CMF / CRF Details

CMF ID: 7730

Install left turn flashing yellow arrow signals and supplemental traffic signs

Description: Install left turn flashing yellow arrow signals with supplemental traffic signs with text "Left Turn Yield on 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: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.857
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value: 14.3   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type: Left turn
Crash Severity: All
Roadway Types: All
Number of Lanes: 2-7
Road Division Type: All
Speed Limit:
Area Type: Urban
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)
Development Details
Date Range of Data Used: 2007 to 2013
Municipality: Peoria
State: IL
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 216 crashes before, 52.62 crashes after
Sample Size (sites): 90 sites before, 90 sites after
Sample Size (site-years): 270 site-years before
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Mar-08-2016
Comments: CMFs of left-turn related crashed on signalized intersections, including not interchange related and interchange related intersections. Applies to approaches with dedicated left turn lanes and PPLT phasing before and after.

[View the Full Study Details]

 

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