Study Of Urban Area Traffic Control Technology

In recent years, traffic congestion and jam has become a common problem to be faced by large and medium-sized cities in the world. And a series of social problems brought by traffic congestion also trouble them, such as traffic accidents, environment pollution, energy crisis and so on. Developing urban intelligent traffic control system is one of the important ways to solve contradictions between traffic demand and supply. Implementing intelligent control of urban traffic system is not only beneficial to improve transportation efficiency and enhance road traffic safety, but also relates to making full use of land source and energy, improving urban environment, developing national economy and social benefit.Urban traffic control systems, generally includes single point control system, trunk control system and regional control system, from either classification or research. Various control system has a different scope of application, but it is clear that the urban traffic congestion is widespread throughout the city. The correlation between the intersections is very obvious in an area. The adjustment of a single intersection signal often affect traffic flow status of a number of adjacent nodes and links. Single intersection in congestion may gradually affect the surrounding intersection.Single point control systems, no matter how optimization cannot be mitigated to traffic congestion of a certain area or the entire urban. Therefore, research on signal control theory of a region or even the entire city more and more attention. Departure from the strategic point of view of the entire system, all intersections in the area as the object of study, all intersection traffic signal control is designed to improve transport efficiency within the entire control area, has become the development of urban traffic control new topics. The focus of this thesis is also here.This thesis aims key technologies research on area traffic control, including the following aspects: (1) In this thesis, the transportation planning concept as one aspect of a macro-control, transport network problems are optimized from the macro level. Based on the balanced flow of ideas, the design of metropolitan area network is set up by the bi-level programming method. Based on the analysis of the general travel time reliability, absolute reliability and relative reliability are posed, which will more refined description of the stability of the road network in the day change. Travel time reliability combined with conventional traffic impedance, as generalized traffic impedance, is introduced to objective function of the upper level of network design. And then a new road is constructed to optimize network design.(2) The traffic state identification problem is studied in this thesis. After summarizes the status of analytical methods, we build the ideas of the control cell division from a quantitative point of view. We designed the principle of division of the cell, and pose a detailed algorithm, which can be used as basic work of traffic system state identification. And examples of large road network demonstrate the feasibility of the algorithm.(3) We focus on the regional traffic signal control problem, and summed up the all type of common structure and control strategy for regional traffic signal control system. Taking into account the differences of traffic state between the various junctions and links are ignored in the majority of the existing model, establishes a bi-level programming model is built based on the equilibrium assignment traffic flow in the thesis. Optimization vehicle delay is worked in upper model, while a balanced flow is solved in the lower model. And the results of state partition, which as an important factor, are introduced to the upper programming model. We also explore the solving algorithm to the bi-level model in the thesis, and intelligent method combining genetic algorithm with simulated annealing and solving ideas based on the gradient projection are put forward. The validity and limitations of the algorithms are verified by a network of standard.(4) Traffic management is treated as a means of macro-control in the thesis, and ideas of integration traffic management and control are introduced into research on traffic problems of the massive activities area. First we analysis the characteristics of traffic demand, traffic flow and traffic control of massive activities. Second, research is focused on control measures from the technical aspects. The bi-level programming model of the active area traffic control is posed to optimize simultaneously three problems:impact on the surrounding traffic of activities, input costs of control measures, evacuation efficiency of the mass departures. The solving idea of combination of rough set and genetic algorithm is set up in the thesis, and the instance of Jinan National Games verifies the traffic control algorithm.Finally, we summarize innovations and shortcomings after explore the issues above in the thesis, and proposes future research priorities and orientations.