基于交通效益的路段无控制人行横道设置

为了使人行横道更好地服务于过街行人,同时不对道路上的车辆产生过大影响,对路段无控制人行横道的设置条件和选址进行了研究.分析了路段上设置与不设置无控制人行横道两种情况下的行人和机动车的运行特征,提出两种情况行人过街条件下交通总费用的计算方法,通过对比提出以总体交通效益最大为目标的路段无控制人行横道设置依据,给出分析计算流程.以交通系统的交通总费用最小为目标建立路段无控制人行横道设置的优化选址模型,采用枚举法和遗传算法进行优化选址,分别给出了计算流程和实例验证.可以用于指导城市道路路段无控制人行横道的设置,优化行人过街环境.     

城市道路中人行横道安全问题研究

道路交通安全越来越成为发展中国家的一个严重的问题,其中行人是最易受到伤害且在城市交通设施设计中不受重视的道路参与者.本文在对上海市徐家汇地区的人行横道的设置对行人的安全影响进行调查的基础上,根据消除行人和驾驶员的盲区确保行人安全,提出了十字路口人行横道附近公交停靠站设置在路口来车方向下游,以及城市高架下人行横道设置在来车和高架立柱之间的合理设置.推导出人行横道设置离公交站点最小距离的计算公式.     

单洞双线隧道紧急救援站横通道风流分布研究

特长铁路隧道紧急救援站横通道内风流分布特性是救援站结构形式和防灾通风设计的基础和依据。本文针对某一单洞双线隧道平导救援站工程,深入研究紧急救援站横通道内风流分布规律,以及不同防灾通风系统和自然风对其的影响。研究结果表明,紧急救援站横通道内风速分布呈现出W型,中部和两端横通道内风速较大,沿两侧风速相对较小。自然风对横通道内风速分布有一定影响,靠近自然风入口一侧大部分横通道内风速显著增大。建议在满足人员安全疏散的基础上,可适当减小救援站中部和两侧横通道面积以及减少相应横通道内风机配置。     

城市信号交叉口人行横道通行能力研究

通过对交叉口过街混合交通流过街特性、过街需求、过街效率指标的分析,得到了人行横道混合交通流相对于行人的通用折算方法,同时提出一种针对我国人行横道交通特征计算行人通行能力的新方法,具有一定的实用价值。     

一种Android平台混合应用运行环境

随着智能终端设备以及移动互联网的发展,智能手机等设备越来越普遍,其上的应用也越来越丰富. 如何能够更快、更高效的开发智能终端上的应用成为开发者面临的巨大问题之一. 在分析了当前存在的跨平台混合应用开发的基础上,设计并实现了一种Android平台混合应用运行环境,利用该运行环境可以实现只用HTML、CSS和JavaScript开发Android应用,为开发者带来极大的便利. 同时该运行环境兼容桌面系统上的混合应用运行环境,利用该运行环境开发的应用经过不同屏幕适配同时可以运行在桌面系统上.     

Optimization of Crosswalk Width Based on Bi-Directional Pedestrian Crossing Time at Signalized Intersections

The effects of the interactions between bi-directional pedestrians on the crossing time and the crosswalk width are studied. Firstly, the crossing process of bi-directional pedestrians is analyzed. The total crosswalk time is divided into a discharge time and a crossing time. The interactions between bi-directional pedestrians are quantified with the drag force theory. Then, a model is developed to study the crossing time based on the kinetic energy theory and momentum theory. Subsequently, the related parameters of the proposed model are calibrated with observed information. The relationships among crosswalk width, signal time, pedestrian volume and level of service are simulated with the proposed model. The results are verified and compared with other models. The proposed model has an absolute value of relative error of 9.38%, which is smaller than that of the Alhajyaseen model (15.26%) and Highway Capacity Manual (HCM) model (12.42%). Finally, suggested crosswalk widths at different conditions are successfully estimated with the proposed crossing time model.     

Red light violations by adult pedestrians and other safety-related behaviors at signalized crosswalks

To study human factors linked to red light violations, and more generally to safety-related behaviors at signalized crosswalks, the present study combines the collection of observational data with questionnaires answered by 422 French adult pedestrians. Thirteen behavioral indicators were extracted (12 before and while crossing, and red light violation), and the roles of several demographical, contextual and mobility-associated variables were examined. The results of the stepwise logistic regression analyses carried out on each of the 12 behavioral indicators observed before and while crossing revealed that gender had no major impact, but age did, with more cautious behaviors as pedestrians were older. The three contextual variables (group size, parked vehicles, and traffic density), as four mobility-associated variables (driving and walking experiences, self-reported crossing difficulties and falls in the street) were also found to be important factors in safety-related crossing behaviors. A wider logistic regression analysis, made specifically on red light violations with all behavioral indicators observed before and while crossings and the several demographical, contextual and mobility-associated variables put together, showed that red light violations were mostly affected by current situational factors (group size, parked vehicles) and particularly associated with some behavioral patterns (looking toward the traffic, the ground, the light, running and crossing diagonally). The overall results encourage the development of safer pedestrian infrastructures and engineering countermeasures.     

The optimization of the geometric cross-section dimensions of raised pedestrian crosswalks: A case study in Qazvin

This study attempts to optimize the geometric cross-section dimensions of raised pedestrian crosswalks (RPC), employing safety and comfort measures which reflect environmental conditions and drivers behavioral patterns in Qazvin, Iran. Geometric characteristics including street width, ramp lengths, top flat crown length and height, and 4672 spot speed observations of 23 implemented RPCs were considered. The authors established geometric and analytical equations to satisfactorily express the discomfort that vehicle occupants experience while traversing an RPC and the crossing risk to pedestrians. Artificial neural networks (ANN) are reputed for their capability to learn and generalize complex engineering phenomena and were therefore adopted to cope with the highly nonlinear relationship between the before-RPC spot speeds, the geometric characteristics, and spot speeds on the RPC. This on-RPC spot speed has been utilized for computing the above-mentioned criteria. Combining these criteria, a new judgment index was created to identify the optimum RPC which fulfills the highest comfort and safety levels. It was observed that the variable with the highest impact is the second ramp length, followed by the first ramp length, top flat crown length, before-RPC spot speed, height, and street width, in order of magnitude.     

Numerical Simulation of Motor Vehicles' Courtesy Behavior on Crosswalk Based on Car-Following Model

In observing driver courtesy towards pedestrians at unsignalized crosswalks, a behavioral model was adopted in a simulation based on the GM Car-Following Model. The SIMI Motion Software was used to extract the vehicle operation data from Wenyi South Road and Hanyuan Road in Xi''an City. The parameters of the GM Car-Following Model were calibrated by genetic algorithm. The road simulation environment based on the Car-Following Model was constructed by MATLAB. In the case of no stopping, uniform deceleration avoidance with advance notice, emergency brake avoidance without advance notice, changes such as the displacement of the Car-Following queue, headway, speed, acceleration, and deceleration were analyzed by numerical simulation. The results show that when there is advance notice before the crosswalk, the minimum headway distances of Car1-Car2, Car2-Car3, Car3-Car4 and Car4-Car5 are 7.09 m, 7.38 m, 7.65 m, 7.91 m, and the average rates of change of the headway during deceleration are 0.78 m/s, 0.74 m/s, 0.71 m/s, 0.68 m/s respectively; in the absence of advance notice before the crosswalk, the minimum headway distances of Car1-Car2, Car2-Car3, Car3-Car4 and Car4-Car5 are 7.28 m, 7.75 m, 8.19 m, 8.59 m, and the average rates of change of the headway during deceleration are 1.57 m/s, 1.25 m/s, 1.04 m/s, 0.96 m/s, respectively. Therefore, in order to effectively prevent the occurrence of vehicle rear-end events, it''s necessary to set traffic signs and markings on the preceding section of the intersection or road exhibiting behavioral comity.     

路段无信号控制人行横道行人过街服务水平研究

通过分析无信号控制路段人行横道处行人过街行为特性、行人可接受等待时间、行人选择通过的机动车临界时距等,建立基于间隙接受理论的行人过街阻力模型,计算得到过街阻力系数为15%的等待时间,并根据行人真实感受的聚类分析结果划分评价标准,最后据此评价行人过街服务水平。此方法结合了基于冲突和基于感受评价的优点,有效解决了以往研究中行人感受主观性、指标复杂性、实践操作困难等问题。