CMF / CRF Details

CMF ID: 2215

Increase separation distance between driveway exit and downstream U-turn by 10% (m) (crashes related to indirect left turns)


Prior Condition:  No Prior Condition(s)

Category: Access management

Study: Impacts of Separation Distance between Driveway Exist and Downstream U-turn Locations on the Safety Performance of Right-turns Followed by U-turns, Liu et al., 2008

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:110
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.013
Crash Reduction Factor (CRF)
Value:4.5  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:1.3
Crash Type:All
Crash Severity:All
Roadway Types:Principal Arterial Other
Street Type:
Minimum Number of Lanes:6
Maximum Number of Lanes:6
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:50
Maximum Speed Limit:55
Speed Unit:mph
Speed Limit Comment:
Area Type:
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:
Traffic Control:
Major Road Traffic Volume:Minimum of 18200 to Maximum of 86300 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:2003 to 2005
Type of Methodology Used:Regression cross-section
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 01, 2009
Comments:Only for crashes related to indirect left turns