CMF / CRF Details

CMF ID: 5231

Convert traffic signals to unconventional median U-turns

Description: Remove existing traffic signals and replace with unconventional median U-turn

Prior Condition:  Three and Four-Leg Signalized Intersections

Category: Intersection geometry

Study: Safety Effect of U-Turn Conversions in Tehran: Empirical Bayes Observational Before-And-After Study and Crash Prediction Models, Leila Azizi and Abdolreza Sheikholeslami, 2013

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:130
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.06
Crash Reduction Factor (CRF)
Value:-13.2  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:6
Crash Type:All
Crash Severity:All
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:3
Maximum Number of Lanes:
Number of Lanes Direction:Both Directions
Number of Lanes Comment:Multi Lane
Crash Weather:Not specified
Road Division Type:Divided by Median
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Urban
Traffic Volume:
Average Traffic Volume:
Time of Day:Not specified
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:Not specified
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 33650 to Maximum of 70579 Average Daily Traffic (ADT)
Minor Road Traffic Volume:Minimum of 9405 to Maximum of 31789 Average Daily Traffic (ADT)
Average Major Road Volume :46666 Average Daily Traffic (ADT)
Average Minor Road Volume :16757 Average Daily Traffic (ADT)
Development Details
Date Range of Data Used:2001 to 2009
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):286 crashes before, 556 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 02, 2013