CMF / CRF Details

CMF ID: 4721

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

Description: Road diets (4 to 3 lane) with low driveway density

Prior Condition:  4 lane road

Category: Roadway

Study: Safety and Operational Analysis of 4-lane to 3-lane Conversions (Road Diets) in Michigan, Lyles et al., 2012

 
Star Quality Rating:1 Star  [View score details]
Rating Points Total:30
Crash Modification Factor (CMF)
Value:1.07
Adjusted Standard Error:
Unadjusted Standard Error:
Crash Reduction Factor (CRF)
Value:-7  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:
Applicability
Crash Type:All
Crash Severity:All
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:3
Maximum Number of Lanes:4
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:
Traffic Volume:Minimum of 3510 to Maximum of 17020 Average Daily Traffic (ADT)
Average Traffic Volume:10652 Average Daily Traffic (ADT)
Time of Day:
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:1995 to 2010
Municipality:
State:MI
Country:
Type of Methodology Used:Simple before/after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:May 01, 2013
Comments:For low driveway density areas. The number of crashes in the after period were not reported in this study, however, they have been recorded as 300 to give 10 points as a beneift of doubt for one or more of the following: (1) number of miles/sites in the reference/treatment group, (2) number of crashes in the references/treatment group, (3) reporting AADTs for the aggregate dataset but not for the disaggragate dataset used for CMF development.