S.B. Liu

An Agent-Based Microscopic Pedestrian Flow Simulation Model for Pedestrian Traffic Problems

Guaranteeing a safe, efficient, and comfortable traveling system for pedestrians is one of the most important aspects of an intelligent transportation system. The microscopic simulation of pedestrian flow has attracted increasing research attention in recent years since a reliable simulation model for pedestrian flow may greatly benefit engineers and operators in mass transportation management, as well as designers and planners in urban planning and architecture. This paper introduces CityFlow, an agent-based microscopic pedestrian flow simulation model. The building floor plan in the model is represented by a continuous space constructed in a network approach, and each pedestrian is regarded as a self-adapted agent. Agent movement is implemented in a utility maximization approach by considering various human behaviors. The influences of parameters in the model on the simulation results are investigated. Typical pedestrian flow phenomena, including the unidirectional and bidirectional flow in a corridor as well as the flow through bottlenecks, are simulated. The simulation results are further compared with empirical study results. The comparison reveals that the model can approach the density-speed fundamental diagrams and the empirical flow rates at bottlenecks within acceptable system dimensions. The simulation results of the bidirectional pedestrian flow also show that the model can reproduce the lane-formation phenomenon.

Modeling Movement Direction Choice and Collision Avoidance in Agent-Based Model for Pedestrian Flow

AbstractAgent-based microscopic pedestrian-flow simulation models are promising tools for designers or engineers to evaluate the level of safety or comfort of crowded pedestrian traffic facilities. Existing models tend to simulate movement direction choice behaviors of a virtual agent based on a joint effect of several physical, psychological, and sociological factors dominating the real-world pedestrian walking behaviors. Challenging questions remain for this type of model, including how to control and balance the influences among these behavioral factors and how to naturally avoid collisions without losing the effect of the behavior factors considered. This article presents an improved utility-maximization approach to determine the movement direction of individuals in an agent-based pedestrian-flow simulation model. A new utility function is proposed. An explicit collision detection and avoidance technique is used as a supplementary rule together with the utility maximization method to improve the colli...

On the Simulation for Rail Tunnel Evacuation with Cross-Passageways

To study the evacuation from rail tunnels is vital for saving human lives when trains are forced to stop inside the tunnel due to fire or other incidents. Although NFPA 130 standard has given limited suggestions on the design of means of egress in rail tunnels, very rare other references can be found about the tunnel evacuation so far. In this paper, an agent based continuous crowd simulation model was developed to study the evacuation from rail tunnel with cross-passageways. This study has focused on the influence of the walkway width and cross-passageway spacing on the egress time and queuing patterns during the evacuation. In our simulation, it was found that if the width of walkway was added by every 100 mm, the egress time would decrease accordingly, but with different sensitivity at different width. The continuous model was proved to be eligible for identifying the continuously change of the dimensions of egress element. The study also revealed that the distance between cross-passageways was highly relevant to the optimized evacuation route choice strategy and certainly was an important parameter for egress time.

On the Use of a Pedestrian Simulation Model with Natural Behavior Representation in Metro Stations

Rapid urbanization in many large cities in China makes metro station an integral part of metropolitan peoples daily life. High density of crowds in metro stations would cause serious congestion problems and pose threats to pedestrian safety. Because of the heterogeneous and complex properties of pedestrians, traditional approaches face difficulties in predicting future pedestrian flow patterns. The use of agent-based simulation approach makes it possible to naturally reproduce various pedestrian behaviors in different scenarios. This paper presented an agent-based microscopic pedestrian simulation model—CityFlow, which was proved to be flexible in revealing most important pedestrian behaviors in metro stations by several simulation cases. The model applications can provide implications in evaluation of design proposals of metro facilities.

Aggregated Metro Trip Patterns in Urban Areas of Hong Kong: Evidence from Automatic Fare Collection Records

AbstractThe automatic fare collection (AFC) system incorporating smart card technology is widely used in transportation systems for revenue management, but the data from this could be mined for wide-ranging applications. This paper used AFC data of eight metro stations in the central area of Hong Kong to analyze metro trip patterns at an aggregate level. Based on the ridership differences between days, time periods, and directed flows, empirical data were categorized into three groups to better understand the station area characteristics. Compared to previous studies, it was found that factors may play varied roles in determining trip quantities for divergent station areas. Shopping and recreational factors demonstrated a statistically significant relationship with metro trips during the afternoon peak at exit flow and the evening peak at entry flow in the commercial districts of Hong Kong, such as Causeway Bay, Tsim Sha Tsui, and Mong Kok. This suggests that the distinctive context characteristics of the...

Using Agent-based Simulation Model for Studying Fire Escape Process in Metro Stations☆

The Hong Kong Metro System has been operating for more than 30 years. With the increase in population, some of the stations are crowded in most time of a day. To facilitate the design and the alteration works for a station, the crowding and passenger movement pattern, especially the escape pattern in case of fire, should be studied. This article illustrated an agent-based people movement model, and a case targeting at the people movement pattern and egress process in a metro station has been studied. The simulation results demonstrate that the model is useful for assisting building designers to evaluate different design alternatives and to support fire safety performance studies.