Spatial gaps in urban public transport supply and demand from the perspective of sustainability

Revitalizing the role of public transport systems has the potential benefit of creating sustainable urban mobility and enhancing social inclusion. However, an imbalanced distribution of public transport services across a population may result in adverse effects for some social groups. One of these, the senior population, is seeing rapid growth, giving rise to increasing concerns. In this context, this paper develops a systematic methodology, supported by Geographic Information Systems (GIS), to identify the relative spatial gaps in public transport supply and demand from seniors, such as census tracts (CTs), traffic analysis zones (TAZs), or neighborhoods, considering sustainability at the statistical area (SA) level. A case study of Edmonton, Canada is described to demonstrate the novelty and practical capabilities of this methodology. The presented results indicate that the concentration degree of transport services varies among all CTs and reflects diversity in terms of various transport supply indicators, but the Gini coefficients of the seniors are all found to be relatively small. Distribution of the public transport supply index (PTSI) and the public transport demand index (PTDI) are found to be diverse among all CTs in terms of geographical locations and the number of CTs in different categories. It is also found that Edmonton features some easily distinguishable over-serviced and under-serviced areas, as well some CTs with balanced service-usually in suburban locations far from the city's core. The findings provide policy makers with evidence to validate a quantitative method for evaluating the relative spatial gaps in public transport services for individual CTs in order to promote greater equality of transport opportunities and increase of transport service efficiency among socially disadvantaged groups. (C) 2018 Elsevier Ltd. All rights reserved.