Pedestrian Crowds Research Articles

Experimental study on enhancing pedestrian efficiency and crowd safety with regular sound under open boundaries

Abstract We empirically investigated the impact of regular sound on planar pedestrian movement in open boundary environments, a rarely studied topic. Participants walked to regular sound with different tempos (70 BPM vs. 100 BPM) and types (monotone vs. periodic ‘tick-tack’ rhythm). We found that regular sounds at 100 BPM, close to the normal walking pace, improve pedestrian efficiency. They reduce passing time by 8.41% and increase average flow by 9.50%. This efficiency enhancement is lower compared to single-file experiment with periodic boundaries, where reaching a high-density jammed phase is easier. Additionally, this efficiency enhancement from sound is reduced by unstable step synchronization under open boundaries and turning behavior. Regular sound significantly improves crowd safety in turning areas, where congestion levels (Cls) and crowd danger (Cd) are highest. Cls decrease by 8.27% with the 100 BPM monotone, and Cd decreases by 19.1% with the 100 BPM periodic rhythm. Operationally, regular sounds at 100 BPM can be used to guide pedestrian flow smoothly and effectively in crowd management.

Investigating pedestrian stepping characteristics via intrinsic trajectory

Investigating pedestrian stepping is essential for pedestrian dynamics research, aiding in understanding pedestrian behavior and crowd modeling. However, how to calculate the basic step metrics is still controversial, and the differences between straight walking and turning steps are often overlooked in past studies. In this work, we proposed the trajectory-based measurement to more accurately calculate the step metrics and further analyze the differences between the straight walking and turning steps. The trajectory-based measurement takes the intrinsic trajectory of the pedestrian as the reference frame to guide a more universal measurement for stepping characteristics. By applying the proposed trajectory-based measurement to revisit the dataset of a single-file experiment, we identify differences between the straight walking step and the turning step from multiple perspectives. The results show that when density is low, straight walking steps exhibit larger step velocity and length, whereas turning steps display more unbalanced lateral motion. As density increases, both types of steps demonstrate greater forward motion imbalance, while pedestrians prefer to take the step on the outer side of the turn to propel their forward motion when taking turning steps. These findings deepen our understanding of pedestrian stepping behavior and provide valuable insights for future studies of pedestrian dynamics.

Phone use by pedestrians - pilot studies

People use mobile phones for almost all activities throughout the day. Phones are used to perform activities such as running, cycling and walking on the sidewalk. Most often we listen to music, browse the Internet or just talk. Unfortunately, it should be noted that the use of a mobile phone is not always safe, as it can distract the attention of a pedestrian or driver, which can lead to a road accident. The topic of using mobile phones at pedestrian crossings is much less frequently discussed compared to using a mobile phone while driving a passenger vehicle. The phenomenon of distracting pedestrians with a mobile phone is becoming an increasingly recognizable phenomenon. In many countries, such behavior is severely punished. The use of mobile phones by pedestrians and drivers reduces attention. Despite the risk of road accidents, many pedestrians and cyclists are accustomed to using their mobile phones while traveling in traffic. The aim of the article is to draw attention to the problem of using a telephone by pedestrians crossing an intersection with traffic lights. The collected results confirm that pedestrians often use mobile phones while crossing the pedestrian crossing. Collected data from observational studies reveal several other important findings. Pedestrians using a mobile phone on a pedestrian crossing walk slower. Pedestrians are oblivious to passing vehicles and often cross the pedestrian crossing without thinking or checking in advance. Pedestrians using a mobile phone at a pedestrian crossing do not pay attention to traffic lights, but follow the crowd of other pedestrians

Viral Transmission in Pedestrian Crowds: Coupling an Open-source Code Assessing the Risks of Airborne Contagion with Diverse Pedestrian Dynamics Models

Viral Transmission in Pedestrian Crowds: Coupling an Open-source Code Assessing the Risks of Airborne Contagion with Diverse Pedestrian Dynamics Models

Understanding pedestrian crowd dynamics on ramps: An empirical study triggered by Seoul Halloween crowd crush

Pedestrian safety on ramps demands greater attention compared to flat surfaces, as exemplified by a tragic crowd crush accident that claimed the lives of over 150 individuals on a densely populated ramp in South Korea in 2022. Understanding the dynamics of pedestrian movement on ramps is crucial for effectively managing mass events and daily pedestrian transportation. This paper presents an empirical study investigating bidirectional pedestrian flows on a simulated ramp with varying inclinations. Flow ratios, indicating the group size of major and minor flows in both directions, were examined. Results show that bidirectional pedestrian streams exhibit self-organizing behavior, characterized by the emergence of distinct lane formation phenomenon in both level and ramp walking scenarios. The shortest overall time required for pedestrians to exit the ramp was observed at a 3° inclination. As the ramp inclination increases, the disparities between upward and downward directions become more pronounced. Specifically, the uphill flow consistently exhibits a lower average speed compared to the downhill flow at the same inclination. In general, an increase in inclination is associated with a decrease in forward speed, an increase in lateral speed, and a greater utilization of handrails. Handrail plays a particularly important role in assisting pedestrians down very steep ramps. Furthermore, we found that the influence of flow ratio on walking parameters undergoes a change from level walking to ramp walking scenarios. Notably, for the same flow ratio, the results can vary significantly depending on whether the major flow is uphill or downhill. Our findings provide valuable insights into crowd management on ramps and hold significant implications for the safer design of ramps in subway stations, underpasses, and overpasses.

Congestion Number Analysis of Cross-Flow Dynamics: Experimental Data and Simulations

We recently proposed the "Congestion Number" (CN) as a metricto evaluate the state of a pedestrian crowd. Such metric, whose definition is based on the gradient of the rotor of the crowd velocity field, appears to provide additional information with respect to traditional metrics based on pedestrian density and flow. We also published two works on the dynamics of orthogonally crossing pedestrian flows under different density regimes. In the first manuscript we analysed experimental data by using traditionalobservables such as density, velocity and relative position between pedestrians, along with less explored ones such as body orientation. In the second one we proposed a hierarchy of simulation models to reproduce the cross-flow dynamics, and used the aforementioned observables to compare such models. Based on theoretical considerations and analysis of real world data, we believe the crossing flow setting to be a good arena to test the CN metric, and in this work we perform a CN analysis on the empirical and simulation data. Results show that simulation models, which reproduced almost perfectly the density time dependence of the pedestrian crowd, fail to reproduce the CN one. Actually, models "outperform" the pedestrian crowd when analysed using CN. These preliminary results suggest that the CN metric may provide useful information not only in crowd assessment but also in model evaluation.

Classification of Pedestrian Crowds by Dimensionless Numbers

Presently, classifications of pedestrian crowds primarily rely on density. This fails to encompass the diverse behaviours and risk profiles observed. We introduce two dimensionless numbers, the Intrusion number In, based on the desire to maintain one’s personal space, and the Avoidance number Av, based on the anticipation of collisions. These two numbers delineate different flow regimes, as we intuitively expect and as we empirically demonstrate using an extensive dataset. Similarly to Fluid Mechanics, where dimensionless numbers guide the choice between different approximations, the dynamics of crowds can be approached in each regime by perturbative expansions, which yield pedestrian models applicable in the corresponding regime (and only there).

Order–disorder phase transitions in front of the exit during human crowd evacuations

Human crowds often exhibit collective behaviors through self-organization, such as orderly queueing and disordered congestion at exits. Understanding the dynamic mechanisms behind these behaviors is crucial for pedestrian traffic management and the handling of mass crowds. Although current models and experiments have provided profound insights into ordered and disordered pedestrian groups separately, the transition mechanism from order to disorder within pedestrian crowds in front of exits remains unclear. In this study, a pedestrian queueing evacuation experiment was presented to demonstrate the phase transition process of pedestrian movement states as urgency levels in the environment change. We discovered the migration pattern of the phase transition point under evacuation control and identified different propagation modes of pedestrian velocity waves. Furthermore, a pedestrian motion model based on experimental data and observed phenomena was established. This model not only replicates the observed phenomena and regularities from the experiments but also reveals the quantitative phase transition mechanism of pedestrian movement under the influence of a single factor (i.e., urgency level or queueing ratio). Our findings hold significant implications for various domains, including pedestrian management, traffic control, and pedestrian dynamics.

Rheology of a crowd: from faster-is-slower to shear thickening

The evacuation speed of pedestrians through bottlenecks usually leads to the faster-is-slower (FIS) phenomenon, which relies on frictional clogging and clusters’ size. However, less attention is given in literature to the rheology of pedestrian crowds and the forces ruling their dynamics. Here, we establish a link between the faster-is-slower phenomenon (FIS) in pedestrian crowds and the shear-thickening rheological behavior of (non)Brownian suspensions. We analyze pedestrian room egress through particle-based simulations using the Social Force Model, revealing an S-shaped shear rate dependency characteristic of discontinuous shear thickening (DST). At the same time, the crowd flow viscosity near the exit exhibits a steep increase coinciding with FIS occurrence, establishing a correlation between FIS and shear thickening. Our results prove that crowd evacuations are governed by two distinct critical jamming densities, one frictional and another frictionless, and that contact forces alone cannot lead to FIS, but social force interactions are necessary to avoid contacts at low desired speeds. Our results point at the suitability of (non)Brownian suspensions as models that provide an original rheological perspective to pedestrian dynamics.

An evacuation model considering pedestrian fall behavior in an inclined passenger ship

Passenger ships are likely to be inclined during and after accidents, which is a vital factor that affects pedestrian behaviors and crowd dynamics in the evacuation process. On a significantly inclined ship, pedestrian fall behavior becomes more complex, increasing the risk of stampedes. Nevertheless, this type of evacuation has rarely been investigated. In this study, an extended cellular automata (CA) model that meets the inherent characteristics of passenger ship evacuations is constructed. The inclination force and self-adjusting force are incorporated into the model to evaluate the balance mechanism of pedestrians, while a method to calculate the probability of pedestrians falling down is established by considering the ship heeling angle and pedestrian heterogeneity. Further, the state of the pedestrians after falling to the ground is analyzed. A hazard field is introduced to describe the interaction between normal pedestrians and fallen pedestrians. The simulation results show that deaths occur when the ship heeling angle is greater than 20° and the crowd is evacuated successfully and fastest at the ship heeling angle of 5°, even better than on the flat ground. The greater the ship heeling angle, the more likely pedestrians are to fall over, and the earlier the first death occurs, thereby resulting in longer evacuation time and increased fatalities. The heterogeneity of passengers has considerable effects on the effectiveness of the ship evacuation, with a greater proportion of strong-resistance pedestrians reducing the crowd death and fall risks, even though the influence of crowd constitution on crowd evacuation time is insignificant. The death toll and evacuation time increased with the initial number of pedestrians aboard the ship. This study is beneficial in terms of understanding the evolution mechanism of evacuation dynamics and developing effective strategies for crowd emergency management on large passenger vessels.

Robust spatial self-organization in crowds of asynchronous pedestrians.

Human crowds display various self-organized collective behaviours, such as the spontaneous formation of unidirectional lanes in bidirectional pedestrian flows. In addition, parts of pedestrians' footsteps are known to be spontaneously synchronized in one-dimensional, single-file crowds. However, footstep synchronization in crowds with more freedom of movement remains unclear. We conducted experiments on bidirectional pedestrian flows (24 pedestrians in each group) and examined the relationship between collective footsteps and self-organized lane formation. Unlike in previous studies, pedestrians did not spontaneously synchronize their footsteps unless following external auditory cues. Moreover, footstep synchronization generated by external cues disturbed the flexibility of pedestrians' lateral movements and increased the structural instability of spatial organization. These results imply that, without external cues, pedestrians marching out of step with each other can efficiently self-organize into robust structures. Understanding how asynchronous individuals contribute to ordered collective behaviour might bring innovative perspectives to research fields concerned with self-organizing systems.

Generating natural pedestrian crowds by learning real crowd trajectories through a transformer-based GAN

Generating natural pedestrian crowds by learning real crowd trajectories through a transformer-based GAN

Dimensionless numbers reveal distinct regimes in the structure and dynamics of pedestrian crowds.

In fluid mechanics, dimensionless numbers like the Reynolds number help classify flows. We argue that such a classification is also relevant for crowd flows by putting forward the dimensionless Intrusion and Avoidance numbers, which quantify the intrusions into the pedestrians' personal spaces and the imminency of the collisions that they face, respectively. Using an extensive dataset, we show that these numbers delineate regimes where distinct variables characterize the crowd's arrangement, namely, Euclidean distances at low Avoidance number and times-to-collision at low Intrusion number. On the basis of these findings, a perturbative expansion of the individual pedestrian dynamics is carried out around the noninteracting state, in quite general terms. Simulations confirm that this expansion performs well in its expected regime of applicability.

The Emergency Braking Game: a game theoretic approach for maneuvering in a dense crowd of pedestrians

We introduce an algorithm that maneuvers a vehicle through an area with randomly moving pedestrians. In non-critical situations, our strategy is to avoid pedestrians by steering, whereas dangerously moving pedestrians are avoided by braking, possibly coming to a complete stop. The distinction between non-critical and dangerous situations, as well as proof of safety, is based on a continuous optimization problem that we define. In this abstract problem, called Emergency Braking Game, one pedestrian is actively trying to collide with a continuously decelerating car. We show how to determine the outcome of the game based on the initial states of the car and the pedestrian. Using this information, our algorithm can initiate deceleration in the real scenario in time to avoid collision. The method’s safety is proven theoretically, and its efficiency is shown in simulations with randomly moving pedestrians.

An experimental study of pedestrian bidirectional flow through bottlenecks

Pedestrian flow passing through bottlenecks is complex, particularly for opposite movement in a room with a single doorway. These bidirectional flows would always cause congestion and further reduce traffic efficiency so the ‘Disembarking precedes embarking’ rule is widely used in the actual management of public spaces. However, the impact of the imbalance of the bidirectional movement of pedestrian numbers on the pedestrian capacity and throughput at the bottleneck still needs further exploration. Therefore, this study investigates the effects of the ratio r of pedestrians leaving the room to the total number of participants and the bottleneck widths (1.2, 1.6 and 2.0 m) on the movement behavior of pedestrians in bidirectional flow and the efficiency of passing through by conducting controlled experiments where pedestrian trajectories, speed, density, flow and time headway are analyzed. Results indicate that the bottleneck width and the pedestrian flow rate are linearly related, whereas the r and flow have a nonlinear relationship. Specifically, r = 10% is the optimal value for improving the pedestrian traffic efficiency at the bottleneck, which is even better than the unidirectional scenario. The most significant density in the measuring area is at r = 30%, corresponding to the greatest probability of clogging. The pedestrian density within the room influences the flow rate at the bottleneck, thereby indicating that wider doors are not always better from a design perspective. The findings presented in this paper can provide actual data to validate bidirectional pedestrian flow simulation models and theoretical support for pedestrian facility and crowd management optimization.

Using Immersive Virtual Reality to Study Road-Crossing Sustainability in Fleeting Moments of Space and Time

Despite a history of year-by-year reduction in road-crossing harm and fatality in the United States, the trend reversed course in 2009 and road-crossing has grown more hazardous since. Within this tendency, there has been a marked uptick in risk to urban crossers who are neither children nor elderly. The age group in between these extremes represents a bulk of urban crossers, for whom theoretical explanations for crossing behavior that are focused on youth and senior crossing factors often do not apply. New insight is likely required to explain why the rate of crossing harm is growing for the 20–44 age group, but declining among the young and elderly. However, it is difficult to experiment with crossing scenarios in a real-world context, where significant dangers are present and for which the uniqueness of crossers and crossing sites is abundant. In this paper, we introduce an end-to-end system for examining crossing behavior using a unique combination of real human crossing behavior, made safe through the combination of agent-based models, motion capture, virtual geographic environments, and immersive technologies from virtual reality. We demonstrate that this combination of methods can be deployed to examine very high resolution and very high specificities of crossing scenarios and behaviors, with reach to individual crossers and their judgment over tiny windows of space and time. We demonstrate that the system can reproduce known effects from the theoretical literature and from existing case studies, while also generating huge swaths of empirical and diagnostically useful data on crossing actions, interactions, and reactions relative to fleeting events and phenomena of urban geography, traffic dynamics, and ambient pedestrian crowds. To prove the concept, we deploy the system to investigate crossing judgment behavior among the 20–44 age group.

Limb articulation of biological motion can induce illusory motion perception during self-motion.

When one walks toward a crowd of pedestrians, dealing with their biological motion while controlling one's own self-motion is a difficult perceptual task. Limb articulation of a walker is naturally coupled to the walker's translation through the scene and allows the separation of optic flow generated by self-motion from the biological motion of other pedestrians. Recent research has shown that if limb articulation and translation mismatch, such as for walking in place, self-motion perception becomes biased. This bias may reflect an illusory motion attributed to the pedestrian crowd from the articulation of their limbs. To investigate this hypothesis, we presented observers with a simulation of forward self-motion toward a laterally moving crowd of point-light walkers and asked them to report the perceived lateral speed of the crowd. To investigate the dependence of the crowd speed percept on biological motion, we also included conditions in which the points of the walker were spatially scrambled to destroy body form and limb articulation. We observed illusory crowd speed percepts that were related to the articulation rate of the biological motion. Scrambled walkers also produced illusory motion but it was not related to articulation rate. We conclude that limb articulation induces percepts of crowd motion that can be used for interpreting self-motion toward crowds.

Disturbance Propagation Model of Pedestrian Fall Behavior in a Pedestrian Crowd and Elimination Mechanism Analysis

Disturbance Propagation Model of Pedestrian Fall Behavior in a Pedestrian Crowd and Elimination Mechanism Analysis

Cross-Video Pedestrian Tracking Algorithm with a Coordinate Constraint

Pedestrian tracking in surveillance videos is crucial and challenging for precise personnel management. Due to the limited coverage of a single video, the integration of multiple surveillance videos is necessary in practical applications. In the realm of pedestrian management using multiple surveillance videos, continuous pedestrian tracking is quite important. However, prevailing cross-video pedestrian matching methods mainly rely on the appearance features of pedestrians, resulting in low matching accuracy and poor tracking robustness. To address these shortcomings, this paper presents a cross-video pedestrian tracking algorithm, which introduces spatial information. The proposed algorithm introduces the coordinate features of pedestrians in different videos and a linear weighting strategy focusing on the overlapping view of the tracking process. The experimental results show that, compared to traditional methods, the method in this paper improves the success rate of target pedestrian matching and enhances the robustness of continuous pedestrian tracking. This study provides a viable reference for pedestrian tracking and crowd management in video applications.

A model for aircraft cabin evacuation considering passenger type

Pedestrian safety evacuation in aircraft cabins has been a challenging problem because of the aircraft's unique characteristics, such as the diversity of passengers and the restricted evacuation environment. It is difficult to reproduce evacuation activities in aircraft cabin due to safety concerns and cost constraints. To fill this gap, an improved cellular automaton model of crowd evacuation for aircraft cabin is established by incorporating the characteristics of cabin space structures and passenger attributes. Passengers are divided into healthy individual passengers and disabled-healthy group passengers, whose movement mechanisms are quantified. Based on the constructed model, simulation experiments are conducted using the configuration cabin layout of B737-800 as an example. The results show that the evacuation time is prolonged with increased passenger density and the number of disabled passengers. Moreover, the overall evacuation time is insignificantly affected by whether disabled-healthy group passengers' seats are close to the aisle or window, and the evacuation efficiency is best when their seats are evenly distributed in the cabin. The evacuation time is the shortest when all cabin doors are open, and pedestrians are evacuated the slowest when the central emergency doors are closed. This study provides valuable insights into effective strategies for pedestrian evacuation and crowd emergency management of civil aircraft.