USING GIS TO ANALYZE STATEWIDE TRAFFIC CRASH DATA IN MICHIGAN

Geographic Information System (GIS) is a powerful tool often used to enhance data analysis for a wide variety of applications by transportation professionals. It provides a means for manipulating vast amounts of data quickly and efficiently. In addition, GIS has the capability of attaching data to maps in order to provide a visual representation to its users. This paper describes how GIS was used to analyze traffic crash data at a statewide level in Michigan. Michigan experiences approximately 400,000 total crashes, 1,300 fatalities and 120,000 injuries each year. Such crash losses amount to approximately 9.6 billion dollars worth of societal costs annually. The authors have conducted a statewide traffic crash analysis in Michigan using two years of past traffic crash data and various exposure factors including vehicle miles of travel (VMT), population and registered vehicles by each county and city/township. The GIS-based traffic crash data was developed using a commercially available GIS software, TransCAD, often used in transportation system applications. Using the GIS interface, the calculated crash rates were incorporated onto color-coded maps containing the entire roadway network for each county. Queries were performed and pattern analyses were conducted in order to identify the high crash locations for the following crash categories: total, injury, fatality, alcohol-related, deer-related, older-driver related, angle, left-turn head-on, head-on, single vehicle, rear end and pedestrian/bicycle. These analyses were performed for the state as a whole, as well as for each local government jurisdiction. The results of this statewide analysis are critical in identifying the problem areas in the state of Michigan and for specific local government jurisdictions. The results will allow the respective governmental agencies to allocate funding to mitigate the traffic crash problems in their high crash areas within their respective communities. By identifying and targeting the high crash areas on the basis of the statewide traffic crash analysis, it will be possible to achieve the overall effect of reducing traffic crashes and injuries in Michigan. For the covering abstract see ITRD E115303.