The Characteristic Of Pedestrian Traffic Flow:Experiment And Modeling

With the fast development of society and economy,travel demand increases explosively.Walk is the base one of all traffic modes,which is indispensable in our daily life.In order to understand the characteristics and rules of pedestrian behaviors,researchers from various fields investigate the pedestrian traffic flow.However,as a complicated nonlinear system,some phenomenon in the pedestrian traffic cannot be well explained,and many problems cannot be solved.According to previous studies,this paper analyses the evacuation process,unidirectional flow and bidirectional flow of the pedestrian.By the controlled experiments and modeling,the theory of pedestrian traffic flow is improved.The specific studies are:The impact of pedestrian number on the evacuation dynamics has been investigated via experiments and modeling.Two sets of experiments have been implemented.The experiments show that the average evacuation time increases with the pedestrian number linearly.Moreover,it is found that the average evacuation time gap is essentially constant,which means that the evacuation speed essentially does not depend on the number of pedestrians that have not yet escaped.The impact of vision on the uni-and bi-directional flow has been investigated via experiment and modeling.In the experiments,pedestrians are asked to walk clockwise/anti-clockwise in a ring-shaped corridor under view-limited condition and normal view condition.As expected,the flow rate under the view-limited condition decreases comparing with that under the normal view condition,no matter in uni-or bi-directional flow.In bidirectional flow,pedestrians segregate into two opposite moving streams very quickly under the normal view condition,and clockwise/anti-clockwise walking pedestrians are always in the inner/outer ring due to right-walking preference.In the first set of experiment,spontaneous lane formation has not occurred under the view-limited condition.Pedestrian flow does not evolve into stationary state.Local congestion occurs and dissipates from time to time.However,in the later sets of experiments,spontaneous lane formation has re-occurred.This is because participants learned from the experience and adapted right-walking preference to avoid collision.The impact of holding umbrella on the uni-and bi-directional flow has been investigated via experiment and modeling.In the experiments,pedestrians are required to walk clockwise/anti-clockwise in a ring-shaped corridor under normal situation and holding umbrella situation.No matter in uni-or bi-directional flow,the flow rate under holding umbrella situation decreases comparing with that in normal situation.In bidirectional flow,pedestrians segregate into two opposite moving streams very quickly under normal situation,and clockwise/anti-clockwise walking pedestrians are always in the inner/outer lane due to right-walking preference.Under holding umbrella situation,spontaneous lane formation has also occurred.However,when holding umbrella,pedestrians may separate into more than two lanes.Moreover,the merge of lanes have been observed,and clockwise/anti-clockwise pedestrians are not always in the inner/outer lane.The basic social force model cannot reproduce the experimental phenomena very well.To model the evacuation dynamics,an improved social force model has been proposed,in which it is assumed that the driving force of a pedestrian cannot be performed when the resultant of physical forces exceeds a threshold.Simulation results are in good agreement with the experimental ones.To model the flow dynamics under view-limited condition,an improved force-based model has been proposed.The driving force has been modified.The right-walking preference has been taken into account.The fact that pedestrians cannot judge the moving direction accurately under limited-view condition has been considered.Simulation results are in good agreement with the experimental ones.To model the flow dynamics under holding umbrella condition,the contact force between umbrellas has been taken into account.Simulation results are in agreement with the experimental ones.This paper is expected to be helpful for the design and management of pedestrian facilities as well as planning guidelines in public events and evacuations.