Travel behavior changes: evidence from a longitudinal travel survey

Understanding changes in travel behavior and changes in the factors affecting travel behavior can provide useful input to policy definitions. It also has important implications for the design of decision support systems to support policy analysis. The premier source on behavioral changes and models for decision support systems is a panel survey - repeated observations of the same persons over time. In this paper the data from nine waves of the Puget Sound Transportation Panel (PSTP) are analyzed to study travel behavior change and the sources for this change. The frequency of trips and the proportion for each mode are studied using a series of Poisson regression models and linear regression models. These models include personal, household, temporal factors, and weather information. A complex pattern of relationships emerged from this analysis with some findings confirming past research while others showing inconsistent correlations in time.