Jerry Kotzenmacher - Amazon Web Servicesmedia.atssa.com.s3.amazonaws.com/default-file/4(09... · a supplemental LT face (but change it to 4-section all-arrows) or delete it in favor

From: Kotzenmacher, Jerry (DOT)To: Wainwright, Scott (FHWA)Cc: Zarling, Susan (DOT); Bangsund, Timothy (DOT); Schwartz, Kevin (DOT); Kalla, Hari (FHWA); Stein, William

(FHWA); Gerbensky, Michael (DOT)Subject: RE: Flashing yellow arrow head for shared left/through lanesDate: Wednesday, October 26, 2011 2:53:10 PMAttachments: Picture 015.jpg

Picture 009.jpgFYA Shared Left-Through Lane Animation, all cases 10-20-11.ppsx

Hi Scott,It been a while since we last discussed MNDOTs FYA happenings. Just a word of thanks forreviewing our last proposal. We did take your advice on the 5 section multi module indication.Attached are a couple pictures of the actual heads in the field. We have operated the signal as splitphase and permissive at different times of the day using the time of day programming features inthe controller. At this time, there are no issues with the operation or design. It’s been operating forabout 2-3 months. Also attached is an animation for different lane configurations with the idea of using split phasingand permissive phasing on the same approach throughout the day. “Case 3” is the configurationand operation of our current signal mentioned above. Case 1 and 2 show a single shared left/thrulane while operating split, protected/permissive (one direction) and permissive operationthroughout the day. We ask that you review each case and comment back to us. MNDOTs Metrodivision has a few intersections that they want to adopt this multi TOD operation. For your information, Minnesota currently has 58 intersections using the FYA. Additionally, MNDOThas adopted the FYA as the standard left turn design for all new signals. Thanks again for you time and consideration of our request. We look forward to your response!

Jerry KotzenmacherSignals/ITS SectionMinnesota Department of [email protected]

From: [email protected] [mailto:[email protected]] Sent: Tuesday, April 05, 2011 2:30 PMTo: Kotzenmacher, Jerry (DOT)Cc: Zarling, Susan (DOT); Bangsund, Timothy (DOT); Schwartz, Kevin (DOT); [email protected];Stein, WilliamSubject: RE: Flashing yellow arrow head for shared left/through lanes

mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:////c/[email protected]

Case 1

Single left,single through movementsCase 2

Single left,double throughmovementsCase 3

Double left,single through movementsCase 4

Double left,double through movements

1a. With right turn lane2a. With right turn lane3a. With right turn lane4a. With right turn lane

1b. Without right turn lane2b. Without right turn lane3b. Without right turn lane4b. Without right turn lane

Flashing Yellow Arrow with Shared Left-Through Lane:

Proposed Heads and Operation

October 20, 2011

Click a case above to view the animation for that case, or

Cycle through all cases

To exit presentation, hit Esc.

Case 1

Single left,single through movementsCase 2

Single left,double throughmovementsCase 3

Double left,single through movementsCase 4

Double left,double through movements

1a. With right turn lane2a. With right turn lane3a. With right turn lane4a. With right turn lane

1b. Without right turn lane2b. Without right turn lane3b. Without right turn lane4b. Without right turn lane

Flashing Yellow Arrow with Shared Left-Through Lane:

Proposed Heads and Operation

Click a case above to view the animation for that case, or

Cycle through all cases

To exit presentation, hit Esc.

October 20, 2011

Pre-menu

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Lane configuration is fixed, 24 hours a day.

Protected-permissive, one direction only (PM peak)

Permissive (midday)

Split phase (AM peak)

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Case 1

Case 1-1 dummy

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Permissive (midday)


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Case 1 Split phase for playback

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2-9 with flashing yellow arrow

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Case 3

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Case 3

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Case 3

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Split phase (PM peak)

Protected-permissive in one direction typically not used with double-left lane configuration.


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Transition between cases

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Jerry, thanks for presenting me with a very interesting question! First, I want to commend you fortaking advantage of FYA to implement variable phasing by time of day -- a great way to improvecapacity and reduce delays, and one of the many benefits of FYA. I’m not aware of any otheragency trying this operation yet. As usual, MnDOT is one of the leading agencies in implementinggood new MUTCD provisions to improve operations, so again, congratulations on your forwardthinking! Now, here’s my response to your specific question about the signal face for the shared thru-leftlane. I don’t think any of your first 3 choices should be used (and I’d be inclined not to approveexperimentation with any of those 3), because all 3 have more than 5 sections and #1 & #2 haveconflicts with some pretty important positioning and clustering provisions in Sections 4D.08 and4D.09. Take a look at the attached document I prepared that lists the applicable provisions andhow your faces #1, 2, and 3 stack up against them. On that document I also included a #4 – theface shown on your “FYA Heads” sheet as the “standard 5-section doghouse” but with a dual-arrow section (steady green arrow and flashing yellow arrow). I recommend that #4 be used. That one best meets the existing MUTCD provisions. And the oneprovision that it technically violates (4D.09 paragraph 06, item C) is not really a violation of theintent. That item in 4D.09 refers to a specific case in Section 4D.25. If you look at Section 4D.25,paragraph 06, item B, you’ll see that the 5-section doghouse with the dual arrow is specificallyallowed for a case of variable lane-use on an approach with shared left-right lane and no thrumovement, in order to not exceed the max of 5 sections per face. The same logic can be extendedto your specific case, where the lane use doesn’t vary but the mode of left-turn operation varies bytime of day, and you still need to not exceed the max of 5 sections per face. I would be very glad todo an Official FHWA Interpretation on this if you think you need it. Otherwise, I think you could gowith face #4 just based on my unofficial interpretation and/or your engineering judgment. Your “FYA Heads” sheet also notes a potential concern about #4 – “color blindness issues?” Theincidence of yellow-green colorblindness is extremely miniscule. It is really red-greencolorblindness that is more prevalent and that is the reason for the specific relative positioning andclustering provisions in the MUTCD. The use of a “dual-arrow” section that includes both greenand yellow indications is specifically allowed in the MUTCD (Section 4D.06, paragraph 06, plus theparagraph in 4D.25 previously cited) because yellow-green colorblindness is not considered asignificant enough concern to warrant outlawing this dual-arrow use, which, as you can see, is avaluable tool. One other thing – if you are uncomfortable using the dual-arrow section, here are two otherpossible sets of signal faces you could use to deal with your variable phasing situation:

- Increase the number of mast-arm mounted faces from 2 to 3 – put a 4-section all-arrowsface over the LT-only lane, another 4-section all-arrows face over the left half of theshared thru-left lane, and a 3-section R-Y-G balls face on the lane line between the sharedthru-LT lane and the RT lane. Maintain min. 8’ separation between the faces. You wouldstill have the far-right pole-mounted 3-section R-Y-G balls face as the second of the tworequired primary thru faces, and you could either retain the far-left post-mounted face as

a supplemental LT face (but change it to 4-section all-arrows) or delete it in favor of theoverhead LT face over the LT-only lane.

- If a max of 2 faces can be mounted on the mast arm due to length or structural limitations,then change the far-left post-mounted face to 4-section all-arrows, put an overhead 4-section all-arrows face over the lane line between the LT-only lane and the shared thru-left

lane, and put the 2nd overhead face (3-section R-Y-G balls) over the lane line between theshared thru-left lane and the RT lane. And retain the far-right pole-mounted 3-section R-Y-G balls face as the second of the two required primary thru faces.

I hope this information is helpful… Scott W. Scott Wainwright, P.E., PTOEHighway Engineer, MUTCD TeamFederal Highway AdministrationOffice of Transportation Operations, HOTO-11200 New Jersey Avenue, S.E., E84-477Washington, DC 20590 phone: 202-366-0857fax: 202-366-3225e-mail: [email protected]

From: Kotzenmacher, Jerry (DOT) [mailto:[email protected]] Sent: Monday, April 04, 2011 2:34 PMTo: Wainwright, Scott (FHWA)Cc: Zarling, Susan (DOT); Bangsund, Timothy (DOT); Schwartz, Kevin (DOT)Subject: Flashing yellow arrow head for shared left/through lanes Hi Scott, Hope things are going well for you. A small percentage of Minnesota signals use a split phase operation. In many of these cross streetsplit phase operations, we have dual left turn lanes with the center left lane marked as a shared left/through lane. As you know, split phase operation at a traffic signal is favorable for peak hoursbut efficiency is lost during off peak hours. MN/DOT has been pondering a flashing yellow arrow indication that could be used as a split phaseoperation, then a concurrent cross street permissive operation via time-of-day programming. Thelane configuration would be fixed 24 hours a day and permissive lefts would be allowed from thecenter shared left/through lane when volumes are light. Attached is a animation of the operation. Also attached are examples of shared left/through heads that we considered. The ones number 1,2 and 3 are what we currently believe would be most understandable to the driving public. Each

mailto:[email protected]:[mailto:[email protected]]

one gives the same message, they are only configured differently. Figure 1 is the favorite. We do want to try this shared left/through lane application at a location now being designed. Itwould be on the cross street. We would only operate the signal as a split phase, then permissive(concurrent) utilizing the FYA. We believe this proposed indication is not breaking any rules within the 2009 Federal MUTCD. Myquestion to you is do you believe the six section indication as proposed is within the limits of theFederal MUTCD and if not, would MN/DOT need to apply for a “request to experiment”? Additionally, has any other agency considered a shared left/through FYA indication as proposed byMN/DOT? Your consideration and response is appreciated.

Jerry KotzenmacherSignals/ITS SectionMinnesota Department of [email protected]
file:////c/[email protected]

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Jerry Kotzenmacher - Amazon Web Servicesmedia.atssa.com.s3.amazonaws.com/default-file/4(09... · a supplemental LT face (but change it to 4-section all-arrows) or delete it in favor