CMF / CRF Details

CMF ID: 7689

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

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

Prior Condition: Protected 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: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 4.778
Adjusted Standard Error:
Unadjusted Standard Error: 1.397
Crash Reduction Factor (CRF)
Value: -377.8   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 139.7
Crash Type: Left turn
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
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: Not specified
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 9100 to Maximum of 49000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 900 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): 12 crashes before, 55 crashes after
Sample Size (sites): 23 sites before, 23 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".