CMF / CRF Details

CMF ID: 9167

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: Safety Evaluation of Two Curve Warning Treatments: In-Lane Curve Warning Pavement Markings and Oversized Chevron Signs, Lyon et al., 2017

Image: View the countermeasure image.

Star Quality Rating: 4 Stars   [View score details]
Rating Points Total: 115
Crash Modification Factor (CMF)
Value: 0.616
Adjusted Standard Error:
Unadjusted Standard Error: 0.092
Crash Reduction Factor (CRF)
Value: 38.4   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 9.2
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes:
Road Division Type:
Speed Limit:
Area Type:
Traffic Volume: Minimum of 590 to Maximum of 7600 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
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:
State: IA, PA
Country: USA
Type of Methodology Used: 2
Sample Size (crashes): 52 crashes before, 67 crashes after
Sample Size (miles): 0.82 miles before, 0.82 miles after
Sample Size (miles): 8.57 mile-years before, 17.37 mile-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-17-2017
Comments: Sample size is small, use with caution. Excludes intersection-related and animal-related crashes.