CMF / CRF Details

CMF ID: 2216

Increase separation distance between driveway exit and downstream U-turn by 10% (m)


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: 3 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.967
Adjusted Standard Error:
Unadjusted Standard Error: 0.0118
Crash Reduction Factor (CRF)
Value: 3.3   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 1.18
Crash Type: All
Crash Severity: All
Roadway Types: Principal Arterial Other
Number of Lanes: 6
Road Division Type:
Speed Limit: 50-55mph
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 Average Daily Traffic (ADT)
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used: 2003 to 2005
State: FL
Type of Methodology Used: Regression cross-section
Sample Size (site-years): 280 site-years
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Dec-01-2009