Intersection

Intersection study definitions are used for studies that locate collisions by a primary street and cross street. This study will append a where clause to the query selected for this study. For the Intersection study to work  a query must be used that identifies the following normalized field:

•Date

•PrimaryStreet

•CrossStreet

Optional fields that can be identified in the query:

•PrimaryStreetUnique1

•PrimaryStreetUnique2

•CrossStreetUnique1

•CrossStreetUnique2

The intersection study will swap the streets as "PrimaryStreet and CrossStreet" and "CrossStreet and PrimaryStreet" in the where clause to obtain all the collisions for a given intersection location.

Example where clause added to the intersection query specified in the study definition:

WHERE 

((   Crash.Crash_Dt BETWEEN '1/1/2008' AND '12/31/2008 11:59:59 PM'))

AND((

(

 (

  (   Crash.Cnty_Id = 26)

 AND 

  (

   (   Crash.Cnty_Id = 26)

 AND 

   (

    (   Crash.City_Sect_Id = 249)

 AND 

    (

     (   Crash.City_Sect_Id = 249)

 AND 

     (

      ((   Crash.St_Full_Nm = 'NW BROADWAY') AND (   Crash.Isect_St_Full_Nm = 'NW MAIN ST')) OR 

      ((   Crash.St_Full_Nm = 'NW MAIN ST') AND (   Crash.Isect_St_Full_Nm = 'NW BROADWAY'))

     )

    )

   )

  )

 )

)

In this example the Crash_Dt field from the Crash table was labeled as the Normalized date field. The Cnty_Id field from the Crash table has been labeled as the PrimaryStreetUnique1 and CrossStreetUnique1 normalized fields. The field City_Sect_ID from the Crash table has been labeled as PrimaryStreetUnique2 and CrossStreetUnique2 normalized fields.  The field St_Full_Nm from the Crash table has been labeled as the PrimaryStreet name, and the Isect_St_Full_Nm from the Crash table has been labeled as the CrossStreet name.

The previous example uses a county and city field to ensure this location is unique to a state area.