陈颖雪

       现阶段，由于我国高架道路出口匝道与地面衔接区域存在诸多问题，交通高峰期间出口匝道经常出现排队，车辆不能快速离开高架道路，导致高架道路的功能未得以较好的实现。针对这一问题，很多学者从设计、组织、控制等方面提出了自己的看法和建议，由于对衔接段进行交通组织有直接针对衔接段的存在问题、实际可操作性强、改善交通见效快等众多优点，而目前已有的相关研究缺乏系统全面的考虑、实际应用时没有完善的依据，由此论文对高架道路出口匝道和地面道路衔接段的组织进行研究。

       衔接段影响因素众多，且我国缺乏相关历史数据，而用仿真软件建模来研究交通运行不仅可以弥补数据缺乏的缺点，还可以针对某一个影响因素进行单独研究，因此论文利用仿真软件建模的方式对衔接段各影响因素进行研究，为衔接段的交通组织提供理论依据。

       首先，论文研究了衔接区域的交通特性，论述衔接区域存在的主要问题，分析问题成因，并陈述了目前经常使用的对策，其一为衔接段无交织处理，继而，针对有交织和无交织衔接形式各自的优缺点研究其适用条件。

       接着，论文利用前人论证过能较好反映交织区运行特性的仿真软件VISSIM来建模进行研究，选择典型的衔接段，采集相关数据，对模型进行参数标定和有效性检验，验证仿真模型能够较好的反映实际情况。

       最后，论文利用建好的仿真模型研究以下问题：一、该仿真模型中出口匝道的疏散能力；二、该仿真模型中出口匝道与地面道路衔接段区域实施工程措施的边界条件；三、少许改变模型使模型更具有普遍性，同时，考虑到我国右转车受机动车和行人干扰严重在交叉口内车速较慢这一现实情况，保留仿真模型中设置的交叉口内右转车减速带。之后，利用该模型进行运行试验，研究交通量、交织区长度、右转车、车辆转向比等因素对交织区运行及交织区邻近区域交通运行的影响。

关键词：高架道路出口匝道与地面道路衔接段，疏散能力，工程措施边界条件，右转车，转向比，交织段长度

    At this stage, due to the joint of at-grade road and out-ramp of city elevated road in China have many problems, during traffic hours queuing is exist at out-ramp, vehic1es cannot leave elevated road rapidly. Elevated road's function will not be realized completely. To solve this problem, many academics proposed their views and suggestions from design, organization, control etc., because the traffic organizations to the joint part has many advantage, such as according to joint part's problems directly, better maneuverability, and improving the efficiency of traffic quickly. The current researches lack of systematic and comprehensive consideration, the engineering application lack of theoretical foundation. This paper is about research on the traffic organization of joint of at-grade road and out-ramps of elevated road.

    Joint of at-grade road has many influence factors, and we lack of relevant historical data in China. And building the model in simulation software to study the traffic operation 110t only can make up for the shortcomings of the lack of data, but also can study on one influence factor separately. So in this paper we use simulation software to build the model to study on influence factors of joint of at-grade road, and to provide theoretical basis to traffic organizations of joint of at-grade road.

    Firstly, in the paper we research on traffic characteristics of joint of at-grade road, discuss the main problems existed in the joint of at-grade road, analyze the causes, and state the current countermeasures usually to be used, one of which is the non-interweaving treatment to the joint of at-grade road, and then, for the respective advantages and disadvantages of interweaving and non-interweaving joint forms, we research its applicable condition.

    Then, we use simulation software of VISSIM which has been proved can ref1ect the operational characteristics of interweaving region very well, to build model for study. We choose typical joint of at-grade road, collect relevant data, complete the model's parameter calibration and effectiveness testing, verify simulation model can reflect practical situation very well.

    Finally, in the paper we use the simulation model to study the following issues:

First, the evacuation ability of out-ramp in the simulation model; Second, boundary condition of engineering measures of joint of at-grade road and out-ramp of e1evated road in the simulation model; Third, a little change in the model to make the model more universal, at the same time, taking into account cars to turn right are influenced seriously by motor vehicles and pedestrians in China, we reserve turn right decelerating band in the intersection of the simulation model. Then use the model for operation tests on affection to traffic operation of interweaving region and neighboring region by the volume of traffic, length of weaving section, right turning vehicle, vehicles steering ratio etc.

Key Words: joint of at-grade road and out-ramp of city elevated road, evacuation ability, boundary condition of engineering measures, right turning vehicle, steering ratio, length of weaving section, Service levels