No abstract

3D, Activity analysis, Geovisualization, GIS, Intra-household interaction, Joint activity, Space-time path, Spatio-temporal GIS, Travel behavior,

Operational models of the household activity-scheduling process have emerged recently. These models replicate the sequence of decisions that leads to observed patterns of human activities and travel, including which activities to conduct, with whom, for how long, at what time and location, and by what mode. Activity priority has been suggested as an important dimension in such scheduling models, particularly as a determinant for the choice and sequencing of activities. The importance of intrahousehold interactions, joint activities in particular, has led to a rapid expansion of research on this topic. However, within most scheduling models, joint activities have been addressed, at best, by assuming that they are preplanned relative to independent activities. Within this context, two important issues concerning the planning of joint activities are explored: the extent to which joint activities are preplanned and whether male and female householders share the same priority when scheduling joint activities. The data set used for the study was the 2003 Computerized Household Activity Scheduling Elicitor survey for Toronto, Ontario, Canada, which recorded information about when a particular activity was planned by respondents. In the analysis, bivariate probit models are estimated for two scheduling alternatives (impulsive or preplanned) for husband and wife. Overall, the empirical results highlight the need to move beyond static priority assumptions for determining the sequencing of activities to develop a behaviorally sound model for activity scheduling. Furthermore, differences in planning priority across individual participants should be taken into account.

IntroductionFew issues in urban transportation have threatened proposed highway projects and sparked as much controversy as claims of induced travel (Cervero, 2003). Highway critics have long argued that building new roads or expanding existing ones to alleviate traffic congestion are exercises in futility. Improved roads, critics contend, spur new traffic (induced traffic) and/or divert traffic from other routes (diverted traffic). Such traffic, known collectively as generated traffic (Litman, 2004), quickly returns a facility to its original congested state. Behavioral responses to capacity expansions are categorized as either short-run or long-run responses (Hill, 1996; Litman, 2004; Scott, 2002). (1) Over the short run, increased capacity reduces travel time. According to Downs (1992), this is followed immediately by three behavioral responses, which he refers to collectively as`triple convergence'. The first of these, spatial convergence, occurs when drivers switch their routes to incorporate the newly constructed or improved facility. Modal convergence, on the other hand, happens when public transit users switch to driving their automobiles. Finally, drivers traveling at off-peak hours may switch to the peak periodöa response known as temporal convergence. In addition to triple convergence, Scott (2002) notes that over the short run new trips may be generated and drivers may choose to travel farther abroad to existing destinations without increasing their travel-time budget (2) due to the increased speeds afforded by capacity improvements.

Activity analysis, Flexible criteria, GIS, Intra-household interactions, Joint activities, Restrictive criteria, Structural equation modeling, Time use, Toronto Travel-Activity Panel Survey,