CMF / CRF Details

CMF ID: 6968

Install centerline and shoulder rumble strips

Description: Milled or rolled rumble strips.

Prior Condition: There are no existing rumble strips

Category: Roadway

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

Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.975
Adjusted Standard Error:
Unadjusted Standard Error: 0.046
Crash Reduction Factor (CRF)
Value: 2.5   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 4.6
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: 2
Road Division Type: Undivided
Speed Limit:
Area Type: Rural
Traffic Volume: Minimum of 782 to Maximum of 25796 Annual Average Daily Traffic (AADT)
Average Traffic Volume: 4990 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: PA
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 1590 crashes before, 577 crashes after
Sample Size (miles): 218 miles before, 218 miles after
Sample Size (miles): 1407 mile-years before, 512 mile-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-01-2015
Comments: CMF for total crashes (all types and all severity levels) excludes intersection-related and animal crashes.