National Park Service Safety Management Locating Crashes Spatially from the National Park Service Service-wide Traffic Accident Reporting System (STARS) Database By Daniel Van Gilder Federal Highway Administration Eastern Federal Lands Highway Division (dan.vangilder@fhwa.dot.gov)
What is STARS The National Park Service uses an crash reporting system called STARS. The STARS system locates crashes based on a node system employed in the parks. A node is a recognized physical location point (usually an intersection) used as a reference location where US Park Police or Park Rangers reference a crash location. The STARS database stores for each crash the Park, Park Route, the node number, the distance the crash occurred from the node, and the cardinal direction from the crash to the node.
Spatially Locating Crashes To locate the crash locations in a GIS System there needed to be a way to geo-locate the crashes. The issues related to that were: Nodes in the parks were never geo-located or referenced to the Park s routes. Nodes are shown on simple maps that are not geo-referenced or to scale.
Example Node Map ACADIA National Park
This is Node 012A. Note that this node is located on Route 12 and Route 13(beginning)
Spatially Locating Crashes To locate the crash locations in a GIS System there needed to be a way to geolocate the crashes. What we did: Nodes in the parks were geo-located by referencing the node location to the Park s Linear Referenced Routes (LRS) Defining the milepost of the Node. Developed automated tools to use the STARS referencing data and the mileposts of the nodes to locate the milepost of the crash
Sample of GIS Map Acadia National Park
Use the Identify Route Locations Tool Use the Identify Route Locations Tool to define the milepost of Nodes
This is Node 012A. Locate this point on the GIS Map and use the Identify Route Location Tool
Clicking here provides the results to the left. Note that for Route 12 the milepost is 4.612
Clicking on the results table for ACAD-0013 provides that data. The Milepost is 0.00.
This is Node 013D. Locate this point on the GIS Map and use the Identify Route Location Tool
Clicking here provides the results to the left. Note that for Route 13 the milepost is 1.633
Input Data into Spreadsheet/Database
STARS DATA ROUTE_IDEN is a field added to the STARS data to help identify which GIS route to use to find the correct node MP_NODE is added to fill in the milepost of the node for the GIS Route and the MP_CRASH is the calculated crash location using the NODEDISMI, NODEDIR fields
The highlighted crash reference below shows that the crash occurred on Route ACAD-0012 referencing Node 0012A
From the data we see that the crash occurred 0.2 miles from the node. This would yield two possible solutions from the data (0.2 miles north of the node and south of the node)
The data also includes a NODEDIR field that says the crash measure is 0.2 miles S or south to the node. So we know the crash occurred to the north of the node so the milepost of the north crash is stored in the MP_CRASH field
The GIS automated tool stores the coordinates of the NODE and the two possible solutions (adding and subtracting the NODDISMI value to the NODE milepost value). It then compares the coordinates, and based on the NODEDIR field, the coordinate value solution that satisfies the direction value is determined and the milepost value of that coordinate pair is stored as the milepost value of the MP_CRASH field.
Issues with the STARS Data Additional fields are added to the STARS data. The GIS automated tool adds additional fields for the possible solutions and an additional filed named ISSUE. This ISSUE field stores the reason why the GIS tool may not have been able to locate a milepost for the crash. The tool may not have found data stored for the node location in the STARS database and a NODE NOT FOUND issue is stored, or if the GIS Route is not found (a GIS route may not be defined - typically for small routes or parking areas these may not have an LRS route defined) then a ROUTE NOT FOUND issue is stored in the ISSUE field
Add Data to GIS Event Table Once the STARS data has fields for ROUTE_IDEN and MP_CRASH then the data can be attached to a GIS map as an EVENT TABLE. The EVENT TABLE option is allowed because the NPS Routes are linear referenced so that the table places the crash locations on the route at the milepost stored in the data.
Future Efforts In 2007 a Safety Management Team (NPS and FHWA partnering) was assembled to look at issues with the database and to see if interim fixes could be applied to improve the database Create a single electronic form interface that more closely matched the crash from used in the field. Find a way to store crash locations using longitude and latitude
Locating Crashes Storing longitude and latitude of the crash was desired but outfitting the entire NPS law enforcement community with GPS would be very expensive were there other options? YES!!
Locating Crashes Options for determining Longitude and Latitude of the crash locations: GPS Using mapping software Google Earth GeoPDF ESRI ArcGIS Explorer NPS Internet Mapping Service NPMap
Let s look at some of the data and Any Questions?