User’s Guide for Flashing Yellow Arrow /
Protected-Permissive Left Turn Phasing
by
Irvine Traffic Research & Control Center
(ITRAC)
Jaimee Bourgeois, P.E.
City Traffic Engineer
April 19, 2017
Definitions
• FYA = Flashing Yellow Arrow
• PPLT = Protected-Permissive Left Turn
• MUTCD = Manual on Uniform Traffic Control
Devices
• NCHRP = National Cooperative Highway
Research Program
• FHWA = Federal Highway Administration
2
Overview
•
•
•
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When to use FYA
How to use FYA for PPLT phasing
Why use FYA for PPLT phasing
City of Irvine case study
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When to Use FYA
• Permissive left turns
• PPLT
– FHWA issued “Interim Approval for Optional Use of Flashing
Yellow Arrow for Permissive Left Turns” in March 2006.
– The 2009 edition of the MUTCD includes the Flashing Yellow
Arrow as an allowable alternative display for permissive left-turn
movements.
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When to Use FYA (PPLT)
Alternative to the green ball used in traditional PPLT to
tell drivers that they can turn left after yielding
Traditional PPLT
FYA PPLT
3-Section FYA PPLT
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When to Use FYA
Crash history
Sight distance
# left turn lanes
# opposing lanes
Left turn volume
Opposing traffic speed
Opposing through volume
Left turn delay
Source: Signal Timing Manual
(Second Edition), NCHRP
Report 812, TRB in cooperation
with FHWA.
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When to Use FYA
• Negative offsets to be removed
Source: Signalized Intersections Informational Guide, Second Edition, FHWA, July 2013.
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How to Use FYA
Typical Positioning
Traditional PPLT
MUTCD: Figure 4D-11
FYA PPLT
MUTCD: Figure 4D-12
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How to Use FYA
CA MUTCD Key Points
• Steady left-turn yellow arrow signal indication shall
be displayed following the left-turn green arrow
signal indication (Section 4D.20-03C).
• It shall be permitted to display a FYA while the
adjacent through movement display steady red and
the opposing left-turn display green arrow (Section
4D.20-03F).
• Lagging left operation: A left-turn green arrow signal
indication shall be displayed immediately upon the
termination of the FYA (Section 4D.20-03G).
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How to Use FYA
Typical Sequence
Steady Red Arrow – Stop
Steady Yellow Arrow – Prepare to stop
Flashing Yellow Arrow – Turn left after
yielding to on-coming traffic and
pedestrians
Steady Green Arrow – Left-turn drivers
have the right-of-way
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How to Use FYA
Sequence With Delay Green & Delay Start of Clearance
Opposing
Through
Steady Red Arrow
Steady Yellow Arrow
Flashing Yellow Arrow
Opposing Through
5
S Movement &
+ FDW Terminates
DONT
WALK
Steady Green Arrow
Delay Green
2 Secs
Walk indication is displayed
while red indications
continue to be displayed to
oncoming through and/or
left turning traffic
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How to Use FYA
• Option to program as protected or permissive
only modes during certain times of the day
• Option to use queue detection to activate the
protected only mode (followed by FYA)
• Option to use lead/lag left turn operation
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Why Use FYA
• Increases capacity of the left turn movement
• Safety enhancements (NCHRP Report 493)
– The FYA display was shown to offer the highest
level of safety
– The FYA was found to be the best overall
alternative to circular green as permissive signal
display for a left-turn movement
– FYA was found to have a high level of
understanding and correct response by motorists
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Keep in Mind
• Motorist may assume that the FYA left turn is
terminating when the FYA indication is
illuminated at the same time as the adjacent
through movement yellow
• No standard MUTCD sign for FYA
• Possible design modifications to remove
negative offset, size mast arm appropriately,
and meet pole wind load standards
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Towngate
City of Irvine Case Study
Sand Canyon Ave
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User’s Guide for Flashing Yellow Arrow /
Protected-Permissive Left Turn Phasing
Q&A