CMF / CRF Details

CMF ID: 9763

Install edgeline or shoulder rumble strips


Prior Condition: Two-lane undivided highway with no edgeline or shoulder rumble strips present

Category: Roadway

Study: Installation Guidance for Centerline and Edgeline Rumble Strips in Narrow Pavements, Savolainen et al., 2017

Star Quality Rating: 4 Stars   [View score details]
Rating Points Total: 115
Crash Modification Factor (CMF)
Value: 0.839
Adjusted Standard Error:
Unadjusted Standard Error: 0.065
Crash Reduction Factor (CRF)
Value: 16.1   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 6.5
Crash Type: Other
Crash Severity: All
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: Not specified
Traffic Volume: Minimum of 10 to Maximum of 17700 Annual Average Daily Traffic (AADT)
Average Traffic Volume: 2428 Annual Average Daily Traffic (AADT)
Time of Day: All
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: 2014 to 2015
State: IA
Country: United States
Type of Methodology Used: Regression cross-section
Sample Size (crashes): 1022 crashes
Sample Size (sites): 13948 sites
Sample Size (site-years): 27896 site-years
Sample Size (miles): 5439.7 miles
Sample Size (mile-years): 10879.4 mile-years
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Oct-27-2018
Comments: This CMF applies to edgeline-related crashes (run off road-right, run off road-straight/right, fixed object crashes that did not included crossing the centerline)