CMF / CRF Details

CMF ID: 4168

Changing left turn phasing on more than one approach from permissive to protected-permissive

Description: CMFs are calculated the intersection level and not the treated approach(es) level.

Prior Condition:  Permissive only left turn phasing on all treated approaches

Category: Intersection traffic control

Study: Evaluation of Safety Strategies at Signalized Intersections, Srinivasan, et al., 2011

Image: View the countermeasure image.

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:110
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.036
Crash Reduction Factor (CRF)
Value:4.2  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:3.6
Crash Type:All
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:Urban
Traffic Volume:
Average Traffic Volume:
Time of Day:Not specified
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 4857 to Maximum of 74990 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 1466 to Maximum of 42723 Annual Average Daily Traffic (AADT)
Average Major Road Volume :31537 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :16292 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:
Municipality:Toronto & North Carolina
Country:Canada & USA
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):1653 crashes before, 2522 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 06, 2012