Flashing Yellow Arrow History: The Evolution and Impact in Traffic Engineering
Detailed overview of the introduction and implementation of the Flashing Yellow Arrow (FYA) in traffic engineering, including its history, studies, installations, and impact on crash rates. The journey from inception to widespread adoption, with insights on its efficacy and safety implications.
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Presentation Transcript
Tim Tharpe TEBM Traffic Engineering Division of Traffic Operations ARROW
Flashing Yellow Arrow History What Is It? KYTC/Louisville Metro/LFUCG Analysis The Future
Flashing Yellow Arrow History initiated In protected/permitted left-turn signal displays Study lasted 7 years, considered many alternatives In 2003, NCHRP Report 493 published FYA performed the best Intuitive Time-of-day, yellow trap , additional signal head Interim approval granted by FHWA on March 20, 2006 Further experimentation Added to 2009 MUTCD 1990, NCHRP evaluation of
Flashing Yellow Arrow History First installation of FYA in Kentucky: Jefferson County KY 1747 (Hurstbourne Lane) @ Dorsey Lane Installed November 9, 2009 Others soon followed throughout the state
Flashing Yellow Arrow KYTC Analysis Comprehensive crash review 50 intersections with FYA as of April 1, 2011 (40 reviewed) Before and After comparison 100 days All crashes (primary focus on left-turn, angle, head-on, sideswipe)
Flashing Yellow Arrow KYTC Analysis Conclusions: FYA did not appear to be a factor in crashes Overall crashes increased 22.13% Left-turn crashes decreased 30% Changes were generally +/- one crash Overall injuries decreased 2.56%
Flashing Yellow Arrow Louisville Metro KY 1447 (Westport Road) @ I-265 On-Ramp Protected/Permitted T-intersection High volumes Significant left-turn crash history Less efficient protected-only not desired
Flashing Yellow Arrow Louisville Metro FYA installed August 20, 2011 No other countermeasures performed Left-turn crashes before FYA installation: 19 (January 2008 August 20, 2011) 5.2 left-turn crashes per year Left-turn crashes after FYA installation: 1 (August 20, 2011 to October 25, 2012) Preferred treatment
Flashing Yellow Arrow Lexington Fayette Urban County Government (LFUCG) FYA installed at numerous locations throughout Lexington Before/After study 18% reduction in all crashes 18% reduction in left-turn crashes 22% reduction in left-turn injury crashes Preferred treatment
Flashing Yellow Arrow Where Do We Go From Here? Approval Process: Preferred treatment for Protected/Permitted No longer requires Central Office approval* *Doghouse to 4-section FYA (with green) OK *Permitted left to 3-section FYA (no green) OK Provide Central Office with a revised Traffic Signal Checklist including date/time of installation Protected-Only to FYA or other phase change Central Office Approval
