CMF / CRF Details

CMF ID: 2774

Install offset right turn lane

Description: Install offset right turn lane to improve sight distance for vehicles on minor road

Prior Condition:  No Prior Condition(s)

Category: Intersection geometry

Study: NCHRP Report 650 - Median Intersection Design for Rural High-Speed Divided Highways, Maze et al., 2010

 
Star Quality Rating:1 Star  [View score details]
Rating Points Total:10
Crash Modification Factor (CMF)
Value:0.94
Adjusted Standard Error:
Unadjusted Standard Error:0.48
Crash Reduction Factor (CRF)
Value:6.15  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:47.7
Applicability
Crash Type:All
Crash Severity:All
Roadway Types:Principal Arterial Other Freeways and Expressways
Street Type:
Minimum Number of Lanes:
Maximum Number of Lanes:
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:All
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 7350 to Maximum of 8000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 1350 to Maximum of 1425 Annual Average Daily Traffic (AADT)
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:2000 to 2006
Municipality:Floyd
State:IA
Country:USA
Type of Methodology Used:Simple before/after
Sample Size (crashes):8 crashes before, 8 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Mar 21, 2011
Comments:For 1 approach. Authors state that adverse weather conditions may have contributed to crashes in after period and that the offset lane may have contributed to driver confusion.