Verifying the applicability of a pedestrian simulation model to reproduce the effect of exit design on egress flow under normal and emergency conditions

Abstract

Crowd egress at narrow exit is a popular research topic, due to its intrinsic importance in architectural designs and building codes. However, relatively few studies have been conducted to verify the performance of pedestrian models for crowd escape at exits, especially relating to different exit designs. This paper aims to verify the applicability of a microscopic pedestrian simulation model, Social Force Model (SFM), embedded in Viswalk software to reproduce the effect of exit design on egress flow under normal and emergency conditions. Empirical data from controlled experiments considering the effects of obstacles size and location of exits under normal and emergency conditions were tested and compared with the simulation from the SFM. Results indicated that after parameter optimization, Viswalk simulation model can provide reasonable estimates for crowd escape under normal situations with a mean RMSE value 1.97s for total evacuation time. However, the simulation model was less capable in reproducing the emergency condition. As compared to the empirical data, clogging events were less spotted under emergency in the simulation. Faster-is-slower effects were not found in both empirical and simulation scenarios. In addition, the exit location effects from simulation data agreed with empirical data, corner exits were more efficient than middle exits under both situations. Meanwhile, the obstacle effects, as observed in empirical data, were less reproduced in the simulation, especially under emergency conditions. The results suggest that the application of the Viswalk model in simulating emergency situations needs scrutiny and further investigations in the future with empirical data.