عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Until now, most studies related to derivation of demands have been conducted on the basis of a classical desirability function and in a continued choice set while, in many cases, individual choices cannot be made in a continued set. In economics, a discrete or quantal choice model is used to describe, explain and predict choices between two or more alternatives. These choices may occur in contrast to classical consumer theory that is made on the assumption of continued amounts of demanded commodities. In the case of classical consumer theory, continued space of alternatives allows the use of calculus to derive optimal amount of goods and modeling the empirical demand by using regression analysis. However, in a discreet choice model that describes the discreet condition, use of the first order condition for optimal solutions is impossible. The discreet choice model uses theoretical and empirical modeling of individual choices with a deterministic choice set and the relationship between each individual choices, characteristics of individuals and characteristics of each alternative by estimating the probability of choosing each alternative for one individual with a logestic and probit model.
Thus, the first part of this paper is allocated to the introduction and modeling of a discreet choice and deriving a travel demand function from it. Then, this framework is empirically used for deriving of travel demands for work and educational trips in Isfahan city in the morning peak time by questionnaires randomly given to 457 travelers. As the results show, the demand for cars is just a function of seeking comfort, while the demand for buses is a function of time, cost and comfort. Also, the demand for taxi is a function of time, cost, comfort and income.