CMF / CRF Details

Convert an open median to a directional median

Countermeasure ID: 5456

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:85
Crash Modification Factor (CMF)
Value:1.13
Adjusted Standard Error:
Unadjusted Standard Error:0.1703
Crash Reduction Factor (CRF)
Value:-13  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:17.03
Applicability
Crash Type:All
Crash Severity:O (property damage only)
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):233 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Apr 30, 2014
Comments:CMF for PDO 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.

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