South Dakota DOT's 2005 Traffic Flow Map.

It is just this technology that has allowed the South Dakota Department of Transportation (SDDOT) to accurately report local road miles, maintain an up-to-date inventory of local roads, provide updates for CAD-based mapping, and develop a dynamically segmented state highway system.

South Dakota has 83,000 miles of roads (serving 755,000 state residents). Of these roads, 7,800 miles are state, U.S., or interstate highways that are in the state highway (trunk) system. The remaining miles constitute 75,000 local, county, city, and township roads that are part of the nonstate trunk (NSTRI) system. GIS has been an invaluable asset to the SDDOT NSTRI program for the inventory and management of those local roads, along with map production and analysis of the state trunk system.

Step-by-Step History of Inventory and Management

Historically, several SDDOT lead crews were required to drive all state roads on a specific schedule to obtain and keep handwritten records of the physical features and surrounding attributes. These crews comprised SDDOT staff who drove the routes accompanied by various representatives of political entities to obtain records of change from previous collection cycles. Over the years, the number of SDDOT people associated with this process had declined for various reasons to the point where one staff person and seasonal employees could not perform the updates to physical features and surrounding attributes as needed.

The SDDOT NSTRI program started out using DOS-based GPS data collection and PC ARC/INFO. In 1995, the SDDOT Planning and Development District III and 1st District Association of Local Governments entered into contracts in which the districts would provide the manpower to use GPS to collect road alignments, attributes, and structures that the SDDOT needed to update its roadway inventory database and convert the GPS data into ArcInfo coverages. In 1997, SDDOT entered into the same type of contract with the Southeastern Council of Governments and the Northeastern Council of Governments. Roadway attributes to be collected included road name, surface width, surface type, shoulder width, shoulder type, city code, county code, parking configuration, speed limits, and DMI (the length of the roadway segment).

As Esri technology has evolved through the numerical software releases, so has the SDDOT NSTRI program. Today's program uses ArcInfo 9.x Workstation and DOS-based GPS data collection. Some modifications have been made to the GPS data collection process to keep pace with the GIS. For the maintenance program, the planning districts supply SDDOT with yearly updates of ArcInfo coverages of roadway changes, additions, or deletions.

A New Standard

In February 2006, SDDOT's NSTRI program set a new standard of personal geodatabases as the environment for roadway data capture, storage, updating, and editing. To help meet the new SDDOT GIS roadway inventory program standard, the planning districts, as independent contractors, chose GIS Workshop, Inc., of Lincoln, Nebraska, an Esri Business Partner, to create a customized GPS data collection interface for Trimble's GPS Analyst software. The GPS software uses hot keys, pull downs, and pick lists in GPS Analyst to create new roads and modify SDDOT roadway alignments in Esri personal geodatabases. These tools populate attribute fields with SDDOT predefined choices.

The SDDOT roads data is being used by several private firms in the area, as well as several government agencies, including the South Dakota Department of Game, Fish and Parks' hunting atlas on walk-in areas; South Dakota Department of Natural Resources; the South Dakota Department of Revenue's sales tax revenue application; U.S. Census Bureau; U.S. Department of the Interior; and several South Dakota county GIS programs.

After 10 years, SDDOT views this program as highly successful. Now, as a maintenance GIS/GPS program, SDDOT receives yearly updates of road changes, additions, or deletions from the planning districts.

More Information

For further information, contact Harry Redman, GIS coordinator, Planning and Development District III, Yankton, South Dakota (tel.: 605-665-4408, e-mail: HarryR@districtiii.org); Ryan Hartley, GIS coordinator, 1st District Association of Local Governments, Watertown, South Dakota (tel.: 605-882-5115, e-mail: ryan@1stDistrict.org); or Roger A. Brees, South Dakota Department of Transportation, Pierre, South Dakota (tel.: 605-773-5444, e-mail: roger.brees@state.sd.us).