CMF / CRF Details

CMF ID: 10317

Install in-lane curve warning pavement markings

Description: Pavement marking showing the word "Slow" and an arrow to alert drivers to an upcoming curve in the road.

Prior Condition:  No Prior Condition(s)

Category: Delineation

Study: Reducing Roadway Departure Crashes at Horizontal Curve Sections on Two-lane Rural Highways, Donnell et al., 2019

Image: View the countermeasure image.

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:115
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.211
Crash Reduction Factor (CRF)
Value:22.9  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:21.1
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:2
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:Undivided
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Rural
Traffic Volume:Minimum of 100 to Maximum of 15998 Annual Average Daily Traffic (AADT)
Average Traffic Volume:2802 Annual Average Daily Traffic (AADT)
Time of Day:Night
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:2005 to 2012
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):17 crashes after
Sample Size (sites):263 sites before, 263 sites after
Sample Size (miles):19.73 miles before, 19.73 miles after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Mar 23, 2020
Comments:This CMF is for crashes on Horizontal Curves.