面向新型混合交通流的智能交叉口网络布局优化

考虑网联自动驾驶车辆(Connected Autonomous Vehicle, CAV)应用先进的车联网与自动驾驶技术，可以采用智能交叉口的组织形式，大幅提升交叉口的通行效率，为降低CAV与人工驾驶车辆(Human-driven Vehicle, HV)混行条件下城市交通系统的整体出行成本，提出智能交叉口在城 市交通网络中的布局优化问题，建立数学优化模型并求解。首先，基于对两类车辆行驶特性的分析，建立混合用户均衡模型，描述CAV与HV的路径选择行为；其次，从交通规划者的角度，以系统最优为目标，整合混合用户均衡模型，建立面向新型混合交通流的智能交叉口网络布局优化模型，并利用改进的遗传算法求解；最后，选取Sioux-Falls交通网络作为案例分析，验证模型与算法的有效性，并研究CAV渗透率变化对优化结果的影响。研究表明，智能交叉口在城市路网中的合理规划极大地提高了新型混行场景下城市交通系统的出行效率，同时，大幅降低了由于网联自动 驾驶单方面技术优势带来的CAV与HV的出行效率差距，增进了出行公平性。     

A two-dimensional simulation model for modelling turning vehicles at mixed-flow intersections

The turning behavior is one of the most challenging driving maneuvers under non-protected phase at mixed-flow intersections. Currently, one-dimensional simulation models focus on car-following and gap-acceptance behaviors in pre-defined lanes with few lane-changing behaviors, and they cannot model the lateral and longitudinal behaviors simultaneously, which has limitation in representing the realistic turning behavior. This paper proposes a three-layered “plan-decision-action” (PDA) framework to obtain acceleration and angular velocity in the turning process. The plan layer firstly calculates the two-dimensional optimal path and dynamically adjusts the trajectories according to interacting objects. The decision layer then uses the decision tree method to select a suitable behavior in three alternatives: car-following, turning and yielding. Finally, in the action layer, a set of corresponding operational models specify the decided behavior into control parameters. The proposed model is tested by reproducing 210 trajectories of left-turn vehicles at a two-phase mixed-flow intersection in Shanghai. As a result, the simulation reproduces the variation of trajectories, while the coverage rate of the trajectories is 88.8%. Meanwhile, both the travel time and post-encroachment time of simulation and empirical turning vehicles are similar and do not show statistically significant difference.     

基于传播模型的非机动车违规过街行为研究

为研究信号交叉口非机动车违规过街行为，选取西安市的7个信号交叉口，通过视频拍摄获取资料，应用复杂网络来分析非机动车网络的结构特征和演化规律.建立了交叉口非机动车网络，基于SI模型的基本思想，提出了非机动车违规过街行为的传播模型.并通过python程序进行模拟分析，在不同的网络结构和不同的传播率下，获取了非机动车违规过街的行为趋势.结果表明：随着等待时间的增加，一旦有骑行者闯红灯，更多的骑行者将加入到违规过街的行列；在内向度和外向度方面，电动自行车均高于普通自行车；非机动车违规行为随着传播率及非机动车流量的增加而增加.     

典型交叉口非机动车二次过街设计方法

以宁波市典型灯控交叉口为例，介绍了非机动车二次过街的设计方法，并详细分析了非机动车二次过街方式的设置条件、左转待转区的设置及二次过街的交通组织方式。     

Estimation of delay variability at signalized intersections for urban arterial performance evaluation

Urban arterial performance evaluation has been broadly studied, with the major focus on average travel time estimation. However, in view of the stochastic nature of interrupted flow, the ability to capture the characteristics of travel time variability has become a critical step in determining arterial level of service (LOS). This article first presents a stochastic approach that integrates classic cumulative curves and probability theories in order to investigate delay variability at signalized intersections, as a dominant part of the link travel time variability. This serves as a basis for arterial travel time estimation, which can be obtained through a convolution of individual link travel time distributions. The proposed approach is then applied in the estimation of travel time along one arterial in Shanghai, China, with abundant automatic vehicle identification (AVI) data sources. The travel time variability is evaluated thoroughly at 30-min intervals, with promising results achieved in comparison to the field measurements. In addition, the estimated travel time distributions are utilized to illustrate the probability of multiple LOS ranges, namely, reliability LOS. The results provide insights into how we might achieve a more reliable and informative understanding of arterial performance.     

信号交叉口集聚车辆的跟驰行为分析与建模

为了更好地模拟城市信号交叉口集聚车辆的跟驰行为,进而应用于城市信号交叉口信号配时和交通流理论研究,采用一种基于视频的交通流数据采集方法来采集信号交叉口的微观交通行为数据.运用灰色关联分析方法对采集到的微观交通数据进行分析,挖掘出其中的有用信息,从而寻求能够最大程度反映信号交叉口集聚车辆跟驰行为的影响变量.构建城市信号交叉口车辆集聚过程中的跟驰模型并进行参数标定、效果验证和比较分析.研究表明,新提出的跟驰模型能够很好地拟合信号交叉口集聚车辆的跟驰行为实测数据,其拟合性和稳定性优于重新标定后的扩展GM模型.     

设置导流岛的信号交叉口交通流特性研究

应用统计推理方法分析设置导流岛后信号交叉口交通流特性.结果表明,设置导流岛后交叉口行人和自行车到达符合泊松分布；行人和自行车分三阶段过街;机非冲突集中在右转车道的人行横道上,机非冲突面大大缩小.     

公路平面信号交叉口左转车道长度设计

平面交叉口作为道路系统的一个重要组成部分,其服务水平的好坏对整个道路系统的安全和效率有着重要的影响。因为来自不同方向的车流在此处合流、分流和交叉,其中频繁的左转车辆阻碍直行车流的行驶,降低了交叉口的通行能力,增加了交叉口的延误,并增大交通事故率。如果合理设置左转车道能够有效地将左转车辆从直行车流中分离出来,减小车流速度方差,并降低追尾事故的发生;而左转车道,长度的设计是设置左转车道的关键元素,本文主要是针对信号交叉口选取适当的设计指标建立模型,并通过TSIS软件进行仿真分析,得出专用左转相位下的左转车道排队长度,进而计算出左转车道的设计长度。     

A macroscopic theory for unsignalized intersections

The following paper presents a dynamic macroscopic model for unsignalized intersections which accounts for time-limited disruptions in the minor stream flow, even in free-flow conditions when the average flow demand is satisfied. It introduces a deterministic fictive traffic light to represent an average alternating sequence of available and busy time periods for insertion depending on the major stream flow. Two allocation schemes of the total outflow during green periods are developed to model the influence or non-influence of the minor stream over the major stream flow. The aggregation of the resulting dynamic flow variations gives relevant capacity values. Moreover, the model predicts accurate average vehicle delay and queue length estimates compared to theoretical and empirical data. It has three easy-to-measure parameters and can be integrated into a dynamic macroscopic simulation tool for urban networks.