Observational characteristics of pedestrian flows under high-density conditions based on controlled experiments

Abstract

High-density crowds are associated with high risks such as stampede accidents. Therefore, it is important to understand the dynamics of high-density crowds. We performed experiments in both a 1.5-m-wide ring corridor and a single-file circular track to study pedestrian flow dynamics under high-density conditions. For the wide-track experiment, we examined global densities as high as 9 ped/m2. Our main findings were as follows. (i) The middle section of our unidirectional fundamental diagram exhibited a clear similarity to that of a single-file pedestrian flow, which enabled us to distinguish two different kinds of congested pedestrian flow. (ii) The unidirectional fundamental diagram for a high-density situation was quantitatively nearly the same as that observed in the empirical data. (iii) In the absence of a bottleneck, typical stop-and-go patterns did not emerge in the unidirectional flow on the 1.5-m track. Instead, some high-density clusters propagating downstream can be observed. (iv) In the bidirectional flow experiments, three different lane formation processes were observed. The processes were quite quick, even under very dense conditions. (v) When three lanes formed, the bidirectional flow rate was much larger than the unidirectional flow rate due to the inhomogeneous distribution of pedestrians across different lanes. (vi) At high densities, the unidirectional and bidirectional flow rates were nearly the same. However, a bottleneck emerged in the bidirectional flow due to the variable width of the opposite streams. Our study helps to achieve a better understanding and modeling of the dynamics of high-density pedestrian flows.