CMF / CRF Details

CMF ID: 4125

Increase shoulder width from 0 to 10 feet

Description: Increase shoulder width from 0 to 10 feet on rural, two-lane roads.

Prior Condition: Increase shoulder width from 0 feet to 10 feet on a rural, two-lane road. The CMF applies to single-vehicle crashes on tangent sections.

Category: Shoulder treatments

Study: Investigating the Effect of Roadside Features on Single-Vehicle Roadway Departure Crashes on Rural Two-Lane Roads, Yichuan Peng, Srinivas Reddy Geedipally, and Dominique Lord, 2012

Star Quality Rating: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.29
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value: 71   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Type: Run off road,Single vehicle
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Not Specified
Number of Lanes: 2
Road Division Type: Undivided
Speed Limit:
Area Type: Rural
Traffic Volume: Minimum of 3500 to Maximum of 3500 Average Daily Traffic (ADT)
Average Traffic Volume: 3500 Average Daily Traffic (ADT)
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: 2003 to 2008
State: TX
Country: USA
Type of Methodology Used: Regression cross-section
Sample Size (crashes): 197 crashes
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-01-2012
Comments: This CMF applies to single-vehicle run-off-road crashes on tangent sections of rural, two-lane roads. Additional CMFs could be derived from the analysis, but the authors only report the crash reduction for the following conditions: ADT of 3500 vehicles per day and change in shoulder width from 0 to 10 feet.