CMF / CRF Details

CMF ID: 2004

Convert 12-ft lanes and 6-ft shoulders to 10-ft lanes and 4-ft shoulders


Prior Condition: 2-lane rural, undivided. Total width = 28 ft; Lane width = 10 ft; Shoulder width = 4 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: 105
Crash Modification Factor (CMF)
Value: 1.2
Adjusted Standard Error:
Unadjusted Standard Error: 0.051
Crash Reduction Factor (CRF)
Value: -20   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 5.1
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
State: PA
Type of Methodology Used: Case-control
Sample Size (sites): 2799 sites
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Dec-01-2009