CMF / CRF Details

CMF ID: 1433

Improve visibility of signal heads

Description:

Prior Condition: Improvements included one or more of the following: signal lens size upgrade, installing new backboards, adding reflective tapes to existing backboards, and installing additional signal heads.

Category: Intersection traffic control

Study: Evaluating the Safety Impacts of Improving Signal Visibility at Urban Signalized Intersections, Sayed et al., 2007

 
Star Quality Rating: 4 Stars   [View score details]
Rating Points Total: 120
Crash Modification Factor (CMF)
Value: 0.94
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value: 6   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
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: 50
Maximum Speed Limit: 50
Speed Unit: km/h
Speed Limit Comment: 50 km/h or 30 mph
Area Type: Urban
Traffic Volume:
Average Traffic Volume:
Time of Day: Day
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
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: 1999 to 2004
Municipality: City of Burnaby, City of Coquitlam, City of Kelowna, City of New Westminster, City of North Vancouver, City of Surrey
State:
Country:
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (sites): 171 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.