CMF / CRF Details

CMF ID: 9413

Convert signal from span wire to mast arm

Description: Convert signals mounted on span wire to signals mounted on mast arm

Prior Condition:  Signalized intersection with signal mounted on a span wire.

Category: Intersection traffic control

Study: Evaluating the Safety Effects of Span Wire to Mast Arm Signal Conversion, Khattak and Fontaine, 2018

 
Star Quality Rating:3 Stars  [View score details]
Rating Points Total:80
Crash Modification Factor (CMF)
Value:1
Adjusted Standard Error:
Unadjusted Standard Error:0.128
Crash Reduction Factor (CRF)
Value:0  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:12.8
Applicability
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
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:All
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Not specified
Intersection Geometry:4-leg
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:
Municipality:
State:VA
Country:United States
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):25 sites before, 25 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Oct 27, 2018
Comments:This CMF applies to all KABC crashes at 4-leg signalized intersections. 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.