Sequence analysis of place-travel fragmentation in California

Sequence analysis is used in this chapter to measure fragmentation in activity participation and travel. We apply this method to a sample of residents in the Central Coast of California that participated in the California Household Travel Survey in 2012-13. This method employs techniques from the sequencing of events in the life course of individuals to explore sequences of daily activity at places such as home, work, and school and travel. Studying sequences of daily episodes (each activity at a place and each trip) is preferable over other techniques of studying activity-travel behavior because sequences include the entire trajectory of a person’s activity during a day while jointly considering the number of activities performed, order of activities in a day, and activity durations. We first identify places visited and duration at each place on a minute-by-minute basis, then we derive representative daily behavior patterns using hierarchical clustering. We study membership to these clusters and find that the usual activity-based models miss important place-travel daily patterns. We also find systematically higher fragmentation in households that have children; furthermore, as expected, day of the week plays a major role in daily activity-travel patterns. Access to opportunities also influences daily patterns.