Simultaneous Equation Model of Travel Demand

A simultaneous equation travel demand model, derived from a choice-theoretic foundation, is conceptually simple, compact, and comprehensive. The advantages over traditional models are: (1)Trip generation sensitive to trip attributes such as travel time and costs; (2)total demand sensitive to substitution opportunities arising from system changes; (3)uniform estimates of the value of time and other common parameters throughout the model; and (4)the efficiency of full-information estimators. A supply function, describing the effect of traffic volume on trip attributes, and an iterative solution process is required for forecasting. An index of social welfare consistent with individual values implicit in the model can be calculated and used to evaluate alternative proposals for improving the transportation system.