CMF / CRF Details

CMF ID: 4030

Adjust All-Red Clearance Interval

Description: The Fitch et al. procedure for calculating all-red clearance intervals takes into account intersection geometry and vehicle speeds. For further detail on this method, please refer to the paper.

Prior Condition:  No Prior Condition(s)

Category: Intersection traffic control

Study: A Rational Method for Setting All-Red Clearance Intervals, Fitch et al., 2011

 
Star Quality Rating:1 Star  [View score details]
Rating Points Total:20
Crash Modification Factor (CMF)
Value:0.6
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value:40  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type:Angle,Head on,Sideswipe
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Not Specified
Street Type:
Minimum Number of Lanes:
Maximum Number of Lanes:
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:
Traffic Volume:
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:
Municipality:Sacramento County
State:CA
Country:
Type of Methodology Used:Simple before/after
Sample Size (site-years):118 site-years before, 118 site-years after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jun 04, 2012
Comments:The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.