DDI contest announcement by 0Ot0AvJ


									                 TRB Traffic Signal Systems Committee Summer Meeting—July 23, 2012

Contest: Can You Operate a Divergent Diamond?

To encourage the development of a range of signal operations and evaluation approaches for divergent
diamonds, present them to a body of experts, and publish them in a white-paper compendium that can
be freely distributed to the community.

To bring traffic signal experts together to do what they love to do: Solve other peoples’ problems and
argue endlessly about which approach is best, preferably well into Happy Hour.

Underlying Principle: Having fun is serious business.

The Problem
Divergent Diamond Interchanges (DDIs) (aka Double Crossover Diamonds), like some other alternative
intersection designs, have captured the interest of not only traffic engineers but also the general public.
Simulations have been constructed in the research environment, examples have been built, and signal
operation has been developed and installed. Lessons have been learned and documented from these
early examples. But experience indicates that innovative geometries sometimes produce unintended
consequences for traffic signal operators that require perhaps several generations of development to
address, and experience also has shown that it takes some trial and error to find those signal operations
schemes that work best.

Your mission, should you choose to accept it, is to design and evaluate signal operation for a real
divergent diamond, at I-44 and MO-13 (See figure).

The construction plans for this interchange are included in the document linked here (27MB download


The Google Maps location is linked here:

                TRB Traffic Signal Systems Committee Summer Meeting—July 23, 2012

Figure 1. I-44 and Kansas Expressway (Mo 13)

Note that this interchange includes a twist—two nearby intersections just north and just south of the
interchange. The intersection to the north is at Norton Road, and to the south at the entrance to the
WalMart, between the McDonalds and the Casey’s (the working name for this street is “Evergreen”, but
it has not been named officially).
                 TRB Traffic Signal Systems Committee Summer Meeting—July 23, 2012

The signal timing plans must include a description of how the operation at the diamond will be
coordinated with the operation at these two intersections. Bonus points will be awarded for providing a
coordination scheme that works in free-actuated mode in addition to coordinated mode.

Your mission includes designing signal operation; evaluating that operation using any tool, method, or
combination thereof that is generally available; and presenting the design and evaluation at the TRB
Signal Systems Committee Summer Workshop on July 23, 2012, at the Beckman Center in
Irvine, in accordance with The Rules.

It is a contest, and there will be points given and prizes awarded. Okay, there won’t be points. Okay,
there won’t be prizes. Okay, there may be humiliation. Certainly there will be good times, camaraderie,
service to our colleagues, and perhaps an appropriately quenched thirst.

Judging will be provided by the crowd based on some variation of mob rule. Forewarned is forearmed.
Each contestant will be challenged during the presentation by a Skeptics Squad, membership to be
determined and announced at the event. Invitations have not been made as yet, but think Rick Denney
and Tom Urbanik. Be afraid. Be very afraid. The Skeptics Squad will have the following charge:

       Identify strengths and weaknesses in the designs and how they are evaluated, particularly in
        relation to the stated objectives
       Generally make the lives of the presenters miserable for the entertainment of the crowd
       Failing that, attack each other for the entertainment of the crowd

Have we scared you off yet? If not, here are The Rules:

The Rules
    1. The objectives of the operation must be articulated. For example, is the objective to provide
       uninterrupted movements on the arterial? Congestion avoidance using throughput
       maximization? Congestion management using queue management? Delay minimization?
       Pedestrian service? Something else? What was the chosen object selected: is the operation
       serving residential neighborhoods? Serving retail land uses? Serving commuter patterns? The
       Skeptics Squad may comment on the relationship between the objectives, design, and
    2. The contestants must provide timings for each of two scenarios—a lunch-time scenario and a
       peak scenario. The volumes are provided below at the end of this document. The volumes are
       15-minute counts provided by MoDOT.
    3. This contest is not about proving or disproving the value of divergent diamonds as a geometric
       solution. Please don’t go there. But please do identify any difficulties in achieving an acceptable
       operation that are the result of the geometry. Then, find a way to overcome them to the extent
             TRB Traffic Signal Systems Committee Summer Meeting—July 23, 2012

4. MoDOT will provide an invited presentation describing their approach, and they will be immune
    from the Skeptics Squad and they will not be part of the competition. Their phasing approach is
    identified in the plans linked above. It’s okay to use their approach, but contestants must be
    prepared to defend that choice. It’s okay to do it differently, but contestants must be prepared
    to defend that choice. Contestants are encouraged to articulate different objectives to provide
    alternative approaches.
5. Signal operation must be possible using conventional NEMA-style controllers using features
    generally available from all manufacturers. (Adaptive control methods should not be used, but
    it’s okay to mention potential adaptive opportunities that emerge.) The contestants may choose
    whether to operate the ends of the diamond with one controller or two. Contestants should
    assume that each approach will have both advantages and disadvantages, and identify them.
6. Any necessary communications infrastructure may be assumed, but must be identified.
7. The design must include the following:
         a. Arrangement of signal heads (in a way that does not require levitation)
         b. Arrangement of pavement markings. Modifying the markings at the test intersection IS
             ALLOWED, but must be justified. Pavement edges may not be moved, nor can number
             of lanes be changed (though their movement assignment can be).
         c. Phase/Overlap assignments to each traffic movement. A NEMA ring diagram is required
             showing barrier and sequence arrangements.
         d. Any controller special features necessary to the operation.
         e. Coordination timing, if used. Bonus points (except that there are no points) will be
             awarded for coordination schemes between the interchange and the nearby
             intersection that can run as actuated free operation.
8. The design must fulfill all the requirements of the MUTCD.
9. The design must accommodate pedestrians in a way that conforms to ADA requirements. The
    demand tables show zero numbers of pedestrians, but that’s because they were not counted.
    Pedestrians may cross at any normal intersection crossing. If pedestrians are prohibited from
    any movements, a plan for how all property can be reasonably accessed by pedestrians must be
10. The evaluation must demonstrate how objectives are achieved.
11. The evaluation must provide some objective measurement. “It operates very nicely, thank you”
    will not be an acceptable evaluation, despite that it is a favorite for at least one of the skeptics.
    Bonus points (except that there are no points) will be awarded for measurement methods that
    can be automated and built into the infrastructure of the signal equipment.
12. The evaluation must use tools and methods that are generally available. Those methods may be
    developed by the contestant, but they must be sufficiently described to allow others to use
    them. The point of the evaluation is not to provide fodder for making judgments, but for
    providing tools for designers and operators that can be traced to objectives.
13. The submission must be in writing (so that we can include it in a compendium), but judging will
    be based on the presentation (because that’s where the mob will be).
14. Pitchforks and torches will not be provided to the audience.
                 TRB Traffic Signal Systems Committee Summer Meeting—July 23, 2012

    15. The presentation must take no longer than 30 minutes, including Skeptic Squad heckling. No, it’s
        not fair. Get over it.
    16. If you don’t follow the rules, oh, well. Did we say there are no points? But at least try.
        Remember the humiliation danger.

Interest statements from prospective participants are required by May 10, and should include who is
participating in that team (if more than one person), who is the corresponding author, a commitment to
send a presenter to the workshop, and a commitment to bring a written document providing the
required information to the workshop. If we have too many participants (miracles could occur), we’ll
devise a strategy to be more selective at that time. That may require some discussion with those who
have expressed interest. If we don’t get interest, arms will be twisted. Interest statements should be
emailed to both of the following:

Rick Denney (richard.denney@dot.gov)

Susan Langdon (susan@savantgroupinc.com)

A Final Word
Obviously, we intend to have a lot of fun. But it is serious, and if we can provide a toolbox of operational
and evaluation methods to practitioners, we can serve our colleagues by productively contributing an
operational perspective to the conversation on divergent diamond interchanges.
                   TRB Traffic Signal Systems Committee Summer Meeting—July 23, 2012

Traffic Volumes for Divergent Diamond Signal Operation Competition
All counts are 15-minute actual counts.

MO13 (Kansas Expressway) and Norton Road
Street Name      Kansas Expressway Southbound            Norton Road Westbound            Kansas Expressway Northbound   Norton Road Eastbound
Start Time         Right    Thru      Left     Peds      Right       Thru   Left   Peds   Right   Thru    Left    Peds   Right    Thru     Left       Peds
12:15 PM           5        160       5        0         5           5      31     0      53      136     46      0      31       10       4          0
4:45 PM            6        166       5        0         24          13     54     0      76      262     43      0      31       11       13         0

MO13 (Kansas Expressway) and I-44 Westbound Ramp
Street Name      Kansas Expressway Southbound            I-44 WB RAMP Westbound           Kansas Expressway Northbound   I-44 WB RAMP Eastbound
Start Time         Right    Thru      Left     Peds      Right       Thru   Left   Peds   Right   Thru    Left    Peds   Right    Thru     Left       Peds
12:15 PM           39       166       0        0         56          0      54     0      0       115     17      0      0        0        0          0
4:45 PM            38       179       0        0         95          0      39     0      0       200     25      0      0        0        0          0

MO13 (Kansas Expressway) and I-44 Eastbound Ramp
Street Name      Kansas Expressway Southbound            I-44 EB RAMP Westbound           Kansas Expressway Northbound   I-44 EB RAMP Eastbound
Start Time         Right    Thru      Left     Peds      Right       Thru   Left   Peds   Right   Thru    Left    Peds   Right    Thru     Left       Peds
12:15 PM           0        149       47       0         0           0      0      0      39      114     0       0      27       0        27         0
4:45 PM            0        129       59       0         0           0      0      0      83      195     0       0      17       0        50         0

MO13 (Kansas Expressway) and “Evergreen” (Walmart Driveway, adjacent to McDonalds)
Street Name      Kansas Expressway Southbound         Evergreen Street Westbound          Kansas Expressway Northbound   Evergreen Street Eastbound
Start Time         Right    Thru      Left     Peds      Right       Thru   Left   Peds   Right   Thru    Left    Peds   Right    Thru     Left       Peds
12:15 PM           39       277       1        0         2           0      2      0      1       191     31      0      29       2        51         0
4:45 PM            54      251        0        0         1           1      3      0      3       287     45      0      35       0        76         0
(Counts provided by MoDOT)

To top