CMF / CRF Details

CMF ID: 6661

Widen shoulder


Prior Condition: Original shoulder width 4-6 ft

Category: Shoulder treatments

Study: Exploration and comparison of crash modification factors for multiple treatments on rural multilane roadways, Park et al., 2014

Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.617
Adjusted Standard Error:
Unadjusted Standard Error: 0.078
Crash Reduction Factor (CRF)
Value: 38.3   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 7.8
Crash Type: All
Crash Severity: All
Roadway Types: Not specified
Number of Lanes: multi
Road Division Type:
Speed Limit:
Area Type: Rural
Traffic Volume: Minimum of 2000 to Maximum of 50000 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
Time of Day:
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 2012
State: FL
Type of Methodology Used: Other before/after
Sample Size (sites): 44 sites before
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Jun-22-2015
Comments: Before condition shoulder width between 4-6 ft. Study method was either EB or CG, the authors chose the method that had the lowest SE.