考虑停靠的干线协调公交优先协作机制及仿真研究

Transit signal priority on coordinated arterial is an important research topic in the signal control field. In transit operation, there are problem of how to coordinate the priority strategies between upstream and downstream intersection to achieve optimal system. Coordinated control considering impact of bus stopping is the key to realize transit signal priority. In order to reduce the negative impact of bus stopping in signal control, this project take the coordinated control system as a prerequisite and background, bus stopping are taken into account in the control strategy, and priority strategies between upstream and downstream intersection is cooperated. First of all, qualitative and quantitative analysis of impacts on bus stopping is analyzed based on traffic surveys and simulation experiments, and theoretical analysis model of impacts on bus stopping is builded by using multivariate analysis. Then, priority strategy is cooperated by forecasting, decision-making, collaboration three steps to transit vehicles on intersection-group between bus stops. If conflict of priority strategy exist between transit vehicles on intersection-group, decision-making is made by the coordination game. Next, testing and optimization to cooperation mechanism is done by simulation experiments. Finally, arterial simulation model is re-builded for case study, and the effect of priority signal control is verified. Through this research, the research results can provide a theoretical basis and experimental method for the research of how to consider the impact on bus stopping on arterial transit signal priority.

干线协调背景下的公交优先是信号控制领域的重要研究课题。公交运行中存在上下游交叉口优先策略如何协调以达到系统最优的问题，考虑公交停靠影响的协调控制是实现公交信号优先的关键。本项目计划以机动车的干线协调系统为前提和背景，在控制策略中增加对公交进站停靠的考虑，并对上下游交叉口的优先策略进行协作，实现在信号控制层面减少进站停靠对公交运行的负面影响。首先，根据交通调查和仿真实验对公交停靠影响进行定性、定量分析，运用多因素分析方法构建停靠影响的理论分析模型；然后，在公交站间的交叉口群内，对行驶的公交车按预测、决策、协作三步骤进行优先策略的协作；如果交叉口群内的多辆公交车之间存在优先策略的冲突，则按协调博弈模型进行决策；再通过仿真实验对协作机制进行测试与优化；最后构建不同的干线模型进行仿真案例分析，验证控制效果。通过本项目的研究，可以为干线层面公交信号优先如何考虑公交停靠影响提供理论依据和实验方法。

干线协调控制背景下，运行在干线上的公交车因为进站停靠无法保持在绿波带中，干线协调控制与公交运行之间存在不协调。本项目以干线协调信号控制框架为约束，详细分析了对公交进站停靠有影响的位置、时间和容量相关三类因素，结果表明涉及时间和位置的影响因素组合对公交车流运行的影响最大。在定量分析的基础上提出一种基于时间距离轨迹的公交站点位置优化方法，在时间距离图上绘制公交车流的行驶轨迹分布图，对比移动公交站前后轨迹分布的变化，选择最优的公交站点布设方案。仿真结果表明，公交站成对布设与站间交叉口群交错衔接的理想布设模式下，公交车流延误最小。为了避免上游交叉口的优先效益在下游交叉口被消减，本项目开展了站间交叉口信号机之间的优先策略协作机制研究。在信号控制策略中考虑上游公交站的影响，在公交站前后布设车辆检测器，根据实时检测信息预测停车线上的到车率分布，据此进行优先策略选择。在站间交叉口群的信号机之间，关键断面处实时检测公交车辆到达信息，各个信号机据此预测停车线上的到车率分布，并初步选定可行的优先策略；在此基础上，以交叉口群最下游交叉口信号机的优先策略为依据，上游信号机依次对初定的优先策略进行调整，避免选用一些不必要的优先策略，以减少公交信号优先对社会车流的负面影响。考虑到站间交叉口群路段上经常运行多辆公交车或车队，多公交车对优先策略的需求可能存在冲突，比如绿灯提前与绿灯延长只能二选一，同时也涉及多种优先策略下富余绿灯时间的分配，为此提出一种基于多方合作博弈的协调策略，在一定程度上实现了局部最优。仿真实验表明，优先策略协作之后的公交延误有一定程度的减少，同时社会车流的延误也有一定的降低。实现了在干线协调下缩短公交运行时间的目的，同时减少了进站停靠对公交运行的负面影响。本项目的研究成果可以丰富干线协调层面公交优先控制理论，也可以为网络层面的优先控制提供参考。