| Activity-based approaches are expected to provide a better framework for travel demand modeling because they recognize the interdependence of travel decisions made by household members and the allocation of household resources, assignment of tasks, and joint activity engagement. This dissertation reports an analysis of the decision to undertake an activity in the home or out of the home and the factors that contribute to the decision. Conceptually, the analysis is based on a utility maximization process described in "new home economics". Empirically, the analysis uses two-day travel-activity data, collected from 4,451 household in the Portland, Oregon, metropolitan area.;A random utility model is used to determine the influence of various socio-demographic characteristics on the choice to conduct a "substitutable" activity in or out of the home. These activities are initially classified into work and non-work activities. Additional analysis further disaggregated the non-work activities into home production and leisure activities. These categories are tested for further levels of disaggregation.;Factors found to influence household travel/activity decisions include the activity itself, gender, age, household size, income, employment status, and number of vehicles. For example, the probability of an individual conducting a substitutable leisure activity out of the home is 2.83 times higher in morning peak and 1.27 times higher in the evening peak than during off-peak hours. Single men have nearly a 40% probability of conducting substitutable home production activities out of the home, while single women have a 24% probability, compared to individuals in three-person households.;The findings indicate that there are differences across household types with respect to the set of activities currently being chosen to maximize the utility functions of individual household members during peak periods. Transportation Demand Management (TDM) programs aimed at reducing congestion during peak periods may have disproportionate impacts across these households. A set of representative cases are presented that illustrate possible equity concerns with regards to current transportation policies. |
