CMF / CRF Details

CMF ID: 7728

Install flashing yellow arrow

Description: Install flashing yellow arrow

Prior Condition:  Permissive phase of the PPLT control operated with a circular green indication.

Category: Intersection traffic control

Study: Safety Effects of Traffic Signing for Left Turn Flashing Yellow Arrow Signals, Schattler et al., 2015

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:120
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value:-4.7  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Type:Left turn
Crash Severity:All
Roadway Types:All
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:7
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:All
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Urban
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:3-leg,4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 3250 to Maximum of 37500 Average Daily Traffic (ADT)
Minor Road Traffic Volume:Minimum of 63 to Maximum of 14700 Average Daily Traffic (ADT)
Average Major Road Volume :17215 Average Daily Traffic (ADT)
Average Minor Road Volume :4576 Average Daily Traffic (ADT)
Development Details
Date Range of Data Used:2007 to 2013
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):155 crashes before, 57.04 crashes after
Sample Size (sites):74 sites before, 74 sites after
Sample Size (site-years):222 site-years before
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Mar 08, 2016
Comments:CMFs of left-turn related crashes on signalized intersections, including roadway with roadway and interchange related intersections. Applies to approaches with dedicated left turn lanes and PPLT phasing before and after. Nearby intersections had supplemental sign "Left Turn Yield on Flashing Yellow Arrow" mounted on mast arm.