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Studies of crowd behavior with related research on computer simulation provide an effective basis for architectural design and effective crowd management. Based on low-density group organization patterns, a modified two-layer social force model is proposed in this paper to simulate and reproduce a group gathering process. First, this paper studies evacuation videos from the Luan’xian earthquake in 2012, and extends the study of group organization patterns to a higher density. Furthermore, taking full advantage of the strength in crowd gathering simulations, a new method on grouping and guidance is proposed while using crowd dynamics. Second, a real-life grouping situation in earthquake evacuation is simulated and reproduced. Comparing with the fundamental social force model and existing guided crowd model, the modified model reduces congestion time and truly reflects group behaviors. Furthermore, the experiment result also shows that a stable group pattern and a suitable leader could decrease collision and allow a safer evacuation process. [ABSTRACT FROM AUTHOR]

The overtaking behavior of individuals under anxious panic is a major causative factor of crowded trampling accidents. In order to simulate the overtaking behavior of individuals experiencing anxiety and panic in a single-exit room within a normal pedestrian flow, an improved social force model is proposed to simulate crowd movement at local medium and high density through introducing the bypass overtaking mechanism, the side overtaking mechanism, and the side avoidance mechanism generated by association. The numerical simulation verifies the model's validity. The effect of the size and number of overtaking individuals on the pedestrian flow are explored. The results show that the new model can simultaneously reproduce a variety of overtaking behaviors and their associated behaviors in line with reality. The larger size of the overtaking individuals are, the easier it is to produce overtaking behaviors and the more difficult it is to overtake. With the increase of the number of overtaking individuals, the evacuation time becomes longer, but there is no linear relationship between them. When the initial pedestrian density is 0. 37 ped / m 2 , with time evolution, the appearance frequency of local density greater than 0. 8 ped / m 2 suddenly increases, and the comfort and safety of pedestrian movement decreases. The results of this paper can enrich the social force simulation model of pedestrian flow and provide a theoretical guidance for the evacuation of pedestrian flow with a few overtaking individuals in the room. • A novel social force model is used to describe individuals' overtaking behavior. • The overtaking mechanism and the side avoidance mechanism are introduced. • The effect of the size and number of overtaking individuals are explored. • The larger size of pedestrians are, the easier it is to produce overtaking behavior. [ABSTRACT FROM AUTHOR]

Fire accidents usually cause large casualties. In this paper, a fire evacuation model based on the dynamic coupling of FDS and CA, which dynamically couples disaster data and evacuation behavior, is designed to reflect the impact of disaster factors on the pedestrian evacuation process in real-time. Furthermore, pedestrians are divided into two categories, one type of pedestrians will choose to move against the wall to reduce the risk of stampede accidents, and the other type of pedestrian will evacuate to the exit according to the normal movement method. And considering the role of information transmission between pedestrians, the two types of pedestrians will transform into each other. In addition, the concept of pedestrian crowding, support, and friction is introduced and viewed as an influencing factor of normal pedestrian falls. Set the panic value as the influencing factor of the efficiency of pedestrian information transmission and the death probability of downed pedestrians. The impact of pedestrian density, pedestrian walking behavior towards walls, evacuation response time, information propagation radius, heat release rate of the fire source, and the interference of smoke on the pedestrians' visibility range on evacuation outcomes has been discussed through numerical simulations. The analysis shows that although the presence of pedestrians walking against the wall will slightly increase the evacuation time, when the available evacuation time allows, the risk of a stampede will be greatly reduced; The increase in evacuation response time will aggravate the panic psychology of pedestrians and increase the risk of stampede accidents; The increase of the pedestrian information transmission radius will reduce the risk of a stampede, and the effect is more obvious when the pedestrian density is smaller; Selecting building materials with lower heat release rates can effectively reduce the risk of fire incidents; The restriction of visibility range by smoke seriously endangers pedestrian safety and reduces the efficiency of evacuation.Our research results can play a reference and guide for future building disaster prevention design and public safety research. [ABSTRACT FROM AUTHOR]

In-depth analysis of pedestrian movement behavior on staircases and escalators can significantly improve their operation efficiency and safety. However, compared with stairs, researchers have generally given little attention to pedestrian movement on escalators. In this paper, we conduct a case study to extract the physical attributes of the escalator, the pedestrians' microscopic movement characteristics, and the macro-level pedestrian flow dynamics on the escalator of Beihang University's canteen. Using the data, we establish a step-length-based CA model to represent the pedestrian movement across the escalator. The CA model can effectively render the pedestrian's grouping formation and walking characteristics at the micro-level and describe the pedestrian flow at the macro-level. Through simulations, we quantitatively analyze some widely used pedestrian guidance strategies on escalators (e.g., the "walk left, stand right" rule, changing the grouping formation). The results may have bearing on real-life escalator management. • A case study is conducted to extract the pedestrian movement characteristics around the escalator area. • A step-length-based CA model is proposed to represent the pedestrian movement around the escalator. • This paper reveals the differences in escalator pedestrian flow under different scenarios. • Some widely used pedestrian guidance strategies on escalator are proposed and analyzed. [ABSTRACT FROM AUTHOR]

This paper demonstrates the fundamental relation that exists between the configuration of a three-dimensional living space and the time needed for the evacuation of all the inhabitants. The evacuation is treated as a physical flow system consisting of pedestrians who move from a volume to one or two exits. The living space has two variable aspect ratios, the floor shape and the profile shape (or the number of floors). First, the paper reports analytically the optimal floor and profile shapes for which the total evacuation time is minimum. Second, the analytical results are complemented and validated by numerical results obtained based on numerous simulations of pedestrian flow from volume to exits. The numerical results are further validated by performing the simulations of pedestrian movement with two different computational codes (Simulex and FDS + Evac). The fundamental relation presented in this paper can be used in the design of larger and more complex living spaces in modern urban settings. [ABSTRACT FROM AUTHOR]

Sloping walkways are common pedestrian traffic facilities in modern cities, especially, in some cities located in mountainous terrain, such as Hong Kong, and Zurich. Compared with level walkways, sloping walkways may lead to the decrease in pedestrian flow efficiency, and are more prone to trigger crowd disasters at extreme crowd densities, for example, recent crowd stampede event in Itaewon, South Korea, did happen on a narrow ramp with an extreme crowd density. Therefore, it is important to study pedestrian flow dynamics on ramps. In this paper, we conducted single-file pedestrian flow experiments in 0°, 3°, 5°, 7°, 9°, 12°, 17°, 22°, 27° uphill and downhill conditions, and analyzed contrastively the influence of walkway slope on pedestrian flow dynamics. Our main findings are as follows. (i) Pedestrian flow efficiency is the highest in 7° downhill condition, indicating that a small downhill slope is advantageous to pedestrian flowing. (ii) Whether it is uphill or downhill, the ramp steeper than 7° will significantly decrease pedestrian flow efficiency, therefore is disadvantageous to pedestrian flowing. (iii) For a ramp, uphill and downhill pedestrian flow efficiencies are not equal. Downhill pedestrian flow efficiency is always larger than uphill pedestrian flow efficiency. These findings provide important guidance for the design of sloping walkways and the safety management of pedestrian crowds on sloping walkways. • The influence of walkway slope on pedestrian flow is studied. • A slope pedestrian flow experiment is conducted. • A small downhill slope around 7°is most advantageous to pedestrian flowing. [ABSTRACT FROM AUTHOR]

Abstract: In China, both the mountainous areas and the number of people who live in mountain areas occupy a significant proportion. When production accidents or natural disasters happen, the residents in mountain areas should be evacuated and the evacuation is of obvious importance to public safety. But it is a pity that there are few studies on safety evacuation in rough terrain. The particularity of the complex terrain in mountain areas, however, makes it difficult to study pedestrian evacuation. In this paper, a three-dimensional surface cellular automata model is proposed to numerically simulate the real time dynamic evacuation of residents. The model takes into account topographic characteristics (the slope gradient) of the environment and the biomechanics characteristics (weight and leg extensor power) of the residents to calculate the walking speed. This paper only focuses on the influence of topography and the physiological parameters are defined as constants according to a statistical report. Velocity varies with the topography. In order to simulate the behavior of a crowd with varying movement velocities, and a numerical algorithm is used to determine the time step of iteration. By doing so, a numerical simulation can be conducted in a 3D surface CA model. Moreover, considering residents evacuation around a gas well in a mountain area as a case, a visualization system for a three-dimensional simulation of pedestrian evacuation is developed. In the simulation process, population behaviors of congestion, queuing and collision avoidance can be observed. The simulation results are explained reasonably. Therefore, the model presented in this paper can realize a 3D dynamic simulation of pedestrian evacuation vividly in complex terrain and predict the evacuation procedure and evacuation time required, which can supply some valuable information for emergency management. [Copyright &y& Elsevier]

Evacuation signs are important for emergency evacuation in complex buildings. The interaction between evacuees and evacuation signs attracted much attention. However, current research mainly considers the visibility of signs and depends on inaccurate video analysis and subjective after-drill questionnaires, and the impact of surrounding people is ignored. This paper utilized an eye-tracking device to collect the sign detection data objectively and concentrated on the following behavior with surrounding people. Based on the results of a series of experiments, it is found that not all pedestrians detect the signs due to objective and subjective ignorance. Even the sign is detected, there exist some evacuees who decide to follow other pedestrians rather than sign guidance. Consequently, a new interaction logic and a new wayfinding method are applied in an evacuation model. The simulation results show the significant difference between the two logics in this paper. It describes that the original logic overestimates the sign guidance effect and underestimates the evacuation time strongly. The new logic can be applied in the building's design and security evaluation to enhance evacuation safety. • Eye tracking device is imported to test the signage detection more reliably. • Hundreds of people are involved to prove the detection and following probabilities. • The impact of surrounding people is discussed in the signage guidance logic. [ABSTRACT FROM AUTHOR]

A social force model is proposed in this paper to study the effect of dedicated exit on the evacuation of heterogeneous pedestrians in a public place. In this model, pedestrians are divided into two groups—powerful pedestrians and weak pedestrians, who have different walking abilities. Several exit design schemes are compared through simulations in a regular room. The main results are: (1) Building a new exit as weak group’s dedicated exit can simultaneously reduce each group’s average evacuation time and maximum evacuation time. (2) Reconstructing an existing ordinary exit as weak group’s dedicated exit can reduce weak pedestrians’ average evacuation time but may increase their maximum evacuation time. (3) If the total number of exits is fixed, compared with the non-dedicated exit scheme, the scheme which designs dedicated exits for each group separately may reduce weak group’s evacuation speed. (4) If the sum of widths of all the exits is fixed, the ratio of width between the dedicated exit and the ordinary exit has a significant effect on each group’s evacuation. The optimal ratio depends on the proportion of weak pedestrians. Finally, a real-world example which involves the evacuation issue in a waiting hall with security checkpoints is used to show the effectiveness of women-only exits in improving the crowd evacuation efficiency. Particularly, it is found that a suitable women-only exit scheme can achieve a win-win situation for both male pedestrians and female pedestrians in the crowd evacuation. [ABSTRACT FROM AUTHOR]

It is well known that a large percentage of occupants in a building are evacuated together with their friends, families, and officemates, especially in China. Small group behaviors are therefore critical for crowd movement. This paper aims to study the crowd dynamic considering different social relations and the impacts of small groups on crowd dynamics in emergency evacuation. Three experiments are conducted in an 11-storey office building. In the first two experiments, all participants are classmates and know each other well. They are evacuated as individuals or pairs. In the third experiment, social relations among the participants are complex. Participants consist of 8 families, 6 lovers and several individuals. Space–time features, speed characteristics and density–speed relations for each experiment are analyzed and compared. Results conclude that small group behaviors can make positive impacts on crowd dynamics when evacuees know each other and are cooperative. This conclusion is also testified by four verified experiments. In the third experiment, speeds of evacuees are lowest. Small groups form automatically with the presence of intimate social relations. Small groups in this experiment slow down the average speed of the crowd and make disturbance on the crowd flow. Small groups in this case make negative impacts on the movement of the crowd. It is because that evacuees do not know each other and they are competitive to each other. Characteristics of different types of small groups are also investigated. Experimental data can provide foundational parameters for evacuation model development and are helpful for building designers. [ABSTRACT FROM AUTHOR]

In this paper, we propose an extension of cellular automata models applied to emergency evacuation pedestrian dynamics. The new extensions are the route change probabilities and group fields. The first extension allows for pedestrians to change direction when necessary to access an alternate exit route. The second extension adds a field that makes groups of pedestrians always walk close to each other and exit together. Several experiments were conducted to study the effects of these new extensions, first to verify the associated collective phenomena and to verify the effect with the security performance measures, more precisely, in the evacuation time, as well as to perform comparisons with other previous models. The main conclusions are that the effects of these new extensions effectively modify the security performance measures and can therefore be important for improving the models and providing better estimates. [ABSTRACT FROM AUTHOR]

The evacuation considering the personnel heterogeneity has yet to be thoroughly studied. Hence, heterogeneous crowd evacuation involving the impact of pedestrian's personality traits on panic is probed by an extended floor field (FF) model in this paper. First, the personality traits are investigated by considering the OCEAN (openness, conscientiousness, extroversion, agreeableness, and neuroticism) personality traits and the panic emotion is explored through a questionnaire-based experiment. Then, based on statistical results of questionnaires, an extended FF model is established to study the heterogeneous crowd dynamics under a fire scenario. The effect of neuroticism parameter φ N , the fire origin position schemes and the differences between the normal walk and the fire evacuation were majorly discussed. Results demonstrate that the panic of pedestrians is highly correlated with the neuroticism parameter φ N. Neuroticism personality trait has a major influence on the crowd evacuation process. With more remarkable neuroticism, pedestrians make decisions more emotionally and tend to evacuate more blindly. In addition, the fire origin position significantly affects the panic evacuation process. When a fire origin is closer to the exit, the evacuation time lengthens. Furthermore, modest panic urges the evacuation process, leading to an accelerated movement of pedestrians. Hence, it makes the evacuation time of a fire hitting case shorter than that of a normal walking one. The study contributes to understanding the influence of the personality heterogeneity on the evacuation and to developing some guidance to design the building structure, which are valuable for crowd management. • The questionnaire results show that pedestrians who feel panicked in the evacuation often have a higher degree of neuroticism. • With the neuroticism parameter φ N increasing, the evacuation time increases gradually. • The position of the fire origin significantly affects the crowd panic evacuation process. • Modest panic urges the evacuation process, leading to an accelerated movement of pedestrians. [ABSTRACT FROM AUTHOR]

Pedestrian social groups are an essential part of a crowd. In emergency situations, they may become principal victims during evacuation from buildings, such as bottlenecks in corridors. However, empirical data on the dynamics of social groups through bottlenecks are limited. In this paper, a controlled experiment was performed to study movement features of social groups through a bottleneck with different widths (i.e., 0.8, 1.4 and 2.4 m). There were 60 participants in the experiment, forming four crowd compositions (i.e., 60 groups of singles, 30 groups of dyads, 20 groups of triads and 15 groups of four-person groups). After extracting their movement trajectories in the video recordings, offset angles, passing performance, interpersonal distances and angles in group walking, relative positions in social groups, etc. were analyzed. The results highlight that the negative effect of bottleneck width on instantaneous speed for larger groups is more significant than for smaller groups. The cooperative behavior of large groups is beneficial to the instantaneous speed of pedestrians under wide bottlenecks. The size of the groups has no evident influence on lane formation. Singles adjust their movement directions more flexibly, and the offset angles of large groups are smaller. Good passing performance can be reflected in large groups through wide bottlenecks. It is proved that interpersonal distances and angles between group members depend on the group size, bottleneck width and pedestrian flow state (free and congested flow). Under the limitation of narrow bottlenecks, the walking structures of large groups can lead to diverse walking structures. The phenomenon of recurring splitting and rejoining of pedestrian social groups can be observed. These findings are helpful for crowd management in buildings. • A controlled experiment was performed to study movement features of social groups through a bottleneck with different widths. • Group size has no evident influence on lane formation. • Interpersonal distances and angles depend on the group size, bottleneck width and flow state (free and congested flow). • At the entrance and exit of narrow bottlenecks, large group size can lead to diverse walking structures. • The phenomenon of recurring splitting and rejoining of pedestrian social groups can be observed. [ABSTRACT FROM AUTHOR]

Floods are regarded as critical disasters that often lead to catastrophic situations and provoke potential injuries and/or fatalities. The consequences of the flood on the exposed population can be realized by exploring the complex behavioral phenomena of the crowd in interaction with the flood hazard. A profound understanding of the time–space distribution of evacuation patterns and vulnerability in floodwater would help in developing a robust risk reduction strategy and mitigating the flood impact. This paper presents a model that combines a macroscopic description of a crowd evacuation model with a hydrodynamic model of flood inundation described by a two-dimensional depth-averaged Shallow Water Equation (SWE), considering two-way dynamic coupling to study the collective behavior of the crowd in a flooded evacuation scenario. Behavioral rules, such as reduced motion in floodwater, route choice through safe areas, and stress due to perception of danger in threatening flood, are imposed to account for the evacuees' reaction to floodwater. Moreover, the disruption in free flood propagation due to the pedestrians' presence in the floodplain has also been modeled. The pedestrian model is solved using a third-order Weighted Essentially Non-Oscillatory (WENO3) scheme, and the hydrodynamic model is numerically handled using a high-resolution Godunov type scheme with HLLC Riemann solver. The potential of the developed model is illustrated through two designed hypothetical test cases, which include the crowd evacuation from a supermarket area exposed to a sudden flood. • Collective behavioral dynamics of crowd in a flooded evacuation scenario. • Risk states of the evacuees with the evolution of flood. • Distressed behavior of crowd due to fear in a threatening flood. • Path selection strategy to maintain safety. [ABSTRACT FROM AUTHOR]

Most evacuation processes require the presence of people outside the scene, such as firefighters, to assist the trapped individuals to evacuate. This paper establishes an extended model for crowd evacuation considering rescue behavior. In the model, rescuers enter from the exit, approach the hazard source, and search for the injured individual. According to the physical condition of the injured pedestrian, there are two rescue methods: supporting or carrying the injured persons on their backs. Persons trapped in a room are evacuated by walking or crawling depending on their health condition, and healthy persons will rescue the surrounding crawling and evacuated individuals with a certain probability. Simulation results demonstrate that during the evacuation process considering rescue behavior: (1) The presence of rescuers improves evacuation efficiency. When the number of rescuers exceeds a certain threshold, the efficiency of evacuation will begin to decline. However, the evacuation efficiency with rescuers is still better than when there are no rescuers. (2) Increasing the possibility of pedestrian mutual assistance can improve evacuation efficiency. However, the effect of pedestrian mutual assistance probability on evacuation has a critical value. (3) The greater the distance from the hazard source to the exits, the smaller is the effect of the hazard source on evacuation. (4) when the total width of all exits is the same, the evacuation efficiency of two exits is higher than that of a single exit. The model and overall simulation results can help to develop different evacuation strategies and improve search and rescue plans according to specific scenes. [ABSTRACT FROM AUTHOR]

The merging flow happens when pedestrians coming from the stair (referred to as stair crowd) encounter those coming from the floor (referred to as floor crowd) on the stair landing, which is usually thought to significantly reduce movement efficiency during building evacuation. However, currently investigations on it are still rare especially the experimental ones with trajectories. In this paper, characteristics of stair landing merging flow are analyzed, based on precise trajectories extracted from the heads through a controlled experiment. Due to the interference of floor crowd, the average path of stair crowd in merging flow experiment is less smooth, compared with that in experiment with no merging flow. Pedestrian total travel time and total travel distance on the stair landing exhibit a linear relation, but the fitting functions are varied depending on the movement directions (ascent and descent), merging conditions (with and without merging flow), and crowd types (floor crowd and stair crowd). The sum of flow rates for stair crowd and floor crowd before merging is larger than the flow rate of overall crowd after merging, due to the occurrence of congestion after merging. Microscopic fundamental diagrams based on Voronoi diagram for different movements are derived and compared. For movements without merging flow, the speed on the stair landing is higher during descent movement. While for movements with merging flow, the speed on the stair landing is higher during ascent movement, which results from the higher speed for ascent floor crowd because ascent floor crowd is not affected by the transition from stair to landing when just stepping onto the stair landing and is less affected by the merging phenomenon. • A controlled experiment on pedestrian movements on the stair landing with and without merging flow is conducted. • The average walking path of stair crowd becomes less smooth with the interference of floor crowd. • Pedestrian total travel time and total travel distance on the stair landing exhibit a linear relation. • The average flow rate after merging is smaller than that before merging due to congestion after merging. • In our experimental setup, ascent floor crowd can move the fastest, leading to higher speed in ascent merging flow. [ABSTRACT FROM AUTHOR]

Evacuation leaders (individuals guiding the crowd) can make crowd evacuation more efficient. Selecting their number and positions within the crowd is particularly important when the other evacuees are not familiar with the internal layout of the building. This paper investigates the effects of leadership on crowd evacuation in rooms with limited visibility range by an extended social force model. We find that, (i) For a large evacuees crowd, a small proportion of the evacuation leaders is already sufficient to guide the whole crowd efficiently, even if the visibility range of the room is very limited. And the smaller the crowd size, the larger the proportion of the leaders is needed to achieve a satisfactory evacuation guidance. (ii) The optimal proportion or number (i.e., the proportion or number that is necessary for guiding the crowd) of the leaders in an evacuees crowd to achieve a satisfactory guidance is related to the visibility range of the room and the distribution range of the evacuees crowd. (iii) Leadership is not always positive to the crowd evacuation. It may have a negative effect on crowd evacuation when the visibility range of the room and the size of the evacuees crowd are large enough. The findings provide a new insight into the effects of leadership on crowd evacuation. [ABSTRACT FROM AUTHOR]

In this paper, we propose a cellular automata model for pedestrian flow to investigate the effects of elementary students’ individual properties on the evacuation process in a classroom with two exits. In this model, each student’s route choice behavior is determined by the capacity of his current route to each exit, the distance between his current position and the corresponding exit, the repulsive interactions between his adjacent students and him, and the congestion degree near each exit; the elementary students are sorted into rational and irrational students. The simulation results show that the irrational students’ proportion has significant impacts on the evacuation process and efficiency, and that all students simultaneously evacuating may be inefficient. [ABSTRACT FROM AUTHOR]

The floor field model is the most popular cellular automata (CA) model which is used to simulate the pedestrian’s behaviors. In the floor field model, the interaction between pedestrians is expressed by the dynamical field. In this paper, we proposed an improved and simple method to calculate the floor field. In our method, the pedestrians are treated as the movable obstacles which will increase the value of the floor field. The additional value is interpreted as the blocking effect of preceding pedestrians. And then, the influence of the exits’ configuration on evacuation process in a room without obstacle is simulated. The evacuation time for different widths and positions of the exits is investigated. In the case of single exit, there is a power law relationship between the evacuation time ( T ) and the exit width ( D w ) with a negative exponent when D w ≤ 6 . Mean flow rates and the using efficiency of each exit cell obtained by our model are higher than other models. The simulation results indicate that pedestrians do not choose the shortest path but a faster path in our model. For the case of two exits, the relationships between the location of the exits and evacuation time are discussed. When the total width of two exits is small (i.e. D w = 2 ), the main factor affecting the total evacuation time T is the exits’ capacity. If the total width of two exits is large (i.e. D w = 12 ), the moving distance of pedestrians to exits is the main factor affecting the evacuation time, and the corresponding phase diagrams are given. [ABSTRACT FROM AUTHOR]

A modified particle swarm optimization algorithm is proposed in this paper to investigate the dynamic of pedestrian evacuation from a fire in a public building—a supermarket with multiple exits and configurations of counters. Two distinctive evacuation behaviours featured by the shortest-path strategy and the following-up strategy are simulated in the model, accounting for different categories of age and sex of the pedestrians along with the impact of the fire, including gases, heat and smoke. To examine the relationship among the progress of the overall evacuation and the layout and configuration of the site, a series of simulations are conducted in various settings: without a fire and with a fire at different locations. Those experiments reveal a general pattern of two-phase evacuation, i.e., a steep section and a flat section, in addition to the impact of the presence of multiple exits on the evacuation along with the geographic locations of the exits. For the study site, our simulations indicated the deficiency of the configuration and the current layout of this site in the process of evacuation and verified the availability of proposed solutions to resolve the deficiency. More specifically, for improvement of the effectiveness of the evacuation from the site, adding an exit between Exit 6 and Exit 7 and expanding the corridor at the right side of Exit 7 would significantly reduce the evacuation time. [ABSTRACT FROM AUTHOR]

Abstract: When planning for the evacuation guidance, how to efficiently set the trained evacuation leaders is an important problem which has great impact on the evacuation process. This paper investigates the effect of the number and positions of evacuation leaders on the evacuation dynamics in rooms with limited visibility range. In the improved social force model, only the trained leaders exactly know the exit positions, and the others could only follow the guidance according to the positions and directions of evacuation leaders. According to the simulation results, only one or two leaders could get remarkable effect for a single-exit configuration. But for configurations with multi-exits, evacuation leaders would make the dynamic slower unless the guidance sufficiently utilizes every exit. The results indicate that, we should set as many leaders as the number of exits in the center of the multi-exits regular squared room, and when emergencies occur, each leader heads to a different exit. Moreover, if we do like this, the evacuation would be even faster than that with 20 random-position-leaders. This work may shed some light on the drawing up of emergency scheme for large public-gathering places like stadiums and shopping malls. [Copyright &y& Elsevier]

Abstract: This paper investigates the dynamics of pedestrian evacuation with the influence of the fire spreading. An extended floor field model is proposed. In the new model, the effect of fire on the evacuation is considered by introducing the fire floor field. Thus, the floor field intensity is weighted by static, dynamic and fire floor fields. Numerical simulations are carried out to study the dynamics in the process of the evacuation. The influence of the parameters–weight of fire floor field, fire spread rate–on the evacuation efficiency is analyzed in detail. The simulation results show that the number of pedestrians evacuated out of the room is highly related to both the original location of the fire and the configuration of the room. Those results can bring some guidance to design the evacuation strategy in panic situation. [Copyright &y& Elsevier]

This paper proposes an extended floor field model considering the spread of fire and detour behavior. It includes a fire spread field and a fire recognition field. An agent who recognizes a fire makes a detour to an exit with the lowest risk considering transition probability based on the weighted static floor field. The improved transition probability takes into account the agent's visibility reduced by smoke diffusion. The proposed model differs from the related models in that the agent dynamically chooses the safety path upon fire detection. Compared to simulations using commercial software, the model predicted longer evacuation times and fewer agents inhaling smoke. The model's implementation included realistic pedestrian movements, such as trying to move away from a smoke-filled space. • In the proposed model, a field that describes the spread of fire and a field that represents an area in which fire can be visually recognized were added. • The detour movement to the safe exits of the agent was implemented by applying the transition probability equation based on the weighted SFF (Static Floor Field), which are calculated in response to smoke diffusion. • The proposed model differs from the existing models in that the agent dynamically chooses a safe path when it detects a fire. [ABSTRACT FROM AUTHOR]

The escape panic version of the Social Force Model (SFM) is a suitable model for describing emergency evacuations. In this research, we analyze a real-life video, recorded at the opening of a store during a Black Friday event, which resembles an emergency evacuation (November 2017, South Africa). We measure the flow of pedestrians entering the store and found a higher value (〈 J 〉 = 6. 7 ± 0. 8 p/s) than the usually reported in "laboratory" conditions. We performed numerical simulations to recreate this event. The empirical measurements were compared against simulated evacuation curves corresponding to different sets of parameters currently in use in the literature. The results obtained suggest that the set of parameters corresponding to calibrations from laboratory experiments (involving pedestrians in which the safety of the participants is of major concern) or situations where the physical contact is negligible, produce simulations in which the agents evacuate faster than in the empirical scenario. To conclude the paper, we optimize two parameters of the model: the friction coefficient k t and the body force coefficient k n. The best fit we found could replicate the qualitative and quantitative behavior of the empirical evacuation curve. We also found that many different combinations in the parameter space can produce similar results in terms of the goodness of fit. • We analyze a real-life stampede that resemblance an emergency evacuation. • The measured flow is 〈 J 〉 = 6. 7 ± 0. 8 p/s. • Different sets of parameters are tested against the empirical data. • We optimize two parameters in order to fit the empirical measurements. [ABSTRACT FROM AUTHOR]

Occupants in building fires usually have difficulties to evacuate safely, and providing guidance may help them select proper routes. However, groups of occupants may not follow guidance because they make their own decisions and are affected by psychological factors. Their reactions to guidance should therefore be considered by an emergency guidance system. Most existing studies assumed that occupants would follow guidance, and congestions might occur if suggested routes were not used. To consider occupants' route choices, the random utility theory is employed to characterize their reactions to guidance, and the guidance is optimized in a leader–follower​ (Stackelberg) game framework in this paper. To partially validate the effect of guidance and determine related parameters of psychological factors, data from virtual reality (VR) experiments are analyzed, where human participants were recruited and their probabilistic route choices were analyzed. Using parameters derived from VR experiments, numerical and simulation results demonstrate that optimized guidance is effective in terms of the overall risk and evacuation times because related congestions are alleviated. A sensitivity analysis is also performed to assess the impacts of different psychological factors on optimized guidance and evacuations. [ABSTRACT FROM AUTHOR]

Car accidents is a major source of congestion that affect the traffic dynamic especially in urban network. In this paper, we studied the impact of evacuation time (T) of damaged cars and transmission probability (r) on traffic characteristics when a car accident occurs at the intersection of two roads. Traffic is temporary stuck for T time steps then the vehicles involved in collision will be removed from the system. Simulation results show the existence of a critical evacuation time (injection rate α) after which the variation of injection rate (evacuation time) hasn't any effect on neither the flow nor the probability of accidents P a c. Moreover, when α ≤ 0. 02 or α > 0. 1 , the system exhibits a second order transition from Low Density Phase (LDP) to High Density Phase (HDP). However, the transition is of first order when 0. 02 ¡ α ≤ 0. 1. Furthermore, car accidents take place if α is higher than a critical value α c. This value does not depend on T when T < 40 or T > 60. Nonetheless, it depends strongly on T if 40 ≤ T ≤ 60. The effects of the transmission probability and the probability to have a collision p' are also studied. Likewise, different phase diagrams of the system are discussed. • We studied the effect of evacuation time and transmission probability on the traffic. • Existence of a critical evacuation time after which α hasn't any effect. • The system exhibits a second/first order transition from LDP to HDP depending de α. • The flow and accidents phase diagrams of the system are proposed. • The probability to have an accident affects traffic characteristics. [ABSTRACT FROM AUTHOR]

Emergency evacuation in case of an emergency is a crucial problem in high-rise buildings, as many occupants are in a limited amount of space. To improve building safety design and evacuation strategies, it is essential to understand how individuals behave during an evacuation in high-rise buildings. This paper surveys the recently available literature on evacuation in high-rise buildings with the following objectives: (1) to review the high-rise building evacuation experiment methods; (2) to review the wayfinding and impact factors in horizontal evacuation; and (3) to review the individual and crowd behaviors in vertical evacuation. The review highlights the application of the virtual reality technology in evacuation experiments and the two-side effect of the group behavior in high-rise buildings. Future research should focus on quantitative pre-evacuation behavior study, the elevator's assistant function, and the impact of group relations on evacuation. As the height of high-rise buildings continues to increase, individual characteristics, such as mobility issues and fatigue, warrant further study. • Review the individual and crowd behavior in high-rise building. • Make an integration of experiment methods about evacuation in high-rise building. • Discuss the horizontal evacuation. Mainly from the two following aspects: the wayfinding and impact factors. • Discuss the vertical evacuation. Mainly contains the behavior in stairs, in elevators, on refuge floor, in group and others. • Discuss the challenges of high-rise buildings evacuation. [ABSTRACT FROM AUTHOR]

Evacuation signage plays a vital role in building evacuation. In order to test the efficiency of evacuation signage, the traditional methods are video analysis and after-drill questionnaires and the human factors are rarely considered. This paper investigates the impact of surrounding pedestrians on the sign guidance efficiency during building emergency evacuation, replacing the traditional ways with eye tracking device method. More than 500 participants were involved in the series of experiments to test the influence of surrounding people on detecting and following signages. It is found that (a) the subjective ignorance and objective ignorance of signs exist obviously and are affected by surrounding people number; (b) strangers and acquaintances have similar effect on the sign detection probability and direction choosing probability in the safe and quick evacuation experiments, contrary to general belief; (c) One surrounding person has an important influence on the sign guidance effect, especially on the following probability, while three surrounding people not. Based on the results of the experiments, a new logic of wayfinding within rooms was put forward and simulated to compared with the original logic. It is shown that the average right direction choosing percentage decreases by 30% after considering the effect of surrounding pedestrians, proving that the impact of surrounding pedestrians must be considered in evacuation modeling and evacuation route design. [ABSTRACT FROM AUTHOR]

Social relation network and group behavior are critical in building evacuation. In this paper, six building evacuation experiments are designed and carried out to study the social relation and group behavior in evacuation, and to explore how social relation influence participants' behavior when they can use elevators as egress. Evacuees are all from one undergraduate class with 30 students. The pre-existing social relations such as friends, girl and boy friends, classmates, and roommates are known. Experiments 1-3 are conducted to study the participants' Social Relation Network (SRN) based on analyzing social network questionnaires. Results indicate that the crowd in evacuation form different small groups based on the pre-existing SRN, and the average influence degree of social relation affected on the leader-and-follower behavior in evacuation experiment is 78.3%. In addition, there are three kinds of evacuees in evacuation experiment, including leaders, followers and lonely evacuees. Experiments 4-6 are carried out to study how social relation, elevator egress and evacuation experience influence their behavior in evacuation. Participants are divided into pairs based on their SRN and the Mutual Believed Degree (MBD) method. It is found that social relation can enhance participants' speeds (participants are young students), and influence their decision making on selecting stairs or elevators for evacuation. Their speeds follow the Normal Distribution N(1.16, 0.18). Several interesting phenomena are observed in the experiments, such as redirection and overtaking. In addition, if the elevators cannot be properly used, evacuation will be delayed. • Group behaviors were analyzed based on evacuation experiments. • Social relation network was carried out to study participants' evacuation behavior. • The average influence degree of social relation affected on the leader-and-follower behavior is 78.3%. • Social relation can enhance evacuees' speeds, and influences their decision-making on egress selection. [ABSTRACT FROM AUTHOR]

Every year, a considerably large number of disasters occur as a result of natural events or human faults. In order to decrease the damage and casualties associated with each disaster, it is crucial to get prepared for these kind of situations. Indeed, emergency evacuation is a crucial part of this preparation. Researchers have been working on creating evacuation simulation systems over the past few decades. They are trying to model the environment, human physiology and psychology as realistic as possible to make the analysis more accurate. However, there is yet no comprehensive system which well cover the emerging situations and guarantees the avoidance of causalities, environmental and economic damage. In this paper, we propose an approach which combines a multi-agent model with fuzzy logic to smoothly and successfully handle multiple features of each individual to simulate common human and group behavior during safety egress. The developed simulation system considers situations where a crowd is blocked inside a building or a zone during a disaster. Agents capture various aspects related to humans who may be present in such a region. Each agent possesses different features to realistically simulate a human by encapsulating the psychology, sociology, mood, reaction, etc. Integrating fuzziness in the model allows for more natural capturing of human behavior during the evacuation process. Different scenarios have been tried in the conducted experiments. The outcome revealed the importance of various characteristics of the zone to be evacuated and how they could positively affect the safeness of the evacuation plans. For instance, increasing the width of an exit up to a certain limit may be very beneficial in the process based on the density of the crowd to be evacuated. Actually, the reported simulation results demonstrate the applicability and effectiveness of the proposed approach. • Every year, a considerably large number of disasters occur due to natural events and human faults. • To decrease effect, it is crucial to be prepared for disasters by developing emergency evacuation plans. • Researchers have been working on creating evacuation simulation systems over three decades. • We propose a multi-agent approach combined with fuzzy logic. • It considers features of individuals to simulate common human and group behavior during safety egress. • The reported simulation results demonstrate applicability and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]