Collective Dynamics (E-Journal)
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Benchmarking Pedestrian Dynamics Models for Common Scenarios: An Evaluation of Force-Based Models
Full text linkExtensive research in pedestrian dynamics has primarily focused on crowded conditions and associated phenomena, such as lane formation, evacuation, etc. Several force-based models have been developed to predict the behavior in these situations. In contrast, there is a notable gap in terms of investigations of the moderate-to-low density situations. These scenarios are extremely commonplace across the world, including the highly populated nations like India. Additionally, the details of force-based models are expected to show significant effects at these densities, whereas the crowded, nearly packed, conditions may be expected to be governed largely by contact forces. In this study, we address this gap and comprehensively evaluate the performance of different force-based models in some common scenarios. Towards this, we perform controlled experiments in four situations: avoiding a stationary obstacle, position-swapping by walking toward each other, overtaking to reach a common goal, and navigating through a maze of obstacles. The performance evaluation consists of two stages and six evaluating parameters - successful trajectories, overlapping proportion, oscillation strength, path smoothness, speed deviation, and travel time. Firstly, models must meet an eligibility criterion of at least 80% successful trajectories and secondly, the models are scored based on the cutoff values established from the experimental data. We evaluated five force-based models where the best one scored 57.14%. Thus, our findings reveal significant shortcomings in the ability of these models to yield accurate predictions of pedestrian dynamics in these common situations
Glossary for Research on Human Crowd Dynamics - 2nd Edition
Full text linkPedestrian and crowd dynamics involves multiple disciplines, including computer science, engineering, mathematics, physics, bio-mechanics, psychology, social science and more. For effective collaboration between disciplines, researchers need a common understanding of key concepts. To address this challenge, A Glossary for Human and Crowd Dynamics was published six years ago, providing researchers with a valuable reference for cross-disciplinary communication.
We now present the second version, which includes 53 new concepts and 12 revisions from the first glossary, collaboratively developed by 65 contributors from various disciplines and regions around the world through a multi-stage process. This process involved identifying new concepts not covered in the first glossary and suggesting revisions to existing entries, voting on proposed additions and modifications, writing definitions for the selected concepts, and collaboratively revising and editing the entries.
By introducing new terms and refining existing definitions, this glossary aims to facilitate clearer communication, improve conceptual consistency, and support collaboration among researchers working within the field of human and crowd dynamics from diverse perspectives
Exploring the Braess Paradox: Static Versus Dynamic Assignment
Full text linkThe Braess paradox is a well-known phenomenon initially observed in road traffic flow. It points out that increasing network capacity can lead to poorer performance in congested situations, when the drivers attempt to optimise their travel time individually. This paradox is not limited to road transport, but also extends to various information networks. In this article, we examine the Braess paradox in a closed network where demand remains constant. First, we determine the user and global optima of the deterministic system in stationary states with flow balancing. We present explicit formulae for the density intervals at which the Braess paradox occurs. We then compute Monte Carlo simulations of a stochastic mesoscopic traffic model using aggregate data obtained from a queueing model to explore the results. Static assignment models match the deterministic stationary results. In addition, the simulations assess the effectiveness of dynamic assignment, whereby drivers select routes in real time to minimise travel time. Interestingly, behaviour with dynamic assignment deviates from the generic static assignment results, particularly in highly congested situations. These results emphasise the significance of dynamic route selection in relation to Braess's paradox
Relationships and Characteristics of Self-Organized Vehicle Groups and Other Remaining Vehicles in Disordered Heterogeneous Traffic
Full text linkThis study examines the relationships between self-organized vehicle groups and remaining vehicles (referred to as "remains") within heterogeneous, disordered traffic flows, and compares their characteristics. The findings reveal that leader–follower relationships are less prevalent among the remains, whereas connections with grouped vehicles are more frequent in both groups and remains. Additionally, groups form longer leader-follower networks with diverse pathways for the propagation of acceleration and deceleration waves. Furthermore, the results suggest that a typical vehicle platoon comprises a sparse distribution of remains interspersed around longer groups. Moreover, owing to their extended network lengths and varied densities, groups are likely to feature amplified acceleration and deceleration waves. The findings also suggest that some remains may gradually disperse, hindering the backward propagation of waves. Thus, this study provides novel insights into the formation and dynamics of groups and remains in disordered traffic, with the aim of enhancing traffic-flow modeling
Nudging Pedestrian Walking Dynamics Using Light Intensity and Color: A Virtual Reality Study
No full textCrowd management attempts to efficiently and safely guide pedestrian crowds. "Nudging" is one way to steer the crowd, gently coaxing people in the right direction. In this study, we study whether light can be used to "nudge" pedestrians' operational walking dynamics. Specifically, we aim to determine the extent to which light intensity and light color influence the average walking speed of pedestrians. Six light conditions are tested in a VR experiment: regular white light (approx. 100 lux), dark (approx. 1 lux), bright (approx. 300 lux), blue, green, and red light. This study concludes that A) the average walking speed decreases in darker light (10.4%) conditions and increases in brighter light (7.7%) or colored (2.8% - 8%) conditions. In addition, pedestrians decelerate more slowly and cautiously in dark light conditions, while the acceleration and deceleration profile do not significantly change for bright, blue, green, and red light conditions.
In addition, this study assessed whether a wireless HMD can be used to study pedestrians' average walking dynamics because a relatively new type of VR simulator was adopted. The validation analysis concludes that VR experiments featuring wireless HMD and open-plan movements overestimate step time (+7.5%) and step length (+12.8%) and underestimate the average walking speed (-22.8%). In addition, we find that relative trends regarding the impact of socio-demographic characteristics on the mean of the three analyzed metrics can, in most cases, be reproduced
Effect of Response Time Distribution in Weak Lane Discipline on Linear Stability
Full text linkThe increase in mixed traffic with weak lane discipline (2D mixed traffic) has attracted significant research attention. To better replicate and understand traffic with weak lane discipline, this study examined the variation in response time relative to the position of the leading vehicle, including lateral shifts. Through experiments conducted using a driving simulator and functional fitting, we demonstrated that changes in response time due to longitudinal and lateral locational shifts are well represented by linear and exponential functions, respectively. Additionally, we proposed an extended formulation of the 2D optimal velocity model (2D OVM) that incorporates variable response times, termed the 2D OVM with varying sensitivities (2D OVMVS). The stability condition was derived using a linear approximation. A comparative analysis of the phase diagrams of the 2D OVM and 2D OVMVS, along with a sensitivity analysis, revealed that the proposed 2D OVMVS exhibited a larger unstable region in the phase diagram and lower stability in stable regions than the 2D OVM. As a result, in 2D traffic with weak lane discipline, the equilibrium formation of vehicles was more susceptible to disruption. Our findings indicate that variable response times, as observed in this study, substantially influence the stability of no-lane traffic. Unlike fixed-response models, incorporating response time variability accentuates unstable tendencies. This underscores the necessity of accounting for non-uniform response time distributions in future traffic models
A Coupled SFM-ASCRIBE Model To Investigate the Influence of Emotions and Collective Behavior in Homogeneous and Heterogeneous Crowds
Full text linkThe understanding of crowd behavior dynamics holds immense significance in ensuring public safety across a range of situations, including emergency evacuations and large-scale events. Our research focuses on two primary objectives: investigating the impact of emotions on crowd movement and gaining valuable insights into collective behavior within crowds. To achieve this, we present a coupled model, incorporating an enhanced ASCRIBE model with an agent displacement model. We introduce heterogeneity into our model by incorporating specific mobility laws for different categories of panicked crowds, considering the influence of emotions on both speed and direction. Through numerical simulations, we analyze the model's parameters, observe the behavior of uniform crowds, and explore the collective dynamics within diverse crowds. By conducting comprehensive simulations and analyses, the findings from this study can contribute to the development of more effective crowd management strategies and emergency evacuation protocols
Analyzing the Effects of a Column in front of a Bottleneck in a Transportation Infrastructure using Real-World Trajectories
Full text linkIn this paper, the effects of placing a column in front of a bottleneck in a real environment under everyday conditions are investigated regarding to person densities, pedestrian flows and personal distances. The study area is a transport infrastructure in Vienna with an attached shopping mall and the column was positioned at various locations in front of the entrance of the shopping mall. For the data analysis, the person trajectories of several scenarios were recorded using video-based sensors. In the scenarios with the column, the densities in front of the bottleneck increased but flows got a nuance smoother with less stop-and-go movements
Tracer Observation of Queuing Behavior During New Year’s Visits to Shrines/Temples Using GPS Log Data
Full text linkCrowd behavior during customary New Year's visits to shrines/temples in Japan was investigated. During these mass gatherings, visitors form a queue along the approach to the Main Hall of the shrines/temples. The unidirectional flow of the queue as the visitors approach the Main Hall to perform rituals is managed by police. The author observed the queuing behavior of visitors by joining the procession and tracked his position over time using a GPS logger. The author also observed the surrounding geometrical features and the procedures for guiding the crowd. Control methods, such as cordons and preparation of extra queuing space, were examined based on the observational data and compared with those of building/fire evacuations. The “everyone is welcome” aspect of New Year's visits required not only cordons in front of bottlenecks such as gates, stairs, and praying areas, but also alteration of the queuing space to accommodate for expansion of the crowd size. In contrast, considering building/fire evacuations, occupancy can be estimated or controlled by ticket quantity or density. Therefore, the accumulation of evacuees at bottlenecks can be predicted and should be considered in the building design phase. Different events or facilities require distinct crowd management approaches
Calibration of Decision-Based Crowd-Behaviour Model
Full text linkVarious methods of calibration are used depending on the model type, application, and individual preferences. While there is no universally applicable method, statistical techniques became popular in recent decades. Introduced calibration concept consists of separate calibration episodes to avoid choosing only a few metrics to describe the whole system and a high computational time increasing exponentially with the number of parameters. These episodes are designed to be separated from each other and to cover one type of pedestrian behaviour captured by some model parameters. The design of the calibration quantities; estimate of the needed simulation time to get stationary results; and the number of iterations by Chebyshev's inequality influencing the quality of the results are discussed. Furthermore, hypothesis testing (James' test) is used to compare the model and experimental data. This calibration process can be applied for any pedestrian model; this paper deals with its application on the crowd-behaviour phase in the author's decision based model