What value may geographic information systems add to the art of identifying crash countermeasures?

Geographic Information Systems (GIS) can be employed to relate, organize, and analyze roadway and crash data, thereby facilitating crash countermeasure identification and evaluation. GIS cannot, however, replace the critical role of the local analyst as a problem solver who still needs to interpret results and recommend engineering, enforcement, or educational improvements. A literature review illustrates many of the analysis capabilities of GIS. Case studies at the corridor and citywide level illustrate how GIS may be used as an instrument to identify potential crash countermeasures. Although the currently available crash and roadway data are not perfect, they are sufficient for applying some GIS-based analytical techniques. By learning how to use GIS now, analysts can be ready to take advantage of more extensive crash and roadway data sets that may become available in the future. Using the PC-based Micro Traffic Records System (MTRS), a software package employed by law enforcement agencies in Virginia that records crashes at either a specific intersection or between two cross streets, it was possible to place approximately 82% of the MTRS crash locations within a GIS. Without crashes that were demarcated at "private property" locations, the placement rate climbs to an estimated 94% for intersection locations and 87% for midblock locations