CMF / CRF Details

CMF ID: 7852

Install left-turn lane

Description:

Prior Condition:  Intersections without left-turn lanes

Category: Intersection geometry

Study: Validation and Application of Highway Safety Manual (Part D) in Florida, Abdel-Aty et al., 2014

 
Star Quality Rating:3 Stars  [View score details]
Rating Points Total:95
Crash Modification Factor (CMF)
Value:0.73
Adjusted Standard Error:
Unadjusted Standard Error:0.17
Crash Reduction Factor (CRF)
Value:27  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:17
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:Rural
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:3-leg
Traffic Control:Stop-controlled
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:2007 to 2011
Municipality:
State:FL
Country:USA
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):18 sites before, 18 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Mar 08, 2016
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.