Transport equity as relative accessibility in a megacity: Beijing

Megacities in China are undergoing transformation in urban functional structure brought on by rapid urbanization and spatial expansion, while private motorization connects disparate functional zones with ever-longer journeys. Policies to control growth of the car fleet while investing in mass public transport, in Beijing and in many other cities, have divided city residents into car users and those dependent on public transport. This paper examines these policies from the transport equity perspective by measuring accessibility disparity between public transport and private car. Cumulative accessibility is measured for each of the two transport modes, while an accessibility equity index (AEI) is developed based on numerical and spatial computation. The recent changes in spatial distributions of population and employment in Beijing are analyzed. Accessibility and AEI are measured using network-based Geographical Information System (GIS) and analyzed quantitatively and spatially. Nine scenarios with different employment location strategies are simulated to analyze their impacts on accessibility and AEI, with clear benefits among the scenarios with regard to accessibility equity for suburban populations. Results suggest that reducing the demand for car use and ownership can be supported through employment spatial redistribution policies, which can be used to raise relative accessibility by public transport. Land use policy can form part of a larger set of spatial and transport policies that includes regulation of the car fleet and public transport development. Such integrated approaches are of particular importance for the present and future megacities of China that are expanding rapidly, with relatively high volume flows on limited movement networks.