The Pinavia Interchange - Any Real-Life Examples?

[Elmer]

I don't believe this type of interchange has been discussed in this
group before, but I do find it quite fascinating:

It's one of those things like, "why hasn't anyone thought of this
before?".

So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.

Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.

Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)

Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)

The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!

Elmer

[Elmer]

Link to Route-1 Project. Has nice aerial photo of existing Copeland
Circle interchange showing "ghost ramps" to unbuilt I-95.
http://www.route1project.com/ProjDescription.html

Google Map of the location: http://g.co/maps/kxa82

The guts of the project are here (32MB):
http://www.route1project.com/EIR/EIR%20Section%204.pdf

In particular, check out figures 4.3-1, 4.3-2, and 4.3-3 for drawings
of the three proposed alternatives. Wouldn't a tailored "Pinavia"
design fit there like a glove?

Elmer

[Larry Sheldon]

Post by Elmer
I don't believe this type of interchange has been discussed in this
http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".
So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.
Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.
Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)
Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)
The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!

...

I have not looked through all the pictures here (
http://www.skyscrapercity.com/showthread.php?t=773712&page=27 ) (will be
a daunting task) but it looks promising.

How would you get in and out of the center commercially without a lot
more overpasses or other complexity?

[Elmer]

Post by Elmer
I don't believe this type of interchange has been discussed in this
  http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".
So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.
Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.
Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)
Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)
The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!

I have not looked through all the pictures here (http://www.skyscrapercity.com/showthread.php?t=773712&page=27) (will be
a daunting task) but it looks promising.
How would you get in and out of the center commercially without a lot
more overpasses or other complexity?

...

Straight in and/out of the center at ground level from all four
directions. It's hard to believe it's really that simple, but here's
another video that shows how the center access flow works:

Elmer

[Gordon]

Post by Elmer

Post by Larry Sheldon
How would you get in and out of the center commercially without a lot
more overpasses or other complexity?

Straight in and/out of the center at ground level from all four
directions. It's hard to believe it's really that simple, but here's
http://youtu.be/38mEuxZnvAA
Elmer

Now that's an accident waiting to happen. I can just see some idiot
in the far left lane, thinking that he is in a passing speed lane, come
tearing into the center development at highway speeds.

[Larry Scholnick]

Post by Elmer
I don't believe this type of interchange has been discussed in this
  http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".
So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.
Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.
Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)
Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)
The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!
Elmer

...

This is the freeway equivalent of a roundabout.

Although it claims that there will be no jams, it only works if 25% of
the traffic approaching the interchange wants to go left, 25% of the
traffic wants to go right, and 50% wants to go straight. At most
typical interchanges a much higher percentage of the traffic (more
than 50%) wants to go straight; this design would generate long queues
before the interchange as through traffic waits for its chance to get
into the 2 through lanes.

If this is done on a freeway that only has 2 lanes in each direction,
then there would be a widened area before the interchange and a
merging area after the interchange where traffic would have to squeeze
back down to 2 lanes.

Unlike a typical interchange, through traffic has to slow somewhat to
go around the circle. In addition, by having traffic that is going
left diverge from the left, this is the equivalent of a Left-Exit,
which is frowned upon these days, in part because slow (truck) traffic
going left has to get to the left of faster traffic in the left-
through lane. Once you fix that defect, you lose your bridge savings.

[Elmer]

Post by Larry Scholnick

Post by Elmer
I don't believe this type of interchange has been discussed in this
  http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".
So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.
Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.
Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)
Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)
The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!
Elmer

This is the freeway equivalent of a roundabout.
Although it claims that there will be no jams, it only works if 25% of
the traffic approaching the interchange wants to go left, 25% of the
traffic wants to go right, and 50% wants to go straight.  At most
typical interchanges a much higher percentage of the traffic (more
than 50%) wants to go straight; this design would generate long queues
before the interchange as through traffic waits for its chance to get
into the 2 through lanes.
If this is done on a freeway that only has 2 lanes in each direction,
then there would be a widened area before the interchange and a
merging area after the interchange where traffic would have to squeeze
back down to 2 lanes.
Unlike a typical interchange, through traffic has to slow somewhat to
go around the circle.  In addition, by having traffic that is going
left diverge from the left, this is the equivalent of a Left-Exit,
which is frowned upon these days, in part because slow (truck) traffic
going left has to get to the left of faster traffic in the left-
through lane.  Once you fix that defect, you lose your bridge savings.

...

It is not equivalent to a roundabout because there is absolutely no
weaving involved or any other contention points in the traffic flows.
For heavier traffic in certain directions, simply add more lanes to
those ramps (e.g.: 3 or 4, lanes as required). Any negatives of the
"left exit" effect are out shadowed by the elimination of weaving, and
mitigated by the through traffic slowing down slightly to curve
around.

Of course, it's not appropriate for all interchanges, especially if
high-speed through traffic is required. But at medium-high speed, it
provides a compelling level of service for using only four simple
bridges.

Elmer

[Paul D. DeRocco]

Post by Elmer
It is not equivalent to a roundabout because there is absolutely no
weaving involved or any other contention points in the traffic flows.

The weaving takes place before entering the interchange. There are a lot of
roundabouts nowadays which require you to decide before entering it whether
you're going a) out on the right, or b) out straight ahead or to the left.
This is an extension of that principle.

[Larry Sheldon]

Post by Elmer
It is not equivalent to a roundabout because there

Another thing missing from the roundabout advantage set is the
no-harm-no-foul recovery from missed turns. I'd never get where I'm
going in places like Milton Keynes if I can't go all the way around for
another shot at the preceding intersection. (A recover technique of
real value to a truck driver.)

[deanej]

Post by Larry Scholnick

Post by Elmer
I don't believe this type of interchange has been discussed in this
  http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".
So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.
Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.
Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)
Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)
The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!
Elmer

This is the freeway equivalent of a roundabout.
Although it claims that there will be no jams, it only works if 25% of
the traffic approaching the interchange wants to go left, 25% of the
traffic wants to go right, and 50% wants to go straight.  At most
typical interchanges a much higher percentage of the traffic (more
than 50%) wants to go straight; this design would generate long queues
before the interchange as through traffic waits for its chance to get
into the 2 through lanes.

...

That assumes that all four lanes were through lanes before entering
the interchange.

Post by Larry Scholnick
If this is done on a freeway that only has 2 lanes in each direction,
then there would be a widened area before the interchange and a
merging area after the interchange where traffic would have to squeeze
back down to 2 lanes.

Perfectly normal for freeway-freeway junctions, at least in NY.

Post by Larry Scholnick
Unlike a typical interchange, through traffic has to slow somewhat to
go around the circle.  In addition, by having traffic that is going
left diverge from the left, this is the equivalent of a Left-Exit,
which is frowned upon these days, in part because slow (truck) traffic
going left has to get to the left of faster traffic in the left-
through lane.  Once you fix that defect, you lose your bridge savings.

It looks like those curves could be handled at 55mph, the highest
speed limit in most urban areas.

Left exits are considered perfectly normal where I grew up (Rochester,
NY), probably because we have nine of them.

[Larry G]

Post by Elmer
I don't believe this type of interchange has been discussed in this
  http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".
So have they? Are there any real-life examples of this concept in use
today? Yes, at first glance, it bears a resemblance to Circle-Stack
interchanges (e.g.: I-787/South Mall Expy.), but after you realize
what's going on, it's actually something quite different.
Essentially, it is a four-way, full-directional, medium-to-high speed
interchange; with no conflict points or weaving; that requires only
four low-level bridges. In the Pinavia video, the application is
perfectly flat and symmetrical, so the interchange is a perfect
circle. However the concept could be applied in a somewhat different
shape to accommodate local terrain or the intersecting roads'
geometry.
Regardless of the actual geometry, are there any known interchanges
that achieve that same functionality with only four, single-level
bridge crossings? (i.e.: the South Mall Interchange does the same
function, but has multiple levels and many bridges)
Where do you think this design would work? Here's my choice of a
perfect place for one. A site familiar to many road geek historians
I'm sure, is Copeland Circle in Revere, MA, where US-1 intersects
MA-60. It is famous for being where I-95 construction through Boston
was cancelled in the 1970's. (it still bears complete, but never used
"ghost ramps" for I-95 to this day)
The interchange is destined to be completely rebuilt in the next few
years. Several designs are being considered; one would change it into
a SPUI. The Pinava design would work much better and fit perfectly
into the site. I also think the City of Revere would love reclaiming
the high-value commercial land in the center of the interchange!
Elmer

...

it uses a LOT of real estate but I like the commercial center.... it
would be unfit for any kind of residential because of the noise....

[Paul D. DeRocco]

Post by Elmer
I don't believe this type of interchange has been discussed in this
http://youtu.be/XDDmE4qoCns
It's one of those things like, "why hasn't anyone thought of this
before?".

I wonder what kind of licensing fee the inventor could get for an
interchange?

[Joe keane]

http://maps.google.com/maps?ll=36.064,-115.181&z=16

The mainlines go through the center, as usual, but both connections
between CC 215 and Las Vegas Blvd. use this trick.

[Elmer]

Post by Joe keane
http://maps.google.com/maps?ll=36.064,-115.181&z=16
The mainlines go through the center, as usual, but both connections
between CC 215 and Las Vegas Blvd. use this trick.

That Nevada example, Joe, is a form of Partial Cloverleaf interchange,
sometimes called a Clover-Stack. There are many of them around. (the
flyover ramps aren't necessarily stacked all that high, depending on
how they wrap around and where they pass over/under the other ramps)
Essentially, it is a Cloverleaf interchange where two opposing "petal-
leaf" ramps (270-degree right turns) are replaced by two "flyover" or
"flyaround" ramps (90 degree left turns). It's a compromise from
building a full-directional Stack interchange; it eliminates the
weaving problem of a Full Cloverleaf, but the two remaining "petal-
leaf" ramps may have safety issues and/or capacity limitations. (you
can build a flyover ramp with any number of lanes, but more than one
lane on a petal ramp is impractical) For this reason, a Clover Stack
style interchange works best when the heaviest traffic flows are using
the flyover ramps, and the least amount of traffic is relegated to the
petal ramps.

Here's my personal favorite Clover-Stack, where I-75 intersects US-27
at the edge of the Everglades; the view from the flyovers is really
spectacular!
http://g.co/maps/jyj6m

But these interchanges aren't like the Pinavia because they have many
more crossing points and consequently require more than four bridges.
I still haven't heard of any real-life examples that achieve this
functionality (no conflicts and no weaving) with only four bridges,
but I also can't believe it hasn't been done somewhere, perhaps with
different (or irregular) geometry.

Elmer

[Nathan Perry]

In article

Post by Elmer
That Nevada example, Joe, is a form of Partial Cloverleaf interchange,
sometimes called a Clover-Stack.

Hey, nice to see my term is still seeing use!

(Apparently I invented the name "cloverstack" ten or eleven years ago; I
vaguely remember that but still have my doubts...)

[Joe keane]

Post by Elmer
That Nevada example, Joe, is a form of Partial Cloverleaf interchange,
sometimes called a Clover-Stack. There are many of them around.

You missed my point. Never mind the mainlines, they are pretty standard
and wouldn't be worth pointing out. But the connections to LVB look a
*lot* like what we're talking about. So maybe it is not useful for
mainline connection, but rather useful for nearby exits or C/D roads.

[Elmer]

Post by Elmer
That Nevada example, Joe, is a form of Partial Cloverleaf interchange,
sometimes called a Clover-Stack. There are many of them around.

You missed my point.  Never mind the mainlines, they are pretty standard
and wouldn't be worth pointing out.  But the connections to LVB look a
*lot* like what we're talking about.  So maybe it is not useful for
mainline connection, but rather useful for nearby exits or C/D roads.

Some would say that tomatoes look a *lot* like apples; but while one
is an edible fruit, the other is an electronic device.

(:-we are missing each other's point-:)

Elmer

[Nathan Perry]

Closet I've found so far is this:

http://g.co/maps/y3gtv

There are subtle differences from the Pinavia, and some of the movements
are missing in this example, but a resemblance is unmistakable (and
there are only the four grade separations).

[Aušrius (Emilijos tėtis)]

Post by Elmer
I still haven't heard of any real-life examples that achieve this
functionality (no conflicts and no weaving) with only four bridges,
but I also can't believe it hasn't been done somewhere, perhaps with
different (or irregular) geometry.
Elmer

Hej, Elmer!

Amazingly, Pinavia is not the end of the story yet.
See this picture:
Failed to load image: http://i814.photobucket.com/albums/zz66/suaua/pinavia_4into3.jpg
(right turns have been omitted - they are trivial).

It shows you can make a junction having the functionality you
mentioned with just THREE bridges. Can you make it with just two??
Apparently mathematicians found this question interesting, here's a
full story:
http://www.saga-network.eu/phocadownload/auron/Krasauskas.pdf

Of course, when you gain something (smaller number of bridges), you
lose something (turns get ugly; no more usable center of the
junction). Still, it constantly amazes me that one can still invent
things - even in such areas, where everything seems to have been
invented long time ago...

Aušrius

[Elmer]

Post by Aušrius (Emilijos tėtis)

Post by Elmer
I still haven't heard of any real-life examples that achieve this
functionality (no conflicts and no weaving) with only four bridges,
but I also can't believe it hasn't been done somewhere, perhaps with
different (or irregular) geometry.
Elmer

Hej, Elmer!
Amazingly, Pinavia is not the end of the story yet.
See this picture:http://i814.photobucket.com/albums/zz66/suaua/pinavia_4into3.jpg
(right turns have been omitted - they are trivial).
It shows you can make a junction having the functionality you
mentioned with just THREE bridges. Can you make it with just two??
Apparently mathematicians found this question interesting, here's a
full story:http://www.saga-network.eu/phocadownload/auron/Krasauskas.pdf
Of course, when you gain something (smaller number of bridges), you
lose something (turns get ugly; no more usable center of the
junction). Still, it constantly amazes me that one can still invent
things - even in such areas, where everything seems to have been
invented long time ago...
Aušrius

...

That's really fascinating, Aušrius! I knew it all boiled down to
mathematics. With that problem solved, it's just a matter of
positioning the three bridges to work best for the topography, etc..
I'm still surprised there are no real-world examples of at least a
four-bridge (functional-mathematically) interchange of some geometry
somewhere.

I mentioned this project below before, but don't you think it'd be
perfect for a tailored "Pinavia" design?

Link to Route-1 Project. Has nice aerial photo of existing Copeland
Circle interchange showing "ghost ramps" to unbuilt I-95.
http://www.route1project.com/ProjDescription.html

Google Map of the location: http://g.co/maps/kxa82

The guts of the project are here (32MB):
http://www.route1project.com/EIR/EIR%20Section%204.pdf
In particular, check out figures 4.3-1, 4.3-2, and 4.3-3 for drawings
of the three proposed alternatives.

Elmer

[James W Anderson]

There may be one on the Rodoanel in Sao Paulo, a partially completed
ring freeway (anel > annulus > ring). Signed as SP-021 around Sao
Paulo. A couple of videos on Youtube show this as having a very
similar interchange to this already built or to be built, as they are
saying the highway's east and north sectors will be finished this
year. The south and west sectors are finished and functioning, and
some of the other sectors are functioning as well.

Most Brazil projects pussyfoot around the stack interchange by using a
variant of the 'Michigan Left' in places along with this, but the
Rodoanel project apparently has one that is closest to the Pinavia.

[Tom Haws]

Post by Aušrius (Emilijos tėtis)

Post by Elmer
I still haven't heard of any real-life examples that achieve this
functionality (no conflicts and no weaving) with only four bridges,
but I also can't believe it hasn't been done somewhere, perhaps with
different (or irregular) geometry.
Elmer

Hej, Elmer!
Amazingly, Pinavia is not the end of the story yet.
http://i814.photobucket.com/albums/zz66/suaua/pinavia_4into3.jpg
(right turns have been omitted - they are trivial).
It shows you can make a junction having the functionality you
mentioned with just THREE bridges. Can you make it with just two??

...

Since a cloverleaf interchange has only one bridge, the great achievements of the Pinavia interchange (at the cost of three additional bridges) seem to be a) lower land cost due to the usable center and b) higher speed.

I would be curious to see an analysis of this "pinavia 4 into 3" vs. a cloverleaf to understand what it achieves at the cost of 2 additional bridges.

[a***@gmail.com]

roads should be laid out in a hexagonal pattern. there are many negatives to this design, but it will reduce congestion.

[b***@gmail.com]

I know I am a few years late, but I found a good example in Charlotte, NC.

https://www.google.com/maps/@35.3488092,-80.734344,16.04z

If you go a little further northeast along I-485, you can find that the next interchange is a diverging diamond interchange and a little further is a dumbbell interchange.

[t***@duh.org]

Post by b***@gmail.com
I know I am a few years late, but I found a good example in Charlotte, NC.

That's a turbine/whirlpool.