CMF / CRF Details

CMF ID: 10437

Conversion of intersection into high-speed roundabout

Description: Conversion of intersection into high-speed roundabout

Prior Condition: Minor Road Stop-Controlled Intersections

Category: Intersection geometry

Study: Evaluation of Roundabouts on High-Speed Roadways, Bagley, D.L., 2020

 
Star Quality Rating: 4 Stars   [View score details]
Rating Points Total: 115
Crash Modification Factor (CMF)
Value: 0.04
Adjusted Standard Error:
Unadjusted Standard Error: 0.04
Crash Reduction Factor (CRF)
Value: 96   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 4
Applicability
Crash Type: Other
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: All
Number of Lanes:
Road Division Type:
Speed Limit: 35-55 MPH
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: Roundabout
Major Road Traffic Volume: Minimum of 2000 to Maximum of 12500 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 400 to Maximum of 11000 Annual Average Daily Traffic (AADT)
Average Major Road Volume : 6000 Annual Average Daily Traffic (AADT)
Average Minor Road Volume : 3600 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used: 1999 to 2019
Municipality:
State: NC
Country:
Type of Methodology Used: 2
Sample Size (sites): 13 sites before, 13 sites after
Sample Size (site-years): 39 site-years before, 39 site-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Jun-01-2020
Comments: This CMF is for Frontal Impact Crashes. 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.