CMF / CRF Details

CMF ID: 10376

Road diet (Convert 4-lane undivided road to 2-lanes plus turning lane)

Description:

Prior Condition:  Urban 4-lane undivided roadway

Category: Roadway

Study: Investigating Safety Impact of Center Line Rumble Strips, Lane Conversion, Roundabout and J-Turn Features on Louisiana Highways, Sun and Rahman, 2019

 
Star Quality Rating:4 Stars  [View score details]
Rating Points Total:125
Crash Modification Factor (CMF)
Value:0.613
Adjusted Standard Error:
Unadjusted Standard Error:0.125
Crash Reduction Factor (CRF)
Value:38.7  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:12.5
Applicability
Crash Type:Non-intersection
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:Undivided
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Urban
Traffic Volume:Minimum of 8333 to Maximum of 13900 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
Time of Day:Not specified
If countermeasure is intersection-based
Intersection Type:
Intersection Geometry:
Traffic Control:
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:2005 to 2016
Municipality:
State:LA
Country:USA
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):60 crashes before, 40 crashes after
Sample Size (sites):4 sites before, 4 sites after
Sample Size (miles):3.92 miles before, 3.92 miles after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Jun 01, 2020
Comments:Safety performance function for 4-lane highway used for the analysis has been previously developed for the state of Louisiana.