Modeling the Influence of Family,Social Context,and Spatial Proximity on Use of Nonmotorized Transport Mode

This paper presents a joint model of the duration of walking and bicycling activity with the use of a hazard-based specification that recognizes the interval nature of time reported in activity–travel surveys. The model structure takes the form of a multilevel hazard-based model system that accounts for the range of interactions and spatial effects that might affect walking and bicycling mode use. In addition to the individual-specific factors, family (household-specific) interactions, social group (peer) influences, and spatial clustering effects are considered potential factors that contribute to heterogeneity in nonmotorized transport mode use behavior. The model system presented is capable of accommodating grouped duration responses often encountered in activity–travel surveys. A composite marginal likelihood estimation approach is adopted to estimate parameters in a computationally tractable manner. The model system is applied to a survey sample drawn from the recent 2009 National Household Travel Survey in the United States. Model results show that significant unobserved family-level, social group, and spatial proximity effects contribute to heterogeneity in walking and bicycling activity duration. The unobserved effects were also found to have a differential impact on bicycling activity duration, thus suggesting the need to treat and model walking and bicycling separately in transportation modeling systems.