CMF / CRF Details

CMF ID: 5455

Convert an open median to a directional median

Description: Convert a full median opening to a directional median opening

Prior Condition:  Roadway with full median openings

Category: Access management

Study: Safety Effects of Median Treatments Using Longitudinal Channelizers: Empirical Bayesian Before-and-After Study, Zhou et al., 2013

 
Star Quality Rating:3 Stars  [View score details]
Rating Points Total:100
Crash Modification Factor (CMF)
Value:0.82
Adjusted Standard Error:
Unadjusted Standard Error:0.0894
Crash Reduction Factor (CRF)
Value:18  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:8.94
Applicability
Crash Type:All
Crash Severity:C (possible injury)
Roadway Types:Principal Arterial Other
Street Type:
Minimum Number of Lanes:4
Maximum Number of Lanes:6
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:Divided by Median
Minimum Speed Limit:40
Maximum Speed Limit:55
Speed Unit:mph
Speed Limit Comment:
Area Type:Urban and suburban
Traffic Volume:Minimum of 27000 to Maximum of 96000 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
Time of Day:Not specified
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 2010
Municipality:Tampa
State:FL
Country:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):109 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Apr 30, 2014
Comments:CMF for C crashes (based on the KABCO scale). The SPF only included VMT. It was not clear if annual calibration factors or other methods were used to account for trends.