Proposal of a new index for link importance estimation in real-scale road networks

In this research a new index has been defined for the evaluation of link importance in real-scale road networks. Such an index is given by the sum of two different functions. The first function takes into account the concept of local link importance and it depends on the average daily traffic (ADT) measured along the link under consideration. On the other hand, the second function estimates the importance of a link for the operations of the network as a whole (global link importance). The latter function is defined to be directly proportional to the variation in the network total cost that users will experience when a certain link is closed. The formulation proposed for the link importance index has been tested in the case study of the road network administrated by Provincia Autonoma di Bolzano (Italy), counting about 1600 nodes and 3500 links. Although the mathematical specification of the index is quite complex, with special reference to the global importance function, the case study demonstrates that such an index is suitable to be adopted by practitioners for performing link importance analyses in real-scale road networks, even in presence of a high number of nodes and links.