Investigating the influence of a cyclist on crowd behaviors on a shared road

Author: Huang Chuanli, Wang Lu, Yu Hang, Li Hongliu, Zhang Jun, Song Weiguo, Lo Siuming, Rafaqat Warda

Keywords: traffic and crowd dynamics, pedestrian flows, density, bicycle, model, speed, Mechanics, Physics

Abstract:

This study investigated the influence of a cyclist on crowd behaviors on a shared road. A series of mixed traffic experiments of a cyclist and a crowd of pedestrians were conducted in a circular wide track under different densities and moving directions. The influence of the cyclist on the fundamental diagram of pedestrians showed a clear difference under unidirectional and bidirectional scenarios. The cyclist restricted the pedestrian flow evidently in the unidirectional flow, while in bidirectional flow, a critical density around 0.9 ped m(-2) was observed, where the restriction on the motion of the crowd was not noticeable unless the critical density was reached. The speed of the cyclist also depended on the relative moving direction, but the discrepancy became negligible when the following effect was eliminated. The lane formation was quantitatively analyzed with Otsu's method. The results showed that the formed lanes were more concentrated in bidirectional flow than unidirectional flow. When two lanes were formed, the distances between the lanes were larger in unidirectional flow. These differences could be explained by the cognition difference of pedestrians in mixed traffic under unidirectional and bidirectional scenarios. It was observed that a major effect of the cyclist on the crowd behavioral mechanism was the generation of backward propagated density waves. A Y-shaped pattern for the formation of high-density clusters was discovered, which implied that stable high-density clusters were likely to form as the forward propagated and backward propagated density waves merged. Moreover, in bidirectional flow, the generated backward propagated density wave could also promote the fading of stable high-density clusters by reducing the heterogeneity of density distribution. Our study helps to achieve a better understanding and modeling of the dynamics of pedestrian-cyclist in mixed traffic.