CMF / CRF Details

CMF ID: 5524

Conversion of signalized intersection into single- or multi-lane roundabout


Prior Condition:  Signalized intersection

Category: Intersection geometry

Study: Evidence of Mixed Safety Performance among Roundabouts Converted from Signalized Intersections, Russo et al., 2014

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:90
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.32
Crash Reduction Factor (CRF)
Value:-16  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:32
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:1
Maximum Number of Lanes:3
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Not specified
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:3-leg,4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 5700 to Maximum of 32900 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 1900 to Maximum of 24200 Annual Average Daily Traffic (AADT)
Average Major Road Volume :17700 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :7900 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:2000 to 2012
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):35 crashes before, 60 crashes after
Sample Size (sites):22 sites before, 22 sites after
Sample Size (site-years):66 site-years before, 89 site-years after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Aug 12, 2014