An improved social force model for non-motorized vehicle overtaking behavior

On roadways with marked lanes separating motorized and non-motorized vehicles, instances occur where non-motorized vehicles cross the dividing lines and occupy lanes designated for motorized vehicles during overtaking maneuvers. The existing models inadequately describe the crossing and returning target positions of the overtaking vehicles, resulting in varying degrees of deviation from the true value of the overtaking trajectories. We measured the overtaking trajectories of non-motor vehicles crossing the line of the motorized and non-motorized demarcated lanes. Based on the classification of cyclists, the traffic behavior characteristics of different types of cyclists crossing the line when overtaking are analyzed. Considering the longitudinal and lateral spacing characteristics of non-motor vehicle overtaking, a concept of virtual boundaries is proposed. These virtual boundaries are discretized into a set of points to determine the lateral offset distance and target position for non-motorized vehicles. The influence of virtual boundary forces is incorporated into the social force model, improving the model during both the crossing and return phases. Finally, the model was validated through the analysis of crossing cycling trajectories, crossing proportions, and velocity-density fundamental diagrams.