山区公路行车视距分析

驾驶员应有足够的视距来判断车辆前方发生的变化,以便采取相应措施确保车辆安全行驶。从山区公路交通流特点和事故成因出发,对平面视距和纵面视距的行车安全性进行了分析,同时从保障行车安全角度总结了行车视距设置应考虑的影响因素,对山区公路路线设计起到一定的指导作用。     

基于安全的山区高速公路路线设计研究

为了提高山区高速公路的安全性,从高速公路设计中运行速度的角度出发,对山区条件下高速公路的平曲线半径、连续纵坡、超高、隧道线形及视距方面进行了探讨,论述这些因素对行车安全的影响。分析了山区高速公路设计中基本参数的确定、方案的选择和车辆通行的安全措施,为山区高速公路路线设计提供了参考。     

城市枢纽互通立交间新增立交方案设计分析

文章以南宁市昆仑大道厢竹大道至那安快速路范围内三座立交为例,结合项目自身特点对该三座立交间距的合理性、三个节点均设置成互通式立交的必要性、保证行车快速安全通行的设计方案以及节省立交建设资金等问题进行整体评价和论证分析,探讨不同立交组合形式的优劣,推荐合理的立交形式,可为今后连续互通间新增立交设计工作提供参考。     

浅谈立交改扩建方案设计

受交通量的发展和路网新布局的形成等因素影响,已建的许多互通式立交面临改扩建。文章以重庆江津西彭互通式立交在原有A型单喇叭三路互通立交基础上改建成四路立交的工程为例,阐述了改扩建立交在选型和设计过程中的思路,总结了一些改扩建立交方案选择的原则,供同行参考。     

高速公路互通式立交安全性评价及设计分析

为了给互通式立交的安全性评价及设计提供指导,探讨高速公路互通式立交安全性评价的主要内容、设计重点、改善措施以及安全性评价方法。通过互通式立交的安全性设计要点对互通式立交的道路条件进行分析,结合相关交通安全理论,提出适用于互通式立交安全性评价的综合指标体系。同时,针对互通式立交设计中的关键要素,如车道宽度、视距、匝道出入口、运行速度等,给出相应的设计改善措施。     

低交通量公路隧道中间段照明节能技术研究

针对川西高原低交通量二级、三级公路隧道带来的照明能源浪费问题,文章利用TOBIIGLASESS2型眼动仪进行实车试验研究,直接计算得到中间段不同照明工况下驾驶员在高原低交通量隧道的行车停车视距,并与《公路隧道照明设计细则》(2014版)中要求的最小停车视距进行对比,在确保驾驶员行车安全的前提下,推荐此类隧道中间段照明设...     

公路路线设计中存在的问题及设计要点研究

在公路工程设计中,路线是重要设计内容。为保证公路的行车安全与行车质量,设计人员需科学、合理地设计公路路线。设计人员在公路路线设计过程中,应严格遵守相关公路设计规范要求,了解、掌握公路工程现场实际情况,综合分析各种路线设计影响因素,对公路路线平面、纵断面、视距、生态环保等方面进行合理化设计。通过对公路路线设计中存在的问题及设计要点进行深入研究,为同类工程设计提供参考。     

济南市济洛路—北园路立交设计布局与选型

简要介绍了立交设计布局与选型原则，立交平纵线型优化设计概况、立交桥梁结构的型式选择原则及立交所采用的结构型式情况，并介绍了立交所采用的经济技术指标等。     

公路车速限制与行车安全视距关系的探讨

通过对新建公路限制车速与行车安全视距值之间的关系探讨,对新建公路限制车速采用的行车安全视距值与影响因素进行量化,提供了新建公路限速选用的行车安全视距范围,可供道路工程设计及高等级公路管理人员参考.     

广清立交方案设计安全性几点研究

将公路安全性评价的理念应用到立交方案设计中,并结合广清立交工程设计实例,从立交型式、匝道与主线速度协调性、匝道出入口设计、地面交通组织等方面分析探讨了城市枢纽性立交在方案设计中必须考虑的公路安全性问题.     

互通立交与服务区、停车区合并设置方案探讨

文章阐述了在条件受限时,一般互通立交与服务区、停车区合并设置在几何设计方面存在的问题,并结合工程实践提出互通立交与服务区、停车区合并设置的建设方案,为今后进一步的研究提供参考。     

Fuzzy-logic-based incident detection for signalized diamond interchanges

This paper documents a fuzzy-logic-based incident detection algorithm for signalized urban diamond interchanges. The model is capable of detecting lane-blocking incidents whose effects are manifested by patterns of deterioration in traffic conditions that require adjustments in signal control strategies. As a component of a real-time traffic adaptive control system for signalized diamond interchanges, the algorithm feeds an incident report (i.e., the time, location, and severity of the incident) to the system's optimization manager, which uses that information to determine the appropriate signal control strategy.The performance of the model was studied using a simulation of an actual diamond interchange. The simulation study evaluated the model's performance in terms of detection rate, false alarm rate, and mean time to detect. The model's performance was encouraging, and the fuzzy-logic-based approach is considered promising.     

Optimization of mainline traffic via an adaptive co-ordinated ramp-metering control model with dynamic OD estimation

Frequently implemented at freeway accesses to streamline traffic, ramp-metering control strategy is often implemented during rush hours in heavily congested areas. This paper presents a novel ramp-metering control model capable of optimizing mainline traffic by providing metering rates for accesses within the control segments. Based on Payne's continuum traffic stream model, a linear dynamic model with a quadratic objective function is constructed for integrated-responsive ramp-metering control. Incorporating on-line origin–destination (OD) estimation of co-ordinated interchanges into the proposed model increases efficiency of the control. In addition, an iterative algorithm is proposed to obtain the optimal solution. Simulation results demonstrate the robustness of the proposed model and its ability to streamline freeway traffic while avoiding traffic congestion.     

Modeling and simulation of vehicle projection arrival–discharge process in adaptive traffic signal controls

Real‐time signal control operates as a function of the vehicular arrival and discharge process to satisfy a pre‐specified operational performance. This process is often predicted based on loop detectors placed upstream of the signal. In our newly developed signal control for diamond interchanges, a microscopic model is proposed to estimate traffic flows at the stop‐line. The model considers the traffic dynamics of vehicular detection, arrivals, and departures, by taking into account varying speeds, length of queues, and signal control. As the signal control is optimized over a rolling horizon that is divided into intervals, the vehicular detection for and projection into the corresponding horizon intervals are also modeled. The signal control algorithm is based on dynamic programming and the optimization of signal policy is performed using a certain performance measure involving delays, queue lengths, and queue storage ratios. The arrival–discharge model is embedded in the optimization algorithm and both are programmed into AIMSUN, a microscopic stochastic simulation program. AIMSUN is then used to simulate the traffic flow and implement the optimal signal control by accessing internal data including detected traffic demand and vehicle speeds. Sensitivity analysis is conducted to study the effect of selecting different optimization criteria on the signal control performance. It is concluded that the queue length and queue storage ratio are the most appropriate performance measures in real‐time signal control of interchanges. Copyright © 2010 John Wiley & Sons, Ltd.     

Planning guidelines for metro–bus interchanges by means of a pedestrian microsimulation model

The big paradigm for cities nowadays is to study the movement of pedestrians at the interface between metro and bus systems – metro–bus interchanges. When these interchanges are not well designed, walking is inefficient and can be unsafe for pedestrians. This paper analyses, by means of a pedestrian microsimulation model, metro–bus interchange spaces in order to propose planning guidelines for the city of Santiago de Chile. Specific objectives are (1) to identify the variables that provide efficiency and safety in those spaces; (2) to simulate different scenarios using the pedestrian simulation model LEGION; (3) to propose planning and design guidelines for pedestrian spaces at metro–bus interchanges; and (4) to contrast the recommendations in the recently opened terminal station on Line 1 of Metro de Santiago: Los Dominicos Station.     

南宁市白沙-友谊大道互通式立交选型设计

文章以南宁市白沙-友谊大道互通式立交为研究对象,介绍了其工程概况与地形地貌,并对其交通量进行预测分析,同时结合其立交功能定位阐述了该立交方案的选型设计思路,通过对互通式立交型式进行综合比选,推荐出了功能完善、造价低的互通方案,可为城市道路立交工程设计提供参考和借鉴。     

Formal scientific research of traffic collision data utilizing GIS

This paper explores the tenuous link between speeding behavior and accident causation, one that has not been well established in the international literature to date. Taking advantage of established engineering conventions and formulae, we were able to set up an a priori hypothesis suitable for testing. Utilizing this formal scientific method (which GIS researchers have been criticised for not using) we establish a statistical link for this relationship. Our methodology can be used to support all police intervention strategies, including the controversial photo radar systems. The results from our research have been entered into a GIS in order to create a map for spatial display. This map illustrates the relative probability or risk of collision occurrence resulting from speeding at all intersections and interchanges within the scope of the study. It is suggested that this methodology could easily be maintained with periodic updates of data, thus creating a dynamic model from which to monitor traffic safety within the city. Furthermore, this model can be utilized to study specific strategies, allowing for the scrutiny of before, during and after effects. The study area is the entire city of Calgary, Alberta, Canada, and includes all traffic collisions occurring during the year of 1994.     

小金口枢纽互通立交拥堵改造分析

文章以广惠高速公路小金口枢纽互通立交工程为依托,在预测交通量的基础上从拥堵匝道的通行能力、服务水平和交通事故等方面分析匝道拥堵的原因,并提出基于光流率和边缘率的主线改善措施和匝道改善方案,为小金口枢纽互通立交及其他立交的拥堵改造提供参考。     

为“零换乘”而穿越上海市轨道交通1、4号线上海体育馆站设计、施工回顾

在已营运多年,原来未考虑换乘和结构预留的1号线上体馆站新建4号线车站并与之形成“零换乘”。地面交通、地下管线、周边高楼对新车站的布置形成了层层制约;软土地基、沉降控制和确保1号线的运营安全都给4号线车站的穿越施工带来了重重困难。对此,通过理性分析,分散风险,探索创新和精心设计、施工,成功地解决了4号线车站布置、周边大楼侵界处理、结构托换、原车站底板大梁加固、穿越施工等难题,最终实现了“零换乘”。五年的历程,充满了挑战和创新。     

Observing freeway ramp merging phenomena in congested traffic

This work conducts a comprehensive investigation of traffic behavior and characteristics during freeway ramp merging under congested traffic conditions. On the Tokyo Metropolitan Expressway, traffic congestion frequently occurs at merging bottleneck sections, especially during heavy traffic demand. The Tokyo Metropolitan Expressway public corporation, generally applies different empirical strategies to increase the flow rate and decrease the accident rate at the merging sections. However, these strategies do not rely either on any behavioral characteristics of the merging traffic or on the geometric design of the merging segments. There have been only a few research publications concerned with traffic behavior and characteristics in these situations. Therefore, a three‐year study is undertaken to investigate traffic behavior and characteristics during the merging process under congested situations. Extensive traffic data capturing a wide range of traffic and geometric information were collected using detectors, videotaping, and surveys at eight interchanges in Tokyo Metropolitan Expressway. Maximum discharged flow rate from the head of the queue at merging sections in conjunction with traffic and geometric characteristics were analyzed. In addition, lane changing maneuver with respect to the freeway and ramp traffic behaviors were examined. It is believed that this study provides a thorough understanding of the freeway ramp merging dynamics. In addition, it forms a comprehensive database for the development and implementation of congestion management techniques at merging sections utilizing Intelligent Transportation System.