When e-activities meet spatial accessibility: A theoretical framework and empirical space-time thresholds for simulated spatial settings

The high penetration of e-activities (e-working, e-shopping, e-leisure) has empowered people to overcome space-time constraints in daily routines, and this trend is growing. Accordingly, new knowledge is sorely needed to incorporate e-activities into accessibility planning and to define new conceptualizations, methods, and quantifiers that recognize digital and in-person accessibility in real life. This paper introduces the framework of “augmented accessibility” and identifies space-time thresholds in which e-activities are more competitive than in-person activities. By being aware of these thresholds, specific policies could be adopted for encouraging people to save travel time and allocate it to reach other in-person destinations, thereby increasing their overall spatial accessibility. At methodological level, time geography concepts and elasticity analysis are combined, estimating space-time thresholds for six simulated spatial settings: from polycentric and compact cases to sprawled and monocentric cases. The results indicate that e-activities are more competitive in sprawled settings and emphasize the relevance of travel directionality (from opportunity hubs to low-density places) for retaining high spatial accessibility levels and increased travel distances. The social and policy implications of space-time thresholds are discussed for each simulated spatial setting by estimating and comparing critical travel distances for different transport modes. The paper closes by discussing aspects related to practical operationalization of the proposed framework, its communicability, interpretability, and usability.