CMF / CRF Details
CMF ID: 4512
Changing left turn phasing from permissive on one leg and protected-permissive on another leg to flashing yellow arrow (FYA)
Description: Two approaches - one with permissive left turns and one with protected-permissive left turns - changed to the flashing yellow arrow (FYA). CMFs are calculated at the intersection level and not the treated approach(es) level.
Prior Condition: One treated leg had permissive left turns and one treated leg had protected-permissive left turns.
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) | |
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Value: | 1.058 |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 0.258 |
Crash Reduction Factor (CRF) | |
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Value: | -5.8 (This value indicates an increase in crashes) |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 25.8 |
Applicability | |
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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 9100 to Maximum of 43000 Annual Average Daily Traffic (AADT) |
Minor Road Traffic Volume: | Minimum of 600 to Maximum of 11350 Annual Average Daily Traffic (AADT) |
Average Major Road Volume : | 23276 Annual Average Daily Traffic (AADT) |
Average Minor Road Volume : | 5028 Annual Average Daily Traffic (AADT) |
Development Details | |
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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): | 46 crashes before, 25 crashes after |
Other Details | |
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Included in Highway Safety Manual? | No |
Date Added to Clearinghouse: | Nov 01, 2012 |
Comments: |