This working paper serves as a starting point for a broader long-term research program on the socialization of travel in an information era. The focus is on the role social networks play in motivating resiliency in transportation infrastructures and their interdependence with other infrastructures. The concept of behavioral resiliency in traffic networks is characterized and further investigated as an outcome of social networks, their connectivity, strength of relations and key members. Two infrastructures providing context are transportation and social infrastructures, which have witnessed rapid socialization, both increasingly intertwining with each other. One motivating factor for this interrelatedness is the market penetration of mobile technologies and apps, such as smart phones, allowing travelers to share information across wide spatial and temporal geographies. A second motivating factor is the emergence of demand-responsive mobility services, such as Uber and bike shares, that rely on advances in technology, changing demographics, and evolving residential and commuting patterns. Both factors provide backdrop for this paper, underscoring the importance of social infrastructures that facilitate social networks, which in turn govern travel decisions in infrastructures with these mobility services.

Serving as an exploratory analysis, this paper will conduct a series of agent-based simulation experiments that explore the resiliency of travelers as a function of travelers’ social networks with varying attributes (i.e. size, connectivity, etc.) and communication mechanisms among members. The decision context will be departure time and route choices in a traffic network, similar to those conducted in past studies (Chen and Mahmassani 2004, 2006; Mahmassani et al. 1982). This paper will make two main contributions to the academic literature. First this paper will examine resiliency from an individual travel decision standpoint, broadening its characterization in the existing literature which has been largely dominated by a systems or network perspective on resiliency. More specifically, given that users face a network perturbation, in this paper resiliency refers to the recover in their decisions to pre-perturbation experiences. More resilient travelers will select alternatives or options that minimize the effects from the perturbation. The specific context here is traffic where travelers make decisions on departure time, route and travel mode. The second contribution of this work is to characterize the relationships between social network and resiliency in transportation infrastructures. A central hypothesis is that social networks matter for ensuring resiliency. From an individual user standpoint, the resiliency of decisions in the aftermath of a perturbation likely depends on the social networks present, which facilitate the sharing of experiences, observations and possible courses of action. While, broadly speaking, the impact of social networks on resiliency from a systems and individual user perspective is expected, the exact mechanisms, such as the interactions between social network members are unknown.