CMF / CRF Details

CMF ID: 4924

Conversion of intersection into single-lane roundabout

Description: Conversion of intersection into single-lane 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: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.64
Adjusted Standard Error:
Unadjusted Standard Error: 0.123
Crash Reduction Factor (CRF)
Value: 35.98   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 12.3
Applicability
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: 2
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 6000 (Total) to Maximum of 21900 (Total) Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:
Average Major Road Volume : 12595 (Total) 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): 88 crashes before, 67 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.- "Traffic Control" included intersections with yield control, two-way stop-control, all-way stop-control, and signal control.- Min, max, avg AADTs are for both major and minor roads.