Non-equilibrium Network Traffic Flow Analysis And Improving Managements Based On MFD Theory

With the intensify of urbanization in China,the scales of Chinese cities and urban population grew explosively in recent years.Cities' development and people's transference not only made the progress of economic,but also motivated increasing of residents' income synchronized the increasing of motorization.However,the capacity of urban traffic network reached the scope of motorized trip demands barely,which has become a huge contradiction followed by series of traffic problems.These traffic problems have gradually become ‘city solid diseases' for the large and medium-sized cities now.Because adjusting the urban trip modes or improving the capacity of traffic system require tremendous capital investments or time investments which are not easy to achieve,optimizing the efficiency of urban traffic system has become an important way to alleviate many traffic problems under the current conditions.According to the background mentioned above,this paper is focused on the topic of non-equilibrium network traffic flow analysis and improving method based on MFD theory.The existing research results were summarized.It pointed out the theoretical difficulties and application obstacles caused by the discrepancy in the scale for nonequilibrium traffic flow researches.Therefore,the idea of using MFD theory to analyze the non-equilibrium network traffic flow was put forward.After that,the definition of non-equilibrium feature and how to select its description tool was discussed in this paper.The conclusion confirmed the hypothesis of using MFD theory to analyze the non-equilibrium of network traffic flow.Moreover,the UE condition was substituted into the equivalent MFD formula to reveal the network equivalent MFD acquisition method under UE condition.Based on the difference between the equivalent MFD and the measured MFD,the non-equilibrium characteristics analysis method and non-equilibrium measure index NE were proposed.Then,a discussion was presented about the necessity of sub-area partition nonequilibrium for improvement in a practical view.Meanwhile,a partition adjusting method using MFD sub-region partition results as the initial solution and integrating the objectives of the comprehensive non-equilibrium similarity and the internal/external traffic density was presented based on optimization theory.The process of proposed subregion partition were given as well.Further,the multi-level non-equilibrium network traffic flow adjustment method was studied in this paper.The necessity of using hierarchical adjustment was demonstrated and the impact factors of network traffic flow was analyzed based on MFD perspective.Then,a non-equilibrium-improve-oriented regional network signal control strategy was developed including boundary and subdomain aspects.Finally,the multi-level nonequilibrium regulation strategy set was constructed by combining macro-meso-micro traffic managements and control strategies.Finally,the road network in Reno,Nevada was selected for the case study.Based on the simulation,the signal control strategy proposed in this paper could ease the level of non-equilibrium by 46.4% and increase the road network efficiency by 9.7%.The analysis and improving strategies in this paper were verified.