This document presents quantitative national estimates of the magnitude of transportation's impacts on the natural environment. It is the most comprehensive compilation of environmental and transportation data to date. This document addresses all primary modes of transportation (highway, rail, aviation, and maritime transport) and all environmental media (air, water, and land resources), and covers the full 'life-cycle' of transportation, from construction of infrastructure and manufacture of vehicles to disposal of vehicles and parts. The information presented in this report highlights that the impacts of transportation are multi-media and extend beyond the air quality impacts of vehicle travel. In addition to presenting quantitative data, this report presents a framework for developing various types of indicators and for categorizing transportation activities that affect the environment. This framework is useful for understanding the limitations and uses of different types of indicators and for identifying existing data gaps. In some cases, where quantified indicators were not available from existing sources, new indicators were developed for this report. In other cases, it is clear that significant gaps in knowledge remain. The report concludes with a description of next steps in the effort to develop and utilize indicators of the environmental impacts of transportation.

Cover title. Publisher information came from cover. "EPA 230-R-96-009"--Cover. "October 1996"--Cover. "EPA"--Cover. Publication location information from the About the Office of Policy (OP)--webpage. Includes bibliographical references.