Embedded Files
Problem
Determine if pavement conditions contributed to vehicle accidents along a specified route in Pitt County, NC.
Analysis Procedures
Pitt County provided the data necessary for this project including accident and pavement event tables, street/road shapefiles, and county and city boundaries. Route event layers were created for both accident events and pavement rating events in ArcMap. These route event layers were then intersected in ArcMap to produce a new event layer of accidents and pavement ratings. Analysis was performed to determine if pavement conditions contributed to vehicle accidents along the specified route.
The county and city boundaries, street/road shapefile including specified route, and event tables were added to ArcMap. All attribute tables for each layer and event table were reviewed. Using the Make a Route Event Layer tool, I proceeded with making an event layer from the accident event table. I used the same tool to make an event layer from the pavement event table. Using the Overlay Route Events tool, I intersected the two event layers (pavement and accidents). In the combined event layer, I used the select by attribute tool to isolate the number of accidents along segments of the road with a pavement rating below 75 and those above 75. Based on calculations (number of accidents per mile) from this, I determined that the pavement rating/condition did not contribute to the number of accidents as the number of accidents was similar along both segments (1.7 compared to 1.6 accidents per mile).
Workflow diagram (Click to enlarge)
Results
Map highlighting relevant accident and pavement events in Pitt County. Pavement conditions did not contribute to the number of accidents. (Click to enlarge)
Application & Reflection
Linear referencing has wide application as it allows an ArcMap user to investigate incidents while offering the potential for determining contributing factors for those incidents. Linear referencing may prove quite useful to me in future projects. I can foresee the possibility of using linear referencing to analyze water contamination/pollution along waterways. Specifically, I could use these procedures to determine the effect of hazardous spills along waterways in Pennsylvania, a state with a significant hydraulic fracturing industry. I would obtain a state boundary shapefile (available on PA Spatial Data Access) and a shapefile of Pennsylvania waterways (created by Penn State University and available on PA Spatial Data Access). I would then have to create event tables on my own from available public data about spills, wildlife die-off, and pollutant levels. Using these event tables, I could then determine the geographic concentration of contamination and pollution along PA waterways.
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