Main factor causing "faster-is-slower" phenomenon during evacuation: rodent experiment and simulation.

Understanding crowd flow at bottlenecks is important for preventing accidents in emergencies. In this research, a crowd evacuation passing through a narrow exit connected with guide-walls is analysed using the discrete element method based on physical and psychological modelling in parallel with empirical rodent research. Results of rodent experiment and simulation demonstrate the faster-is-slower (FIS) effect, which is a well-known phenomenon in pedestrian dynamics. As the angle of the guide-walls increases, agents rapidly evacuate the room even though they have low velocity. The increase in this angle causes agents to form lanes. It is validated that ordered agents evacuate expeditiously with relatively low velocity despite expectations to the contrary. The extracted experimental and simulation data strongly suggest that the agents' standard deviation of velocity can be a key factor causing the FIS effect. It is found that the FIS effect can be eliminated by controlling the standard deviation.