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:2 Stars  [View score details]
Rating Points Total:50
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
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:2
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:All
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
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.