ALLOCATION AND VALUATION OF TRAVEL-TIME SAVINGS. IN: HANDBOOK OF TRANSPORT MODELLING

Understanding travel demand is nearly like understanding life itself. The day has 24 hours, and travel time usually consumes a substantial proportion of the truly uncommitted time. In general, individuals would rather be doing something else, either at home, at work, or somewhere else, than riding a bus or driving a car. Accordingly, travelers would like to diminish the number of trips, to travel to closer destination and to reduce travel time for a given trip. Therefore, individuals are willing to pay some amount for a travel-time reduction, which has a behavioral dimension that seems more a consequence of a general time-allocation problem than an isolated decision. On the other hand, the individual reallocation of time form travel to other activity has a value for "society" as well, either because production increases or simply because the individual is better off and that matters socially. This implies that changes in the transport system that lead to travel-time reductions generate reactions that are important to understand from a behavioral viewpoint, and increase welfare, which has to be quantified for social appraisal projects. In general, the reassignment of time from one activity to another is more pleasurable indeed has a value for the individual. This subject has been explored for more than 30 years by researchers from many different perspectives, including those with an interest in either the study of the labor market, that analysis of home activities, or the understanding of travel behavior. The theories of time allocation deal with the issue of time valuation in many different ways. From these, many concepts of value of time emerge, depending on how a period of time is looked at: as a valuable resource, as something reassigned, or as something to be reduced.