Mixed-traffic intersections with high-density bicycle traffic flow are one of the most common bottlenecks in the urban cycling network. Due to the shared space and frequent interactions with other traffic users, through bicycle flow shows the obvious tendency of lateral dispersion, resulting in severe influences of traffic efficiency and safety. However, existing microscopic simulation models of through bicycles disregard the dynamic variations of the dispersion extent under changing traffic context, and they also simplify cyclists’ behaviors and interactions, which has limitations in showing a good representation of reality. This paper presents a microscopic simulation model of through bicycles by embedding a dynamic boundary model and behavior decision models into the original social force model. The dynamic boundary model determines the boundary of the actual cycling area in each signal cycle to capture the dynamic characteristics of the lateral dispersion. The decision module uses the rule-based method to select a suitable behavior in four alternatives: freely moving, following, overtaking, and merging. Finally, behavior decisions and boundary constraints are exerted by corresponding behavior forces. The proposed model is tested by comparing simulation results with the original social force model and with the empirical data which contains 743 through bicycle trajectories collected in Shanghai, China. The comparison results show the proposed model is capable of reproducing the realistic motion features of through bicycles. This new microscopic model can be used to simulate the through bicycle flow to fulfill the need for traffic efficiency evaluation, safety assessments, and infrastructure designs of mixed-traffic intersections.

CICTP