CMF / CRF Details

CMF ID: 9171

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: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.647
Adjusted Standard Error:
Unadjusted Standard Error: 0.33
Crash Reduction Factor (CRF)
Value: 35.3   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 33
Applicability
Crash Type: Other
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: 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:
Municipality:
State: IA, PA
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 2 crashes before, 4 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: This cmf applies to nighttime run-off road crashes. Sample size is small, use with caution. Excludes intersection-related and animal-related crashes.