Application of social force model to pedestrian behavior analysis at signalized crosswalk

Limited pedestrian behavior models shed light on the case at signalized crosswalk, where pedestrian behavior is characterized by group or individual evasion with surrounding pedestrians, collision avoidance with conflicting vehicles, and response to signal control and crosswalk boundary. This study fills this gap by developing a microscopic simulation model for pedestrian behavior analysis at signalized intersection. The social force theory has been employed and adjusted for this purpose. The parameters, including measurable and non-measurable ones, are either directly estimated based on observed dataset or indirectly derived by maximum likelihood estimation. Last, the model performance was confirmed in light of individual trajectory comparison between estimation and observation, passing position distribution at several cross-sections, collision avoidance behavior with conflicting vehicles, and lane-formation phenomenon. The simulation results also concluded that the model enables to visually represent pedestrian crossing behavior as in the real world.     

A macroscopic loading model for time-varying pedestrian flows in public walking areas

A macroscopic loading model applicable to time-dependent and congested pedestrian flows in public walking areas is proposed. Building on the continuum theory of pedestrian flows and the cell transmission model for car traffic, an isotropic framework is developed that can describe the simultaneous and potentially conflicting propagation of multiple pedestrian groups. The model is formulated at the aggregate level and thus computationally cheap, which is advantageous for studying large-scale problems. A detailed analysis of several basic flow patterns including counter- and cross flows, as well as two generic scenarios involving a corner- and a bottleneck flow is carried out. Various behavioral patterns ranging from disciplined queueing to impatient jostling can be realistically reproduced. Following a systematic model calibration, two case studies involving a Swiss railway station and a Dutch bottleneck flow experiment are presented. A comparison with the social force model and pedestrian tracking data shows a good performance of the proposed model with respect to predictions of travel time and density.     

Prohibited–permitted right-turn phasing strategy based on capacity analysis of right-turn movements

In traffic-crowded metropolitan areas, such as Shanghai and Beijing in China, right-turn vehicles that operate with a permitted phase at signalized intersections are normally permitted to filter through large numbers of pedestrians and bicycles. To alleviate such conflicts and improve safety, traffic engineers in Shanghai introduced a prohibited–permitted right-turn operation, adding a subphase to the permitted phase in which right-turns are prohibited. Unfortunately, the prohibited subphase would reduce the capacity of right-turn movements when it prohibits right turns even if there are few pedestrians and bicycles crossing the street. This paper aims at quantifying the impact of both non-vehicular flows and the prohibited subphase on the right-turn capacity, and then proposes a strategy to determine appropriate prohibited–permitted right-turn operation that minimizes the capacity reduction caused by the prohibited subphase. To achieve this goal, we improved the pedestrian and bicycle adjustment factor described in the Highway Capacity Manual by taking into account: (1) the variety in space competition between pedestrians and bicycles, and (2) the effect of two conflict zones in each phase on right-turn operation. In addition, we revised the capacity estimation model in the Highway Capacity Manual, and developed a model based on bicycle/pedestrian volume fluctuation to describe the capacity reduction due to both non-vehicular flows and the prohibited subphase. Furthermore, we proposed a timing strategy for the onset and duration of appropriate prohibited subphase. When bicycle and pedestrian volumes are low, the actuated strategy turns to the permitted phase. When these volumes are moderate, the strategy turns to the prohibited–permitted operation. With the volumes increasing, the prohibited subphase onset advances and duration increases. In these two scenarios, the new strategy has higher right-turn capacity than the current pretimed prohibited–permitted operation. Unfortunately, when bicycle and pedestrian volumes are high, the strategy yields similar right-turn capacity. However, the new prohibited subphase has less potential vehicle–bicycle and vehicle–pedestrian conflicts.     

A three-stage evacuation decision-making and behavior model for the onset of an attack

Pedestrian behavior models have successfully reproduced human movement in many situations. However, few studies focus on modeling human behavior in the context of terrorist attacks. Terrorist attacks commonly occur in crowded public areas and result in a large number of casualties. This paper proposes a three-stage model to reproduce a series of complex behaviors and decision-making processes at the onset of an attack, when pedestrians generally do not have clear targets and have to deal with fuzzy information from the attack. The first stage of the model builds a Bayesian belief network to represent the pedestrians’ initial judgment of the threat and their evacuation decisions. The second stage focuses on pedestrians’ global assessment of the situation through an analogy with diffusion processes. The third stage uses a cost function to reproduce the trade-offs of distance, safety, and emotional impact when considering a path to take. The model is validated using a video from the November 2015 Paris attack. The behavioral characteristics and trajectories of three pedestrians extracted from the video are reproduced by the simulation results based on the model. The research can be used to set rules when performing risk analysis and strategic defensive resource allocation of terrorist attacks using agent-based simulation methods.     

Walking-distance introduced queueing model for pedestrian queueing system: Theoretical analysis and experimental verification

We have introduced the effect of delay in walking from the head of a queue to the service windows in the queueing model and obtain a suitable type of queueing system under various conditions by both computational simulation and theoretical analysis. When there are multiple service windows, the queueing theory indicates that mean waiting time in a fork-type queueing system (Fork), which collects pedestrians into a single queue, is smaller than that in a parallel-type queueing system (Parallel), i.e., queues for each service window. However, in our walking-distance introduced queueing model, we have examined that mean waiting time in Parallel becomes smaller when both the arrival probability of pedestrians and the effect of walking distance are large. Moreover, enhanced Forks, which shorten waiting time by reducing the effect of walking distance, are considered, and parts of our results are also verified by real queueing experiments.     

码头建设投资对最佳泊位利用率影响的研究

港口工程的设计原则之一是使港口企业、船公司和货主三方的在港费用总和最低,追求国民经济效益的最大化.海港总平面设计规范中的最佳泊位利用率是某一范围内的推荐值,与码头投资无关.以某业主码头原油泊位为例,根据排队论原理利用计算机模拟技术推算出的最佳泊位利用率,超出了规范推荐值的范围,分析其原因是码头投资过大.采用4组假定的不...     

汽车行人保护开发与研究进展

行人保护是汽车安全技术领域的前沿和热点问题。随着各国立法的推进,各汽车厂商面临的行人保护压力将越来越大。现行主要法规有EEVC系列、GTR、Euro NCAP等。文中综述了国内外行人保护研究的最新方法和技术,展望了行人保护技术的发展趋势和方向。面向行人保护的被动安全技术核心在于碰撞能量的吸收,主要的技术路线包括新材料的应用和安全结构的改进。而能避免事故发生的主动安全技术将逐渐成为汽车安全领域研究的新趋势。     

Parameters of moving sidewalks for airport terminal pier fingers

A moving sidewalk system installed at an airport pier finger is analyzed. The optimal length of the moving sidewalk and the optimal spacing between the access points which minimize the total cost of the system are obtained using methods of calculus, for a number of cases based on the different proportions of arriving, departing and transferring passengers and for two different types of moving sidewalks: elevated, at‐grade.

The optimal length of the moving sidewalk is shown to be linearly related to the length of the concourse, and to the total passenger demand. The effect due to preticketed transferees is insignificant.

The optimal spacing between access points is shown to be proportional to the square‐root of either the cost of an access escalator or the cost of inconvenience to a passenger due to an intermediate gap, depending on the moving sidewalk system under consideration. It also changes with the percentage of preticketed transferees.     

轿车碰撞安全性的评价及车身碰撞安全性设计

汽车的安全越来越受到重视，各国各地区都加强了对安全法规的制定工作，尤其是碰撞安全性更是得到关注。目前，在美国、日本、欧洲及澳洲都有称为NCAP的组织机构，对不同车型进行汽车碰撞安全性评估。汽车碰撞安全性评估主要包括正面碰撞、侧面碰撞、儿童保护和行人保护4个方面。防正面碰撞的车身结构设计已经成熟，由刚性的乘员舱与前后的吸能区组成，并注意吸能后撞击力的分流；防侧面碰撞的车身结构设计也正趋完善，重点是放在加强车身刚性和冲击力分流2个方面；为满足保护行人法规要求，整车的造型和汽车前部结构发生了很大的变化。     

谈孟克河人行桥的美学设计

以桥梁美学设计为出发点,主要阐述桥梁美学设计的基本观点、美学标准、美学设计的三要素及其实现方法;以此美学原理为基础分析孟克河人行桥的美学设计过程和特点。阐明设计时,如何使人行桥造型与形式、功能、环境相一致。