CMF / CRF Details

CMF ID: 9794

Conversion of intersection into single-lane roundabout

Description: Conversion of intersection into single-lane roundabout

Prior Condition: Traffic circle

Category: Intersection geometry

Study: Crash Modification Factors Based on Crash Histories of 148 Modern Roundabouts in Five States, Zhang and Wang, 2017

 
Star Quality Rating: 1 Star   [View score details]
Rating Points Total: 10
Crash Modification Factor (CMF)
Value: 0.5
Adjusted Standard Error:
Unadjusted Standard Error: 0.72
Crash Reduction Factor (CRF)
Value: 50   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 72
Applicability
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes:
Road Division Type:
Speed Limit:
Area Type: Not specified
Traffic Volume:
Average Traffic Volume:
Time of Day: Not specified
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry: No values chosen.
Traffic Control:
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used: 2005 to 2013
Municipality:
State: FL, IN, NY, PA, WA
Country: USA
Type of Methodology Used: 3
Sample Size (sites): 2 sites before, 2 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Oct-27-2018
Comments: Traffic circle to single lane roundabout The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.