Effects of underground logistics system on urban freight traffic: A case study in Shanghai, China

With the rapid development of China's ports, the growth of port throughput has led to a large increase in the amount of hinterland container transportation, causing traffic congestion and significant vehicle emissions. While a port promotes the prosperity of a city, the contradiction between the expansion of urban space and the land use required for ports has become more serious. The underground logistics system (ULS) provides a good technical option for solving these problems. Because of the large-scale projects that the ULS undertakes and the major investment required to conduct these projects, it is important to study the impact of ULS from the perspective of the urban transportation system. In this paper, an empirical method is proposed to assess the impact of the ULS on the state of traffic and the issue of emissions from the perspective of the urban road network; the specific research area is the ULS from Waigaoqiao Port to the Jiading District in Shanghai. Using highway toll data, traffic flow data, and traffic survey data, a traffic analysis model and an emissions model are established. These models are used to analyze the changes in traffic flows and emissions in the urban road network before and after the construction of the ULS. The analysis results show that the ULS can account for 27.0% of the highway transportation of containers from Waigaoqiao Port. After the construction of the ULS, the container traffic volume of the expressway segments near Waigaoqiao Port decreased by more than 20%, the emissions on most parts of Outer Ring Expressway dropped 16%-28%, and the emissions on expressways parallel to the ULS decreased 20%-40%. The empirical method proposed in this study can be considered as references for the benefit assessment of the ULS for container transportation. (C) 2020 Elsevier Ltd. All rights reserved.