Distance to the nearest road in the conterminous United States

Product Type: 

Fact Sheet




Watts, R.D., R.W. Compton, J.H. McCammon, C.L. Rich, and S.M. Wright

Suggested Citation: 

Watts, R.D., R.W. Compton, J.H. McCammon, C.L. Rich, and S.M. Wright. 2005. Distance to the nearest road in the conterminous United States. Fact Sheet 2005-3011. Fort Collins, CO: U.S. Geological Survey. 2 p.

The USGS Geographic Analysis and Monitoring (GAM) program has developed a national, high resolution dataset that gives the distance to the nearest road every 30 meters across the conterminous 48 states. This work provides the first unified national picture of roadless space, vehicular accessibility, and intensity of road construction. The new dataset is the first member of the National Overview Road Metrics (NORM) family of road related indicators. This indicator measures straight-line or Euclidean distance (ED) to the nearest road, and is given the compound name NORM ED. The full resolution dataset for the conterminous states is made up of 8.7 billion values. The road network of the United States is one of the largest human constructions on Earth. It consists of more than 4 million miles of mapped roads, plus many additional utility roads, 4-wheel-drive trails, and private routes. The documented roads and their rights-of-way occupy approximately 1% of the land area of the United States, roughtly the area of South Carolina. Roads are the circulatory system of our culture. They are used to bring raw materials to processing sites, to distribute processed goods, and to carry people to their schools, workplaces, jobs, and friends. The value of roads is reflected in the significant size of the economic sectors - energy, automotive manufacturing, mining, and construction, among others - that support their building and use. The U.S. road network is little studied as an integrated object. Spatial relationships between the network and intervening roadless areas are important to ecological and hydrological resources. The NORM indicators provide basic descriptions of the association of roads with their surroundings. NORM ED, in particular, focuses not the characteristics of the road network itself, but rather on the extent of spaces between roads.