This synthesis will be of immediate interest to land use and transportation planning officials, with special interest to state, regional, and local planners and administrators who must respond to the requirements of the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA). The process for incorporating the 15 factors into the comprehensive land use and transportation plans by metropolitan planning organizations (MPOs) and the 23 factors into statewide plans by state planning agencies is described in this synthesis. Because the planning process is in a constant state of flux and many deadlines have been shifted, this report of the Transportation Research Board represents practice during mid 1994, and includes several case study examples of MPO approaches to addressing the 15 factors in their region. This synthesis provides information on how some agencies have succeeded in incorporating the 15 factors in the early stages of ISTEA implementation; however, it is not intended to be a guideline. Specific issues and concerns, both now and in the future, are highlighted, as are the elements that need to be considered throughout the complex process of responding to ISTEA and the 1990 Clean Air Act Amendments requirements.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3340