CMF / CRF Details

CMF ID: 4968

Convert a 2 ft. turf shoulder to a 10 ft. paved shoulder (bituminous base)

Description: Convert a 2 ft. turf shoulder to a 10 ft. paved shoulder (bituminous base)

Prior Condition:  2 ft. turf shoulder

Category: Shoulder treatments

Study: Safety Effectiveness of Various Types of Shoulders on Rural Two-Lane Roads in Winter and Non-Winter Periods, Zeng and Schrock, 2013

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:105
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.038
Crash Reduction Factor (CRF)
Value:16  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:3.8
Crash Type:All
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:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Rural
Traffic Volume:
Average Traffic Volume:3535 Annual Average Daily Traffic (AADT)
Time of Day:Not specified
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:2003 to 2007
Type of Methodology Used:Regression cross-section
Sample Size (crashes):3091 crashes
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Aug 01, 2013
Comments:CMF represents winter period crashes only. Study assumes a 6 month winter period from October 16 through April 15.CMF is significant at the 0.05 level.