Book excerpt: This synthesis presents information on current practices used by transportation agencies to complete the transportation development process (TDP). This process involves linking the planning, project development, environmental, design, construction, operations, and maintenance aspects of the overall transportation program. The purpose of the TDP is to implement a seamless process in which all these elements come together and in which there is continuous public involvement. This report will be of interest to regional and state transportation, planning, and environmental agencies who participate in the TDP and who are involved in both the development and policy aspects of the TDP. This report of the Transportation Research Board describes the history of the TDP, as well as the federal requirements that must be met under both transportation and environmental regulations. This process is made more complex by state and local regulations that must be observed in most jurisdictions. Throughout this process, as carried out by the state transportation agencies and the metropolitan planning organizations, there is continuous public involvement. Other programs, such as the transportation implementation plan, state transportation implementation plan, and environmental programs such as the National Environmental Policy Act, the Clean Air Act Amendments of 1990, and requirements of other environmental laws must be integrated into the TDP. The complexities of this process are described, and some unique approaches to meeting its demands are presented.