Alternative Structures for the Estimation and Forecasting of Urban Travel Demand

The preceding chapter introduced a model of the "comprehensively rational" decision-making household, where location of residence and job, auto ownership, frequency of trips for various purposes, destination, time-of-day of travel, and mode were all the result of choice of an overall lifetime plan. This model is unrealistic in two respects, one practical and one behavioral. The practical difficulty is that description and forecasting of lifetime household decisions would require data and a system structure of a level and complexity greatly exceeding current modeling capacity. The behavioral difficulty is that everyday experience and experimental evidence indicate that individuals find it impossible or impractical to process the information required to form comprehensive overall decisions. They instead use "boundedly rational" rules-of-thumb for decision-making on various pieces of their overall decision problem, without full integration of the pieces into a whole, or feedback to ensure complete compatibility of various decisions. Similarly, the multiple-person household typically fails to operate as an "organic" decision-maker, instead decentralizing many decisions.