This report is the third status update to the National Bicycling and Walking Study, originally published in 1994 as an assessment of bicycling and walking as transportation modes in the United States. Following the 5-year status report (1999) and 10-year status report (2004), the 15-year update measures the progress made toward the original goals of lowering the number of fatalities while increasing the percentage of trips made by bicycling and walking. Injury and fatality statistics are presented to measure this progress, as well as results from surveys related to travel habits. The 15-year report, unlike its two predecessors, examines a range of efforts to increase bicycling and walking in the United States. Programs at the Federal, State, and local levels are included, as well as case studies on best practices. Finally, the report makes recommendations for research, policy, and other measures that can be taken to meet the goals of the original study.