Modeling timing and duration of activities and trips in response to road-pricing policies

A model of timing and duration of activities and travel is outlined. The model assumes that marginal utility derived from activities encompasses two distinct components, one derived from duration of activity involvement and the other derived from activity participation at a particular time of day. To test travelers ' responses to road-pricing schemes, an operational model is developed and calibrated on a stated-preference data set collected in a previous study in London. The estimation results suggest that utility derived from work is partly duration dependent and partly time-of-day dependent. A model in which the duration-dependent marginal utility is described by a logarithmic function and the time-of-day-dependent marginal utility is described by a Cauchy function provides the best description of trip and activity timing. The model is used to evaluate the effect of various pricing schemes for the estimation sample. The predictions suggest that pricing policies have a considerable impact on commuters ' trip and activity scheduling, involving shifts to earlier and later departure times. Also discussed are the implications of the model for value-of-time estimates. The results indicate that the value of time changes through the day depending on the utility profiles of the activities.