CMF / CRF Details

CMF ID: 6940

Install centerline and shoulder rumble strips

Description: Milled or rolled rumble strips.

Prior Condition: Existing shoulder rumble strips, centerline rumble strips are added

Category: Roadway

Study: Safety Evaluation of Centerline Plus Shoulder Rumble Strips, Persaud et al., 2015

Star Quality Rating: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.48
Adjusted Standard Error:
Unadjusted Standard Error: 0.142
Crash Reduction Factor (CRF)
Value: 52   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 14.2
Crash Type: Head on
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: 2
Road Division Type: Undivided
Speed Limit:
Area Type: Rural
Traffic Volume: Minimum of 1282 to Maximum of 20433 Annual Average Daily Traffic (AADT)
Average Traffic Volume: 6101 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:
State: KY
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 36 crashes before, 15 crashes after
Sample Size (miles): 164 miles before, 164 miles after
Sample Size (miles): 604 mile-years before, 764 mile-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-01-2015
Comments: CMF for head-on crashes (all severity levels) excludes intersection-related and animal crashes. This may only reflect the benefit of added centerline rumble strips because centerline rumble strips were added to existing shoulder rumble strips.