CMF / CRF Details

CMF ID: 9851

Increase Median Width

Description: Increase median width

Prior Condition: Existing Median Width

Category: Roadside

Study: In-Service Performance Evaluation of Median Cable Barriers in Iowa, Savolainen et al., 2018

Star Quality Rating: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: Equation
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Type: Cross median
Crash Severity: All
Roadway Types: Principal Arterial Other Freeways and Expressways
Number of Lanes:
Road Division Type: Divided by TWLTL
Speed Limit:
Area Type: All
Traffic Volume: Minimum of 1832 to Maximum of 37580 Annual Average Daily Traffic (AADT)
Average Traffic Volume: 10232 Annual Average Daily Traffic (AADT)
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: 2011 to 2015
State: IA
Country: USA
Type of Methodology Used: Regression cross-section
Sample Size (crashes): 1715 crashes
Sample Size (sites): 3629 sites
Sample Size (site-years): 18145 site-years
Sample Size (miles): 1140 miles
Sample Size (mile-years): 5700 mile-years
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-19-2018
Comments: Applies to cross-median crashes on expressways not related to animals. Median width measured in feet.