Study On Coordinated Control Of Urban Expressway Entrance Ramp And Ground Intersection

Urban expressway appeared as urban trips brought great convenience, also greatly reducing the urban inter-regional travel, at the same time, with the urbanization and ramp inefficient management and many other issues, urban expressway often appeared "fast is not up" phenomenon. In contrast with urban expressway,which is design for safe, fast, efficient, comfortable and convenient, the expressway congestion even spread to the main ground intersection, affecting the normal operation of ground transportation.On-ramp is the necessary path from the ground traffic to the expressway, what’s more, it’s traffic management largely decided the overall service level of freeway system. On-ramp metering is considered one of today’s most effective treatment method to solve expressway system traffic problems, it’s purpose is to ensure maximum benefits of expressway mainline, meanwhile the traffic pressure is transferred to the ground. Only the entrance ramp and ground whole joint convergence intersection control, in order to maximize the overall interests of the study freeway ramp intersection coordination with ground control has practical significance.In this paper, the urban expressway mainline traffic flow, On-ramp traffic flow and ground intersection traffic flow will be analysed,along with the expressway system in Kunming city (Jinma overpass-Dashuying overpass),which provided a theoretical basis for thestudy of the following research.In the metering mechanism, this paper introduces the principle on-ramp metering, the basis and system components of on-ramp system, and on-ramp metering methods grouped together in research and introduced the single point of control algorithms and ramp coordinated control algorithm, finally introduces the basic theory of ground intersetion signal control, laid the theoretical foundation of this paper.The basic premise of the paper leads to the on-ramp metering, and analized Kunming expressway (Jinma-Dashuying expressway overpass) road traffic situation, according to the on-ramp metering threshold, dividing different control traffic state (ramp metering, ramp closed and ramp open), and achieved the control strategy for the following research.The paper draws on the expressway traffic flow coordinated system proposed by Ghang G L model, the use of sub-division of fluid dynamics analysis of this study area traffic flow modeling, in order to achieve optimal segmentation evaluation purposes, minimum average delay will be used as the objective function in this paper, and established the coordinated control model. Finally, the control strategy in this papers will be simulation analyzed with VISSIM simulation simulation software, as a result, the average delay, average queue length and maximum queue length also will be contrasted and analized.