Geo-Coding Survey Truck Route Data: GIS Analytical Applications

The application of Geographic Information Systems (GIS) has been widely accepted in a number of areas, i.e. transportation, utility network, land-use, city planning, and policy planning. Transportation policy planners and transportation network analysts, for instance, use the GIS software to analyze highway traffic and congestion problems in urban areas as well as planning for new highway infrastructure and maintenance. This paper is the first attempt in the freight transportation area to develop an automatic algorithm which allows identifying specific segments of highways used by each observed truck using the application of the GIS software. This paper utilizes data collected from the Strategic Freight Transportation Analysis (SFTA) truck survey which examined truck movements in the state of Washington. The survey includes approximately 24,000 observations of trucks traveling within (or through) the state of Washington with information on origin city and state, destination city and state, truck type, truck weight, type of commodity on board and the list of highways utilized. With known origins, destinations and the list of highways used, Arc-Info may be utilized to specifically identify unique route segments used by each truck and assign geographic attributes to the route data. Utilizing several different software features within ArcMap, including the Utility Network Analysis tool, data from a traditional relational database is input into the GIS software where several logical conditions are examined to identify unique route attributes associated with each survey response. The logical conditions examined include many attributes collected on the roadside questionnaire and help minimize error associated with the geo-coding process. This process is then automated and applied to the entire database. Many different analytical capabilities related to freight highway flows are then possible and applicable once specific routes have geographic properties, several of which are provided in this paper. These include specific highway segment properties and traffic profile, including upstream/downstream contribution of freight flows by different highways and commodities throughout the highway network.