CMF / CRF Details

CMF ID: 2281

Improve pavement friction (increase skid resistance)

Description:

Prior Condition:  Sections of pavement with both a high proportion (35-40%) of wet-road crashes and low friction numbers (<32).

Category: Roadway

Study: Safety Effects of a Targeted Skid Resistance Improvement Program, Lyon and Persaud, 2008

 
Star Quality Rating:4 Stars  [View score details]
Rating Points Total:130
Crash Modification Factor (CMF)
Value:0.261
Adjusted Standard Error:0.066
Unadjusted Standard Error:0.066
Crash Reduction Factor (CRF)
Value:73.9  (This value indicates a decrease in crashes)
Adjusted Standard Error:6.6
Unadjusted Standard Error:6.6
Applicability
Crash Type:Rear end,Wet road
Crash Severity:All
Roadway Types:Not Specified
Street Type:
Minimum Number of Lanes:
Maximum Number of Lanes:
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Wet road
Road Division Type:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:All
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:3-leg
Traffic Control:Signalized
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:1994 to 2003
Municipality:
State:NY
Country:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (site-years):348 site-years before, 309 site-years after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jan 01, 1970
Comments:The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.