车路协同环境下自适应信号配时优化模型

在车路协同环境下,车辆位置和速度等信息容易获得,为交通信号控制系统提供了新的数据源。针对现有信号控制系统鲁棒性差,不能适应交通流实时变化特征等问题,本文提出了一种车路协同环境下交叉口自适应实时控制优化模型。该模型以交叉口车均延误最小为优化目标,相位绿灯时长为约束条件,采用遗传算法对模型进行求解,实现了对交叉口信号配时方案的实时优化。最后,通过调查数据并设计仿真实验,证明了文中模型比感应控制效果更好,车辆平均延误减少了30%,同时能够保证交叉口各个转向的车均延误均衡。     

考虑多交叉口相互影响的干道相位差仿真优化研究

为解决传统相位差优化方法以相邻交叉口为基础,忽略了连续交叉口对应的多个相位差之间的内在相关性的问题,以连续交叉口的多个相位差为研究对象,建立干道车辆延误与相位差关系的神经网络模型,采用遗传算法求解。首先,根据调查数据搭建仿环境获取不同相位差对应的干道延误数据,基于此采用神经网络拟合干道车辆延误与相位差之间的关系。然后通过遗传算法寻找神经网络中的最优延误对应的各个交叉口的相位差值。最后,将本文优化结果与Synchro进行比较分析。结果表明,本文模型能够有效改进相位差配时方案,方案性能提升了22.27%。     

交叉口间接左转多目标信号协调配时优化

为提升城市交叉口主干交通的通行效率，探究在“右转-掉头-直行”间接左转模式下对车流进行信号协调控制的配时方法。在模型构建部分，兼顾主干车流、转向车流和行人通行效益，使用模糊偏好法分配权重，构建多目标优化模型，并采用粒子群算法求解。在实例分析部分，选取典型交叉口为分析对象，以四相位等饱和度的信号配时设计作为常规方案，以间接左转的信号协调控制作为改进方案，对比两者的通行效益。结果表明，改进方案下主干车流延误降低50.8%，通行能力提升57.6%，左转车流延误升高31.2%，交叉口整体延误降低26.3%，主干交通通行状况改善明显。     

网联交通环境交叉口公交优先信号滚动优化模型

该文提出一种基于网联车辆实时数据的单交叉口公交优先信号配时滚动优化方法。建立了以所有出行者的总出行时间最小化为目标的混合整数线性规划(MILP)模型,采用灵活的信号框架,不限制信号周期和固定的相位组合及相序,并进一步提出了滚动优化执行框架。信号配时优化方法不要求交叉口设置公交专用道,而且可在优先考虑公交的同时,避免对普通车辆的通行产生的不公平的负面影响。仿真结果表明,与触发响应式的传统公交优先方法相比,该文中公交优先信号配时优化模型可以显著减少车均及人均延误,同时可使交叉口通行能力提高25%以上。     

改进的遗传算法及其在交通信号优化中的应用

以典型的四相位交叉口为例,基于改进的遗传算法,研究了在相对固定周期条件下集合交通流量变化而实时调整配时方案的优化算法,利用各进道口上车辆平均延误时间最小为目标建立目标优化函数,通过仿真分析对比,证明改进以后的遗传算法用于交通配时优化问题是有效的。     

城市交通信号灯的自动控制设计分析

在分析城市交通信号控制研究现状的基础上,提出一种基于神经网络模糊控制的单路口交通信号灯控制方法,通过检测当前相位的排队长度和下一相位的排队长度得出当前相位以及下一相位的车流密度,进而判断是否进行相位变换,以每个周期内交叉口的车辆平均延误作为控制指标,来判断该控制器的控制性能。本文根据城市交通系统的实际状况,依据交叉口个方向车流的来车信息,对等待车队长度、延长时间等进行模糊语言描述,从而对车流动态信息采用模糊控制规则与运算规则进行描述,得出相应的调度模式。设计了模糊控制器,并对该控制器进行了仿真研究,结果表明该方法应用方便可靠,可以有效地改善交叉路口的通行能力,为优化城市交通控制提供了一种参考方法。     

道路交叉口不同控制方式交通噪声预测

以不同行驶状态的机动车噪声排放模型为基础，对三种典型控制方式下的交叉口噪声进行预测研究。采用实验的方法分别对大、中、小型单辆车在怠速、匀速、加速、减速等各种行驶状态下的噪声值进行测定，通过回归分析得到不同行驶状态下的机动车噪声排放模型，并以某信号控制交叉口的实测数据为例，用计算机仿真的方法证明该模型对于交叉口噪声模拟的较高适用性。进而将该排放模型应用于信号控制、无信号控制以及环形等控制方式的交叉口进行噪声预测，通过不同交通流量时交叉口的平均噪声级以及噪声的分布情况等对比，得到各种控制方式下交叉口噪声的若干特点和区别。     

模特排时法在餐饮作业效率的应用研究

模特排时法是融动作分析与作业时间测定为一体的作业时间测定方法,餐饮业是劳动密集型、高服务效率要求的服务业。用模特排时法并辅之以作业分析法对某高校饮食服务中心的原饭菜销售作业进行了动作因素分析记录,利用"5W1H"提问技术和"ECRS"改善原则分析了原作业方案的存在问题和改善要点,制定了基于模特排时法的3个改善方案,并对新旧4个作业方案从服务周期时间、时间利用率、员工数量、设施数量方面进行对比分析。结合改善方案的制定过程和效果,总结了模特排时法在餐饮业中的具体作用和如何在餐饮业中应用模特排时法。     

城市道路交叉口信号协调优化控制研究

城市道路信号交叉口是城市道路的重要节点,它把城市道路相互连接起来构成道路网,其通行能力直接影响城市道路的通达,交叉口的交通流密度过大,将会造成路口的拥挤与堵塞,影响城市道路的正常运行,而提高信号交叉口通行能力、减少道路交叉口的车辆因停车与延误造成的损失,是城市道路交通管理相关部门追求的目标,鉴于此,本文以信号交叉口为研究对象,通过典型交叉口的调查,探究其通行能力,并分析信号交叉口的运行状况。     

基于线性回归的单柱塞泵单向阀参数优化

针对单柱塞泵系统中配流单向阀参数不合理所导致的吸油不充分、系统响应慢等问题,提出了一种基于线性回归的多参数优化方法。首先,通过AMESim软件进行单柱塞泵系统仿真分析,并利用MATLAB拟合工具箱分别探讨了不同单向阀参数（弹簧预紧力、弹簧刚度和阀芯质量）与进油口流量的关系。然后,在利用主成分分析法消除各参数之间相关性的基础上,以进油口流量为因变量,弹簧预紧力、弹簧刚度和阀芯质量为自变量,各参数的取值范围为约束条件,建立了基于线性回归的单向阀参数优化模型,并采用遗传算法进行优化求解。最后,根据优化前后的单向阀参数,对单柱塞泵系统进行仿真分析和实验验证。仿真结果表明,优化后进油口流量提高了21.3%;实验结果表明,优化后进油口的实际流量提高了16.8%。研究表明,所提出的多参数优化方法是一种有效的方法,可为单柱塞泵系统中配流单向阀的参数优化提供参考。     

Turning-lane and signal optimization at intersections with multiple objectives

Traffic congestion at intersections is a serious problem in cities. In order to discharge turning vehicles efficiently at intersections to relieve traffic jams, multiple left-turn and right-turn lanes are often used. This article proposes a novel multi-objective optimization method for signal setting and multiple turning-lane assignment at intersections based on microscopic traffic simulations and a cell-mapping method. Vehicle conflicts and pedestrian interference are considered. The intersection multi-objective optimization problem (MOP) is formulated. The cell-mapping method is adopted to solve the MOP. Three measures of traffic performance are studied including transportation efficiency, energy consumption and road safety. The influence of turning-lane assignment on intersection performance is investigated in the optimization. Significant impacts of the number of turning lanes on the traffic are observed. An algorithm is proposed to assist traffic engineers to select and implement the optimal designs. In general, more turning lanes help increase turning traffic efficiency and lower fuel consumption in most cases. Remarkable improvement in traffic performance can be achieved with combined optimization of lane assignment and signal setting, which cannot be obtained with signal setting optimization alone. The studies reported in this article provide general guidance for intersection planning and operation. The proposed optimization methodology represents a promising emerging technology for traffic applications.     

Study on the Signal Control System of Urban Traffic with a Genetic Algorithm

In the paper the aim and meaning of traffic microscopic simulation is discussed first, and then three sub-models of the system are established, e. i. the model for random generation of the vehicles, the model for car-following and lane change influenced by an adjacent vehicle, and the model for control and optimization of intersection with signal. Optimization of the traffic signal timing with a genetic algorithm and a microscopic simulation is carried out. It represents a novel approach to solving optimal signal timing.     

Connected Vehicle-Based Traffic Signal Coordination

This study presents a connected vehicles (CVs)-based traffic signal optimization framework for a coordinated arterial corridor. The signal optimization and coordination problem are first formulated in a centralized scheme as a mixed-integer nonlinear program (MINLP). The optimal phase durations and offsets are solved together by minimizing fuel consumption and travel time considering an individual vehicle’s trajectories. Due to the complexity of the model, we decompose the problem into two levels: an intersection level to optimize phase durations using dynamic programming (DP), and a corridor level to optimize the offsets of all intersections. In order to solve the two-level model, a prediction-based solution technique is developed. The proposed models are tested using traffic simulation under various scenarios. Compared with the traditional actuated signal timing and coordination plan, the signal timing plans generated by solving the MINLP and the two-level model can reasonably improve the signal control performance. When considering varies vehicle types under high demand levels, the proposed two-level model reduced the total system cost by 3.8% comparing to baseline actuated plan. MINLP reduced the system cost by 5.9%. It also suggested that coordination scheme was beneficial to corridors with relatively high demand levels. For intersections with major and minor street, coordination conducted for major street had little impacts on the vehicles at the minor street.     

车路协同下基于交通密度的交叉口交通信号控制方法与仿真

车路协同环境下路侧单元可实时获取车辆的位置、速度等信息,为改进交通信号控制提供了机遇和条件。本文借助感应控制方法的思路,以单个交叉口为研究对象,提出车路协同下基于交通密度的交通信号控制方法,该算法将依据交叉口进口道的交通密度,实时选择车流放行方向,并依据排队消散时间确定进口放行绿灯时间。为验证算法的有效性,以虎门大道--连升路交叉口为例,利用Vissim交通仿真软件,对高峰、平峰、低峰等3个交通需求分别进行仿真建模,并分别分析同一交通需求下,本文算法与感应控制方式、定时控制方式的平均行程时间、平均延误时间、平均停车次数及平均排队长度等各项交通信号控制指标优劣。仿真结果表明:在不同交通需求下,与感应控制方式、定时控制方式相比,本文算法各项交通信号控制指标均有明显的改善。     

Reducing red light running through longer yellow signal timing and red light camera enforcement: results of a field investigation

Red light running is estimated to account for 900 intersection crash fatalities annually. Two principal methods used to reduce red light running involve lengthening the duration of yellow change intervals and automated red light enforcement. The present study evaluated the incremental effects on red light running of first lengthening yellow signal timing, followed by the introduction of red light cameras. At six approaches to two intersections in Philadelphia, Pennsylvania, yellow change intervals were increased by about 1s, followed several months later by red light camera enforcement. The number of red light violations was monitored before changes were implemented, several weeks after yellow timing changes were made, and about 1 year after commencement of red light camera enforcement. Similar observations were conducted at three comparison intersections in a neighboring state where red light cameras were not used and yellow timing remained constant. Results showed that yellow timing changes reduced red light violations by 36%. The addition of red light camera enforcement further reduced red light violations by 96% beyond levels achieved by the longer yellow timing. This study shows that the provision of adequate yellow signal timing reduces red light running, but longer yellow timing alone does not eliminate the need for better enforcement, which can be provided effectively by red light cameras.     

圆染色在城市交叉路口交通信号相位个数设计中的应用

以城市交叉路口交通信号相位的优化为背景,分析了用圆染色解决这个问题的合理性,并给出现实中了几类交叉路口的最优相位个数。     

The fully actuated traffic control problem solved by global optimization and complementarity

Global optimization and complementarity are used to determine the signal timing for fully actuated traffic control, regarding effective green and red times on each cycle. The average values of these parameters can be used to estimate the control delay of vehicles. In this article, a two-phase queuing system for a signalized intersection is outlined, based on the principle of minimization of the total waiting time for the vehicles. The underlying model results in a linear program with linear complementarity constraints, solved by a sequential complementarity algorithm. Departure rates of vehicles during green and yellow periods were treated as deterministic, while arrival rates of vehicles were assumed to follow a Poisson distribution. Several traffic scenarios were created and solved. The numerical results reveal that it is possible to use global optimization and complementarity over a reasonable number of cycles and determine with efficiency effective green and red times for a signalized intersection.