National Center for Sustainable Transportation

The relative share of passenger miles of travel undertaken during non-routine out-of-town longer-distance trips is large (potentially 30% or higher) and growing. Research on long-distance travel, whether by surface or air modes, has been limited in the United States by lack of data, in part because household travel survey data focuses on daily routine travel. Planners will need to take long-distance travel and its associated impacts into consideration if they hope to address policy questions related to transportation system sustainability. These impacts include environmental degradation from greenhouse gasses and other emissions, and raise challenging questions about who “owns” or is associated with these emissions. Equity impacts include the relationship between travel and quality of life. Intercity travel provides access to employment, education, and experiential opportunities. It also provides access to increasingly large and geographically dispersed social networks and the important face-to-face interactions with family, friends, and colleagues.

This policy brief summarizes findings from the project, which had two main research questions. First, what is the best way to measure individuals’ long-distance travel in order to inform planning and policy? Second, what factors are associated with long-distance travel and do they suggest inequitable access to intercity and more distant destinations? This project relied on several innovative existing datasets, original interviews, and a unique survey of travel and social network geography.

View the NCST Project Webpage