TRAVEL-TIME CONSTRAINTS ON DESTINATION-CHOICE SETS

The importance of travel-time constraints in spatial choice is widely recognized in the literature of geography and related disciplines, but little work has been done toward developing operational models of spa tial choice wherein these constraints and their effects are made expli cit. The purpose of the paper is to test the accuracy of predictions p roduced by a destination choice model that does not take explicit acco unt of travel constraints under the assumption that observed choices a re made from choice sets delineated by a constraint of maximum travel time. Observed choices are generated by simulation from a new random u tility model consistent with the constrained nature of individual choi ce sets. Results show that the characteristics of constraints are a de cisive factor in the accuracy of thc unconstrained choice model. Choic e probabilities of the constrained reality are predicted with a reason ably good accuracy in some instances, but predictions are less impress ive, and even poor, in many others.