缪芳

入学时间：2013级

答辩时间：2016年

论文题目：公交线路运行可靠性评价及影响因素分析

中文摘要

摘要

公交可靠运行关系到管理者、运营者及出行者。对于管理者而言，公交运行可靠是确定和编制公交时刻表的基础，是公交服务品质化的标志；对于公交运营者而言，公交运行可靠是企业运输服务的承诺，同时，可以避免因车辆聚簇而带来的调度计划调整和额外车辆投放，减小企业运营成本；对于公交出行者而言，公交运行可靠是乘客合理规划和安排出行时间的依据，从而节约乘客出行成本。本文围绕公交运行可靠性评价的相关理论与实现技术展开研究，主要包括站点和线路的运行可靠性评价，以及基于评价的影响因素分析、中途站时刻表编制和公布批次建议等内容，具体分为以下几个方面：

本文首先选取了基于站间行程时间的公交运行准点性指标和基于发车间隔的车头时距稳定性指标，从站点和线路、微观和中观层面构建了公交线路运行可靠性评价模型。并通过对海量公交实时运行数据的挖掘处理，实现公交线路运行可靠性评价和分时段分类型的对比分析，验证了模型的有效性和适用性。

在公交运行可靠性评价基础上，以如何发现公交运行低可靠区间并有针对性的提出外部通行条件改善建议为研究问题，通过微观站点层面的运行可靠性评价，结合运行可靠性影响因素回归模型，分析公交线路运行特征及影响公交运行可靠性的主要因素和影响程度，有针对性的提出改善建议，为公交系统外部通行条件改善及可靠性提升提供数据支撑和决策支持。

基于公交线路运行可靠性评价结果，结合统计分析手段，提出公交线路运行可靠性等级划分和时刻表公布批次建议。并通过计划时刻表和GPS数据分析提出中途站时刻表编制方法及实施保障对策。

本文研究成果对于评价公交线路运行可靠性现状，发现公交运行低可靠区间及引起公交运行不可靠的因素，判别线路时刻表公布批次等具有较大的理论指导意义和实践操作价值，为政府指挥决策和企业运营管理提供良好的理论指导和数据支撑。

关键词：公交线路，运行可靠性，影响因素，通行环境，时刻表

英文摘要

ABSTRACT

It is generally accepted that bus transit operating reliability is an important service quality that impacts managers，operators and travelers. For Managers，reliability is the basis for designing bus operation timetable and the symbol of high quality for public transit service. For operators, reliability is taken as their service commitment. Meanwhile, transit operating reliably help to avoid clustering which may further lead to interruption for scheduling plan and vehicles expansion, so as to reduce operating cost. Travelers are affected by service reliability, with which they may predict bus arrival time and adjust travel plan accordingly, allowing bus ride more controllable. This research focused on the theory and methods related to transit reliability assessment, including reliability assessment from the aspect of stations and lines, influence factors analysis based on that, stop timetable design methods, and suggestion of timetable releasing batch. The main research contents are as follows:

First, reliability assessment index system is established and validated, including travel time constancy between two adjacent stations and headway stability from departure interval. Thus transit reliability assessment model is built from aspects of station and line, corresponding to microscopic and mesoscopic levels. Then the applicability and effectiveness of the model was verified through overall assessment and comparative analysis in different time periods for various bus modes with the massive bus real-time travel data in Shanghai.

With the above analysis, bus service reliability is further examined to locate the segments that affect bus operation stability most, in search for effective optimization of external operation environment. Through regression model, factors that possibly worsen bus reliability are integrated with sensitiveness analysis. Then specific optimization suggestions are proposed to help decide how to improve bus operating conditions on base of systematic data analysis.

Based on bus reliability assessment, statistical methods are employed for grading reliability and timetable releasing batch. With departure timetable and GPS data analysis, timetable for stops is proposed as well as assurance measures concerned.

The research makes an attempt in evaluating reliability of bus routes both theoretically and practically. And it proposes the criteria to locate road segments that deteriorate reliability, through factor analysis and sensitiveness testing. Then timetable releasing method is proposed to facilitate passenger travel. That will provide decision direction for government and operating enterprise in refining bus service system.

Key words: transit routes, operating reliability, influencing factor, operation conditions, timetable

江泽浩

入学时间：2013级

答辩时间：2016年

论文题目：城市道路信号控制交叉口通行能力概率特征研究

中文摘要

摘要

通行能力理论是交通工程学的基础理论之一，交叉口是城市道路网络的咽喉，其运行情况直接影响到城市路网的运行情况。正确地认识与理解交叉口的通行能力，对于指导交叉口的规划、设计、改建及优化配时，具有重要的意义。

在外部条件一定时，通行能力通常被作为一个常量处理，用期望值来描述。但期望值只能从某一角度来描述通行能力，不能完全反映关于通行能力的全部信息。交通是动态的，影响信号控制交叉口通行能力的一些因素更是变化的、随机的，这些现象与问题均启发我们采用新的数学方法去描述信控交叉口的通行能力——即指向了信控交叉口通行能力概率特征。

本文首先对信控交叉口通行能力计算方法进行了综述；其次对信控交叉口通行能力研究的基础——车辆排队消散模型进行归纳与比较，特别注意了饱和车头时距、绿灯损失时间这两个关键性因素的研究现状与进展；此外，对本文采用的主要的数学工具——可靠性理论进行了综述，特别注意了其在交通学科中的运用。

根据信号相位切换（特指由红灯到绿灯的切换）的不同，对上海市中心城区的三个典型的信控交叉口（scenario1~scenario3）进行了实际观测，建立了各自的车辆排队消散模型。模型表明：对于不同的相位切换方式，车辆排队消散模型随着对驾驶员提示信息强度的区别而明显不同。特别的，scenario1~scenario3的实际观测均表明：信控交叉口饱和车头时距呈现出很明显的单峰、正偏态分布，可以用Log-Normal Distribution曲线拟合；绿灯损失时间呈现出比较明显的单峰、正态分布，可以用Normal-Distribution曲线去进行拟合。

在此基础上得到了饱和车头时距及绿灯损失时间分布的基础上，设计了Monte-Carlo数值仿真算法，利用公式仿真得到信控交叉口车道组通行能力的数值解，并进行分布拟合。结果表明：scenario1~scenario3三种情境下的信控交叉口的通行能力均能够很好的服从正态分布。为避免仿真的随机性，设计了敏感性分析内容，结果表明：在饱和车头时距及绿灯损失时间概率分布类型确定的前提下，特征参数即使在较大范围内变动，信控交叉口通行能力对正态分布仍然有较好的收敛。

求得信控交叉口通行能力的概率表达后，结合交通量的概率分布得到信控交叉口通行能力的可靠度。通过分析不同情境下的通行能力可靠度需求，调整可靠度的不同取值，自然得到了信控交叉口的设计通行能力。

另外，考虑到我国混合交通的实际情况，针对HCM2010中对信控交叉口通行能力影响因素研究的薄弱环节，选取了重车修正系数（HCM2010未考虑车辆排队的随机性）这个代表性的因素进行了分析。

最后，对本研究之不足及进一步的研究方向进行了简要的讨论

综上，本文基于实际观测实验，建立了基于信号相位切换方式的车辆排队消散模型，提取了饱和车头时距及绿灯损失时间的概率分布特征；通过Monte-Carlo数值仿真得到信控交叉口车道组通行能力服从Normal-Distribution的结论；利用可靠性理论，通过分析不同情境下的通行能力可靠度需求，得到了信控交叉口的设计通行能力；最后针对HCM2010中对信控交叉口通行能力影响因素研究的薄弱环节进行了若干补充性的研究。

关键词：设计通行能力，概率特征，可靠性理论，信号控制交叉口，通行能力

英文摘要

ABSTRACT

Capacity theory is one of the basic theories in transportation engineering, and intersections are the throats of the urban road network. The operation conditions of intersections directly affect the performance of the whole road network. Holding an accurate knowledge and understanding of the intersection’s capacity is significant for the planning, design, reconstruction and timing optimization of the intersection.

Currently, with fixed external conditions, the capacity is often tacitly treated as a constant and is described with an expected value. But，the expected value can only describe capacity to some degree, but not reflect the whole information within capacity. Because the traffic is dynamic, and the influence factors of the capacity are always varying and even random. Obviously, all these phenomena and problems inspire us to adopt new methodologies to describe the capacity of an SI - the probability feature of an SI’s capacity.

This paper firstly reviews the calculation methods of the capacity of SI; then concludes and compares the departure model, which is the foundation of the research in capacity of SIs. Note that special attentions are paid to the saturation headway and lost time in green, which are two key influence factors. Besides, the mainly used math tool in this paper- the reliability theory - is also reviewed, and the focus is on its use in transportation engineering.

Based on different phase switching (refers to red switches to green in this paper) patterns, three typical SIs (Scenario 1~3) in the central area in Shanghai are chosen for observation. The vehicle departure models are then built for each scenario. The results reveal that, in different phase switching patterns, the vehicle departure model varies greatly with the changes in information intensity provided to the drivers. Specially, the field observations in Scenario 1~3 all indicate that, the saturation headway of the SIs shows obvious unimodal, positive skewness distribution, which can be fitted by a log-normal distribution curve; while the green lost time shows obvious unimodal, normal distribution, which can be fitted with a normal distribution curve.

Based on the above distributions of saturation headway and green lost time, this paper then designs the Monte-Carlonumerical simulation algorithms, and obtains the capacity of SIs through simulations. The distribution fitting are then conducted for the obtained capacity. The results show that, the capacities of SIs in Scanario 1~3 all obey normal distribution very well. To further avoid the randomness of simulations, the sensitivity analysis are conducted, and they prove that under a fixed probability distribution of saturation headway and green lost time, the capacity of an SI will always well obey normal distribution, regardless of the big variation ranges of characteristic parameters.

Combining the above probability expression of the capacity and the probability distribution of the traffic volume, we can then gain the reliability of the capacity. Through the analysis of the reliability demands for capacity in different scenarios, we can easily calculate the design capacity for an SI by adjusting the value of reliability.

Moreover, considering the actual conditions in China, this paper analyzes a representative factor that is the week point in HCM 2010: the heavy truck correction coefficient (the randomness of vehicle queuing is not considered in HCM 2010)

At last, a brief discussion is conducted about the disadvantages in this research and the outlooks in the future.

In conclusion, on the basis of field observations, this paper builds the vehicle departure model based on the phase switching patterns, extracts the probability distribution characteristics of saturation headway and green lost time; concludes that the capacity of an SI obeys the normal distribution throughMonte-Carlo numerical simulation; obtains the design capacity of SI by analyzing the capacity reliability demands in different scenarios with the reliability theory; and compensates some week points in the researches concerning capacity of SI in HCM 2010.

Key words:design capacity, probability feature, reliability theory, signalized intersection, capacity