The Predictive Analysis application facilitates creating, managing, evaluating, and updating an agency’s Safety Performance Functions (SPFs) in an easily accessible interface.
Learn more about the Predictive Analysis application here.
Segments: Predictive Attributes
The following outlines Indiana’s chosen predictive attributes used to generate Optimal Fit SPF groupings for segments:
Attribute
Local-Owned/State-Owned
Urban/Rural
Two Lanes or Less
More Than Two Lanes
Freeway/Non-Freeway/Ramp
Interchange Area
Non-Interchange Area
Resulting Peer Groups
Locally-Owned, Urban, Two Lanes or Less, Non-Freeway Segment
Locally-Owned, Rural, Two Lanes or Less, Non-Freeway Segment
Locally-Owned, Urban, More than Two Lanes, Non-Freeway Segment
State-Owned, Urban, More than Two Lanes, Non-Freeway Segment
State-Owned, Urban, Two Lanes or Less, Non-Freeway Segment
Rural, More than Two Lanes, Non-Freeway Segment
State-Owned, Rural, Two Lanes or Less, Non-Freeway Segment
Ramp Segment
Urban Freeway Segment, Non-Interchange Area
Urban Freeway Segment, Interchange Area
Rural Freeway Segment, Non-Interchange Area
Rural Freeway Segment, Interchange Area
Requirements for Optimal Fit Creation
Minimum Crashes: 100
Minimum Segments: 50
Note
There were not enough Locally-Owned, More than Two Lanes, Rural, Non-Freeway segments to form a stand-alone peer group, so these were combined with the state-owned segments to create a Rural, More than Two Lanes, Non-Freeway Segment.
There were not enough Locally-Owned Freeway segments or ramps to have a stand-alone peer group, and these were combined with the state-owned freeway and ramp segments.
Intersection crashes are not included in the segment network screening.
Intersections: Predictive Attributes
The following outlines Indiana’s chosen predictive attributes used to generate Optimal Fit SPF groupings for intersections:
Attribute
Local-Owned/State-Owned
Urban/Rural
3-Leg
4-or-More Leg
Rural/Urban City Limits
Resulting Peer Groups
Locally Owned, Urban, 4-or-More Leg Intersection
Locally Owned, Rural, 4-or-More Leg Intersection
Locally Owned, Urban, 3-Leg Intersection
Locally Owned, Rural, 3-Leg Intersection
State Owned, Urban, 4-or-More Leg Intersection
State Owned, Rural, 4-or-More Leg Intersection
State Owned, Urban, 3-Leg Intersection
State Owned, Rural, 3-Leg Intersection
Note
Intersection traffic control type (signalized, stop-controlled, etc.) is not utilized to determine which peer group an intersection is included within.
If any leg of an intersection is a state-controlled route, the whole intersection is counted as a state-controlled intersection.
Ramp terminal intersections should be treated as intersections for the purposes of network screening. The number of legs for a ramp terminal intersection should be 4 for a traditional diamond interchange and 3 for a folded diamond interchange. For most interchanges, each terminal intersection should be analyzed separately (i.e., a diamond interchange contains two terminal intersections).
Requirements for Optimal Fit Creation
Minimum Crashes: 100
Minimum Segments: 50