CMF / CRF Details

CMF ID: 2008

Convert 12-ft lanes and 6-ft shoulders to 12-ft lanes and 3-ft shoulders


Prior Condition:  2-lane rural, undivided. Total width = 34 ft; Lane width = 10 ft; Shoulder width = 7 ft

Category: Roadway

Study: Safety Effectiveness of Lane and Shoulder Width Combinations on Rural, Two-Lane, Undivided Roads, Gross et al., 2009

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:95
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.063
Crash Reduction Factor (CRF)
Value:-11  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:6.3
Crash Type:Run off road
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:Undivided
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Rural
Traffic Volume:Minimum of 1000 Annual Average Daily Traffic (AADT)
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 2001
Type of Methodology Used:Case-control
Sample Size (sites):1411 sites
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 01, 2009