CMF / CRF Details

CMF ID: 5246

Provide split phases

Description: The regular 2 phases of a cycle are split into three phases. Pedestrians receive a "walk" display while the parallel traffic that would normally turn left or right through the crosswalk is held with a left or right red arrow signal and the through movement proceeds on a green signal. After the pedestrian crossing is completed, a red "steady hand" is displayed and the turns are then made on a green arrow signal while the through movement continues to move. Split phase requires dedicated turn lanes since through and turning movements are governed by different signal indications.

Prior Condition:  Without split phasing

Category: Intersection traffic control

Study: Safety countermeasures and crash reduction in New York City - Experience and lessons learned, Chen et al., 2013

Image: View the countermeasure image.

 
Star Quality Rating:2 Stars  [View score details]
Rating Points Total:65
Crash Modification Factor (CMF)
Value:0.83
Adjusted Standard Error:
Unadjusted Standard Error:0.12
Crash Reduction Factor (CRF)
Value:17  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:12
Applicability
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:
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
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:1989 to 2008
Municipality:New York City
State:NY
Country:
Type of Methodology Used:Other before/after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jan 01, 1970
Comments: The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.