CMF / CRF Details

Change from protected-permissive to flashing yellow arrow protected-permissive on approach

Countermeasure ID: 9402

Description: Change from protected-permissive left-turn phasing to FYA on one approach. CMF applies at the approach level.

Prior Condition: Left-turn approach with protected-permissive phasing

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:2 Stars  [View score details]
Rating Points Total:70
Crash Modification Factor (CMF)
Value:0.9778
Adjusted Standard Error:
Unadjusted Standard Error:0.1216
Crash Reduction Factor (CRF)
Value:2.22  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:12.16
Applicability
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
Municipality:
State:UT
Country:United States
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):247 crashes before, 472 crashes after
Sample Size (sites):68 sites before, 68 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Oct 27, 2018
Comments:This CMF applies to left-turn related crashes on the approach level.

View the Full Study Details