Destination and route choice models for bidirectional pedestrian flow based on the social force model

In this study, social force model (SFM) is extended by using a discretisation grid to permit pedestrians to change their desired speed directions dynamically. In reality, other pedestrians may obscure the visions of the behind pedestrians, so the behind pedestrians will be blocked if they insist to walk in the final desired directions calculated by the SFM. So, a dynamic destination choice model is established to provide pedestrians a series of available intermediate destinations. Based on the dynamic destination choice model, the authors use a discretisation grid to represent all the potential moving directions of pedestrians, and model the weight of every potential moving direction. The direction with the maximum weight is selected as the optimal route at that time step. Besides, pedestrians prefer to pass near to crowds with a low relative velocity and choose the low space occupancy route when several routes have the same pedestrian density. So, pedestrian speeds, space un-occupancy, route length, crowd density and object pedestrian ratio are used to develop the weight model. The modified SFM guarantees pedestrians to obtain an available and optimal route. Compared to other models, the proposed models can be used to reproduce the behavior of bidirectional pedestrians more really.