Bicycling and walking are the two major non-fuel-consuming, non-polluting forms of transportation in the United States. This report examines the environmental benefits of bicycling and walking in the following chapters: (1) Executive Summary; (2) Commentary: Reversing the Marginalization of Human-Powered Transport; (3) Discussion of Findings Presented in the Tables; (4) Other Environmental Benefits from Bicycling and Walking Not Quantified Here; (5) Estimating Current Levels of Bicycling and Walking in the United States; and (6) Year-2000 Scenarios. The tables discussed in the third chapter are as follows: (1) Estimated Bicycle Miles Traveled in the United States, 1991; (2) Estimated Walking Miles Traveled in the United States, 1991; (3) U.S. Bicycling and Walking Miles Relative to Passenger Vehicles; (4A) Fuel Savings from Bicycling and Walking in the United States, 1990-1991 Time Frame; (4B) Fuel Savings from Bicycling and Walking in the United States, Year 2000 Time Frame; (5A) Emission Savings from Bicycling and Walking in the United States, 1990-1991 Time Frame; (5B) Emission Savings from Bicycling and Walking in the United States, Year 2000 Time Frame; (6) Emission Factors for Light-Duty Gasoline Vehicles; and (7) Annual U.S. Miles of Travel by Region and Roadway Type, 1989.