Study On Pedestrian Characteristics And Entry Restrictions In Typical Bottlenecks Of Subway Space

With the rapid development of urbanization and the rapid expansion of the urban population,urban public spaces and their internal "bottleneck" sites are characterized by a large number of personnel,frequent personnel gatherings,complex and diverse personnel behavior,and easy spreading of panic,so high security risk exists.The study on pedestrian characteristics and pedestrian guidance measures in these specific places is also extremely urgent.The establishment of reasonable flow-limiting measures in these "bottleneck" locations where the flow of these people is large and the walking space is suddenly contracted can save the walking space to the greatest extent,facilitate pedestrians' travel,improve the efficiency of pedestrian facilities,and reduce the possibility of personnel congestion.Therefore,it is particularly important to scientifically study the individual decision-making behaviors in the presence of entry restriction facilities and the movement characteristics of dense populations.This article aims at the characteristics of pedestrian movement in typical bottleneck positions of subway space—staircases,escalators,and dual-exit bottleneck venues.The purpose is to analyze and evaluate the effectiveness of current limiting facility settings,optimize the entrance design of pedestrian facilities,and reasonably organize and manage the movement of dense populations.The results can provide accurate,targeted solutions and theoretical support for the safety management of public places,and improve the emergency management level of subways under large passenger flow conditions.First,the study on the pedestrian macroscopic movement characteristics was carried out.The traffic flow,crowd density and passengers' walking speed of the bottleneck facilities under different conditions of entrance fence were measured by field observation and video recording.When the length of the escalator is increased to 2m,the inlet flow of the escalator/staircase system increases from 1.1 persons/(m s)to 1.38 persons/(m·s);as the fence length increases,the fluctuation of waiting area density reduces with time,and individual speed becomes relatively uniform.Then the analysis of the three fundamental diagrams further indicates that the degree of congestion in the waiting area can be adjusted by changing the length of the entry fence set at the entrance of the escalator/staircase system.Within a suitable terrain limit(i.e,L = 2 to 2.5 m),density can directly affect the passenger's choice.In addition,proper terrain restrictions can promote the orderly movement of passengers and avoid cross-conflict before the escalator,ensuring that the utilization rate of staircase maintains high when the flow of escalator is large.In addition,the micro-behavior analysis of pedestrians focused on the discrete choice behavior of pedestrians.First,a small-scale psychological questionnaire was used to determine the personal and social characteristics that may affect choice,including gender,age,companions,luggage/baby carrying,passenger flow peak/peak travel dates,fence length,and crowd density in front of the escalator.Then 11010 sample data were collected from a field observation in subway station,and parameters were estimated using discrete choice models(Logit models).There are heterogeneity preferences for the factors of middle-aged,carrying baggage,escalator density and balustrade length.Among these factors,carrying luggage has the greatest impact on the choice of escalators,but the heterogeneity among passengers is also the biggest.The random distribution of the density near escalator shows that the crowd-avoidance mentality and following behavior all play important roles in the choice of facilities.In addition,the "middle length" fence(2.5?3.1 m)is most effective in promoting the use of escalators and can minimize the individual heterogeneity of crowding perception near the escalator entrance.As the entry fence length increases,the model's predictive performance increases by 4.35%.The correct prediction of the stairs use by the model is lower than that of the escalator,but the mixed model is better than the binary model.Based on the phenomena of avoiding crowding and imitating following behavior in front of pedestrian facilities,the simulation method of the cellular automata floor field model was used considering the visual obscuring effect,and Perceptive Density(PD)and Motion Similarity(MS)perceptual floor fields were built in the model.The moving characteristics with the variable-width and variable-appeal dual-exit bottleneck were studied.The role of the MS field makes pedestrians more inclined to keep their direction,and the influence of the PD field will keep them away from others.As the field of view increases,the effect of the perceived field will increase.The setting of the entrance fence has a great influence on the moving process of pedestrians passing through a narrower(? 1.2m)or wider(?3.6m)exit which is less attractive.The results show that with the fence set in between double exits increasing to 3.6 m,the average transit time is reduced by 10%.The analysis of the four macro-parameters of transit time,congestion duration,unit flow,and average density show that longer separation fence ensures the stability of the outlet flow and density during the congested period.Finally,the effectiveness of the fence length corresponding to different outlet widths was pointed out through the comprehensive evaluation.Results were compared with the field observations and show good consistency.