CMF / CRF Details

CMF ID: 9888

Change permissive left-turn phasing to protected only or protected/permissive

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

Prior Condition: Intersections with permissive left-turn signal phasing.

Category: Intersection traffic control

Study: Safety Evaluation of Protected Left-Turn Phasing and Leading Pedestrian Intervals on Pedestrian Safety, Goughnour et al., 2018

Star Quality Rating: 4 Stars   [View score details]
Rating Points Total: 122
Crash Modification Factor (CMF)
Value: 1.136
Adjusted Standard Error:
Unadjusted Standard Error: 0.146
Crash Reduction Factor (CRF)
Value: -13.6   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 14.6
Crash Type: Vehicle/pedestrian
Crash Severity: All
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:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:
Traffic Volume:
Average Traffic Volume:
Time of Day: All
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: Not specified
Traffic Control: Signalized
Major Road Traffic Volume: Minimum of 9912 to Maximum of 36500 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 4133 to Maximum of 26148 Annual Average Daily Traffic (AADT)
Average Major Road Volume : 19546 Annual Average Daily Traffic (AADT)
Average Minor Road Volume : 12917 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used: 2005 to 2014
Municipality: Chicago
State: IL
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 127 crashes before, 90 crashes after
Sample Size (sites): 27 sites before, 27 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Mar-11-2019
Comments: Crash Type = Vehicle-Pedestrian Crashes