CMF / CRF Details

CMF ID: 10436

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: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.38
Adjusted Standard Error:
Unadjusted Standard Error: 0.1
Crash Reduction Factor (CRF)
Value: 62   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 10
Applicability
Crash Type: Other
Crash Severity: All
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: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 39 crashes before, 16 crashes after
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.