CMF / CRF Details

CMF ID: 1886

Install a combination of chevron signs, curve warning signs, and/or sequential flashing beacons

Description: Along a curve with a small radius, large deflection angle, available sight distance smaller than stopping sight distance, and superelevation smaller than demanded at design and operating speed

Prior Condition:  No curve delineation treatment. Deflection angle is less than 60 gon.

Category: Signs

Study: Safety Evaluation of Curve Delineation Improvements An Empirical Bayes Observational Before-After Study, Montella, 2009

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:120
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.11
Crash Reduction Factor (CRF)
Value:41.8  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:11
Crash Type:All
Crash Severity:O (property damage only)
Roadway Types:Principal Arterial Other Freeways and Expressways
Street Type:
Minimum Number of Lanes:4
Maximum Number of Lanes:4
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:Not specified
Traffic Volume:Minimum of 7400 to Maximum of 13975 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:2001 to 2005
Municipality:Trans European Road Network, Italy
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 01, 2009