Estimating public transport accessibility in metropolitan areas incorporating population density

It is important to measure public transport accessibility to help improve the sustainability of transport systems in metropolitan areas. Although many studies have defined different approaches for measuring public transport accessibility, there have been limited methods developed for measuring accessibility levels that incorporate spatial aspects. Population density is an important distributional indicator that has also been ignored in previous methods developed for quantifying accessibility. This paper introduces a new approach to measure the accessibility of public transport in metropolitan areas. A Public Transport Accessibility Index (PTAI) is formulated and a case study in the Melbourne metropolitan area, Australia is presented. A public transport network model is applied to identify the service coverage of public transport modes using geographical information systems. The framework outlined provides a consistent method for evaluating public transport accessibility for different levels of analysis, from single elements, including public mode stops to network analysis. The Victorian Integrated Survey of Travel and Activity (VISTA) was used to evaluate the index and investigate the association between the level of accessibility and commuting trips undertaken by public transport modes. It was found that areas with higher a PTAI, had more public transport patronage