CMF / CRF Details
Change permissive left-turn phasing to protected only or protected/permissive
Countermeasure ID: 4161
Description: Treatment group includes intersections where signal phases were changed from permissive to protected-only or protected/permissive.
Prior Condition: Treatment group includes intersections where signal phases were changed from permissive to protected-only or protected/permissive.
Category: Intersection traffic control
Study: Left-turn Phase: Permissive, Protected, or Both?, Li Chen, Cynthia Chen, and Reid Ewing, 2012
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 65 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.36 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 64 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability | |
|---|---|
| Crash Type: | Head on,Sideswipe |
| Crash Severity: | All |
| Roadway Types: | Not Specified |
| Street Type: | |
| Minimum Number of Lanes: | 1 |
| Maximum Number of Lanes: | 5 |
| 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: | All |
| If countermeasure is intersection-based | |
| Intersection Type: | Roadway/roadway (not interchange related) |
| Intersection Geometry: | 3-leg,4-leg,More than 4 legs |
| Traffic Control: | Signalized |
| Major Road Traffic Volume: | |
| Minor Road Traffic Volume: | |
| Average Major Road Volume : | |
| Average Minor Road Volume : | |
| Development Details | |
|---|---|
| Date Range of Data Used: | 1995 to 2009 |
| Municipality: | New York City |
| State: | NY |
| Country: | USA |
| Type of Methodology Used: | Simple before/after |
| Sample Size (crashes): | 206 crashes before, 29 crashes after |
