F Fariya Sharmeen

Incorporating Time Dynamics in Activity Travel Behavior Model: A Path Analysis of Changes in Activity and Travel Time Allocation in Response to Life-Cycle Events

The study of dynamics in activity and travel behavior is not a new research interest in the transportation field. A few areas of these dynamics have been partially covered, yet some remain rather unexplored. In contemporary research, short-term dynamics of activity and travel behavior are better understood than long-term changes. For instance, intrahousehold decision making, day-to-day dynamics of activity travel generation and scheduling, and out-of-home or in-home activity organization have been addressed by a number of studies. However, studies on the dynamics of time allocation in activities and travel that are related to life-cycle events are rare. This study contributes to the understanding of such long-term dynamics. By using path analysis, this study shows the effect of several life-cycle events on the changes in time allocation in activities and associated travel. Data were collected in the Netherlands in September 2011 by using an event-based questionnaire survey that asked the respondents to report a weekly activity and travel schedule before and after an event. Results show the interdependencies between the types of activity and travel. The authors conclude that life-cycle events have significant impact on changes in time allocation for activities and travel. The effects vary in direction, intensity, and existence in relation to the type of event and activity. The findings here contribute to the specification of dynamics in the allocation of activity travel time and to the prediction of the rapid and far-reaching changes in addition to day-to-day dynamics.

Predicting the evolution of social networks with life cycle events

This paper presents a model of social network evolution, to predict and simulate changes in social networks induced by lifecycle events. We argue that social networks change with lifecycle events, and we extend a model of friendship selection to incorporate these dynamics of personal social networks. The model uses theories of homophily and reciprocity and is formulated in a random utility maximization framework to predict the formation of social ties between individuals in the population. It is then extended to predict the evolution of social networks in response to life cycle events. The model is estimated using attribute data of a national sample and an event-based retrospective dataset collected in 2009 and 2011 respectively. Findings suggest that homophily has a strong effect on the formation of new ties. However, heterophily also plays a role in maintaining existing ties. Although the motivation of this research stems from incorporating social network dynamics in large-scale travel behaviour micro-simulation models, the research can be used in a variety of fields for similar purposes.

The Governance of Demand-Responsive Transit Systems: A Multi-Level Perspective

In the new-generation smart mobility paradigm, Mobility-as-a-Service (MaaS) systems have shown the most potential to offer integrated mobility platforms. MaaS is essentially an amalgamation of services tailored to match individuals’ diverse travel demands, many of which are demand-responsive transit (DRT) or DRT-like, addressing the much-needed last-mile problem of transit systems. Managing a DRT system could be a simple first step in understanding the governance of MaaS, as the two types of system share the common features of flexibility and individualistic, online platform-based service provision. With that view, we deliberate this exploration here, reflecting on the governance of a DRT case study. We borrow from the schools of transition management and industrial economics to elaborate our understanding. Using the framework of the Multi-level Perspective (MLP), we investigate the drivers and barriers for the diffusion of DRT through the (transit) regime. The main drivers of DRTs are found to be the willingness of local governments and transit operators to implement DRT, whereas the main barriers stem from infrastructure, technology, and market practices. Alignment among the regime elements remains largely partial, which is consistent with our conceptualization of MaaS governance challenges. This research adds to the literature by offering a comprehensive foundation exercise to reflect on the governance of innovative mobility services.