CMF / CRF Details

CMF ID: 7933

Increase from 4 lanes to 6 lanes

Description:

Prior Condition: 4 lane roadway

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: 5 Stars   [View score details]
Rating Points Total: 135
Crash Modification Factor (CMF)
Value: 0.702
Adjusted Standard Error:
Unadjusted Standard Error: 0.084
Crash Reduction Factor (CRF)
Value: 29.8   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 8.4
Applicability
Crash Type: All
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Not specified
Number of Lanes:
Road Division Type:
Speed Limit: 40-60
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: 2
Sample Size (crashes): 162 crashes before
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Mar-08-2016
Comments: CMF after 4th year of treatment 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.