Most of the highway system in the United States is already built. The ways in which transportation agencies maintain the current system have a major impact on environmental quality, but this is given only limited consideration in the current paradigm for addressing environmental quality. Activities to maintain the current system include crack sealing, light pavement actions, pothole filling, signs, markings, mowing and vegetation management, culvert cleaning, and winter maintenance.   These activities are undertaken in a regulatory environment intended to reduce negative environmental consequences.  The response to regulation for maintenance activities is often fragmented and on a case by case basis.  A new framework is needed for integrating environmental performance and sustainability into the existing state highway maintenance system.  The paradigm might draw from the environmental stewardship approach that many states undertaken for their construction programs.   An excellent step in this direction would be to perform a synthesis study of instances in which states have instituted programmatic strategies for addressing environmental needs in highway maintenance.  Examples include the Oregon DOT fish passageway program and the New York DOT Adirondack Park invasive species program.  The synthesis would summarize the current types of state and federal regulations that pertain to environmental effects of highway maintenance.  The project would then identify and describe instances of programmatic approaches and systematic strategies for incorporating environmental concerns into ongoing state transportation agency maintenance activities.  The work would be accomplished through literature review, survey of transportation and resource agencies, and targeted interviews.  The report would include case studies of exemplary practices.