Spatial resolution impact on public transport accessibility measurement error

Place-based accessibility measures are critical to transport planning. However, their accuracy can vary greatly depending on the spatial resolution of representative points used in calculations. This study refers to this precision issue as measurement resolution error, and its impacts have not yet been comprehensively explored in public transport accessibility analysis. Using Melbourne, Australia, as the study area, this study examined measurement resolution error across various spatial resolutions, public transport service levels, opportunity densities, types of accessibility measures and time thresholds. Results reveal that while the errors are generally small, their magnitude is highly context dependent. Smaller time thresholds, lower service levels, opportunity density that leads to lower accessibility values, and more complex accessibility measures all increase sensitivity to this error. Suburban areas with sparsely populated mixed land use that are served with modest public transport services are the most vulnerable to measurement resolution error, creating significant transport equity implications. The study recommends the use of data at resolutions that can reflect land use information for general public transport accessibility analysis, while building-level resolution data should be selectively applied if analysis objectives warrant such granularity. These findings highlight the importance of being aware of measurement resolution errors and provide evidence-based guidance for balancing analytical precision with computational efficiency in transport planning.