CMF / CRF Details

CMF ID: 9401

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 left-turn phasing on the approach.

Category: Intersection traffic control

Study: Approach-Level Safety Comparison of Permissive-Protected and Protected Left Turn Phasing to Flashing Yellow Areas, Shea and Medina, 2018

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:90
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.3093
Crash Reduction Factor (CRF)
Value:-242.8  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:30.93
Crash Type:Left turn
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:Not specified
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Not specified
Intersection Geometry:
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:2011 to 2016
Country:United States
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):64 crashes before, 180 crashes after
Sample Size (sites):40 sites before, 40 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Oct 27, 2018
Comments:This CMF applies at the approach level, not at the intersection level.