Modeling Social Distance and Activity-Travel Decision Similarity to Identify Influential Agents in Social Networks and Geographic Space and Its Application to Travel Mode Choice Analysis

Because humans are social beings, people are members of social networks and interact with other members. As a result of social interaction, people can be influenced by the behavior of others. The present study addresses conformity behavior in activity-travel decisions, implying that in making such decisions people mimic the behavior of other members of their social networks. The presence of conformity behavior in social networks implies that sustainable behavior can be dispersed through networks. Therefore, knowing which people in a network are influential can help make a sustainable transportation policy more effective. In particular, information about the topology of social networks and geographical distribution can help maximize the policy’s spill-over effects in social and geographic spaces. This study suggests a framework to locate influential agents in relation to activity-travel decisions using three procedures: (1) estimating social distance associated with similarity in activity-travel decisions, (2) identifying influential agents by measuring centralities, and (3) exploring the spatial and activity-travel characteristics of the influential agents. The suggested framework is applied using the travel mode choices of people who had recently taken trips by road beside/alongside the Han River in Seoul, South Korea.