CMF / CRF Details
Convert to roundabout interchanges
Countermeasure ID: 9440
Description: Convert to interchange roundabouts with either a single roundabout or a pair.
Prior Condition: Interchanges without roundabout ramp terminals
Category: Interchange design
Study: Safety Performance Analysis of Roundabout Interchanges in Missouri, Claros et al., 2018
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 95 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 1.066 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | -6.6 (This value indicates an increase in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | All |
| Street Type: | |
| Minimum Number of Lanes: | 1 |
| Maximum Number of Lanes: | 2 |
| Number of Lanes Direction: | |
| Number of Lanes Comment: | |
| Crash Weather: | Not specified |
| Road Division Type: | |
| Minimum Speed Limit: | 25 |
| Maximum Speed Limit: | 45 |
| 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 (interchange ramp terminal) |
| Intersection Geometry: | No values chosen. |
| Traffic Control: | Roundabout |
| Major Road Traffic Volume: | Minimum of 2060 to Maximum of 16715 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 647 to Maximum of 5630 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 8186 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 2721 Annual Average Daily Traffic (AADT) |
| Development Details | |
|---|---|
| Date Range of Data Used: | 2003 to 2016 |
| Municipality: | |
| State: | MO |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 240 crashes after |
| Sample Size (sites): | 13 sites before, 13 sites after |
| Sample Size (site-years): | 50 site-years before, 53 site-years after |
