CMF / CRF Details

CMF ID: 6631

Change horizontal curve radius from straight tangent to radius of R feet (at speed limit of V in mph)

Description:

Prior Condition:  No Prior Condition(s)

Category: Alignment

Study: Evaluating the Need for Surface Treatments to Reduce Crash Frequency on Horizontal Curves, Pratt et al., 2014

 
Star Quality Rating:3 Stars  [View score details]
Rating Points Total:105
Crash Modification Factor (CMF)
Value:Equation
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value:
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Principal Arterial Interstate
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:Divided by Median
Minimum Speed Limit:80
Maximum Speed Limit:80
Speed Unit:mph
Speed Limit Comment:
Area Type:
Traffic Volume:Minimum of 972 to Maximum of 70368 Average Daily Traffic (ADT)
Average Traffic Volume:15633 Average Daily Traffic (ADT)
Time of Day:Not specified
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:2007 to 2011
Municipality:
State:TX
Country:USA
Type of Methodology Used:Regression cross-section
Sample Size (crashes):1807 crashes
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jun 22, 2015
Comments:For situations where the existing (prior) condition is not a straight tangent, calculate CMFs separately for the existing condition and the proposed condition and then divide the proposed condition CMF by the existing condition CMF to arrive at the final CMF.