CMF / CRF Details

CMF ID: 7111

Install median barrier

Description:

Prior Condition: No median barrier present

Category: Roadside

Study: NCHRP Report 794: Median Cross-Section Design for Rural Divided Highways, Graham et al., 2014

 
Star Quality Rating: 3 Stars   [View score details]
Rating Points Total: 80
Crash Modification Factor (CMF)
Value: 7.04
Adjusted Standard Error:
Unadjusted Standard Error: 0.427
Crash Reduction Factor (CRF)
Value: -604   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 42.66
Applicability
Crash Type: Fixed object
Crash Severity: All
Roadway Types: Principal Arterial Other Freeways and Expressways
Number of Lanes: 4
Road Division Type: Divided by Median
Speed Limit:
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 2007
Municipality:
State: MO, NC, OH
Country: USA
Type of Methodology Used: 2
Sample Size (sites): 302 sites before, 302 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 all median barrier types installed on four-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.