CMF / CRF Details

CMF ID: 6945

Increase median shoulder width

Description: Increase median shoulder width

Prior Condition: Median shoulder with unspecified width

Category: Shoulder treatments

Study: NCHRP Report 794: Median Cross-Section Design for Rural Divided Highways, Graham et al., 2014

 
Star Quality Rating: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.87
Adjusted Standard Error:
Unadjusted Standard Error: 0.041
Crash Reduction Factor (CRF)
Value: 13   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 4.1
Applicability
Crash Type: Other
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Principal Arterial Other Freeways and Expressways
Number of Lanes: 4
Road Division Type: Divided by Median
Speed Limit:
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: 2001 to 2005
Municipality:
State: CA
Country: USA
Type of Methodology Used: Regression cross-section
Sample Size (miles): 303 miles
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-01-2015
Comments: This CMF applies to a one foot increase in median shoulder width for rollover crashes on four-lane freeways with traversable medians.