ABSTRACT
This chapter outlines a coherent set of definitions for the measurement of movements. Each of the elements of that definition can be the starting point of a travel survey. Customer movement can be defined according to a variety of criteria, depending on the purpose. The definition of a stage which discounts activities performed during movement provides a clear, basic unit for discussing movement. While the definition of a trip hinges on the definition of an activity, the definition of a journey requires a reference location. In daily travel this will normally be the home of the respondent. The problem of aggregation from stages to trips and from trips to tours or journeys is acute for those variables which can not be added together: mode and activity type. The proposed definitions can structure the movements and activities of the respondents into units chosen by the researcher.
