CMF / CRF Details
Conversion of intersection to roundabout
Countermeasure ID: 10082
Description: Conversion of stop- and signal-controlled intersections into roundabouts
Prior Condition: Intersections without roundabouts
Category: Intersection geometry
Study: Safety Evaluation of Roundabouts in Georgia, Gbologah et al., 2019
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 85 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.623 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 37.7 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | Not specified |
| 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: | Undivided |
| 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: | 4-leg |
| Traffic Control: | Not specified |
| Major Road Traffic Volume: | |
| Minor Road Traffic Volume: | |
| Average Major Road Volume : | |
| Average Minor Road Volume : | |
| Development Details | |
|---|---|
| Date Range of Data Used: | 2007 to 2014 |
| Municipality: | |
| State: | GA |
| Country: | United States |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 241 crashes before, 255 crashes after |
| Sample Size (sites): | 16 sites before, 16 sites after |
| Sample Size (site-years): | 62 site-years before, 85 site-years after |
