CMF / CRF Details

CMF ID: 4172

Changing left turn phasing from protected to flashing yellow arrow (FYA)

Description: CMFs are calculated the intersection level and not the treated approach(es) level.

Prior Condition:  All treated approaches had protected left turn

Category: Intersection traffic control

Study: Evaluation of Safety Strategies at Signalized Intersections, Srinivasan, et al., 2011

Image: View the countermeasure image.

Star Quality Rating:5 Stars  [View score details]
Rating Points Total:140
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.097
Crash Reduction Factor (CRF)
Value:-33.8  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:9.7
Crash Type:All
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 8260 to Maximum of 43000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 600 to Maximum of 13745 Annual Average Daily Traffic (AADT)
Average Major Road Volume :22575 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :4285 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):29 sites before, 29 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 06, 2012