CMF / CRF Details
CMF ID: 4491
Changing left turn phasing on one approach from permissive to protected-permissive
Description: CMFs are calculated the intersection level and not the treated approach(es) level.
Prior Condition: Permissive only left turn phasing on the treated approach
Category: Intersection traffic control
Study: Crash Modification Factors for Changing Left Turn Phasing, Srinivasan et al., 2012
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 85 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 1.128 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.266 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | -12.8 (This value indicates an increase in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 26.6 |
| Applicability | |
|---|---|
| Crash Type: | Rear end |
| 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: | |
| Minimum Speed Limit: | |
| Maximum Speed Limit: | |
| Speed Unit: | |
| Speed Limit Comment: | |
| Area Type: | Urban |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | Not specified |
| If countermeasure is intersection-based | |
| Intersection Type: | Roadway/roadway (not interchange related) |
| Intersection Geometry: | 4-leg |
| Traffic Control: | Signalized |
| Major Road Traffic Volume: | Minimum of 4857 to Maximum of 22000 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 1715 to Maximum of 12000 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 13660 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 5818 Annual Average Daily Traffic (AADT) |
| Development Details | |
|---|---|
| Date Range of Data Used: | |
| Municipality: | |
| State: | NC |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 41 crashes before, 51 crashes after |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Nov 01, 2012 |
| Comments: | |
