Experimental Study On Spatiotemporal Movement Dynamics Of Two-people Social Groups In Pedestrian Flows

Statistical results show that the majority of pedestrians in the crowd are social groups,they walk with their group members with social relationships in general,and the proportion of two-people social groups is the highest among social groups.There is abundant evidence that social groups can affect pedestrian dynamics under normal and emergency conditions.However,previous studies on the controllable experiments of social groups are still relatively lacking.In this paper,the spatiotemporal movement characteristics of two-people social groups in unidirectional and multidirectional flows are quantitatively studied by controlled experiments under normal conditions.The vol-unteers in our experiments were college students.To avoid the influence of social rela-tionships on experimental results,a strong relationship with maintaining physical con-tact is employed.The thesis is summarized as follows:In this paper,We carried out experiments of unidirectional pedestrian flow in a corridor with different densities.Trajectories of pedestrians' heads were extracted.The density and velocity data of pedestrian movement were calculated based on the Voronoi Polygon method.The Permutation test was used to test the difference between social groups crowd and the individual crowd on fundamental diagrams.The profiles of den-sity and velocity of different crowds were plotted according to the density and velocity data.Results show that,within the density range of this experiment,there is no dif-ference in fundamental diagrams between the two-people social groups and individuals in unidirectional flow under normal conditions.The experimental data can provide a theoretical basis for the validation of the two-people social groups model.Quantitative differences of micro-level between two-people social groups and in-dividuals in unidirectional flow under normal conditions are revealed.The differences in personal space,distance from the nearest neighbor pedestrian,and the number of overtaking behaviors between two-people social groups with a strong relationship and individuals were compared.The relative distances and positions of the two-people so-cial groups at different positions in the corridor were obtained.Results show that there are differences in the above micro behaviors between the two-people social groups with the strong relationship and individuals in unidirectional flow under normal conditions.It can provide a theoretical basis for parameter selection and verification of two-people social group models.A series of multidirectional flow experiments were carried out in this paper.The movement characteristics of two-people social groups in multidirectional flows are stud-ied.A parameter for quantifying pedestrian movement path was proposed.The classi-fication rules of pedestrian movement strategies were established based on our exper-imental data.The movement time of different strategies was compared and analyzed.Results show that most pedestrians obey the principle of the shortest path.Compared with two-people social groups,individuals are more willing to choose a detour strategy in complex multidirectional flow under normal conditions.In complex multidirectional flow,a moderate detour strategy can improve the efficiency of crowd movement.