flashing yellow arrow experience if you utilize the …sp.scote.transportation.org/documents/scote...

Flashing Yellow Arrow Experience

Question 1 If you utilize the FYA, is it your standard design practice or is it used only under certain criteria?

Responses:

Alabama

Alabama installed its first FYA in December 2014 at one intersection in the Birmingham area. Then, onemonth later, in January of this year, we installed FYA at 14 intersections on a corridor near Mobile. Wehave plans to install FYAs at 22 intersections in Tuscaloosa and 16 in Huntsville as part of corridor upgradeprojects.

Alaska

In 2009 Alaska adopted the Flashing Yellow Left Turn Arrow (FYA) as a standard for new installations andreconstructions. Lesser retrofit projects could install the FYA, if the four section head could be positionedat least over the lane line of the left turn lane. If the mastarm was not long enough or couldn’t handle theloading, the project wasn’t required to install the FYA, and could retain the five-section “doghouse” forprotected-permitted operation. (Our Chief Engineer Directive is attached. We have since incorporated thelanguage into our state supplement with the most recent MUTCD.)

ConnecticutDave, Connecticut also does not yet use the FYA. We are considering use, but have run into a couple oftechnical issues with some of our standard equipment. I’d be interested to get a copy of what you find outfrom other states.

Delaware We only have one FYA in DE that I can think of and it’s for a right-turn, not left.

GeorgiaFYAs are our standard design practice. For all protected/permissive left turns, we are now installing FYAs.For permissive left turns with an offset storage bay, we are installing 3-section permissive only FYAs.



Responses:

Illinois

In Illinois, we started implementing FYA about 4 years ago in Peoria (our District 4 area) as part of aresearch project. We are still in the process of collecting after-data, but so far the data has shown overall a20%-30% reduction in left-turn crashes. FYA use has since expanded throughout most of our District 4 areaand last year, was first introduced along a corridor in Springfield. FYA is not our standard practice at thistime and several of our districts are still hesitant to implement it, but I do anticipate its use increasingthroughout the state in the near future.

IndianaYes, per our design guidance FYA with 4 section heads are to be used for any protected/permissive left turnmovement (single left turn lane).

Kansas

The DOT has just begun utilizing the flashing yellow arrow (FYA) for about 18 months. As an agency, weonly maintain about 50 traffic signals and only one has the flashing yellow arrow. On the eastern side ofthe state, in Johnson County, many cities have utilized the FYA from the start. The DOT was not receptiveto the FYA initially but some attended a course on signals and were told that the new MUTCD would onlyallow FYA as the option for protected permitted left turn phasing. I would say as of now, FYA would bestandard design practice for KDOT; however, we will allow the cities the option to use or not and supportwhatever their decision is.

Kentucky

We still have option of either FYA or 5-section head, but FYA is quickly becoming our most commoninstallation for new signals/phasing modifications. There are a few situations where our current controller(170) will not accommodate flashing yellow (such as railroad preemption, advance warning flashers, etc.). We are experimenting with 2070 controllers to overcome the limitations in these situations.

MaineMaine only has two of them, we have had mixed comments regarding these, not something we are lookingto do on a regular basis as of now.



Responses:

Maryland Maryland does not use the FYA at this time

Mass

MassDOT has adopted the Flashing Yellow Arrow as our standard for protected-permissive left-turnphasing at approaches that have a separate left-turn only lane since 2013. This standard applies to all newor reconstructed traffic signals on the State Highway system and any locally-owned signal that receivesstate or federal aid for construction costs. At this time we are also recommending that FYA operation beused for permissive-only left turns on approaches with a separate left-turn lane at intersections or incorridors that will be using FYA for protected-permissive movements. FYA remains optional for right-turnmovements, though it is occasionally recommended at intersections that have safety problems associatedwith concurrent pedestrian phases.

Michigan

If we are installing a permissive-protected operation for left turn phasing, we typically install the FYAoperation. On rare occasions we will use the five section head (doghouse) for permissive-protectedoperation. Those are usually at T type intersections where there is left turn phasing in only one direction. If analysis indicates the left turn phasing must be protected only, we have a three color head for the leftturns.

Minnesota

Dave, in Minnesota the FYA is now the standard design practice on our state roadways that have anexclusive left turn lane. Several other local agencies in Minnesota are also starting to install them on thelocal road system too. This decision was based on the FHWA studies regarding the safety aspects of usingthe FYA in place of the green ball for already permissive movements and for the flexibility of operationwhen using the FYA to allow a permissive movement where a protected movement may have been used 24hours a day previously.



Responses:

FYA is Missouri’s standard left turn indication. This is implemented on any new signalized intersectionsinstalled and can be retrofitted on existing intersections if desired. Information for retrofits can be foundin our Engineering Policy Guide, Article 902.5.29.5.

Here is a link to our Engineering Policy Guide where a lot of the information regarding Missouri's use of flashing yellow arrows can be found: http://epg.modot.mo.gov/index.php?title=902.5_Traffic_Control_Signal_Features_%28MUTCD_Chapter_4D%29#902.5.23_Signal_Indications_for_Left-Turn_Movements_.E2.80.93_General_.28MUTCD_Section_4D.17.29 If you would like more information or have any questions, please contact Julie Stotlemeyer at 573-751-0982.

New Hampshire

We were the first state in New England to adopt the FYA. It is our standard display for any permissive leftturn movements on new or upgraded traffic signals. We only have ten or so locations statewide.

New York

New York is just starting to use FYA. We have about a half dozen test sites in the state (mostly in Binghamton) and they were well received. So now we are moving on and are including them in new signal installations where a permissive operation is possible. Like New Hampshire, we underutilize permissive left turns as we had a point in time (20 to 25 years ago) where we began using protective phasing almost exclusively at all new signals. The following link will take you to TSMI 14-05 re: flashing arrows: http://axim22.nysdot.private:7779/portal/page?_pageid=39,401034,39_3875804&_dad=portal&_schema=PORTAL

Missouri



Responses:

North Carolina

Since becoming an approved traffic control device with the 2009 MUTCD, the 4-section FYA is currently ourpreferred method of operation for PPLT signal operation for new and upgraded locations. We use the 3-section FYA for permissive left turns when the face is positioned directly over an exclusive left turn lane,but still use green balls for shared lanes or when the face is not located directly over the exclusive left turnlane (in accordance with the 2009 MUTCD, this is a "should" condition).

North Dakota

North Dakota DOT has been recommending these as part of traffic signal studies for several years. Onlyrecently have cities within North Dakota started to install these. North Dakota DOT currently does nothave any FYAs on any of our state DOT maintained signals. However, that will change for futureinstallations.

OhioOhio DOT currently does not utilize the flashing yellow arrow display within any state signal installation.Would be interested also in your findings.

South Dakota

South Dakota is installing flashing yellow arrows; we began this with the 2009 MUTCD. We are installingthem on projects as we upgrade existing signals or install new ones. We are not systematically replacing all5 section heads with the 4 section flashing yellow arrow head.

Texas

Flashing Yellow Arrows were made a standard by the 2009 National MUTCD and adopted in the 2011 TexasMUTCD. Many cities in Texas implemented the Flashing Yellow Arrow protected permissive operation priorto TxDOT. Attached is TxDOT guidance for implementing the operation on TxDOT signals. The guidelinesdo not make the operation required immediate change out for all signalized intersections. However, theMUTCD has specific standards for allowable signal displays for permissive protected left turn operation thatin many cases require the use of the FYA displays.



Responses:

Virginia

The FYA has become VDOT’s preferred signal head when using protected-permissive left-turn phasing. FYAmay be used anywhere protected-permissive left-turn phasing is used. We are also considering FYA use forpermissive-only left-turn phasing as well. In limited situations, we are also varying the left-turn phasing bytime-of-day using the FYA. We anticipate expanding this technique to leverage all the operationalimprovement opportunities available from the FYA.

WashingtonFlashing yellow arrow is optional for WSDOT. We typically install them to match in with a corridor where alocal agency has opted to use them.

West Virginia

West Virginia is in the same situation and carefully considering FYA use. We look forward to the surveyresults.

Wyoming

Standard. All state signals have been converted to FYA. Approximately 200 movements. We have severaldual left FYA installations that operate protected/permissive. Motorists have figured this out beyond mybelief. Wyoming DOT has adopted the flashing yellow arrow (FYA) display statewide and has replacedalmost every protected/permitted left-turn head on the state highway system to the 4-section all-arrowheads.


Question 2 If it's your standard, what factors did you consider in establishing this standard? If used only under certain criteria, what are those criteria?

Responses

Alabama

It isn't exactly our standard yet to go exclusively FYA but we began employing it when upgrades were neededat positively offset left turn bays with individual signal faces for the left turns, thus requiring the FYA. Wedecided to upgrade all other protected/permissive left turns on those corridors to FYA to be consistent inour operations. An extensive media campaign was launched in the Mobile area prior to implementation with a smaller outreach effort in Birmingham. Driver response has been positive with no reported operationalproblems or crash concerns. Since our 5 regions are somewhat autonomous, THEY make the decision onwhether or not to convert to FYA and some have yet to embrace it. Those that have are excited about themove and are making plans to replace traditional 5-section ‘dog house’ displays with the FYA (4-sectionheads) on future corridor projects and eventually with maintenance forces as those funds allow.

Alaska

We considered the NCHRP Report 493 showing the FYA: “offered the highest level of safety” among thepermissive left turn options tested; was effective at eliminating the “yellow trap;” was readily understood bymotorists; and showed a “higher fail-safe” response as compared to other indications like the circular green. (Fail-safe is a driver response to stop as opposed to go on the green ball indication). For new installations,there shouldn’t be any other considerations.

Delaware

Historically DE has used flashing red arrow (FRA) with good success. In fact, all of the original research onthis topic showed that FRA did well or better compared to the permitted circular green display, but theresearch panel did not like the “come to a full stop” message that was conveyed, in that they were lookingfor a replacement for the traditional permitted display. DE has used FRA as an in between countermeasure,often going to FRA when a crash problem was evident at a traditional permitted or protected-permittedoperation. We stopped installing new FRA in the mid-2000s (fear of it becoming banned in the MUTCD), andonly recently started installed new ones that are compliant with the current manual.

Our guidelines for use are shown on page 107 (Chapter 4) of our newly adopted Traffic Design Manual: http://www.deldot.gov/information/pubs_forms/manuals/traffic_design/index.shtml.



Responses

Georgia

Our main factors for going this route were operational, safety, and practical. Safety-wise, a reduction incrashes had occurred, and operationally we are able to lead-lag more intersections as well as someinnovative time-of-day operation. Practically, we saw the next MUTCD revision moving towards the FYAbeing preferred, and made a decision to adopt early – though that was primarily for safety and operations.

Illinois

I will point out that we have utilized lead/lag with the FYA and have still had some left-turn trap issues forlocations where the left turn lane is directly adjacent to the through lane(s). Drivers were still having atendency to see or focus on the adjacent through lane indications going yellow. We have recommended that lagging protected phases not be used with FYA unless the left turn lane is buried or separated from thethrough lanes for the same direction. We also recommend the use of a LEFT TURN YIELD ON FLASHINGYELLOW ARROW sign as we’ve seen better compliance and understanding of FYA with the sign. At this time,we are not using FYA to switch between protected/permissive and protected only. We would like to getIllinois drivers more accustomed to FYA operation before considering changing left turn modes by time ofday. I would be interested if other states have had any issues with using variable left turn modes with FYA.

IndianaWe considered studies that showed improved driver recognition, and liked the additional flexibility in signaloperation which can decrease delay.

Kansas

The decision to make it our standard is based on a few things: 1) a course some of us attended mentionedthat the upcoming MUTCD is expected to only allow FYA for protected permitted left turn phasing; 2) anumber of cities in Kansas are using FYA, particularly on the eastern half of the state; 3) many communitiesdesire a signal head over the left turn lane. We do support having a sign to help communicate to the driverwhat they are to do when encountering a FYA.



Responses

We originally experimented with locations such as the following:1. Intersections with positive offset left-turn lanes. FYA allows us to hang a separate head over the left-turnlane as opposed to using a shared signal head.2. Intersections with issues regarding left-turn trap and the controller setting we use to eliminate conflict.Examples include: A-Locations where you want protected-permitted in one direction and protected-only inthe other direction. B-Intersections where you want lagging protected-permittted phasing for coordinationpurposes (not possible with current head due to left-turn trap). 3. Community wide modification involving small number of traffic signals and captive audience. We havesince opened up the use of FYA to intersections outside this original criteria.

Mass

While MassDOT is the largest single owner of traffic signals in the Commonwealth (1,400), the majority ofthe traffic signals in Massachusetts are owned and operated by municipalities and state Parks and Portentities. While we cannot dictate what they do on their roadways, they tend to follow our lead, so many arestarting to implement FYA on their own. MassDOT is in the middle of a 4-year project (one 2-year contractfollowed by several shorter contracts) to retrofit the approximately 350 signals on State Highway thatoperate protected-permissive left-turn phasing with FYA operation. These projects are being paid for usingour statewide HSIP money. MassDOT is in the middle of a 4-year project (one 2-year contract followed byseveral shorter contracts) to retrofit the approximately 350 signals on State Highway that operate protected-permissive left-turn phasing with FYA operation. These projects are being paid for using our statewide HSIPmoney.

Which operations we use is all based on analysis of the particular intersection. We use the crash experienceand sight distance for left turning traffic. We also consider the operating speeds of the roadway.

This is a link to our Left turn guidelines: http://mdotcf.state.mi.us/public/tands/plans.cfm Scroll down to Signal Operations and the Left turn guidelines.

Kentucky

Michigan



Responses

Minnesota

We are currently working on putting together guidance to help signal operators determine how to operatorthe signal by time of day. Currently it really is up to the signal operator to know their intersection and whatthe traffic counts are out there by time of day to determine when to operate protected and when to operatepermissive. While this will always be the case, we are hoping to provide some guidance to help the operatormake this decision.

MissouriThe NCHRP research that shows it is a safer left turn operation and the flexibility it provided for time of dayphasing changes.

North Carolina

The research that was conducted (NCHRP Project 3-54, NCHRP Report 493, and NCHRP w123) showed fewerfail-critical responses to the 4-section PPLT FYA display as compared to the 5-section “doghouse” style PPLThead. We wanted to experiment with this new type of operation to see if we could experience the sameresults in NC. Under FHWA Interim Approval, we deployed our first FYA in February, 2005 with good results. We began slowly turning out more designs throughout the state. Our Safety Evaluation Group begancompiling before and after studies and we determined the crashes were showing a decline where the 5-section PPLT heads were being replaced with 4-section heads using FYA operation for PPLTs. We may electto keep 5-section heads in place at certain intersections along corridors where adjacent intersections are stillusing 5-section heads. If at all possible, we are trying to stay consistent from one intersection to the next.As funding become available, the goal is to change the displays at adjacent PPLTs along a corridor to FYAs atthe same time. The same would be true when coming in with the 3-section FYA for permissive left turns.

North Dakota

FYAs are not North Dakotas standard. However, we follow guidance of the MUTCD.



Responses

Texas

The criteria used in the guidelines is basically the same criteria used to determine permissive, protected onlyor permissive protected operation, i.e. number of lanes, speed, geometry, traffic volumes (turning volumesand opposing volumes), crash history, sight distance. etc. There was a 2011 national study (CrashModification Factors Clearinghouse, Study Title: “Evaluation of Safety Strategies at Signalized Intersections”)that indicates a crash reduction when a green ball display is replaced with a flashing yellow arrow display.Initially, it was challenging to implement from a hardware standpoint. However, traffic signal equipmentmanufacturers have improved and updated their equipment to better address the operation. As youimplement, public education is important. We have placed information on our website at:http://www.txdot.gov/inside-txdot/division/traffic/safety/laws/flashing-yellow-arrows.html. If youhave any additional questions, please contact Henry Wickes at 512-506-5125.

Virginia

Originally, our draft FYA guidance noted that left-turn signal indications, whether FYA or circular green,should be consistent along a given corridor. We have since relaxed that, recognizing that it is not possiblefor such wholesale change to happen at once. Except in unusual circumstances, FYA deployment is currentlylimited only by the technical capabilities of the controller & cabinet or the structural loading limitations ofexisting ancillary structures (for retrofit installations). When FYA was first introduced, we did not have aconsistent practice for left-turn phasing decisions. Early in our evaluation, we determined that the criticalquestion was not where to use FYA, but how to choose the appropriate signal phasing. We determined thatonly when protected-permissive signal phasing was appropriate, should the FYA be used. Within the past 3months, VDOT has released a new policy and guidance related to left-turn signal phasing decisions. Thisinformation can be found on our website. We anticipate that as we more critically evaluate our left-turnphasing decisions based on our policy and guidance, we will be using more protected-permissive left-turnphasing and in-turn moreFYA indications.

A flashing yellow arrow is allowed for protected/permissive left-turn operations under the followingconditions:• The approach has a separate left-turn storage lane.



Responses

• At least one separate four-section signal face, in addition to the minimum of two signal faces for theprimary traffic movement on the approach, is to be provided for the left-turn movement. The separate left-turn signal face is to display, from top to bottom (or left to right in a horizontally aligned face), the followingset of indications: steady left-turn red arrow, steady left-turn yellow arrow, flashing left-turn yellow arrow,and steady left-turn green arrow. If the left-turn movement is always operated in the permissive-only mode,the green arrow signal section is to be omitted.• During a protected left-turn movement, the left-turn signal face displays only a steady left-turn greenarrow signal indication.• During a permissive left-turn movement, the left-turn signal face displays only a flashing yellow arrowsignal indication.• During a prohibited left-turn movement, the left-turn signal face displays only a steady left-turn red arrowor a steady circular red.• A steady left-turn yellow arrow signal indication is displayed following every steady left-turn green arrowsignal indication.• A steady left-turn yellow arrow signal indication is displayed following the flashing left-turn yellow arrowsignal indication if the permissive left-turn movement is being terminated and the left-turn signal willsubsequently display a steady red signal indication. The steady left-turn arrow signal indication and theflashing left-turn yellow arrow signal indication are to be separate displays for permissive left turns.

• When a permissive left-turn movement is changing to a protected left-turn movement, a steady left-turngreen arrow signal indication is to be displayed immediately upon termination of the flashing left-turn yellowarrow signal indication. A steady left-turn yellow arrow signal indication is not to be displayed between thedisplay of the flashing left-turn yellow arrow signal indication and the display of the steady left-turn greenarrow signal indication.

Washington



Responses

Wyoming

We were under a rather unique situation in that we had been using 5-section doghouse signals centeredover the left turn lanes, and that was prohibited under the new MUTCD, so we had to make some changes.The positive guidance of the flashing yellow versus a green ball and overall flexibility of operation and theability to lag the left-turn phases (and possibly lead some and lag some or lead/lag by time-of-day tofacilitate progression) were the primary reasons we adopted the flashing yellow arrows. We felt statewideuniformity of all left turn displays was important. We really wanted to lag most of turn arrows to reduceintersection delay. Did not worry about complainers since we built some roundabouts.

Question 3Comparing FYA and circular green only displays for permissive left turns, what does your crash data indicate?

Responses

AlabamaGiven that ours have only been operational for about 5/6 months, we don’t have any before/after crashdata but hope to perform that analysis after sufficient time has elapsed.

Alaska

We haven’t yet performed an in-state analysis of left-turning crashes at locations converted to FYA. Wegenerally wait until we have three full years of post construction crash data, and we’ve just about reachedthat point. 2012 is our latest year of available crash data. We’re getting to more timely data, but we’re notthere yet.

GeorgiaOur crash data is still limited, but currently we are seeing a significant reduction on most intersections. Wecannot yet determine if this is due to the FYA or just because of a change in display in general.

Illinois We hope to have a final report for our FYA research project complete by early next year.

IndianaOur first deployments were in the fall of 2013. We are completing a study through JTRP & Purdue U. that should include crash data, but the data is not available yet.

KansasThe DOT has not run any studies regarding crash data and FYA. Again of the signals we are responsible foronly 1 has a FYA. I am not sure what analysis communities have completed if any. The communities whouse the FYA differ in the type of FYA sign they prefer or if they use a sign at all.



Responses


Early studies conducted by the City of Lexington produced the following results (based on initial/limiteddata):

● Total All Collisions: Percent Reduction: 18%● Total Left Turn Collisions: Percent Reduction: 18% ● Total Injury Left Turn Collisions: Percent Reduction: 22%

The Cabinet’s initial studies did not show any significant safety improvements with FYA. However, weproceeded with its use due to operational efficiencies when compared to 5-section/shared heads. To thebest of my knowledge, there have been no recent crash analysis associated with FYA.

Mass At this time we do not have enough data available to us to make any qualified statements on the safety

MichiganWe haven’t done any in-depth analysis on the crash patterns based on the different indications. The leftturn type crash pattern at an intersection is part of our analysis when reviewing an intersection fordedicated left turn phasing.

Minnesota We have not done any crash analysis at these locations at this time.

Missouri We have not completed any evaluations at this point.

North Carolina

From a 2014 safety evaluation:• where the circular R-Y-G head was replaced with the 3-section FYA for permissive left turns, target crashes were reduced by 50% (57 intersections studied).• where the 5-section heads were changed to 4-section FYA PPLT operation, target crashes were reduced by 22% (105 intersections studied). [Studies conducted in 2010 at 39 sites showed a 37% reduction.]

Kentucky


Responses


North Dakota

We haven’t used these long enough to obtain any usable crash history.

South Dakota

We have not performed a crash analysis of the locations with flashing yellow arrows to compare this tocircular green permissive operation.

Virginia

We analyzed crash data for some of our initial installations and reported a 67% reduction in crashes. In fact,one of our first FYA installations was prompted to address a left-turn crash problem (32 crashes in a 4-yearperiod). Since FYA was installed, there have been no left-turn crashes at this particular intersection. Whileit's unrealistic to expect this experience at all locations, we are confident in the reported FHWA FYA crashreduction factors.

WashingtonWe have only had the flashing yellow operation for a couple years or so, so we haven’t done a comparisonbetween the two yet.

Wyoming

On the crash data, anecdotal evidence is that we certainly didn't add to the crash picture by switching to theFYAs, and we're pretty confident that the crashes are down somewhat; but we've been too short-handed todo a thorough before/after analysis to say how much, if any, changes have happened, nor have we beenable to calculate a definitive crash modification factor to associate with conversion from 5-section leadingdoghouse heads to 4-section lagging FYA heads. Good luck with your investigation. We're happy with ourdecision to change to the FYAs. It did not change much. However, no formal study has been done to date.We are focused more on high speed dilemma zone protection.

Opposing traffic signal headsviewed as if transparent.

Flashing Yellow Left Turn Signal Survey Results

Flashing Yellow Left Turn Signal Survey Results

WYDOTTraffic Program

1

Executive Summary

This report contains a detailed statistical analysis of the results to the survey titled 2013 flashing Yellow Left Turn Arrow Survey. The results analysis includes answers from all respondents who took the survey in the 30 day period from Wednesday, April 17, 2013 to Friday, May 17, 2013. 22 completed responses were received to the survey during this time.

2

Survey Results & Analysis Responses Received: 22

1) Has your state, or any of the local agencies in your state, adopted the flashing yellow left turn arrow heads for use at intersections running both protected and permissive left turn phasing?

3

2) Where are they being used (check all that apply):

Other Responses: New standard for protected/permissive and permissive left turn indication, where appropriate for safety (not high speed or more than 2 opposing thru lanes, etc.) We have upgraded all current signals which have PPLT left-turn phasing Changing to the FYA as locations are modernized Originally installed at locations with special situations such as: offset left-turn lanes, need for pro-perm in one direction and pro-only in other, need for lagging pro-perm, crash history, etc. Now considering everywhere. We have also mostly completed upgrading the 5 section doghouse heads to FYA on the state highway system. Upgrades to existing Prot-Perm intersections but not solely based on crashes Most of our signalized intersections utilize protected only left turn phasing, however, this FYA may be used for locations with protected-permissive phasing

4

3) Have you ever used the 3-section all-arrow left turn heads with flashing

yellow permissive left turn arrows on approaches running permissive-only left turns?

5

4) If you or any of the local agencies in your state use the flashing yellow turn arrow heads, what controller standard does your state use to run them (check all that apply)?

Other Responses: State uses 170. City of Lexington uses 2070.

6

5) What central server do you use to run the 4-section heads (e.g., NWSCentral/Voyage, McCain QuicNet Pro/Omni eX)?

Econolite Centracs NWS NWS Central/Voyage n/a Tactics, IQ Central In-house program NWSCentral/Voyage ? Varies based on the maintaing agency TransSuite MIST (2070/170) FYA operation is supported in the local controllers and MMU Naztec ATMS.now CTNET and in future, Transcore's TSMSS None

7

6) What local controller software do you use to run the 4-section heads (e.g., NWSCentral/Voyage, McCain QuicNet Pro/Omni eX)?

Siemens Eagle EPAC M52, Econolite ASC/3-2100 NWS Voyage Seimans EPAC MOD50 controllers MARC Closed Loop Wapati NWSCentral/Voyage ? Varies based on the maintaing agency NWSCentral/Voyage D4 (2070) Econolite ASC/3 with Reno 1600GE MMU, Siemans EPAC with EDI MMU Siemens EPAC Naztec TSCP (An in-house developed 2070 controller local software) EPAC controller

8

7) When both protected and permissive left turn phasing is used at an intersection do you (choose one)?

9

8) Please check the reasons for always leading the left turn phases (check all that apply):

Other Responses: Driver expectancy, but may lead/lag by time of day, in limited circumstances like T-intersections or where intersection geometry requires "splitting the left turn phase". Has been standard practice and driver expectancy We do it so the motorists have something that is predictable because of the confusion that we have seen with protected-permissive phasing This has been our state's standard protocol. No problems noted that I am aware of. We are using lead/lag for three SCATS projects. The lead/lag varies with TOD for best coordination. General driver expectancy statewide is a leading LT, very few lagging across entire area, only specifc coordination cases with problems

10

9) Please check the reasons for always lagging the left turn phases

(check all that apply):

11

10) Please check the reasons for leading some and lagging other left

turn phases, but not changing the order throughout the day (check all that apply):

Other Responses: The all red phase look funny so some drivers for leading lefts

12

11) Please check the reasons for leading some and lagging other left turn phases, and changing the order throughout the day (check all that apply).

13

12) Describe the type of agency you represent:

14

13) My agency is responsible for the operation and maintenance of roughly (number)

950 446 (with about 20 FYA, more on the way) 0 300 62 3200 155 N/A 2000 1400 2500 1500 2,600 NDOT does not maintain or operate signals 1,500 3060 375 25 3600 190 5,000 20

FYA GUIDANCE – April 17, 2012 1 | P a g e

Guidelines - Flashing Yellow Arrow Display

For Left-Turn Operations

PURPOSE

To provide guidance on new requirements for the design, use and operation of signalized

intersections resulting from the adoption of the 2011 Texas Manual on Uniform Traffic Control

Devices (TMUTCD). These guidelines apply specifically for Signalized Left Turn Operations.

BACKGROUND

The 2011 TMUTCD contains significant changes from the 2006 TMUTCD regarding the

requirements for traffic signal displays. These changes will affect the design and operation of

traffic signals. These changes include the addition of a flashing yellow arrow display for left

turn operations. While a 5-section signal face with a circular green may still be used in a shared

left turn signal face, the use of a circular green indication in a separate left turn signal face has

been prohibited. The flashing yellow arrow (or flashing red arrow) is now the only allowable

indication for a permissive left turn in a separate left turn signal face. The same requirements

also apply to separate signals for right turns.

A definition of shared left turn signal face and separate left turn signal face is provided in the

TMUTCD as follows:

Shared Turn Signal Face—a signal face, for controlling both a turn movement and the

adjacent through movement, that always displays the same color of circular signal indication

that the adjacent through signal face or faces display.

Separate Turn Signal Face—a signal face that exclusively controls a turn movement and that

displays signal indications that are applicable only to the turn movement.

The following are requirements set by the 2011 TMUTCD for protected only, protected /

permissive, and permissive only left turn operations relating to both “shared” and “separate” left

turn signal faces.

For shared signal faces in a protected only operation:

A four-section head with Circular RED, Circular YELLOW, Circular GREEN and left turn

GREEN ARROW is required.

Shared signal faces for protected only operations shall only be used if the Circular GREEN

and GREEN ARROW always terminate together (i.e. Split Phasing).


The figure shown below illustrates the signal face configurations for this left turn operation:

For separate signal faces in a protected only operation:

Signal indications for protected only mode left turns in a separate signal face is required to be

a 3 section signal face with RED ARROW, YELLOW ARROW, GREEN ARROW

indications.



For shared signal faces in a protected / permissive operation:

A five-section head with Circular RED, YELLOW, GREEN, as well as YELLOW ARROW,

GREEN ARROW is required.

Five-section signal faces mounted overhead must be centered over (or slightly right of) a

projection of the lane line dividing the through lane and the turn lane.

The circular indications must display the same color as the adjacent through indications.


For separate left turn signal faces in a protected / permissive operation:

A four-section head with steady left turn RED ARROW, steady left turn YELLOW

ARROW, flashing YELLOW ARROW and steady left turn GREEN ARROW is required.

(As a practice, TxDOT does not currently use the dual arrow signal section.)

The flashing YELLOW ARROW indication is permitted to be displayed while adjacent

through signals display a steady circular RED indication.

The use of a RED ARROW is required to terminate a steady yellow arrow. (Past TxDOT

practice to not use RED ARROW indications is now superseded by this new TMUTCD

requirement.)



For shared signal faces in a permissive only operation:

A three-section head with Circular RED, Circular YELLOW, Circular GREEN is required


For separate signal faces in a permissive only operation:


A three-section head with RED ARROW, steady YELLOW ARROW, and flashing

YELLOW ARROW is required.


DETERMINING LEFT TURN SIGNAL CONTROL MODE

Left-turning traffic is controlled by one of four modes as follows:

A. Permissive Only Mode—turns made on a CIRCULAR GREEN signal indication, a flashing

left-turn YELLOW ARROW signal indication, or a flashing left-turn RED ARROW signal

indication after yielding to pedestrians, if any, and/or opposing traffic, if any.

B. Protected Only Mode—turns made only when a left-turn GREEN ARROW signal indication

is displayed.

C. Protected/Permissive Mode—both protected and permissive modes can occur on an approach

during the same cycle.

D. Variable Left-Turn Mode—the operating mode changes among the protected only mode

and/or the protected/permissive mode and/or the permissive only mode during different

periods of the day or as traffic conditions change.

An engineering study should be conducted to determining the appropriate left-turn signal control

mode (protected only, protected / permissive, permissive only, split phasing, or variable by time

of day) for signalized intersections. The study should take into consideration left turn volumes,

crash history, 85th

percentile (posted) speed, sight distance, number of left turn lanes, number of

opposing through lanes, pedestrian volumes and opposing through volumes. In addition to the

above considerations, intersection geometry can affect the selection of the left turn signal control

mode. Intersections with wide medians, conflicting turning paths, non-standard alignments, etc.

are also factors in determining left turn signal mode.


There are many sources for determining left turn control mode, two flow charts obtained from

recent research projects that may be used as an aid in determining the appropriate left-turn

control mode are:

“Figure 62: Decision-Making Flowchart for Selecting Left-Turn Signal Control Mode,

FHWA/TX-09/0-5840-1, Development of Left-Turn Operations Guidelines at Signalized

Intersections”, Authors: Lei Yu, Yi Qi, Hongxi Yu, Lei Guo and Xin Chen,

Appendix A, “Figure A-6. Guidelines for Determining Left-Turn Operational Mode,

FHWA/TX-11/0-6402-P1, TRAFFIC SIGNAL OPERATIONS HANDBOOK, Second

Edition” Authors: J. Bonneson, S. Sunkari, M. Pratt, and P. Songchitruksa

Development of Left-Turn Operations Guidelines at Signalized Intersections and the Traffic

Signal Operations Handbook can be found at the following links:

http://itri.tsu.edu/Reports/TxDOT_5840-R1.pdf

http://tti.tamu.edu/documents/0-5629-P1.pdf

SIGNAL INDICATIONS FOR LEFT TURN CONTROL MODE

Permissive Only Mode

The 2011 TMUTCD allows for permissive only mode left turns using either a circular GREEN,

flashing YELLOW ARROW, or RED ARROW. If a separate signal section is provided for the

left turn lane, the signal face will need to be as shown in Figure 4D-7 and will require

modification to the controller cabinet to provide the Flashing Yellow Arrow (FYA) operation.

Alternatively, the approach can be provided with signal faces as illustrated in Figure 4D-6,

without need for cabinet modification.

Protected Only Mode

Signal indications for protected only mode left turns in a separate signal face is required to be a

3 section signal face with RED ARROW, YELLOW ARROW, GREEN ARROW indications.

Signal indications for protected only mode in a shared signal face is required to be Circular RED,

YELLOW, GREEN, GREEN ARROW indications. This would be for use where the circular

GREEN and GREEN ARROW indications always begin and end together (i.e. Split phasing).

Protected / Permissive Mode

Signal indications for protected / permissive mode in a separate left turn signal face are required

to be RED ARROW, YELLOW ARROW, Flashing YELLOW ARROW, and GREEN ARROW

(a flashing RED ARROW is also allowed).

Signal indications for protected / permissive mode in a shared signal face are required to be

Circular RED, YELLOW, GREEN, YELLOW ARROW and GREEN ARROW.

TxDOT practice for protected / permissive left turn mode for standard diamond interchanges is

to use a shared signal face, (Flashing YELLOW ARROW is not used for standard diamond

interchanges).

http://tti.tamu.edu/documents/0-5629-P1.pdf


Variable Left Turn Mode

Variable mode operation requires signal indications as defined above for a protected / permissive

separate signal face. Variable mode may be implemented by time of day or possibly by rail or

emergency preemption.

FLASHING YELLOW ARROW LEFT TURN OPERATION INSTALLATION

Where to Install

FYA is an option for permissive/protected left turn phasing. However, as with protected /

permitted operation in general, careful consideration is needed in deciding on where to install the

FYA.

General Guidelines are provided as implementation will vary from one area of the state to

another, there will be varying interest and involvement from local jurisdictions. Some have

existing FYA installations others have no experience with the display. Generally,

implementation should consist of an initial pilot or demonstration project consisting of a few

isolated intersections or a small section of corridor. The district should obtain local buy-in and

approval, providing press releases and information on where the FYA installations are being

installed, what the FYA indications mean, how the motorists should interpret the indications,

explain why we are changing (the benefits).

In identifying pilot projects, typically, sections of corridors with signalized intersections that

have the following characteristics may be considered for installation of protected permissive left

turn operation (Flashing Yellow Arrow or 5 section head):

Low speeds

1 left turn bay per approach

3 or less through lanes

low number of left turn related crashes

adequate driver sight distance to oncoming vehicles

low left turn volume during peak periods

low traffic volume, and

signal coordination plans indicate operational improvement with the FYA permissive-

protected operation

Consideration for installation of protected / permissive left turn operation (Flashing Yellow

Arrow or 5 section head) on sections of corridors with signalized intersections with the following

characteristics is discouraged:

Corridors with multiple signalized intersections in view using solid green ball for permissive

phase

high speeds

dual left turn lanes

4 or more through lanes

high left turn crash history

poor sight distance to oncoming vehicles

high left turn volumes during peak periods or


high traffic volumes

While it is desirable to be consistent in the application of left turn treatment along a corridor for

driver expectation, it may not be practical to install FYA left turn protected / permissive mode in

a consistent manner along a corridor. For example, FYA left turn operation requires a separate

left turn signal face. Signalized intersections along a corridor equipped with shared signal faces

that would require installation of new signal poles with longer mast-arms may be cost prohibitive

to convert to FYA left turn operation. There are existing implementations of FYA that have

resulted in a mix of FYA and 5 section green ball protected / permissive operation. However, it

would be appropriate to install the FYA at a new signalized intersection meeting the criteria for

protected / permissive left turn mode operation on the corridor without immediately modifying

the other existing intersections along the corridor. Preferably, the intersection should not be

within view of other intersections with 5-section green ball.

FYA protected /permissive mode at a location that previously operated in protected only mode

should be considered only after careful study of the intersection. Research study of locations that

were converted from protected only mode to FYA protected /permitted mode saw an increase in

the crash frequency1.

Do not remove protected-only left turn phasing if opposing sight distance

is inadequate for permissive left turns, operating speed is too great, roadway geometry is

complicated or there are too many opposing through lanes. If the protected-only left turn was

installed for other safety reasons (crash prevention when under less restrictive phasing), care

should be used in operating a possible FYA installation protected/ permissive.

Prior to the addition of the FYA left turn signal display to the federal 2009 MUTCD, the FYA

left turn operation was approved as an experimental signal display for protected-permitted mode

and was studied fairly extensively. Before and after crash data indicate there is an improvement

in safety over other protected-permitted left turn displays.

Emergency Pre-emption

Installing Permissive/Protected FYA operation along emergency vehicle preemption routes

requires special study and consideration as well. It will be necessary to work closely with

emergency-vehicles to provide the preemption operation that best fits their preference. Careful

consideration is needed regarding whether to allow or terminate FYA for the opposing left

during preemption. If the FYA is to be turned off during preemption, it will be necessary to

terminate the through phases (go to all red) prior to dropping FYA for preemption.

For example, if the intersection is displaying circular green and flashing yellow arrow for both

approaches of an arterial when a pre-emption becomes active to provide a protected through and

left turn (circular green and green arrow dwell phase) to the approach for the emergency vehicle,

there are 2 possible states for the opposing left turn FYA. The FYA may be allowed to continue

to flash during the preemption dwell phase or it may be terminated. If in the above scenario it is

decided to terminate the opposing left turn FYA, it would be necessary to go to all-red prior to

displaying the dwell phase.

Variable Mode Operation


Variable mode operation, changing between protected only to protected / permissive mode, or

between protected /permissive to permissive only operation by time of day is possible with the

4-section FYA signal face where a study shows this type of operation to be beneficial. However,

it is important to ensure that the traffic signal controller is capable switching between modes in a

manner such that the flashing yellow arrow indication and the opposing through movement

indication terminate together.

In other words, the controller should be capable of transitioning between modes without the

flashing yellow arrow terminating while the opposing through movement stays green.

Additionally, when switching between protected / permissive to permissive only, ensure that the

controller is capable of reassigning the left turn detectors to call the associated through phases by

time of day.

Public Notification

Installation of FYA left turn operation should be coordinated with the District Public Information

Office. Consider press releases with specific details on when the public can expect to see the

new indications. Press releases should be prepared and sent out (approximately 2 weeks or more

in advance of conversion). Special attention should be given to the first installation in an area, if

available, place portable changeable message signs in advance of the affected signals at least

five (5) days before the FYA activation date.

Equipment Issues

The majority of current TxDOT traffic signal equipment is not compatible with FYA operation.

TxDOT signal cabinets can be modified to perform FYA with fairly minor equipment changes.

Prior to installing or converting an intersection to FYA left turn operations it will be necessary to

ensure that there is adequate field wiring, the signal controller cabinet has adequate channels

(load switches), and the controller and Malfunction Management Unit (MMU) are capable of

FYA operation. Configuration of the traffic signal cabinet may be dependent on several

conditions at the intersection. The controller requirements; the monitor requirements; the cabinet

size and available load switches, whether pedestrian signals are being utilized are just a few of

the issues. Careful planning is required to ensure a successful installation.

Cabinet Modification

Controller manufacturers have not standardized on FYA operation. Cabinet modification will

depend on controller make and model. An MMU capable of FYA operation is required. Install a

new MMU recommended by the controller manufacturer. A modification to the cabinet flash

programming is required. Contact the manufacturer representative or TRF-TE Signal Operations

Branch for assistance if needed.

Signing While the 2011 TMUTCD does not require this signing, a “Left Turn Signal – Yield on Flashing

Arrow” (with no graphics) sign should be installed adjacent to the new head for clarification. If

the FYA face is to be installed at an existing location with a 5 section face, verify the sign can be

installed and ensure any conflicting signs such as the “Left Turn Yield on Green” sign (R10-12)

is removed if in place.


Observations

Signal observations should be performed periodically as discretely as possible, and particularly

during the times where the phasing has changed from the previous installation. When converting

left turn signal operations to FYA protected-permissive be sure to observe driver behavior,

especially when the intersection was previously a protected only operation.

Crash Data With the initial FYA installations in your area, monitor the crash data for at least one year after

installation.

Other Considerations

The 2011 TMUTCD provides a new figure, Figure 4d-3, “Recommended Vehicular Signal

Faces for Approaches with Posted, Statutory, or 85th

Percentile Speed of 45 mph or

Higher,” and a new table, Table 4D-1. Recommended Minimum Number of Primary Signal

Faces for Through Traffic on Approaches with Posted, Statutory, or 85th

-Percentile Speed

of 45 mph or Higher. These are shown below for reference. Requirements from this table are a

“should condition,” the table should be consulted for minimum number and location of primary

signal faces for through traffic.


References:

1. David A. Noyce, Casey R. Bergh, Jeremy R. Chapman, NCHRP Web Only Document, 123,

Evaluation of the Flashing Yellow Arrow Permissive-Only Left-Turn Indication Field

Implementation

2. Yi Qi, Xiaoming Chen, Lei Yu, Yubian Wang, Min Zhang, Peina Yuan

and Khali R. Persad, FHWA/TX-09/0-6568-1, “Use of Flashing Yellow Operations to Improve

Safety at Signals with Protected-Permissive Left Turn (PPLT) Operations”

3. Manual on Uniform Traffic Control Devices (MUTCD). Federal Highway Administration,

2009

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