Area and Road Ruggedness Scales

The USDA, Economic Research Service’s (ERS) Area and Road Ruggedness Scales data product provides measures of topographic variation, or "ruggedness," for census tracts across the 50 U.S. States and Washington, DC. Building on USDA, ERS's longstanding work on geographic classifications, the data product serves as a resource for researchers, Federal agencies, policymakers, and practitioners. The data product enables better comprehension of the role of terrain in rural development and demographic change, as well as individual and community well-being. To our knowledge, these are the first ruggedness measures with full nationwide coverage for the United States and the first to provide a roads-only version to help study the impact of rugged terrain on travel by car.

Highlights

• This data product provides continuous and categorical measures of topographic variation for vintage 2010 and vintage 2020 census tracts, offering users the flexibility to utilize measures of rugged terrain that meet their unique needs.
• The Area Ruggedness Scale (ARS) has six categories that are based on the changes in elevation for all terrain and classifies census tracts as: (1) level; (2) nearly level; (3) slightly rugged; (4) moderately rugged; (5) highly rugged; and (6) extremely rugged.
• The Road Ruggedness Scale (RRS) has five categories that are based on the changes in elevation beneath roads and classifies census tracts as: (1) level; (2) nearly level; (3) slightly rugged; (4) moderately rugged; and (5) highly rugged.
• The grid-cell-level Terrain Ruggedness Index (TRI) underlies the ARS and RRS. The TRI is the sum change in elevation between each grid cell and its neighboring cells, with lower values indicating smaller changes in elevation and higher values indicating larger changes.
• Two TRIs were developed, one using all grid cells nationwide—the Area TRI—and one using just the subset of grid cells that contain roads—the Road TRI. Aggregate TRI measures for census tracts were derived by calculating the summary statistics (mean, standard deviation, median, minimum, maximum, and range) of the grid-cell TRI values within each census tract.
• The data files include geographic identifiers, including the census tract, county, and State identifiers, as well as region and rurality codes. These identifiers can be used in mapping applications and to explore various spatial categories.

Additional information about the measures can be found in the downloadable Excel file—which includes the data, definitions and sources, and a codebook for the Area and Road Ruggedness Scales and supporting variables. For more details on the background and creation of the Area and Road Ruggedness Scales, see the Documentation and Descriptions and Maps pages. A discussion of the differences between the 2010 and 2020 versions of the Area and Road Ruggedness Scales is also available in the Comparing 2010 and 2020 page.