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.

Efforts to preserve rail corridors or restore rail service to dormant rail alignments across the United States are very uneven. A handful of states have aggressive, well-funded programs to support the preservation or reuse of rail alignments; more states have modest programs to support short line operations on a case-by-case basis, but attach no value to corridor retention per se. In 2005, California completed what is perhaps the nations most comprehensive physical plant inventory of active and abandoned rail corridors; a review driven by interest in passenger rail and nonmotorized corridor interests. A foundation has been set to more fully lever these valuable alignments in this country's most populous state. This synthesis was undertaken to document current practices with respect to rail corridor preservation. State departments of transportation (DOTs), selected metropolitan planning organizations, commuter rail agencies, short line holding companies, and Class I rail carriers were all surveyed for information. Response rates to the survey were moderate, averaging 24%, and overall supporting the notion that preservation of rail alignments is not a high-priority issue in many jurisdictions. A handful of state respondents, however, had a great deal of experience and valuable observations on rail preservation policies and could be said to have become experts on this subject through their dealings with several dozen rail corridors over the past two decades. North Carolina, Ohio, and Pennsylvania DOTs each have serious, well-established rail sections and a history of successful preservation efforts.

This report examines the general concept of planning for and protecting land designated to serve as new highway corridors in developing areas. It generally presents a review of the state of the practice by describing several methods for protecting potential highway corridors, some of which may be implemented immediately and some of which would require legislative or regulatory changes at either the federal, state, or local level. The report also presents a prospectus for future activities at the federal level regarding corridor preservation.