CMF / CRF Details

CMF ID: 1444

Install larger signal lenses (12 inch)

Description:

Prior Condition: Replace 8 inch signal heads with 12 inch signal heads.

Category: Intersection traffic control

Study: Low-Cost Safety Improvements Chapter 27, The Traffic Safety Toolbox: a primer on traffic safety, Polanis, 1999

 
Star Quality Rating: 2 Stars   [View score details]
Rating Points Total: 40
Crash Modification Factor (CMF)
Value: 0.54
Adjusted Standard Error:
Unadjusted Standard Error: 0.075
Crash Reduction Factor (CRF)
Value: 46   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 7.5
Applicability
Crash Type: Angle
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: Winston Salem
State: NC
Country:
Type of Methodology Used: Simple before/after
Sample Size (sites): 44 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.