evaluate the movement of conflicting people and make adjustments to facilitate their motion. The simulation results reproduce the faster-is-slower effect as a contrasted dynamics of increasing velocity and rising conflicts. For the heterogeneous crowd, pedestrians with higher aggressiveness hold the advantage. With different initial aggressiveness, the comparison of results shows that the evolution promotes evacuation efficiency at two extremes while not helping for moderate initial values. The average value and variance of crowd aggressiveness present a convergence to a stationary state which is initialization dependent. In addition, the emergency level and pedestrians’ sensitivity to conflicts have distinct effects on the temporal variation of aggressiveness. The linear dependency of the evacuation time with increasing crowd densities and the diminishing marginal assistance of a wider exit are also discussed.