Value of Time by Time of Day: A Stated-Preference Study

This paper proposes an alternative, dynamic framework for estimatingtime-varying values of travel time savings and values of schedule delay, in whichtime-preferences are represented as the time-varying excess willingness to pay(EWPT) to being in the one location, over being elsewhere. It is shown how theconventional linear model, with time-independent values of travel time savings andschedule delay costs, is a special case of our model, and that it is implausibleparticularly in that it implicitly assumes that the willingness to pay for spending a minute at home instead of being in the vehicle does not vary by time of day, even not for very early departures. The framework is applied to SP data representing the respondents departure time choices for the morning commute. The results suggest that individuals time-related shadow prices indeed vary strongly over the morning peak, and values of travel time savings are consequently strongly time-dependent, following plausible and intuitive patterns.