CMF / CRF Details

CMF ID: 1410

Add 3-inch yellow retroreflective sheeting to signal backplates

Description:

Prior Condition:  No Prior Condition(s)

Category: Intersection traffic control

Study: Safety Impact of Increased Traffic Signal Backboards Conspicuity, Sayed et al., 2005

 
Star Quality Rating:4 Stars  [View score details]
Rating Points Total:120
Crash Modification Factor (CMF)
Value:0.85
Adjusted Standard Error:
Unadjusted Standard Error:0.005
Crash Reduction Factor (CRF)
Value:15  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:0.5
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:All
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:
Municipality:
State:notusa
Country:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):17 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 01, 2009
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.

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