CMF / CRF Details

CMF ID: 3421

Install shoulder rumble strips

Description:

Prior Condition: No Prior Condition(s)

Category: Shoulder treatments

Study: NCHRP Report 641: Guidance for the Design and Application of Shoulder and Centerline Rumble Strips, Torbic et al., 2009

 
Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.76
Adjusted Standard Error:
Unadjusted Standard Error: 0.0861
Crash Reduction Factor (CRF)
Value: 24   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 8.61
Applicability
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 948 to Maximum of 9067 Average Daily Traffic (ADT)
Average Traffic Volume:
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: 1997 to 2006
Municipality:
State: PA
Country: U.S.A.
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 171 crashes before, 86 crashes after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Mar-21-2011
Comments: The authors collected data on thru lanes and speed limits but did not provide those data in the report (see p. 50).