CMF / CRF Details

CMF ID: 5523

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: 4 Stars   [View score details]
Rating Points Total: 130
Crash Modification Factor (CMF)
Value: 1.92
Adjusted Standard Error:
Unadjusted Standard Error: 0.07
Crash Reduction Factor (CRF)
Value: -92   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 7
Crash Type: All
Crash Severity: All
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
State: MI
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 743 crashes before, 1875 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