CMF / CRF Details

CMF ID: 7938

Increase from 4 lanes to 6 lanes

Description:

Prior Condition:  4 lane roadway with LOS E

Category: Roadway

Study: Assessment of safety effects for widening urban roadways in developing crash modification functions using nonlinearizing link functions, Park et al., 2015

 
Star Quality Rating:4 Stars  [View score details]
Rating Points Total:110
Crash Modification Factor (CMF)
Value:0.742
Adjusted Standard Error:
Unadjusted Standard Error:0.157
Crash Reduction Factor (CRF)
Value:25.8  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:15.7
Applicability
Crash Type:All
Crash Severity:K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Not specified
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:
Minimum Speed Limit:40
Maximum Speed Limit:60
Speed Unit:mph
Speed Limit Comment:
Area Type:Urban
Traffic Volume:Minimum of 20500 to Maximum of 60683 Annual Average Daily Traffic (AADT)
Average Traffic Volume:
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:2003 to 2012
Municipality:
State:FL
Country:
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):37 sites before
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Mar 08, 2016
Comments:LOS change from E (4 lanes) to D (6 lanes) 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.