ABSTRACT
The primary focus of model development is the identification and specification of the relatively permanent structural factors that determine the demand for automobile travel. This chapter examines the procedures used to select the specific arguments or variables for the equation. It describes the nature of the data base and discusses the selection of the form of each variable. The chapter focuses on the procedures used to transform or combine the variables in the raw data set for the purpose of creating a set of working variables for use in the final regression equation. It describes the criteria for the initial selection of variables for further analysis and describes the data base condensation process, with emphasis on the use of regression techniques to help in the selection of the final set of variables.
