CMF / CRF Details

CMF ID: 4920

Install a "Vehicles Entering When Flashing" (VEWF) system (combination of overhead and advance post mounted signs)

Description: Safety effectiveness of "Vehicle Entering When Flashing" (VEWF) intersection conflict warning systems at stop-controlled intersections

Prior Condition:  stop-controlled

Category: Signs

Study: Evaluation of the Safety Effectiveness of "Vehicle Entering When Flashing" Signs and Actuated Flashers at 74 Stop-Controlled Intersections in North Carolina, Simpson and Troy, 2013

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:105
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.115
Crash Reduction Factor (CRF)
Value:25  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:11.5
Crash Type:All
Crash Severity:All
Roadway Types:Not specified
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:
Minimum Speed Limit:45
Maximum Speed Limit:55
Speed Unit:mph
Speed Limit Comment:
Area Type:All
Traffic Volume:
Average Traffic Volume:
Time of Day:
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:4-leg
Traffic Control:Stop-controlled
Major Road Traffic Volume:Minimum of 3000 to Maximum of 30000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:1996 to 2010
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):67 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Aug 01, 2013
Comments:A linear assumption was used to account for changes in traffic volume at the treatment sites (instead of SPFs).