Modeling the interactions of pedestrians and cyclists in mixed flow conditions in uni- and bidirectional flows on a shared pedestrian-cycle road

The mixed flow of pedestrians and cyclists is frequently observed on the roads they share, but investigations of the dynamics of this kind of mixed flow have been very limited. This study proposes a heuristic-based model to reproduce the mixed-flow dynamics of pedestrians and cyclists, and the model is calibrated with an experiment on the mixed traffic flow of pedestrians and cyclists. Pedestrians/cyclists were asked to walk/ride on a ring-shaped track. In the uni/bidirectional flow scenario, pedestrians and cyclists moved in the same/opposite direction. A genetic algorithm was used for parameter calibration. The model could reproduce the experimental results well. Under both scenarios, pedestrians and cyclists formed their own lanes. The pedestrians walked in the inner lane, and cyclists rode in the outer lane in a self-organized process. The widths of the pedestrian lane and the cyclist lane were found to be more uniform during bidirectional flow. The pedestrian flow rate was higher in the unidirectional flow scenario than in the bidirectional flow scenario. In contrast, at low cyclist densities, the cyclist flow rate was essentially the same in both scenarios. When the density was high, the cyclist flow rate is higher in the unidirectional flow scenario. Sensitivity analyses showed that cyclist speed had little effect on the pedestrian flow rate. A higher cyclist speed led to a higher cyclist flow rate at low densities, but the cyclist flow rates approached the same value at high cyclist densities. As the proportion of pedestrians/cyclists increased, the flow rate of cyclists/pedestrians decreased. The simulation results on a straight track were largely consistent with those on a ring-shaped track.