A new investigation in the ArcLessons (http://www.esri.com/arclessons) library invites the investigation of transportation networks. Entitled “On the Road Again—Transportation Analysis in the USA,” (http://gis.esri.com/industries/education/arclessons/search_results.cfm?id=392), this 70-question lesson and spatial data are used within ArcGIS software to study the spatial pattern of transportation in the USA. The data source for this lesson is the wonderful National Transportation Atlas Database: http://www.bts.gov/publications/national_transportation_atlas_database/2008/

From ancient times, roadways have altered the mobility of everything from individuals, goods, services, warfare, to disease. American roadways, formalized with the US Highway system (1920s) and the Interstate Highway System (1950s), became “the world’s largest public works project” and “has…reshaped the American landscape and way of life.” --U.S. News & World Report.

Highways are a source of employment for millions on a daily basis, from engineers, truck stop attendants, and construction workers to transportation GIS analysts. Highways have adversely affected urban neighborhoods, affect water quality in local streams, and have a daily impact on the national economy. They have been loved and hated. They are a fundamental part of the national psyche.

Highways were placed where they are because of physical geography, including mountain ranges, passes, swamps, and rivers, and cultural geography (urban areas, commercial corridors, and airports). Their traffic volume is affected by other transportation networks, urban centers, commuting patterns, seasons, and even evacuations during natural disasters. Therefore, spatial analysis within a GIS environment is an excellent way to understand transportation.

In the lesson, students find out how the highways are numbered. They discover that while Interstate 80 is the longest interstate highway, even longer is the longest US Highway, US 20, at 2,940 miles, visible by the yellow line on the map below.

Students examine traffic volumes to assess the impact of urban areas, discover the busiest and widest highways, consider why I-80 through the Great Plains is busier than I-70, and investigate traffic in their own community. Explore this lesson and data and deepen your understanding of highways, waterways, and railroads, and how GIS might be used to investigate networks.

- Joseph Kerski, ESRI Education Manager