CMF / CRF Details
Conversion of intersection into high-speed roundabout
Countermeasure ID: 10434
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: |  [View score details] |
| Rating Points Total: | 110 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.59 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.1 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 41 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 10 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | All |
| Street Type: | |
| Minimum Number of Lanes: | |
| Maximum Number of Lanes: | |
| Number of Lanes Direction: | |
| Number of Lanes Comment: | |
| Crash Weather: | Not specified |
| Road Division Type: | |
| Minimum Speed Limit: | 35 |
| Maximum Speed Limit: | 55 |
| Speed Unit: | mph |
| 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: | 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): | 67 crashes before, 40 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: | |
