CMF / CRF Details

CMF ID: 5459

Convert an open median to a left-in only median

Description: Convert a full median opening to a left-in only median

Prior Condition: Roadways 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: 2 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 1.31
Adjusted Standard Error:
Unadjusted Standard Error: 0.4669
Crash Reduction Factor (CRF)
Value: -31   (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 46.69
Applicability
Crash Type: All
Crash Severity: K (fatal),A (serious injury)
Roadway Types: Principal Arterial Other
Number of Lanes: 4 to 6
Road Division Type: Divided by Median
Speed Limit: 40mph to 55mph
Area Type: Urban and suburban
Traffic Volume: Minimum of 45000 to Maximum of 75000 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): 26 crashes after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Apr-30-2014
Comments: CMF for KA 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.