CMF / CRF Details

CMF ID: 4666

Convert a conventional unsignalized intersection to an unsignalized superstreet

Description: Convert a conventional unsignalized intersection to an unsignalized superstreet (also known as a restricted crossing U-turn intersection or a J-turn intersection)

Prior Condition:  Conventional unsignalized intersection.

Category: Intersection geometry

Study: Field Evaluation of a Restricted Crossing U-Turn Intersection, Inman and Haas, 2012

Image: View the countermeasure image.

 
Star Quality Rating:2 Stars  [View score details]
Rating Points Total:65
Crash Modification Factor (CMF)
Value:0.56
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value:44  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type:All
Crash Severity:All
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:4
Maximum Number of Lanes:4
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:Divided by Median
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Rural
Traffic Volume:
Average Traffic Volume:
Time of Day:Not specified
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:4-leg
Traffic Control:Stop-controlled
Major Road Traffic Volume:Minimum of 10000 to Maximum of 45000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:
Municipality:
State:MD
Country:USA
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):262 crashes before
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:May 01, 2013
Comments:Although the empirical Bayes method was adopted, a reference group was not chosen for calibrating the SPFs. Standard errors were not provided for the CMF.