CMF / CRF Details

CMF ID: 10613

Improve Curve Delineation

Description: Treatments can include new chevrons, horizontal arrows, and advance warning signs as well as the improvement of existing signs using fluorescent yellow sheeting.

Prior Condition: No Prior Condition(s)

Category: Signs

Study: Safety Evaluation of Improved Curve Delineation, Srinivasan et al., 2009

Star Quality Rating: 5 Stars   [View score details]
Rating Points Total: 140
Crash Modification Factor (CMF)
Value: 0.725
Adjusted Standard Error:
Unadjusted Standard Error: 0.073
Crash Reduction Factor (CRF)
Value: 27.5   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 7.3
Crash Type: Non-intersection
Crash Severity: All
Roadway Types: All
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 354 to Maximum of 20479 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: 1993 to 2007
State: CT, WA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 302 crashes before, 176 crashes after
Sample Size (sites): 228 sites before, 228 sites after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: