Catching the Next Big Wave: Are the Observed Behavioral Dynamics of the Baby Boomers Forcing Us to Rethink Regional Travel Demand Models?

Aging American baby-boomers create a variety of new policy contexts and problems. Their changing demand for transportation services may be positive or negative depending on the preparedness of our institutions and the baby boomers’ behavior. In this paper we describe this potential change in demand through an analysis of individual longitudinal histories over long period (1989 to 2003) exploring the impacts of person-specific changes (e.g., entry to and exit from the labor force) household changes (e.g., relocation and dissolution) and land use. To do this we use the Puget Sound Transportation Panel (PSTP), which is a record of approximately 20,000 person diaries of Seattle residents that provided reports of their travel in two-days repeatedly for ten repeated contacts (waves). In the analysis we study within-household dynamics and the impact events of within-household change have on individual well as household behavior. We employ focus groups to extract behavioral themes, Latent Class Cluster analysis to identify groups of behavior, and an array of regression models of change to identify key determinants underlying behavioral dynamics. Key findings include need to focus on employment, heterogeneity in the impact of land uses, and a significant affect of household composition. All this implies a need for models that can handle more diverse behavior and the need to accommodate employment status and within household demographics in the forecasting models.