CMF / CRF Details

CMF ID: 5606

Change permissive left-turn phasing to protected/permissive

Description: Treatment group includes intersections where signal phases were changed from permissive to protected/permissive.

Prior Condition:  Signals with permissive only left turn phasing

Category: Intersection traffic control

Study: Evaluating the Safety Effects of Signal Improvements, Schultz et al., 2014

 
Star Quality Rating:2 Stars  [View score details]
Rating Points Total:35
Crash Modification Factor (CMF)
Value:0.21
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value:79  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type:Head on
Crash Severity:
Roadway Types:All
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:30
Maximum Speed Limit:65
Speed Unit:mph
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:No values chosen.
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:2002 to 2011
Municipality:
State:UT
Country:
Type of Methodology Used:Other before/after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Aug 12, 2014
Comments:The hierachical Bayesian model was used. CMF for four roadway types: other principal arterials, other freeway/expressway,minor arterial,and major collectors.