This synthesis will be of interest to transportation agency administrators, planners, attorneys, environmental officials, and engineers in federal, state, and local governments, as well as to citizens interested in corridor preservation. It is especially timely in view of the ISTEA provisions for corridor preservation, although the requirements and conditions are changing. This synthesis describes the state of the practice with respect to the experience and status of corridor preservation for highways in the United States. The report describes the many elements of the corridor preservation process, including project development, advance acquisition, fee-simple acquisitions, and other options, as well as environmental issues. This report of the Transportation Research Board presents detailed information on acquisition techniques such as exactions, subdivision control ordinances, transfer of development rights, purchase options, and access management. Detailed discussions of maps of reservation and legal issues, such as land use law, are also addressed. In addition, innovations in corridor preservation are highlighted and future research is suggested. This synthesis also contains several case examples that illustrate a range of practice.