CMF / CRF Details

CMF ID: 8658

Install safety edge treatment

Description: The safety edge is a low-cost treatment that is implemented in conjunction with pavement resurfacing and is intended to help minimize drop-off-related crashes.

Prior Condition:  Roadway without safety edge

Category: Shoulder treatments

Study: Safety Edge Crash Modification Factors, Hallmark et al., 2016

 
Star Quality Rating:5 Stars  [View score details]
Rating Points Total:140
Crash Modification Factor (CMF)
Value:0.87
Adjusted Standard Error:
Unadjusted Standard Error:0.038
Crash Reduction Factor (CRF)
Value:13  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:3.8
Applicability
Crash Type:Non-intersection
Crash Severity:All
Roadway Types:All
Street Type:
Minimum Number of Lanes:2
Maximum Number of Lanes:2
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:Undivided
Minimum Speed Limit:45
Maximum Speed Limit:
Speed Unit:mph
Speed Limit Comment:> = 45 mph
Area Type:Rural
Traffic Volume:Minimum of 25 to Maximum of 2500 Annual Average Daily Traffic (AADT)
Average Traffic Volume:1406 Annual Average Daily Traffic (AADT)
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:2004 to 2014
Municipality:
State:IA
Country:USA
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):524 crashes after
Sample Size (sites):659 sites before, 659 sites after
Sample Size (miles):418 miles before, 418 miles after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Nov 06, 2017
Comments: