Urban rail network (URN) system, line, station complex morphology : a longitudinal study, the case of Shenzhen

Abstract

For the Degree of Master of Philosophy at The University of Hong Kong in October 2019 The unprecedented pace of urbanization in China has led to an impressive increase traffic demand in large cities. Along with the spatial extension of the urban area, rapid and extensive urban rail network (URN) have been implemented since the 1990s. The ongoing urbanization and rapid growth of URN have brought problems such as overcrowded systems and stations contrasted with various transport-oriented development strategies and level of success. Many studies have focused on the built environment around stations in operation, largely neglecting how the expansion and evolution of URN morpho-topology may influence system and station performance. In the last 10 years a range of cross-sectional study, using network science have shown the impact of the morpho-topology of URN on overall system performances. However, few cross-sectional studies have shown the influence of URN morpho-topology on the performance of station. This study examines the morpho-topology evolution of the fast-paced growth of urban rail network (URN) of the mega city of Shenzhen from 2004 to 2023 using spatial analysis based on network science and graph theoretic measures. The morpho-topology of the Shenzhen URN is analysed at three levels: system-level, line-level, and station level. At system-level, three main characteristics are described, State, Form and Structure respectively. At line-level, I investigated the link between metro lines and the built environment, relation of network indicators and annual ridership of each line was discussed. To measures that are computed at the system-level, indicators defined at the station-level allow investigating the spatial variation of topological properties among station. So, at station level, two centrality indicators: betweenness and closeness are considered. To facilitate the investigation of system and line level network characteristics, at station-level the interaction of URN centrality evolution and road network centrality evolution was investigated. The results of the analysis are discussed in relationship to the underlying and evolving spatial planning policies in Shenzhen. The results show that the evolution of Shenzhen URN is characterized by three distinctive development phases of stagnation, growth, and rapid growth. URN developments experienced stagnation (2004-2009) period and followed by a period of extension (2010-2016), and it is currently undergoing considerable densification and extension. The results show an URN development pattern that is non-standard due to the overall linear spatial morphology of Shenzhen. Changes in URN network indicators exhibit the signature of urban planning policies. The increasing centralization of the URN network and road network seems that the development of transport network may not contribute to the expectation of planning policies of encouraging the construction of sub-centre. The longitudinal study of the comprehensive URN and the parallel evolution of the centrality of the road network and a rapidly evolving URN from 2004 to 2023 at different spatial level of a mega city are the original and unique contribution of this study. To date no such parallel longitudinal analysis has been performed. The identification of what seems a contradiction between road network and URN development and policy goals should contribute to a better understanding of the relative contribution of the road and URN network as key mobility systems in the mega city of Shenzhen. The study provides analytical means to better understand and align mobility network design and implementation as well as the signature of top-down planning interventions.