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:
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:
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.