Measuring destination-based segregation through mobility patterns: Application of transport card data

This study explores the level of segregation experienced by seniors, children/youth, and passengers with disabilities, compared to normal-fare passengers at their trip destination when using public transportation. One week's travel records of public transit passengers were extracted from Seoul's transport card data to compute dissimilarity and exposure indices, theoretically equivalent to those developed in segregation research, to capture destination-based segregation through mobility patterns. Additionally, a multigroup entropy index was computed to measure diversity by assessing the social mixture of all passenger flows in a spatial unit. The results revealed that segregation levels experienced by passengers based on their social groups are notably different depending on the time of day and the day of the week. The computed exposure measure illustrates that the potential interaction between the selected social groups and normal-fare passengers is relatively higher during peak hours on weekdays. The results also show that subway stations provide more opportunities for interaction among different social groups. These findings can contribute to a better understanding of social segregation through mobility patterns as well as the effective quantification of the public transport network performance in terms of providing an interaction opportunity for the groups.