Nebraska organizes its segments and intersections into the following categories to generate meaningful Safety Performance Functions (SPFs). Each segment or intersection is placed into a group based on the criteria outlined below. An SPF is generated using the observed crash data from each of the segments/intersections in the group. This SPF is then used to support network screenings with predicted and expected performance measures for each associated roadway.
Segment Grouping Criteria
Urban Status
Rural
Urban
Number of Lanes
2-Lane
Multi-Lane
Unknown
One-Way Status
One-Way
Non-One-Way
Expressway Status
Expressway
Interstate
Other Roadway
Surfaced Shoulder
With Surfaced Shoulder
Without Surfaced Shoulder
Intersection Grouping Criteria
Number of Legs
2-Leg
3-Leg
4-Leg
5-Leg
6-Leg
7-Leg
8-Leg
Urban Status
Rural
Urban
Unknown
Functional Classification
Local Roadway
Major Collector
Minor Arterial
Minor Collector
Other Freeway and Expressway
Other Principal Arterial
Unknown Roadway