The Key Feature Of Urban Road Network Structure Optimization For Traffic Efficiency

Urban traffic congestion problem is increasingly serious, in addition to the traffic demand and transportation supply imbalance, the improper layout of micro road is also a major cause of traffic congestion in china. Therefore, in order to increase the efficiency of residents travel and improve road congestion, it has an important practical significance to study how to carry out road resource allocation, and optimize the layout of the road network when facing with the relatively unlimited traffic demand.The paper is based on the national natural science foundation of "The research of the cumulative energy consumption mechanism and coordinated control method of urban road traffic flow (No.51178158)". This paper takes two typical urban road network layout patterns as the research object, and the core content is divided into two parts:(1) The layout optimization of the micro road network in the grid road networkThe research object is based on the typical grid road network, and under the certain condition of road area ratio and traffic demand distribution, deduce the relationships between the distance of road network and the density of road network, the density of intersection and the size of the lane. The minimum total of residents travel time is putted as the objective function, and the spacing optimization model of grid road network is established for traffic efficiency. Finally, taking the single-center of small and medium cities as research cases, the optimal value of the distance is derived from the minimum of the residents’ travel time, then quantitatively analyzing the influence of road network density on road network traffic efficiency and the average network speed at the same time, and the suggestions for improvement are putted forwarded for the planning index of road network in China.(2) The layout optimization of the micro road network in ring radial road networkThe "Ring+radiation" road network is the research object. Firstly, the concept of road network range is defined, and the problem of loop and radial range configuration is researched, then the minimum total of residents travel time is putted as the objective function, and the spacing optimization model of grid road network is established for traffic efficiency during the premise condition of meeting the reasonable range of the loop and the shooting range and under the certain condition of road area ratio and traffic demand distribution. Finally taking the concentrated block of single center big city as the research case, the best reasonable distance between the two rings is derived, and the feasibility of the model is verified under the assumption that the inner ring and outer ring of the city have been formed.