Evaluation of Viaducts' Contribution to Road Network Accessibility in Yunnan–Guizhou Area Based on Node Deletion Method

It is necessary to evaluate the construction effect of viaducts and identify the viaducts that play a key role in road networks. Based on the node deletion method, this paper proposes a method to identify the importance of viaducts in road networks. After applying this method to simulate the importance of viaducts in the highway networks in Yunnan and Guizhou Provinces from 2001 to 2020, the results show the following: (1) The viaducts with high importance were mainly built in 2002, 2009, 2015 and 2016. They are mainly distributed on expressways, such as the HUKUN Expressway, HANGRUI Expressway and YINBAI Expressway. Among the viaducts, the Mengzhai Bridge and Beipanjiang Bridge Hukun are the most important. (2) The importance of viaducts will increase, decrease or increase first and then decrease after viaduct construction. Among the years studied, 2012 and 2016 are important time nodes for change. The trend of changes is affected by the construction of highways and viaducts in other locations. In this road network, there are strong coupling relationships between nodes. (3) The importance of some viaducts is not prominent in the whole region, but that does not mean that their construction value is low. They may have a high connectivity effect on specific regions from a local perspective.