CMF / CRF Details

CMF ID: 7120


Star Quality Rating:	[View score details]
Rating Points Total:	80

Crash Modification Factor (CMF)
Value:	2.28
Adjusted Standard Error:
Unadjusted Standard Error:	0.538

Crash Reduction Factor (CRF)
Value:	-128 (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:	53.78

Applicability
Crash Type:	Fixed object
Crash Severity:	K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:	Principal Arterial Other Freeways and Expressways
Street Type:
Minimum Number of Lanes:	6
Maximum Number of Lanes:	6
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:	Not specified
Road Division Type:	Divided by Median
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:
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:	2000 to 2005
Municipality:
State:	NC,OH
Country:	USA
Type of Methodology Used:	Before/after using empirical Bayes or full Bayes
Sample Size (sites):	25 sites before, 25 sites after

Other Details
Included in Highway Safety Manual?	No
Date Added to Clearinghouse:	Nov 01, 2015
Comments:	This CMF applies to all fixed-object crashes for flexible barriers installed on six-lane freeways. 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.