Road Network Zoning Model Research Base On Traffic Equilibrium Assignment

In urban traffic management, a road network is divided into several traffic areas by a path or a tree to practice traffic control, known as network zoning. How to finding a path and how to finding a tree to divide a network into several sub-networks efficiently? The road network zoning problem has important theoretical and practical value. In the past, there are two types of research on the network zoning:one type of study only considers the network topology; the other type of study considers traffic flow base on the network topology, make the total flow in each sub-networks is similar. Past studies, there are empty of index to measure the effect of the network zoning; and there are not combine with traffic equilibrium assignment to analysis network zoning, which is determined the flow on the node in network. This can not meet the actual demand. Based on the above, this paper considers the theoretical and practical of traffic equilibrium assignment, define a different parameter for measuring the effect of traffic zoning. Then study the problem of finding a path to zoning a universal traffic network into 2 sub-networks efficiently. Further more, study the problem of finding a path or a tree to zoning a special grid network into several sub-networks more quick and simple.The major work and innovative achievements of this paper are as follows:Finding a path to zoning a universal road network efficiently. First, the thesis considers the theoretical and practical of traffic equilibrium assignment, define a different parameter—zoning efficiency loss—for measuring the efficiency loss for traffic zoning equilibrium assignment, which is the ratio between the sum travel times of 2 sub-networks (traffic routing in each sub-network such that the sum of all travel times is minimized, called as subsystem optimum) and that of a whole network (traffic routing in whole network such that the sum of all travel times is minimized, called as system optimum). Second, build model for finding a path to zoning network. We call a path which results the minimal zoning efficiency loss as a zoning vital path, to zoning a universal network into 2 sub-networks efficiently; and show an algorithm for finding the zoning vital path in universal network. Third, it shows an example from the real map of Chongqing, which has typical free road network, the results show that the model and algorithm is effective.Finding a path or a tree to zoning a grid road network efficiently. First, analysis the special nature of the grid network, calculate the zoning efficiency loss. The results show that in a special grid network, choose random path to zoning network, the zoning efficiency loss is equal. On the basis of this nature, give a different rule—bisection rule:as far as possible make the zoning path in the central line of the network. Then define the zoning vital path in grid network, build model for finding the zoning path, and show an algorithm for the zoning vital path in grid network quick and simple. Second, consider the equilibrium of the total flow in each sub-network, build model for finding a tree to divide a grid network into several sub-networks, and show an iterative algorithm for the zoning tree in grid network. Third, the actual road network of Xi'an within the Ming City Wall as an example, the results show that the model and algorithm is effective.