CMF / CRF Details

CMF ID: 9899

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: 5 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.942
Adjusted Standard Error:
Unadjusted Standard Error: 0.028
Crash Reduction Factor (CRF)
Value: 5.8   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 2.8
Applicability
Crash Type: Other
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: All
Number of Lanes:
Road Division Type:
Speed Limit:
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:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used: 2001 to 2014
Municipality: Chicago, New York City, Toronto
State: notusa, IL, NY
Country: USA, Canada
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 3993 crashes before, 2410 crashes after
Sample Size (sites): 148 sites before, 148 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Mar-11-2019
Comments: Crash Type = Vehicle-Vehicle Crashes