CMF / CRF Details

CMF ID: 4934

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

Description:

Prior Condition: The intersection was operating under signal control.

Category: Intersection geometry

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

 
Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.955
Adjusted Standard Error:
Unadjusted Standard Error: 0.317
Crash Reduction Factor (CRF)
Value: 4.54   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 31.7
Applicability
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: 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: Signalized
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 : 20170 (total entering) Annual Average Daily Traffic (AADT)
Average Minor Road Volume :
Development Details
Date Range of Data Used: 1994 to 2010
Municipality: Statewide
State: WI
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 50 crashes before, 90 crashes after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Aug-01-2013
Comments: - Study included three-year before and after crash data for each site.- Reported traffic volume is total entering volume.