CMF / CRF Details

CMF ID: 6316

Widen paved shoulder from 6 ft to 8 ft

Description: Widening the existing paved shoulder

Prior Condition:  6 ft wide paved shoulder

Category: Shoulder treatments

Study: Safety Effects of Shoulder Paving for Rural and Urban Interstate, Mulitlane, and Two-Lane Highways, Li et al., 2013

 
Star Quality Rating:4 Stars  [View score details]
Rating Points Total:110
Crash Modification Factor (CMF)
Value:1.02
Adjusted Standard Error:
Unadjusted Standard Error:0.02
Crash Reduction Factor (CRF)
Value:-2  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:2
Applicability
Crash Type:Fixed object,Head on,Run off road,Sideswipe
Crash Severity:A (serious injury),B (minor injury),C (possible injury)
Roadway Types:Not specified
Street Type:
Minimum Number of Lanes:3
Maximum Number of Lanes:
Number of Lanes Direction:Both Directions
Number of Lanes Comment:Multi Lane
Crash Weather:Not specified
Road Division Type:
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:
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:2000 to 2006
Municipality:
State:IL
Country:USA
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Mar 11, 2015
Comments:Crash type is "Run-off-road right, then head-on and sideswiped with a vehicle in the opposite direction; Run-off-road right, then sideswiped with a vehicle in the same direction of multilane highways; Run-off-road right, then collided with fixed object on the right; Run-off-road right, then collided with fixed object on the left; Run-off-road right, then overturned in road or roadside involving single vehicle; and Run-off-road right, then overturned in road or roadside involving multiple vehicles" 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.