Determination of key nodes in urban road traffic network

The fundamental purpose of the urban road traffic network is to satisfy the resident travel demand. The two parts of the urban residents travel are the transportation medium and the transportation carrier. The vehicles as the transportation carrier running on the urban roads as the transport medium can from the traffic flow. The shortest-distance path usually was selected by the residents to complete the travel demand. But the different roads always have the different traffic capacity, such as the traffic capacity of the arterial road is higher than the collector street. In order to optimize allocation of the road resources and reduce road congestion, the paper provided a definition of the maximum efficient-traffic path as the optimal path. It can make the highest efficiency of the whole network traffic as far as possible. The modified Dijkstra algorithm was given to calculate the maximum efficient-traffic path. Based on these paths the efficient-traffic betweenness of the nodes can be got. The key nodes of the network can be determined. At last the paper took the Beijing urban road traffic network as an example to describe the whole calculation process in detail, and the different decreasing degree of the road network traffic efficient after attacking the different node can verify the correctness of the method.