基于信号控制的城市路网旅行时间计算模型

交通控制信号对交通流的影响是干扰实时交通数据计算准确性的重要因素。为此,提出一种基于信号控制的城市路网旅行时间计算模型。将城市道路的旅行时间分为2个部分,即路链有效旅行时间和路口延误时间,设计改进的信号控制延误模型用于计算路口延误时长,并给出路链合并算法。实验结果表明,该模型起点到终点的旅行时间误差率能降低5%~15%。

城市道路行程车速影响因素分析

行程车速由行驶车速和路口停车延误共同决定。为了研究行驶车速和路口停车延误的影响因素 ,分别在沈阳、大连、杭州进行了调查 ,依据调查数据 ,应用回归法分析机非干扰状况、车道宽度、车流密度等因素对城市道路上行驶车速的影响 ,以及车流密度。

Optimization method for evacuation zone with network reconfiguration based on dynamic simulation

Abstract： With a determinate danger zone and evacuation demand caused by an emergency, an optimization method for the evacuation zone with network reconfiguration based on dynamic simulation is proposed. The method contains three modules. First, the network in the evacuation zone is optimized by a model with the integrated strategy of lane reversal and intersection conflict elimination. Secondly, the dynamic evacuation simulation model based on the cell transmission model is applied to simulate the dynamic propagation process of evacuated vehicles in the network in the evacuation zone. The evacuation time for all evacuated vehicles leaving the danger zone is obtained and the setting of the current evacuation zone is fed back. Thirdly, the arrival distributions of evacuated vehicles at critical intersections of the evacuation zone are also obtained to estimate the delay at critical intersection to determine whether the intersection should be taken as the critical intersection in the next iteration. The evacuation zone is expanded gradually through iteration, and the reasonable evacuation zone and the optimal evacuation network is confirmed. Based on the survey of the parking lot and urban street network around Nanjing Olympic Sports Center, the models and the iterative algorithm were applied to obtain the optimal plan of the evacuation zone with network reconfiguration in an evacuation situation to verify the validity of the proposed method.

道路车辆快速运行路径优化选择仿真研究

研究道路车辆快速运行路径优化选择问题,出行者进行路径选择时多根据路径行程时间长短作为路径选择的依据,但现有研究对车辆行程时间的随机动态性考虑不足,且其值不唯一。根据车辆排队长度与相位、车流消散速度之间的关系,预测随机动态路径行程时间,再根据可靠性理论将得到的行程时间集转化为行程时间可靠性,作为路径选择的依据,并对该算法进行案例仿真分析验证。实验结果表明,使用行程时间可靠性作为随机动态路网条件下的路径选择依据,既能将路网的随机动态影响考虑在内,又能避免行程时间的不确定性给出行者带来的选择困扰,是一种合理有效的路径选择方法。

本溪市路网仿真研究

结合目前本溪城市道路,本文利用PTV-Vissim软件对主要道路进行仿真研究,对现状路口延误调查,通过分流、信号灯配时优化等措施后,相比于现状,延误时间减少近45%,交通拥堵情况大幅度缓解。

Delays caused by motorized vehicles unable to clear intersections in China: Graphical analysis

In many Chinese cities,motorized vehicles （M-vehicles） move slowly at intersections due to the interference of a large number of non-motorized vehicles （NM-vehicles）.The slow movement makes a part of M-vehicles fail to leave intersections timely after the traffic signal tums red,and thereby conflicts between vehicles from two directions occur.The phenomenon was analyzed graphically by using the cumulative vehicle curve.Delays in three cases were modeled and compared：NM-vehicle priorities and M-vehicle priorities with all-red intervals unable to release all vehicles,and longer all-red intervals ensuring release all vehicles.Marginal delays caused by two illegal behaviors that occasionally happened in mixed traffic intersections were also investigated.It is concluded that increasing the speed of M-vehicles leaving intersections and postponing the entering of NM-vehicles are the keys in mathematics,although they are uneasy in disordered mixed traffic intersections due to a dilemma between efficiency and orders in reality.The results could provide implications for the traffic management in the cities maintaining a large number of M-and NM-vehicles.

Delay Analysis and Formulation Inference of Signalized Intersection for Traffic Congestion Conditions

Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.

基于GPS与GIS的动态交通信息估计研究

描述了用GPS和GIS相结合估计实时路段行程时间与路口延误时间的应用。首先,根据不同的路口情况,确定了不同的路口检测点分布,并由此区别路段直行、左转、右转行程时间的不同;而后介绍了具体的计算过程。主要分为三部分:数据采集、数据滤波、数据处理;数据采集主要是通过GPS接收机根据一定的采样间隔采集车辆运行的位置信息,数据滤波过程通过地图匹配算法和偏差检测方法对采样的数据进行处理,得到道路匹配点数据。数据处理主要是利用匹配点数据计算车辆的停车信息、通过检测点的信息、相应的路段平均速度、瞬时速度的信息以及车辆通过路口的延误时间等;最后给出了一个具体算例,结果表明此方法是有效的。