An Accessibility Measurement Based on Commuter Behaviour and Living Conditions: An Empirical Analysis of the High-Speed Railway Network in the East of China

High-speed railways as a competitive intercity transport solution in areas of high population density have been constructed rapidly in the last decade. Accessibility measurements have been frequently tested and applied with various definitions, indicators, and processing methods for assessing traffic system utility. In this paper, an improved method of accessibility measurement based on travellers’ profitability is introduced. Three levels of accessibility indicators, Daily Commute Accessibility (DACC), Daily Work Commute Accessibility (DWACC), and Weekly Commute Accessibility (WACC) were designed based on different commuting frequencies and purposes. The average traveller’s income and local living cost were integrated to simulate the real commute scenario and assess the status of the transport system. In the case study, a series of statistics, containing 50 lines of travelling data and 10 years of economic data, was collected from the historical railway service record and local economy yearbook, in an area with 11 cities connected by conventional normal-speed and upgraded HSR networks in the east of China. An index sheet measuring the three levels of accessibility indicated the changes in the travel benefit ratio throughout the test period following popularisation of the high-speed service. To validate the practicability of the new methodology, regression analysis of four groups of panel data, including the accessibility index and local demographic data, was implemented to illustrate the population fluctuation impacted by the HSR services. The results proved that the HSR service is more beneficial in reducing population aggregation than the conventional railway service, which has the opposite effect, leading to the generation of cities with a high population density, and could help to rebalance the local uneven population distribution and promote the progress of urbanisation.