CMF / CRF Details

CMF ID: 8364

Install w-beam guardrail or concrete barrier

Description:

Prior Condition:  No roadside barrier

Category: Roadside

Study: Evaluation of the Safety Effectiveness of Installing Roadside Barriers with Different Driver, Vehicle, Weather, and Time of Day Conditions, Park et. al., 2016

 
Star Quality Rating:4 Stars  [View score details]
Rating Points Total:115
Crash Modification Factor (CMF)
Value:0.62
Adjusted Standard Error:
Unadjusted Standard Error:0.25
Crash Reduction Factor (CRF)
Value:38  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:25
Applicability
Crash Type:Run off road,Other
Crash Severity:K (fatal),A (serious injury),B (minor injury)
Roadway Types:Principal Arterial Other Freeways and Expressways
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:5
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:50
Maximum Speed Limit:70
Speed Unit:mph
Speed Limit Comment:
Area Type:Not specified
Traffic Volume:Minimum of 35000 to Maximum of 104600 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:
Traffic Control:
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:2003 to 2011
Municipality:
State:FL
Country:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):147 sites before, 147 sites after
Sample Size (miles):68 miles before, 68 miles after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jan 17, 2017
Comments:CMF is for run off road crashes involving older drivers (more than 64 years old) 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.