Car-following model featured with factors reflecting emergency evacuation situation

A new emergency evacuation car-following model （EECM） is proposed. The model aims to capture the main characteristics of traffic flow and driver behavior under an emergency evacuation, and it is developed on the basis of minimum safety distances with parts of the drivers＇ abnormal behavior in a panic emergency situation. A thorough questionnaire survey is undertaken among drivers of different ages. Based on the results from the survey, a safety-distance car-following model is formulated by taking into account two new parameters： a differential distributing coefficient and a driver＇ s experiential decision coefficient, which are used to reflect variations of driving behaviors under an emergency evacuation situation when compared with regular conditions. The formulation and derivation of the new model, as well as its properties and applicability are discussed. A case study is presented to compare the car-following trajectories using observed data under regular peak-hour traffic conditions and theoretical EECM results. The results indicate the consistency of the analysis of assumptions on the EECM and observations.

Location-allocation modeling for emergency evacuation planning with GIS and remote sensing:A case study of Northeast Bangladesh

This work developed models to identify optimal spatial distribution of emergency evacuation centers(EECs)such as schools,colleges,hospitals,and fire stations to improve flood emergency planning in the Sylhet region of northeastern Bangladesh.The use of location-allocation models(LAMs)for evacuation in regard to flood victims is essential to minimize disaster risk.In the first step,flood susceptibility maps were developed using machine learning models(MLMs),including:Levenberg-Marquardt back propagation(LM-BP)neural network and decision trees(DT)and multi-criteria decision making(MCDM)method.Performance of the MLMs and MCDM techniques were assessed considering the area under the receiver operating characteristic(AUROC)curve.Mathematical approaches in a geographic information system(GIS)for four well-known LAM problems affecting emergency rescue time are proposed:maximal covering location problem(MCLP),the maximize attendance(MA),p-median problem(PMP),and the location set covering problem(LSCP).The results showed that existing EECs were not optimally distributed,and that some areas were not adequately served by EECs(i.e.,not all demand points could be reached within a 60-min travel time).We concluded that the proposed models can be used to improve planning of the distribution of EECs,and that application of the models could contribute to reducing human casualties,property losses,and improve emergency operation.

Simulation Modeling on Emergency Evacuation in High-Speed Railway Stations in China

A simulation study on occupant evacuation in high-speed railway stations （HSRSs） was presented in China. Pathfinder was employed as the simulation platform and a typical HSRS in a medinm-sized city in China was selected for model development. The model was carefully calibrated and validated by comparing simulation results with field data. Evacuation efficiency could be improved with the increased door width while such effect decreased when the door width reached a marginal value. And the marginal value varied under different occupant densities. An exponential function between evacuation lime and occupant density was fitted, indicating that occupant density significantly affected evacuation efficiency. A set of different evacuation strategies were compared, in terms of their evacuation performances. It was found that a balanced door usage would result in more efficient evacuations in HSRSs. Thus occupant flows were suggested to be managed considering door capacity. To avoid potential safety issues caused by such strategy （ e. g. , more occupants could be evacuated from a smaller area designed with higher door capacity ）, occupants needed to enhance their awareness of following evacuation guidance instead of panic escape in emergencies. Moreover, such safety issues could also be avoided during the design phase that the evacuation capacity was designed to be proportional to the room capacity for each floor. The results of this study provide valuable information for HSRS design and flow management in China.

Simulation of fire emergency evacuation in a large-passenger-flow subway station based on the on-site measured data of Shenzhen Metro

Because of its large capacity,high efficiency and energy savings,the subway has gradually become the primary mode of transportation for citizens.A high density of passengers exists within a large-passenger-flow subway station,and the number of casualties and injuries during a fire emergency is substantial.In this paper,Pathfinder software and on-site measured data of Pingzhou station in Shenzhen(China)were utilized to simulate a fire emergency evacuation in a large-passenger-flow subway station.The Required Safe Egress Time(RSET),number of passengers and flow rates of stairs and escalators were analysed for three fire evacuation scenarios:train fire,platform fire and hall fire.The evacuation time of the train fire,which was 1173 s,was the longest,and 3621 occupants needed to evacuate when the train was fully loaded.Occupants could not complete the evacuation within 6 mins in all three fire evacuation scenarios,which does not meet the current standard requirements and codes.By changing the number of passengers and the number of stairs for evacuation,the flow rate capacity and evacuation time were explored,which have reference values for safety management and emergency evacuation plan optimization during peak hours of subway operation.

ABM-based emergency evacuation modelling during urban pluvial floods:A“7.20”pluvial flood event study in Zhengzhou,Henan Province

Increasing urban pluvial flood disasters due to climate change and rapid urbanisation have been a great challenge worldwide.Timely and effective emergency evacuation is important for reducing casualties and losses.This has become a bottleneck for emergency management.This study aimed to develop a commonly used Agent-Based Mode(ABM)for pluvial flood emergency evacuation at the city scale,exploring the cascading impacts of pluvial flooding on human behaviour and emergency evacuation.The July 2021 pluvial flood event in Zhengzhou,Henan Province,claiming 380 lives and 40.9 billion yuan in direct losses,was selected as this case study.A raster-based hydraulic model(ECNU Flood-Urban)was used to predict flood inundation(extent and depth)during an event in Zhengzhou’s centre.Moreover,a comparative analysis of emergency evacuations was conducted before and after the pluvial flood event.The results showed that crowd behaviour plays an important role in an emergency evacuation,and extensive flooding leads to an 11-83%reduction in the number of evacuees.This study highlights the importance of risk education and contingency plans in emergency response.The ABM model developed in this study is proven to be effective and practical and will provide support for decision-making in urban flood emergency management.

Simulation Study on Emergency Evacuation Behavior of College Students in Considering the Influence of Dormitory Interpersonal Relationship

As one of the most common social relationships among college students,the dormitory interpersonal relationship has important effects on students'psychology and behavior.For quantitative analysis of the dormitory interpersonal influence on college students'emergency evacuation behavior,an evacuation simulation experiment of college students carried out and coupling questionnaire survey,measurement and social force model of society to visualize the normal dormitory interpersonal relationship and emergency evacuation following relationship of college students,then simulation experiment is used to explore the impact of different types of dormitory relationship structure on emergency evacuation.The results show that dormitory interpersonal relationship is an important component of college students'interpersonal network and has an important impact on emergency evacuation behavior.The close and united dormitory relationship has a good promotion effect on the emergency evacuation efficiency.When the emergency occurs,the dormitory interpersonal relationship of college students will partly transform into the leader-following behavior relationship,and the evacuation efficiency will decrease.The influence of dormitory interpersonal relationship on evacuation behavior is related to gender and grade which is higher for female students than male students,and is higher for junior students than senior students.

Simulation of Emergency Evacuation in Virtual Reality

A virtual reality system was developed to simulate emergency evacuations during fires. The spreading of the flame and smoke in the virtual fire was modeled based on numerical fire simulations, so that the conditions are similar to real life. A multi-grid, multi-base-state database model was used to overcome the disadvantages of traditional smoke spreading simulations. Textured images and particle systems provide visualization of the flame and smoke. The system immerses the user in a virtual environment with detailed interactions between the users and the virtual environment. The system can show which evacuation methods are effective for building safety evaluations.

A review on passenger emergency evacuation from multimodal transportation hubs

Multimodal transportation hubs serve as transfer points with the function of collecting,transferring,and distributing passengers and play a significant role in the entire multimodal transportation network.In an emergency,the development of an effective and efficient emergency evacuation strategy to evacuate passengers from multimodal transportation hubs is very important.This paper aims to conduct a comprehensive review on passenger emergency evacuations from multimodal transportation hubs,summarize the achievements,identify gaps in existing literature,thus to lay a solid foundation for future studies.This paper first reviewed studies on evacuee behavior characteristics in emergency evacuations,including pedestrian characteristics,pedestrian behavior characteristics,and pedestrian flow characteristics.Then evacuation models,including pedestrian evacuation models and multimodal transportation evacuation models,were investigated.In addition,a retrospective analysis was carried out for evacuation simulation.It is found that while many studies have been conducted on passenger emergency evacuations from multimodal transportation hubs,most of them focus more on evacuating pedestrians from inside to outside of hub buildings;the studies on evacuation at multimodal transfer points are limited.It is also found that most existing studies tried to establish a general model to handle all types of emergency evacuations;in fact,a model would be more efficient if it is just established for a specific emergency and for a specific type of hubs.Also,existing data collection methods may collect biased data;new data collection methods need to be explored to increase the accuracy of data collection.Future study directions include the evacuation at multimodal transfer points,interactive effects between individual pedestrian behavior and pedestrian group behavior,more specific types of emergency evacuations,more accurate data collection methods,and tradeoffs between cost and benefit in emergency evacuations.

Experiment and simulation study of emergency evacuation during violent attack in classrooms

In recent years,as a disaster,terrorist attacks have occurred throughout the world.However,emergency evac-uation behaviors during these incidents were not clear,and the traditional emergency plans were not suitable for such incidents.In this paper,evacuation behaviors under armed assault attack in a classroom were studied based on evacuation experiments.A total of 103 participants took part in three experiments.In each experiment,the attacker’s attacking route was set differently to study the impact of the attacking route on evacuation be-haviors.Pre-evacuation delay,panic of the evacuees,exit choices,evacuation time,and evacuees’trajectories in the experiments were all analyzed.The results of the experiments showed that when a terrorist attack occurs,there is a long delay before evacuation,and most of the evacuees were in the state of“observation”before they moved.When one of the participants started to evacuate or shout,other participants would begin to recognize the danger and escape quickly.These three experiments showed that the route of the attacker had a significant impact on the routes and exit choices of the evacuees.Rather than searching for the nearest exit,the primary purpose of evacuees was to keep a safe distance from the attacker.The average speed of the evacuees in these three experiments was 1.07 m/s,0.81 m/s,and 0.84 m/s,respectively.The density distribution during the crowd evacuation process was uneven,with the highest density occurring at the area from the seats to the aisles.The research can provide data support for the design of emergency plans and the computer simulation of the armed assault attack.

Simulation based on a modified social force model for sensitivity to emergency signs in subway station

The subway is the primary travel tool for urban residents in China. Due to the complex structure of the subway and high personnel density in rush hours, subway evacuation capacity is critical. The subway evacuation model is explored in this work by combining the improved social force model with the view radius using the Vicsek model. The pedestrians are divided into two categories based on different force models. The first category is sensitive pedestrians who have normal responses to emergency signs. The second category is insensitive pedestrians. By simulating different proportions of the insensitive pedestrians, we find that the escape time is directly proportional to the number of insensitive pedestrians and inversely proportional to the view radius. However, when the view radius is large enough, the escape time does not change significantly, and the evacuation of people in a small view radius environment tends to be integrated. With the improvement of view radius conditions, the escape time changes more obviously with the proportion of insensitive pedestrians. A new emergency sign layout is proposed, and the simulations show that the proposed layout can effectively reduce the escape time in a small view radius environment. However, the evacuation effect of the new escape sign layout on the large view radius environment is not apparent. In this case, the exit setting emerges as an additional factor affecting the escape time.

Passenger emergency evacuation from bus carriage:Results from realistic data and modeling simulations

One of critical challenges in the development of pedestrian models is the lack of relevant data under emergency conditions.In this paper,we reveal several behavior characteristics of passenger emergency evacuation from a burning bus carriage,by observing and analyzing a video recording,attempting to close the gap between practical observation and theoretical modeling.The analysis results show that there are considerable differences between real emergency evacuation and experimental normal evacuation with respect to the cumulative flows,flows,and time gap distributions.Additionally,the behavior of falling-down,which contributes to the formation of movable obstacles,interrupts the continuity of the evacuation process.Then,we incorporate these behavioral characteristics into a microscopic pedestrian model with a fine lattice space representation.The simulation results indicate that the escape is slowed down by the falling behavior,as well as by the luggage-carrying behavior.

Method of Generating Strategic Guidance Information for Driving Evacuation Flows to Approach Safety-Based System Optimal Dynamic Flows: Case Study of a Large Stadium

In previous evacuation flow planning, a system optimal dynamic traffic assignment(SODTA) did not consider the exogenous costs caused by potential traffic accidents. A traffic accident,which might occur as a result of traffic congestion, will impact an evacuation process because of accidentrelated delays experienced by the downstream vehicles. This paper establishes a safety-based SO-DTA linear programming model in which the generalized system cost incorporates both the travel time and the accident-related delay. The goal is to minimize the generalized system cost under the cell transmission setup. Furthermore, the authors provide strategic guidance information that considers both the objective of the decision maker and the route choice behavior of the evacuees. Mathematically,the authors propose an unconstrained non-linear programming model aimed at minimizing the gap between the safety-based flows and the stochastic real-world evacuation flows, to provide strategic travel time information to be published on variable message signs(VMS). In the case study, the authors found that the safety-based SO-DTA model can reduce congestion and improve the evacuation efficiency; the stochastic real-world evacuation flows, guided by strategic information, can approach the safety-based flows.

Evacuation based on spatio-temporal resilience with variable traffic demand

The efficient evacuation of people from dangerous areas is a key objective of emergency management.However,many emergencies give little to no advanced warning,leading to spontaneous evacuation with no time for planning or management.For large emergencies,destinations become less certain,with traffic demand imbalanced and concentrated on a few oversaturated routes familiar to evacuees.Ultimately,this leads to rapid congestion and delay on some routes,while others remain barely used,extending clearance times with an accumulating population at risk.In this study we address these issues through incorporating spatio-temporal traffic resilience dynamics into a destination choice model utilizing the available capacity of the overall network.We validate our model through a post-concert egress event.The results suggest that our method can reduce total egress times and average travel time by 20%-43%over the no-guidance condition.Our method can be used to estimate and quantify emergency conditions to optimally guide destinations and routing choice for evacuees and/or autonomously moving vehicles during evacuations.

Crowd Simulation and Its Applications: Recent Advances

This article surveys the state-of-the-art crowd simulation techniques and their selected applications, with its focus on our recent research advances in this rapidly growing research field. We first give a categorized overview on the mainstream methodologies of crowd simulation. Then, we describe our recent research advances on crowd evacuation,pedestrian crowds, crowd formation, traffic simulation, and swarm simulation. Finally, we offer our viewpoints on open crowd simulation research challenges and point out potential future directions in this field.

A survey on indoor 3D modeling and applications via RGB-D devices

With the fast development of consumer-level RGB-D cameras, real-world indoor three-dimensional(3 D) scene modeling and robotic applications are gaining more attention. However, indoor 3 D scene modeling is still challenging because the structure of interior objects may be complex and the RGB-D data acquired by consumer-level sensors may have poor quality. There is a lot of research in this area. In this survey, we provide an overview of recent advances in indoor scene modeling methods, public indoor datasets and libraries which can facilitate experiments and evaluations, and some typical applications using RGB-D devices including indoor localization and emergency evacuation.