CMF / CRF Details

CMF ID: 7684

Change from permissive only to flashing yellow arrow protected/permissive left turn

Description: Change from permissive only to FYA - protected/permissive left turn

Prior Condition: Permissive phasing

Category: Intersection traffic control

Study: Safety Effectiveness of Flashing Yellow Arrow: Evaluation of 222 Signalized Intersections in North Carolina, Simpson and Troy, 2015

Star Quality Rating: 2 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.598
Adjusted Standard Error:
Unadjusted Standard Error: 0.105
Crash Reduction Factor (CRF)
Value: 40.2   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 10.5
Crash Type: Left turn
Crash Severity: All
Roadway Types: Not specified
Number of Lanes:
Road Division Type:
Speed Limit: 35-55
Area Type: Not specified
Traffic Volume:
Average Traffic Volume:
Time of Day:
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: 3-leg,4-leg
Traffic Control: Signalized
Major Road Traffic Volume: Minimum of 7000 to Maximum of 49000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 600 to Maximum of 17000 Annual Average Daily Traffic (AADT)
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used: 2003 to 2013
State: NC
Type of Methodology Used: Other before/after
Sample Size (crashes): 31 crashes before, 23 crashes after
Sample Size (sites): 30 sites before, 30 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-01-2015
Comments: Target crashes are defined as "left-turn same roadway crashes with the left-turner on an approach treated with FYA and occurring during the time of day when FYA is in operation".