Timing utility of daily activities and its impact on travel

As an activity-based approach, this study focuses on the methodology of estimating the timing utility of people's daily activities and examines how such utility interacts with travel time. This study argues that the utility of time for undertaking a specific activity may vary over the course of day. That is, each activity has its ideal time to be undertaken. The utility of ''saved'' travel time thus depends on not only the value of travel time, but also ''where'' the ''saved'' time slot is ''located'' and the increasing utility due to rescheduling other activities to make use of this time slot. The estimation of such utility therefore needs a methodology to estimate people's timing choices and timing utility over all major daily activities. To achieve this goal, a two-stage simulation model is established. The hazard-rate duration is used to estimate the revealed preferences of Canadians on their major daily activities. The estimates are then applied to a scheduling program to examine how trip makers determine the optimal objective to maximize their total timing utility. With the results of this simulation, the tradeoff between travel time and the scheduling choices is examined and a commuter equilibrium is established on a basis of activity timing utility, work start-time, and travel time. (C) 1996 Elsevier Science Ltd