CMF / CRF Details

CMF ID: 8361

Install w-beam guardrail or concrete barrier


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]
Crash Modification Factor (CMF)
Value: 0.69
Adjusted Standard Error:
Unadjusted Standard Error: 0.09
Crash Reduction Factor (CRF)
Value: 31   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 9
Crash Type: Run off road,Other
Crash Severity: K (fatal),A (serious injury),B (minor injury)
Roadway Types: Principal Arterial Other Freeways and Expressways
Number of Lanes: 2 to 5
Road Division Type:
Speed Limit: 50-70 mph
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
State: FL
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 middle age drivers (25-64 years old)


The information contained in the Crash Modification Factors (CMF) Clearinghouse is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in the CMF Clearinghouse. The information contained in the CMF Clearinghouse does not constitute a standard, specification, or regulation, nor is it a substitute for sound engineering judgment.