Summary
- For crash mapping DOH location information is used to compose ROUTE_NAME for alternate and base reference system.
- Calculating Travel Direction for Crash Base reference system is used for assigning crashes on interstate (sign system=1) and for crashes on other roads (sign system ≠1) alternate reference system is considered.
- Travel direction is calculated from vehicle information from vehicle tables.
- A ‘rule-based’ matching is considered due to uncertainty of getting correct roadway traffic direction from vehicle table or law enforcement roadway description. In this case travel direction and roadway type will be used to assign proper route.
- The rule based method is more like an optimistic matching. Therefore, if certain criterion fails to find a candidate route, more relaxed criteria are chosen.
Step By Step Process
The following is the step-by-step process for locating crash on LRS:
- Step 1 - Transformation of Crash Location Attributes
- Step 2 - Calculating Travel Direction for Crash
- Step 3 - Create a Crash Location View
- Step 4 - Comparison of Crash Components to corresponding LRS
Notes: In summary, the following important aspects have been considered for crash mapping: The ‘travel direction’ is determined by the decision trees.
- The mapping is ‘optimistic’ meaning for crashes that do not have a valid route using the travel direction the five route components (County ID, Route, Sub Route, Supplementary Code) are used to form the 11-digit code to match with the first 11-digit of Route Name.
- If 11 digit codes are used for mapping there will be multiple candidates of potential routes for specific crashes.
- Several system job executables in crash interface take care of the crash location mapping part.
- Safety business user should take some strategic changes in their business to ensure the conformity of the crash database in line of wvOASIS LRS setup or post-process police collected data at source accordingly.
