Evolutionary Dynamics Of Normal Pedestrian Traffic Based On The Improved Social Force Model

As the most traditional means of transportation,walking is always an important form for urban residents to participate in urban transportation.The continuous progress of urbanization accelerates the gathering of population in cities and the large-scale construction of pedestrian transportation infrastructure.The researches on pedestrian traffic has attracted extensive attention for its important status in the field of modern traffic science.The study of pedestrian models and pedestrian dynamics in normal scenarios is helpful to provide theoretical guidance and scientific methods for traffic planning,design,management and optimization on the basis of scientifically grasping the inherent mechanism and evolutionary law of pedestrian behaviors.In order to achieve a more accurate description of pedestrian traffic behavior in normal scenarios,this paper improves the original social force model.We analyze the rationality of the improved social force model and explore the evolution law of pedestrian dynamics by simulation.Field dynamics theory is the basic of the social force model.There are three parts of the social force model to determine pedestrian movement: the pedestrian’s own expectation,the influence of other pedestrians,and the influence of obstacles such as boundary.However,the direct application of the traditional social force model to describe the behavior dynamics of pedestrians in normal scenarios will lead to deviation,which cannot be neglected.In order to improve the accuracy of the model,this paper proposes an improved social force model.In this paper,the conflict avoidance force is added to the improved model.Meanwhile,the response range of potential conflict is related to the response time and the relative velocity vector.The interaction between pedestrians actually are anisotropic.This paper improves the anisotropy coefficient by considering the influence of the relative position and the velocity vector on visual field and pedestrian attention.We adds the group force considering the attractive and repulsive effects of pedestrians in a group,as well as the posture adjustment of pedestrians.The influence of building boundary and other obstacles on pedestrian psychology is not always been existing.Only when pedestrians think that there is such a conflict that hinder their own movement can there be the corresponding repulsive effect.According to it,we improve the interaction force between the boundary and the pedestrians.By taking two groups of typical scenario as examples,this paper exploring the source of the pedestrian dynamics.Then,the calculate results of both the circular specification and the velocity-dependent elliptical specification will lead to deviation for its ignoring of the potential conflict.Simulation results demonstrate that the conflict avoidance force plays an important role in guiding pedestrian dynamics.The improved social force model makes pedestrian trajectories smoother and more realistic.Moreover,for high pedestrian density(no congestion),there may exist moderate values of response time,resulting in the minimum evacuation efficiency.