Use of Global Positioning System to Identify Crash Locations in South Carolina

To overcome some of the issues with geocoding crash data based on traditional location referencing systems (i.e., route and distance to intersection, route and milepoint, or both), the South Carolina Department of Transportation purchased Global Positioning System (GPS) units for all enforcement agencies in South Carolina responsible for reporting crashes. Reporting officers were instructed to use the GPS units to determine coordinate location data for recording on the crash report. Some of the problems experienced when trying to geocode 3 years (2004 to 2006) of crash data for use in safety analysis are discussed. Overall, approximately 80% of the crash records were located within reasonable levels of accuracy. Trends in the errors over the 3 years indicate a potential for targeted training to significantly reduce error. Recommendations are provided to help improve the success rate of the geocoding process. These recommendations focus on training officers and data entry personnel, designing data entry filters, and possibly changing the crash report form.