CMF / CRF Details

CMF ID: 5227

Conversion of intersection into low-speed roundabout

Description: Conversion of intersection into low-speed roundabout

Prior Condition: The intersection was operating under no control, yield, TWSC, AWSC, or signal control.

Category: Intersection geometry

Study: Evaluation of Roundabout Safety, Qin et al., 2013

Star Quality Rating: 1 Star   [View score details]
Rating Points Total: 30
Crash Modification Factor (CMF)
Value: 1.099
Adjusted Standard Error:
Unadjusted Standard Error: 0.118
Crash Reduction Factor (CRF)
Value: -9.94   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 11.8
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: 2,4
Road Division Type: All
Speed Limit:
Area Type: All
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: Other
Major Road Traffic Volume: Minimum of 4100 (total entering) to Maximum of 48100 (total entering) Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used: 1994 to 2010
Municipality: Statewide
State: WI
Country: USA
Type of Methodology Used: 2
Sample Size (crashes): 164 crashes before, 180 crashes after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Aug-01-2013
Comments: - Study included three-yearbefore and after crash datafor each site.- In this case, the reported before-crashes represent the "expected crashes" after treatment.- "Traffic Control" includes intersections with yield control, two-way stop-control, all-way stop-control, and signal control.- Reported traffic volume is total entering volume.