CMF / CRF Details

CMF ID: 4200

Install dynamic signal warning flashers

Description: Dynamic signal warning flashers (DSWF) provide drivers with advance notice of the phase change. Specifically, the DSWF is linked to the signal and flashers are actuated when the signal is about to change from green to yellow.

Prior Condition:  Signalized intersection without advance warning flashers.

Category: Intersection traffic control

Study: Evaluation of Safety Strategies at Signalized Intersections, Srinivasan, et al., 2011

Image: View the countermeasure image.

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:115
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.086
Crash Reduction Factor (CRF)
Value:25.5  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:8.6
Crash Type:Angle
Crash Severity:All
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:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:All
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:3-leg,4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 7500 to Maximum of 99000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 40 to Maximum of 20100 Annual Average Daily Traffic (AADT)
Average Major Road Volume :27529 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :4836 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:1994 to 2008
Type of Methodology Used:Regression cross-section
Sample Size (crashes):961 crashes
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 06, 2012
Comments:Average major and minor road volumes are computed based on weighted average in NV and VA. AADT applies to all sites.