Spatial Distribution Of Pedestrians Research Articles

Temporal and spatial distribution of pedestrians in subway evacuation under node failure by multi-hazards

The metro has become an important component of the urban traffic system. Due to the dense crowd, if sudden accidents occurred during rush hours in station, such as fires, explosions or natural disasters, the casualty and injury would be very enormous. Accidents happening in the underground station are prone to trigger domino effect, causing complex multi-hazards consequence. Therefore, more attention should be focused on the crowd evacuation strategy in underground stations. In this paper, for studying the temporal and spatial distribution characteristics of evacuation in dense subway stations under node failure caused by multi-hazard coupling conditions, a large-scale evacuation model was established by Massmotion based on the social-force, combined with the on-site measured data of Nanjing Xinjiekou subway station, one of the largest stations in Asia. A series of key node failures in the station that represents the bad impact of multi-hazards is set in the model. Through analyzing the evacuation time and the occupant density, etc, the results show that if pedestrians tend to escape by the lowest cost, it will cause extreme pressure on some narrow region. If those nodes fail unfortunately, the global evacuation efficiency will be seriously affected. Yet, an excessively scattered targets strategy obviously wastes traffic capacity and delay evacuation process. Therefore, it is necessary to balance the global evacuation time and local density in the process of crowd evacuation. The current conclusion will be useful to prompt the administrators to formulate a reasonable evacuation strategy and disperse the regional evacuation risk.

Review of Pedestrian Load Models for Vibration Serviceability Assessment of Floor Structures

Innovative design and technological advancements in the construction industry have resulted in an increased use of large, slender and lightweight floors in contemporary office buildings. Compounded by an ever-increasing use of open-plan layouts with few internal partitions and thus lower damping, floor vibration is becoming a governing limit state in the modern structural design originating from dynamic footfall excitations. This could cause annoyance and discomfort to building occupants as well as knock-on management and financial consequences for facility owners. This article presents a comprehensive review pertinent to walking-induced dynamic loading of low-frequency floor structures. It is intended to introduce and explain key walking parameters in the field as well as summarise the development of previous walking models and methods for vibration serviceability assessment. Although a number of walking models and design procedures have been proposed, the literature survey highlights that further work is required in the following areas; (1) the development of a probabilistic multi-person loading model which accounts for inter- and intra-subject variabilities, (2) the identification of walking paths (routes accounting for the effect of occupancy patterns on office floors) coupled with spatial distribution of pedestrians and (3) the production of a statistical spatial response approach for vibration serviceability assessment. A stochastic approach, capable of taking into account uncertainties in loading model and vibration responses, appears to be a more reliable way forward compared to the deterministic approaches of the past and there is a clear need for further research in this area.

Modeling and simulation on interaction between pedestrians and a vehicle in a channel

The mixed traffic flow composed of pedestrians and vehicles shows distinct features that a single kind of traffic flow does not have. In this paper, the motion of a vehicle is described by the finer deterministic Nagel-Schreckenberg model, while the motion of pedestrians is mimicked by the lattice gas model with taking the floor field into account. Then the interaction between a certain vehicle and pedestrians in a narrow channel is investigated in two cases, i.e., pedestrians move in the same as or opposite to the direction of vehicle. The direction of the pedestrian movement is determined by the floor field, and the vehicle (and its influential area), regarded as a movable obstacle, and thus causing the floor field to change. Because of the timely change of vehicle speed and the size of impact area, the floor field must be calculated at each time step. Through numerical simulation, the fundamental diagram for pedestrian flow under the typical parameters is obtained together with the average speed of the vehicle as a function of pedestrian density. It is found that there are two critical densities, i.e., <i>ρ</i><sub>1</sub> and <i>ρ</i><sub>2</sub>. When <i>ρ</i><sub>1</sub> ≤ <i>ρ</i> ≤ <i>ρ</i><sub>2</sub>, the fundamental diagrams in the two cases are significantly different. This is due to the reverse movement of pedestrian and vehicle, the congestion ahead of the vehicle makes the average speed of pedestrians significantly lowered. In this case, the flux of pedestrians is a linear function of pedestrian density, and its slope indicates the speed at which pedestrian congestion propagates upstream. It can also represent the speed of the moving bottleneck formed by the vehicle. The slope mainly depends on the width of the vehicle and the anticipation time of pedestrians. When <i>ρ</i> < <i>ρ</i><sub>1</sub> and <i>ρ</i> > <i>ρ</i><sub>2</sub>, there is no obvious difference between the two cases. We further investigate the effect of three parameters, i.e., the anticipation time of pedestrians, the width and the speed limit of the vehicle. When pedestrians have the same direction as the vehicle, these parameters only have negligible effects. However, in the case that pedestrians move oppositely to the vehicle, the width of the vehicle influences the mixed traffic significantly. When the width of the vehicle is small, even in rather high pedestrian density, the vehicle can move forward. In addition, larger anticipation time of pedestrians is helpful in improving the speed of vehicle, while the effect of the speed limit of vehicle is relatively small. The spatial distribution of pedestrians and the vehicle and the short time average speed of the vehicle are also provided to reveal more information about both pedestrians and the vehicle.

An entropy model to measure heterogeneity of pedestrian crowds using self-propelled agents

An entropy model to characterize the heterogeneity of a pedestrian crowd in a counter-flow corridor is presented. Pedestrians are modeled as self-propelled autonomous agents that are able to perform maneuvers to avoid collisions based on a set of simple rules of perception and action. An observer can determine a probability distribution function of the displayed behavior of pedestrians based only on external information. Three types of pedestrian are modeled, relaxed, standard and hurried pedestrians depending on their preferences of turn and non-turn when walking. Thus, using these types of pedestrians two crowds can be simulated: homogeneous and heterogeneous crowds.Heterogeneity is measured in this research based on the entropy in function of time. For that, the entropy of a homogeneous crowd comprising standard pedestrians is used as reference. A number of simulations to measure entropy of pedestrian crowds were conducted by varying different combinations of types of pedestrians, initial simulation conditions of macroscopic flow, as well as density of the crowd. Results from these simulations show that our entropy model is sensitive enough to capture the effect of both the initial simulation conditions about the spatial distribution of pedestrians in a corridor, and the composition of a crowd. Also, a relevant finding is that entropy in function of density presents a phase transition in the critical region.

Urban area types and spatial distribution of pedestrians: Lessons from Tel Aviv

This study examines the role of two urban area types – traditional and contemporary – with regard to pedestrian movement volume and distribution. This study focuses on four dimensions of urban areas which have potential influence on pedestrian movement: (i) a spatial dimension based on road network structure; (ii) a functional dimension of land uses such as retail fronts; (iii) a physical dimension of road sections; and (iv) a demographic dimension of population and employment densities. Four research areas in Tel Aviv are examined and each of these areas is divided to two adjacent sub-areas — a traditional sub-area and a contemporary one. The aim is to clarify: (i) the character of urban areas that were created following different urban design paradigms; (ii) the relative contribution of the spatial, functional, physical and demographic dimensions to pedestrian movement in urban areas of different types. The findings show significant differences between adjacent traditional and contemporary sub-areas. Specifically, traditional sub-areas have higher levels of spatial connectivity and retail fronts distribution as well as higher pedestrian movement volume. The spatial dimension has the strongest overall connection to pedestrian movement, and particularly for traditional sub-areas, while the physical dimension has the strongest connection to pedestrian movement for the contemporary sub-areas.

The effects of spatial accessibility and centrality to land use on walking in Seoul, Korea

The debate on pedestrian-friendly urban structures has increased interest in the connections among land use, accessibility, and pedestrian volume. Most econometric models have focused on the individual and separate effects of density, land-use patterns, and street connectivity on the spatial variation of walking. This study investigates the effects of spatial accessibility and centrality by land-use types on pedestrian presence in Seoul in 2009. The model employs four newly developed accessibility indices and identifies the differentiated effects of land-use accessibility and centrality on pedestrian volume, controlling for street features, location and transportation characteristics, and neighborhood land-use attributes. The model results confirm that the effects of land-use accessibility and centrality vary with the spatial distribution of pedestrians. This analysis highlights the importance of investigating accessibility effects by land-use volume. Indeed, policies on pedestrian-friendly urban structures should consider local contexts as well as the complex relationship between land-use accessibility and walking.

Pedestrian flow dynamics in a lattice gas model coupled with an evolutionary game

This paper studies unidirectional pedestrian flow by using a lattice gas model with parallel update rules. Game theory is introduced to deal with conflicts that two or three pedestrians want to move into the same site. Pedestrians are either cooperators or defectors. The cooperators are gentle and the defectors are aggressive. Moreover, pedestrians could change their strategy. The fundamental diagram and the cooperator fraction at different system width W have been investigated in detail. It is found that a two-lane system exhibits a first-order phase transition while a multilane system does not. A microscopic mechanism behind the transition has been provided. Mean-field analysis is carried out to calculate the critical density of the transition as well as the probability of games at large value of W. The spatial distribution of pedestrians is investigated, which is found to be dependent (independent) on the initial cooperator fraction when W is small (large). Finally, the influence of the evolutionary game rule has been discussed.

Modeling Pedestrian Dynamics in Montreal's Underground City

This study is an examination of the daily dynamics and system stability of pedestrian movement within an extensive, indoor walkway system. Temporal and spatial stability in the distribution of pedestrians was established using an efficient census-taking technique. It was found that the spatial distribution of pedestrians was weakly related to the integration of the Underground system. Centrally located links were marginally more attractive to pedestrians. Relatively minor differences in pedestrian distribution were discovered between weekday and weekend day. The absence of directional flows over time was also observed. The highly stable dynamic structure of the Underground is in direct relationship with a describable urban environment. This paper concludes with recommendations for research into other explanatory environmental factors.