The objective of this report is to assess the potential for interagency and intermodal integration of transit systems in u.s. urban areas, drawing on an analysis of the successful experience of European systems. Vol. 1 documents the need for transit integration in U.S. urban areas, presents the conceptual and evaluative framework, and reviews current transit integration efforts by Federal, state, and local governments. Vol. 2 describes in detail four major European transit systems (London, Hamburg, Paris, and Munich); give brief descriptions of six others (Newcastle upon Tyne, Edinburgh, Stockholm, Gothenburg, Copenhagen, and Oslo); and summarizes and appraises the applicability to U.S. transit systems of techniques which have contributed to the success of these European systems. Vol. 3 deals with the application of these techniques to three major U.S. cities (Philadelphia, San Francisco, and Seattle) and to an archetypal smaller urban area, "Middletown." The report is summarized in the fourth volume. Appendices include contacts in u.s. cities, UMTA study grants, and questionnaire forms. Approximately 150 references are listed at the ends of individual sections and in a bibliography in the summary volume.