The perception of the availability of transportation alternative for various trip purposes. Draft manuscript: Subject to revision. Paper prepared for the 55th Annual Meeting of the Transportation Research Board TRB, Washington, D.C., January 1976.

Mode choice models require five decisions concerning model structure. These are the selection of (1) a statistical technique; (2) the method of comparing the characteristics of competing modes; (3) the method of representing socioeconomic variables; (4) objective or subjective measures of times and costs; and (5) objective or subjective criteria for separating those who choose among modes from those who are captive to a mode. The latter is discussed.