Rolling-horizon–based strategy of fully cooperative traffic under signalized intersections

Dedicated left-turn lanes are traditionally used at intersections. This practice may not be optimal where heavy traffic exists from multiple directions. As is well known, the capacity can be increased if vehicles are grouped in the same direction in advance, but the additional infrastructure is usually needed, such as presignal systems. Fortunately, under the development of connected and automated vehicle (CAV) technology, the presignal system can be achieved by coordinating vehicles directly. To this end, we establish a modeling framework and management strategies for pure CAV traffic to achieve direction-based grouping. A rolling time-horizon–based sorting strategy is developed to achieve real-time coordination under uncertain vehicle arrivals. A series of numerical experiments have shown that the improvement of the proposed sorting strategy is significant and robust compared with traditional dedicated left-turn lane intersections without coordination, especially when the traffic is busy.     

Increasing Signalized Intersection Capacity with Unconventional Use of Special Width Approach Lanes

Heavy traffic volume coupled with insufficient capacity due to limited space cause most of traffic congestion at urban signalized intersections. This article presents an innovative design to increase the capacity of heavily congested intersections by using the special width approach lane (SWAL), which consists of two narrow approach lanes that are dynamically utilized by either two passenger cars or a heavy vehicle (e.g., buses or trucks) depending on the composition of traffic. The impact of the SWAL on the saturation flow rate is quantified and validated, followed by an optimization model for best geometric layout and signal timing design with the presence of the SWAL. The optimization model is formulated as a mixed‐integer‐linear‐program for intersection capacity maximization which can be efficiently solved by the standard branch‐and‐bound technique. Results of extensive numerical analyses and case studies show the effectiveness of SWAL to increase intersection capacity, indicating its promising application at intersections with very limited space that prevents the addition of separate lanes.     

重庆市朝天门地区综合交通规划方案研究

道路是形成城市空间最重要的部分,道路交通枢纽设计和改造以交通分析研究为基础,由于认识和手段原因,过去以定性分析为主。本文通过对朝天门中心地区综合交通研究和仿真分析,提出整合道路交通规划、道路交通解决方案和设想,供重庆市交通枢纽地区研究参考。     

Random Process Model for Urban Traffic Flow Using a Wavelet‐Bayesian Hierarchical Technique

Abstract: The existing well‐known short‐term traffic forecasting algorithms require large traffic flow data sets, including information on current traffic scenarios to predict the future traffic conditions. This article proposes a random process traffic volume model that enables estimation and prediction of traffic volume at sites where such large and continuous data sets of traffic condition related information are unavailable. The proposed model is based on a combination of wavelet analysis (WA) and Bayesian hierarchical methodology (BHM). The average daily “trend” of urban traffic flow observations can be reliably modeled using discrete WA. The remaining fluctuating parts of the traffic volume observations are modeled using BHM. This BHM modeling considers that the variance of the urban traffic flow observations from an intersection vary with the time‐of‐the‐day. A case study has been performed at two busy junctions at the city‐centre of Dublin to validate the effectiveness of the strategy.     

剪刀叉式接地匝道在城市高架道路中的应用

传统城市高架道路接地匝道往往存在交织段较短、交通负荷较重、交叉口拥堵情况严重等问题。针对这些问题,提出了一种剪刀叉式接地匝道设计方案,即在单侧高架道路上先布置下匝道,再布置上匝道,在立面上,先下后上的2根匝道形成"剪刀叉"的形态,在平面上2根匝道并列布置,其中1根匝道布置在道路内侧,另1根匝道布置在道路外侧。高架道路的另一侧也按此方法布置匝道,避免高架道路车流的短距离交织运行,同时也使地面交叉口最多只面对2根匝道,减轻了地面交叉口的交通负荷,改善了运行情况及服务水平。     

快速路出口匝道交织区交通组织方法研究

城市快速路出口匝道与下游交叉口归纳成3种交通组织方法,即常规交织布置、车道转向置换及交替放行控制。利用微观交通仿真软件进行回归分析,提出城市快速路典型衔接交织段的延误计算公式,可对交织区运行延误进行量化计算。最后结合工程实例对3种方法的运行效果进行比较,提出快速路出口匝道设计和管理的方法。     

老城区道路交叉口改造方法简介

根据城市老城区各交叉口的情况,在利用交叉口现有面积,不增加城市拆迁面积的前提下,对平面交叉口进行了渠化设计及路口改造,从而达到提高通行能力,改善交通的目的.     

高架下匝道与前方地面跨线桥交织长度验算

介绍了高架道路下匝道设置与地面道路的3种关系模型。以下匝道设置在地面道路中间、部分地面车流提前分流至匝道外侧这种模型为例,提出了下匝道前方有地面跨线桥的地面道路模型。嘉闵高架在曹安公路节点处设置的1对匝道,受净空限制,下匝道与前方跨线桥之间的间距仅120 m。根据交通流量预测资料,应用VISUM软件验算交织长度是否满足流量需求。结果显示,交织段交织车辆的平均行驶速度可以达到40 km/h,能够满足交织段的需求,为工程设计提供了理论依据。     

环境污染限制及最优信号控制条件下的综合离散网络设计问题

现代城市综合交通网络设计问题研究的主要内容就是通过新建或改善道路网络,用以减少现代交通带来的环境污染、合理设置交通信号等诸方面的问题。将道路环境能力限制、最优交通信号设置问题与城市交通离散网络设计问题结合起来研究,一方面通过修建新的路段使交通需求量达到最大从而满足城市中不断增长的交通需求;另一方面通过道路环境能力限制使交通网络的最大需求量能符合现代城市环境保护的要求。给出了描述上述问题的一个双层规划模型及其启发式求解算法。最后,通过一个简单的算例,说明该算法是可行并且有效的。     

港湾式公交停靠站设计模式和优化设计方法

根据公交进出站运行机制,结合公交站点泊位折减,建立符合实际的公交停靠站通行能力模型,给出标准的港湾式公交停靠站设计模式。按照主干路、次干路和支路等不同的道路等级,对港湾式公交停靠站设置于交叉口、路段的模式及尺寸进行一体化设计。设计模式已在苏州工业园区得到应用,它为城市道路设计,特别是公交停靠站的设计提供必要的参考依据。     

An approach for modelling CO2 emissions from road traffic in urban areas

An approach that incorporates three modelling components has been developed to estimate road traffic CO2 emissions for an urban area with street level resolution. The first component enables the determination of the road traffic characteristics using the SATURN (Simulation and Assignment of Traffic in Urban Road Networks) model. The output from this component is then analysed using MATrix LABoratory (MATLAB) programming to provide estimates of CO2 emissions for the urban area. Finally, ArcGIS is used to illustrate the model output. The three components are integrated using a Loose-Coupling approach in which the individual components each load the necessary data to give an independent output. The model structure is discussed in the current paper and the modelling results for a small city (Norwich, UK) are presented.     

城市主干道交叉口连续交通仿真分析

利用VISSIM微观仿真系统对采用连续交通组织方式的城市主干道交叉口进行了仿真分析,研究了道口车辆路段行程时间随交织段长度、车流量的变化规律,得出了综合效益最佳的交织段长度。最后对道路设计和管理给出了几点建议。     

Methodology for spatio‐temporal predictions of traffic counts across an urban road network and generation of an on‐road greenhouse gas emission inventory

On‐road emission inventories in urban areas have typically been developed using traffic data derived from travel demand models. These approaches tend to underestimate emissions because they often only incorporate data on household travel, not including commercial vehicle movements, taxis, ride hailing services, and other trips typically underreported within travel surveys. In contrast, traffic counts embed all types of on‐road vehicles; however, they are only conducted at selected locations in an urban area. Traffic counts are typically spatially correlated, which enables the development of methods that can interpolate traffic data at selected monitoring stations across an urban road network and in turn develop emission estimates. This paper presents a new and universal methodology designed to use traffic count data for the prediction of periodic and annual volumes as well as greenhouse gas emissions at the level of each individual roadway and for multiple years across a large road network. The methodology relies on the data collected and the spatio‐temporal relationships between traffic counts at various stations; it recognizes patterns in the data and identifies locations with similar trends. Traffic volumes and emissions prediction can be made even on roads where no count data exist. Data from the City of Toronto traffic count program were used to validate the output of various algorithms, indicating robust model performance, even in areas with limited data.     

地域主义理念控制下的城市交通建筑实践--成都东客站综合交通枢纽道路客运场站设计

从交通功能性建筑的基本特征出发,结合地域主义理念的精髓思想,阐述城市交通系统发展与成都东客站综合交通枢纽交通组织之间的关系,交通枢纽组织下的城市TOD体系的建立对城市功能圈的构成,特定功能区域及功能内容在交通枢纽功能复合化的指导,地理位置及民族特性对形态原则构成等具体层面的反射,从而探讨地域主义理念对城市交通综合体设计的全方位影响,并且基于此多层面的理念影响,指导成都东客站综合交通枢纽道路场站的具体设计实践。     

Integrated Planning of Supply Chain Networks and Multimodal Transportation Infrastructure Expansion: Model Development and Application to the Biofuel Industry

Abstract: As the biofuel industry continues to expand, the construction of new biorefinery facilities induces a huge amount of biomass feedstock shipment from supply points to the refineries and biofuel shipment to the consumption locations, which increases traffic demand in the transportation network and contributes to additional congestion (especially in the neighborhood of the refineries). Hence, it is beneficial to form public‐private partnerships to simultaneously consider transportation network expansion and biofuel supply chain design to mitigate congestion. This article presents an integrated mathematical model for biofuel supply chain design where the near‐optimum number and location of biorefinery facilities, the near‐optimal routing of biomass and biofuel shipments, and possible highway/railroad capacity expansion are determined. The objective is to minimize the total cost for biorefinery construction, transportation infrastructure expansion, and transportation delay (for both biomass/biofuel shipment and public travel) under congestion. A genetic algorithm framework (with embedded Lagrangian relaxation and traffic assignment algorithms) is developed to solve the optimization model, and an empirical case study for the state of Illinois is conducted with realistic biofuel production data. The computational results show that the proposed solution approach is able to solve the problem efficiently. Various managerial insights are also drawn. It shall be noted that although this article focuses on the booming biofuel industry, the model and solution techniques are suitable for a number of application contexts that simultaneously involve network traffic equilibrium, infrastructure expansion, and facility location choices (which determine the origin/destination of multi‐commodity flow).     

新老城区的整合与联动发展——浙江桐庐滨水发展轴城市设计

针对近年来国内城市新区发展往往与老城相脱节,导致许多弊端的现状,对浙江桐庐滨水发展轴城市设计案例进行介绍,从城市设计的层面对城市建设中新老城区的联动发展进行了思索和探讨。调查分析了桐庐的城市现状和自然条件,确定了滨江区域的发展目标,认为应将桐庐滨江区域发展放到城市整体发展的高度,将其建设成为新的、多样化、集约化的城市中心,并从功能、交通、景观环境等多角度对新老城区进行整合,从而令新老城区之间紧密结合、相互促进,形成整体效应。这一研究工作为国内城市新区发展提供了新的尝试。     

城市地铁与地下物流系统协同运输方式研究

预防货物运输导致的环境恶化和交通拥堵正成为城市交通规划领域亟需解决的问题。采用地下物流系统在城市范围内运输货物,是突破交通网络运输能力瓶颈、改善城市环境和提高城市物流服务质量的有效方式。但地下物流系统前期建设周期长,投资巨大,因此,依托城市地铁的富余运能,结合地下物流系统实现协同运输,可以解决地铁沿线地区货物运输问题。笔者针对地铁与地下物流系统协同运输的可行性进行分析,提出了协同运输的3种可行方式。考虑地铁客运特征、地下货物运输特征和城市货物需求3个因素,提出运用K-means聚类和Dijkstra算法来定量化分析3种协同运输系统对城市地铁客运和地面物流配送的影响,为未来城市地铁和地下物流的规划建设提供支撑。     

End‐to‐End Deep Learning Methodology for Real‐Time Traffic Network Management

This article presents a novel real‐time traffic network management system using an end‐to‐end deep learning (E2EDL) methodology. A computational learning model is trained, which allows the system to identify the time‐varying traffic congestion pattern in the network, and recommend integrated traffic management schemes to reduce this congestion. The proposed model structure captures the temporal and spatial congestion pattern correlations exhibited in the network, and associates these patterns with efficient traffic management schemes. The E2EDL traffic management system is trained using a laboratory‐generated data set consisting of pairings of prevailing traffic network conditions and efficient traffic management schemes designed to cope with these conditions. The system is applied for the US‐75 corridor in Dallas, Texas. Several experiments are conducted to examine the system performance under different traffic operational conditions. The results show that the E2EDL system achieves travel time savings comparable to those recorded for an optimization‐based traffic management system.     

城市交通节点空间综合增效设计思路与方法

交通节点作为城市动态运行系统的关键地段,兼具交通基础设施与城市公共空间两个基本属性.随着城市集约程度和系统化运行要求的不断提升,在交通节点范围内不仅交通行为高密频繁,更表现出空间组织立体多变、建筑功能叠加交织的特征,对系统的影响性日益增大,使交通节点成为实现城市空间综合效益的瓶颈点、机会点和驱动点,也是以公共交通为导向的发展(TOD)实践的关键场域.针对这一特定空间类型,剖析其空间综合增效发展的内涵、构成和标准,阐释城市设计实现交通节点增效的基本思路,提出城市交通节点综合增效设计的总体框架、设计思维和权衡流程.     

旅游镇慢行系统的规划设计思考

五大连池新镇是依托风景名胜区及自然保护区资源而新建的旅游镇,兼具生态移民镇与游客服务基地的功能,其规模适中,十分适宜发展慢行交通系统。本文综合了该镇贯穿于概念规划、总体规划、控制性详细规划及城市设计等不同阶段的慢行系统规划设计理念与方法,从“慢”格局、“慢”交通、“慢”游赏三个角度,对整体规划格局到局部的设计意向都进行了剖析,较系统的总结了规划组对于旅游镇慢行系统的规划设计思考及其成果。