CMF / CRF Details

CMF ID: 4819

Change shoulder width from X to Y (in feet)

Description: Change shoulder width on a rural two-lane highway from X to Y (in feet)

Prior Condition: Rural two-lane highway with shoulder width X (in feet)

Category: Shoulder treatments

Study: Efficacies of roadway safety improvements across functional subclasses of rural two-lane highways, Labi, 2011

Star Quality Rating: 2 Stars   [View score details]
Rating Points Total: 40
Crash Modification Factor (CMF)
Value: Equation
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value: Equation
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Type: All
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Major Collector
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:
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 2000
State: IN
Type of Methodology Used: Regression cross-section
Sample Size (site-years): 2160 site-years
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: May-01-2013
Comments: There is no indication of statistical significance in the paper. As such, the star rating does not reflect the level of significance. Also, there is no indication of sample size in terms of number of crashes. The star rating reflects a moderate sample based on the number of site-years.