Analysis of Individuals’ Joint-Activity Engagement Using a Model System of Activity-Travel Behavior and Time Use

Abstract

With the recognition that joint-activity engagement should be analyzed not only for more accurate travel-demand forecasting but also for better assessment of transportation policy options, individuals’ joint-activity engagement with other individuals is analyzed using activity diary data. First, a structural equations model system is developed. Its exogenous variables represent activity engagement with family members, with other individuals, or by oneself, and in home or out-of-home, and its endogenous variables also represent travel patterns and subjective assessment of the quality of life. The results of model estimation indicate that travel patterns and subjective assessments of the quality of life depend on joint-activity engagement quite substantially. Following this analysis, a model of time allocation is developed using diary data and stated preference (SP) data that are based on the assumption of random utility maximization. The model system is formulated as a structural Tobit model system that accounts for the correlation between error terms. In the modeling formulation, SP responses on time allocation are combined with revealed preference (RP) observations on time allocation, and relations among latent preference factors are incorporated. The modeling approach is believed to be effective for modeling out-of-home joint-activity engagement with other individuals, which is an important element in travel-demand analysis but may be difficult to account for by RP variables alone. Time-use patterns for joint activities are also shown to depend on personal and household attributes.