基于均衡流量的城市停车费用优化模型

基于随机用户平衡原则, 分析了出行者的路径选择和停车选择行为, 建立了满足Logit关系的城市道路停车流量分配模型。基于收益管理思想, 以停车收益最大为决策目标, 建立了城市停车费用的双层规划模型, 并以7个节点和2个停车场的小型网络进行实例验证。分析结果表明: 当停车需求为10 000pcu·h^-1时, 随着停车场2停车费用的提高, 停车流量不断向停车场1转移, 停车场1在停车费用不变的情况下收益不断增加, 当停车场2的停车费用为4元·h^-1时, 总的停车收益达到最大; 当停车需求为20 000pcu·h^-1时, 随着停车费用的上升, 总的停车收益将持续增加; 2个停车场之间存在博弈关系, 停车费用存在纳什均衡点, 当停车需求为10 000pcu·h^-1时, 2个停车场的最优停车费用均为5元·h^-1; 当停车需求为20 000pcu·h^-1时, 2个停车场的最优停车费用均为最高限价10元·h^-1。     

高速公路车辆排队尾部交通事故时空分布特征

根据高速公路常发拥堵路段的交通流数据, 采用累计占有率法绘制交通流占有率波动曲线, 用来判断拥堵路段内车辆排队尾部轨迹, 分析了占有率、里程位置、时间间隔的关系, 确定了累计占有率曲线的拐点。分析了排队传播、消散过程中交通事故频数与时间、空间距离的关系, 对分布特征进行了统计分析。分析结果表明: 车辆在时间和空间上接近排队车辆尾部时, 发生交通事故的频数明显增加, 时间距离与空间距离以排队尾部为中心呈现正态分布, 不同行驶方向路段内正态分布曲线不存在显著差异, 但拥堵传播与消散过程的正态分布曲线存在显著差异。建立的事故发生概率的联合正态分布模型, 可用于预测排队车辆尾部附近的交通事故风险, 为实施动态交通控制以提高快速道路交通安全提供理论依据。     

中美城市交通模型现况评估

交通需求模型预测未来一个区域内对交通系统的需求.这些模型是辅助交通官员与专家对重大交通项目投资和政策策略作出理性决定的重要工具.根据本刊2008年第1期对中国具有代表性的几个城市交通模型系统的示例介绍,对中国目前的交通模型研发、数据及应用进行总结,并比较了中美交通模型的差异.通过对现阶段中国交通模型建设和使用的深入了解,并结合已有研究和实际工作经验,对中关交通模型及其相关的工作进行系统性和前瞻性的讨论.     

轨道交通建设对北京市商业空间布局的影响

在分析北京市轨道交通和商业发展现状的基础上。重点探析轨道交通建设对北京商业空间布局的影响机理和演化过程,说明轨道交通的建设会带来新商业区的兴起、传统商业区或中心商务区的功能强化、枢纽站点附近的商业区地位提升、轨道交通辐射范围外的区域商业功能弱化等变化。提出轨道交通引导商业空间布局有序发展的策略体系,为北京市轨道交通规划建设和商业空间布局优化提供理论依据和决策参考。     

全自动泊车系统的模型设计与仿真

全球汽车保有量的增多,直接造成城市交通的拥堵以及停车位空间的减小。随之而来的就是泊车安全性问题,新手驾驶员或疲劳驾驶人员如何能在不发生碰撞的情况下,快速安全地泊车入库,成为当下研究的热点。针对以上问题,本文将对全自动泊车系统展开研究。基于B样条曲线设计出泊车路径,基于滑模变结构与预瞄方式进行泊车路径的跟踪。最后通过搭建SIMULINK与CARSIM仿真模型进行联合仿真。     

A planning tool for evaluating vehicles miles travelled and traffic safety forecasts of growth management scenarios: A case study of Baton Rouge and New Orleans

This study describes an adaptable planning tool that examines potential change in vehicle miles travelled (VMT) growth and corresponding traffic safety outcomes in two urbanized areas, Baton Rouge and New Orleans, based on built environment, economic and demographic variables. This model is employed to demonstrate one aspect of the potential benefits of growth management policy implementation aimed at curbing VMT growth, and to establish targets with which to measure the effectiveness of those policies through a forecasting approach. The primary objective of this research is to demonstrate the need to break with current trends in order to achieve future goals, and to identify specific policy targets for fuel prices, population density, and transit service within the two study regions. Models indicate based on medium growth scenarios, Baton Rouge will experience a 9 percent increase in VMTs and New Orleans will experience 10 percent growth. This translates to corresponding increases in crashes, injuries and fatalities. The paper provides forecasts for planners and engineers to consider an alternative future, based on desired goals to reduce VMTs and therefore improve safety outcomes. A constrained-forecast model shows a cap on VMTs and crash rates is achievable through policy that increases fuel prices, population density and annual transit passenger miles per capita at reasonable levels through a growth management approach.     

The vulnerability of the environment to spills of dangerous substances on highways: A diagnosis based on multi criteria modeling

Highways and freeways are the main infrastructure channel used to transport cargo in Brazil. This cargo often includes dangerous chemical products which can, in the event of an accident, negatively impact the environment. The development and implementation of tools for the rapid diagnosis of environmental vulnerability in the transportation of dangerous goods has been studied. However, for highways and freeways there is a lack of studies based on environmental attributes, and not just based on statistical data which demands a specific period for collection and analysis and only after that the implementation of preventive measures. Thus, evaluation grounded on multiple criteria embedded in Geographic Information System (GIS) has significant potential for the practical implementation of risk management of road transportation of dangerous goods. This study has determined the environmental vulnerability of route BR 050, specifically the segment between the cities of Uberlândia and Uberaba in the state of Minas Gerais, where multi criteria analysis has been efficient in determining the most vulnerable areas. The main attributes analyzed were the drainage density, soil type and geology, determining that in case of an accident with dangerous substances the regional environment would be immediately affected, and so endorsing the use of this tool in many segments involved in environmental management of highway enterprises.     

A hybrid optimization-simulation approach for robust weekly aircraft routing and retiming

We address the robust weekly aircraft routing and retiming problem, which requires determining weekly schedules for a heterogeneous fleet that maximizes the aircraft on-time performance, minimizes the total delay, and minimizes the number of delayed passengers. The fleet is required to serve a set of flights having known departure time windows while satisfying maintenance constraints. All flights are subject to random delays that may propagate through the network. We propose to solve this problem using a hybrid optimization-simulation approach based on a novel mixed-integer nonlinear programming model for the robust weekly aircraft maintenance routing problem. For this model, we provide an equivalent mixed-integer linear programming formulation that can be solved using a commercial solver. Furthermore, we describe a Monte-Carlo-based procedure for sequentially adjusting the flight departure times. We perform an extensive computational study using instances obtained from a major international airline, having up to 3387 flights and 164 aircraft, which demonstrates the efficacy of the proposed approach. Using the simulation software SimAir to assess the robustness of the solutions produced by our approach in comparison with that for the original solutions implemented by the airline, we found that on-time performance was improved by 9.8–16.0%, cumulative delay was reduced by 25.4–33.1%, and the number of delayed passengers was reduced by 8.2–51.6%.     

组团型大城市绕城高速公路互通立交一体化布局模型

为合理规划布置大城市绕城高速公路互通式立交工程,做到既能够提升出入境交通的可达性和便利性,又不影响过境交通及城市内部交通系统的运行效率,在对绕城高速公路出入境交通组织特性分析的基础上,提出了以系统运行时间和出入境交通可达性二者组合效应最好为目标的绕城高速公路互通式立交一体化布局模型,并提出了模型求解的实用方法.最后,以...     

城市综合交通调查的规范与创新

城市综合交通调查在中国已有30余年的广泛实践,当前的信息化和大数据背景下正历经发展与变革.在分析城市综合交通调查现状问题的基础上,提出制定《城市综合交通体系规划交通调查导则》(以下简称《导则》)的必要性.从目标与总体框架、调查项目分类、术语定义、调查内容与问题选项分类、调查流程规范几个层面对《导则》的主要思想与关键内容进行解析.提出城市综合交通调查未来发展方向应是将信息化技术与传统调查手段结合,提高调查效率与质量,关注信息化手段未能涵盖的交通特征.