APPLICATIONS OF VALUE OF TRAVEL TIME TO TRAVEL DEMAND ESTIMATION

Potential areas of application of the value of time within all the predictive models in the transportation planning process are identified, and basic problems associated with such application and the urban transportation planning package are discussed. Three alternatives are described for determining the function of value of time in predictive models. The major applications of values of travel time are in the conventional travel demand models: trip generation, distribution, mode choice, and route assignment. A formulation that would involve the use of costs and times as major explanatory variables in the various decision processes is discussed. Broad areas in which the generalized cost concept in urban transportation models may be applied are indicated (for possible exploration), and gains that it may provide in terms of realism and accuracy of existing models are considered. The need for considerable research in modeling of trip generation before operational models are produced, incorporation of generalized cost in models of trip distribution and mode choice, use of an algorithm in trip assignment procedures, and model interaction are discussed. The reasons for the lack of a set of modeling tools for interurban travel are noted, and choice situations that should be differentiated are indicated. The value of time should be used specifically in predicting the market for possible new modes of intercity travel.