"2pi" by Dr. Belisario Hernandez Romo

[johndoe]

Hello everyone, I've been lurking this forum for a while and figured I should join in the fun.  I've seen the DDI, CFI, and parallel flow discussed on here...but couldn't find any discussions of this particular geometry.

(The same user has additional videos)

It's kind of funny, if you read about these intersections/interchanges it seems that someone is very insistent that they are to thank for all the world's unique geometry    One of those videos claims that it's the same as a "divergent diamond" (no).  Some pages also call this design a "superstreet", which adds to the confusion since that means something totally different to most engineers.

I was just curious if anyone had experienced one of these before, or researched anything about it.

Here's a story about the DDI where an employee of Romo got on to trumpet his glory (see the comments section):
http://www.popsci.com/bown/2009/product/diverging-diamond-interchange

You'll find some interesting discussion there, with descriptions of some of these in Mexico and Venezuela.  Here's one of the Mexican locations (check out the interchange to north as well): http://goo.gl/maps/JnS1l

[Anthony_JK]

Hello everyone, I've been lurking this forum for a while and figured I should join in the fun.  I've seen the DDI, CFI, and parallel flow discussed on here...but couldn't find any discussions of this particular geometry.

(The same user has additional videos)

It's kind of funny, if you read about this interchange it seems that someone is very insistent that they are to thank for all the world's unique geometry    One of those videos claims that it's the same as a "divergent diamond" (no).  Some pages also call this design a "superstreet", which adds to the confusion since that means something totally different to most engineers.

I was just curious if anyone had experienced one of these before, or researched anything about it.

Here's a story about the DDI where an employee of Romo got on to trumpet his glory (see the comments section):
http://www.popsci.com/bown/2009/product/diverging-diamond-interchange

You'll find some interesting discussion there, with descriptions of some of these in Mexico and Venezuela.  Here's one of the Mexican locations (check out the interchange to north as well): http://goo.gl/maps/JnS1l

Ummm....technically speaking, that is NOT an interchange, but a consolidation of CFI's. Interchanges by definition include grade seperations.

[tradephoric]

Does anyone have the coordinates of the intersection seen in the video?  Not sure where Columbia Laredo is.

[kphoger]

Does anyone have the coordinates of the intersection seen in the video?  Not sure where Columbia Laredo is.

I'm not either.  My first thought was Colombia, Nuevo León, which has one of the Laredo international crossings.  But this intersection is definitely not there.  There is no street in Laredo named Colombia, and the one in Nuevo Laredo is a very minor side street with almost nothing on it.

I've sent an email to the gentleman who designed it, asking where the intersection is.  Hopefully my email won't go in his junk folder.

[kj3400]

I think it might actually be in Colombia, as in the South American country, because the pavement arrows are a match, but I couldn't find the intersection itself.

[kphoger]

It's on the outskirts of Monterrey, NL.  I'm pinning him down for the exact location, and will let you know when I hear back.

[kj3400]

Could this be it?

http://goo.gl/maps/jTKZA

It looks similar, but the metro line is throwing me off.

[kphoger]

Not sure, but there will be plenty to post about it when I hear back from him.  He sure has a lot to say about how they screwed the thing up.

[NE2]

Could this be it?

http://goo.gl/maps/jTKZA

It looks similar, but the metro line is throwing me off.

Everything else seems to fit; the metro line must be new (2008 per http://es.wikipedia.org/wiki/Sendero_(Metrorrey)).

PS: what kind of route is this? https://maps.google.com/maps?hl=en&ll=25.767096,-100.294916&spn=0.002203,0.004128&t=k&z=19&layer=c&cbll=25.767096,-100.294916&panoid=ZAeI17FDGm5TMUUxAfL8Rw&cbp=12,112.23,,0,-1.46

[kphoger]

Could this be it?

http://goo.gl/maps/jTKZA

It looks similar, but the metro line is throwing me off.

Everything else seems to fit; the metro line must be new (2008 per http://es.wikipedia.org/wiki/Sendero_(Metrorrey)).[/b]

Yes, that is the intersection.  The name makes total sense, now:  if you're heading north, the road that splits to the right goes to Laredo, whereas the road that splits to the left goes to Colombia (both are border towns).

Here is his response:

Two road start and end at this extremely busy intersection 37,000 vph (Peak).

It was designed in 1999 as an hybrid interchange (overpass + 2pi for left turns) what you are looking at is the interim  2pi(C) Two Phase Enhanced At-Grade design.

For 10 years it work like a clock in two phases per cycle. The "new" people in the government without any understanding of traffic engineering decided to "scramble" the phasing "adding" phases....just like that, in order to cause congestion and justify building a cloverleaf and a three leveled overpass.

To that end they "eliminated" the left turns (naturally) not even bothering to call to hear my opinion. Well you know that's politics $$$$$ in Mexico.

In Mexico anybody can be traffic engineer (P.TO.E) . All they need is to be put in charge.

http://www.facebook.com/bhromo2pi

In this FB page you might find some more information on the system and previous designs.

Belisario H. Romo P.E., Ph.D, P.T.O.E.

PS: what kind of route is this? https://maps.google.com/maps?hl=en&ll=25.767096,-100.294916&spn=0.002203,0.004128&t=k&z=19&layer=c&cbll=25.767096,-100.294916&panoid=ZAeI17FDGm5TMUUxAfL8Rw&cbp=12,112.23,,0,-1.46

If you're referring to the '17' shield, then it is a numbering system for major avenues in Monterrey–a metropolitan route system, if you will.  For more information click here.

[pianocello]

So this is like a continuous flow intersection on steroids. Interesting.

One question: where did the name "2pi" come from? At first I thought it had something to do with a circle, and then I saw the intersection.

[Alps]

Could this be it?

http://goo.gl/maps/jTKZA

It looks similar, but the metro line is throwing me off.

That's the one for sure, must just be a new line. Mexico is big on the CFI. Interestingly, this and the English intersection (a variant) have both been patented in this country, but NJ 168 at US 130 has been around for longer than either patent. I would be perfectly willing to design an intersection, have them file suit, and then point out "all I did was copy this design" and watch them squirm.

[NE2]

One question: where did the name "2pi" come from? At first I thought it had something to do with a circle, and then I saw the intersection.

2 phase intersection?

Incidentally, a DDI is also two-phase.

[tradephoric]

Frogger level 28

[Scott5114]

Could this be it?

http://goo.gl/maps/jTKZA

It looks similar, but the metro line is throwing me off.

That's the one for sure, must just be a new line. Mexico is big on the CFI. Interestingly, this and the English intersection (a variant) have both been patented in this country, but NJ 168 at US 130 has been around for longer than either patent. I would be perfectly willing to design an intersection, have them file suit, and then point out "all I did was copy this design" and watch them squirm.

Prior art should have invalidated the patent. Unfortunately the patent office usually isn't aware of prior art, so it has to be brought up in lawsuits later.

[agentsteel53]

If you're referring to the '17' shield, then it is a numbering system for major avenues in Monterrey–a metropolitan route system, if you will.  For more information click here.

shield and direction banner - I'll be damned.  never seen anything like it in Mexico, just INICIA and TERMINA banners for some Baja California state routes.

[kphoger]

If you're referring to the '17' shield, then it is a numbering system for major avenues in Monterrey–a metropolitan route system, if you will.  For more information click here.

shield and direction banner - I'll be damned.  never seen anything like it in Mexico, just INICIA and TERMINA banners for some Baja California state routes.

The municipal route system is unique to Monterrey (others may have a system, but I'm not aware of any shield signage elsewhere).

I've seen at least one directional banner on a federal highway–leaving Monterrey on the free 40, heading for Saltillo.  I found it on GMSV here.

[agentsteel53]

I've seen at least one directional banner on a federal highway–leaving Monterrey on the free 40, heading for Saltillo.  I found it on GMSV here.

cutouts, no less!  I'd never seen a cutout before in Mexico.  Are they more prevalent in Nuevo Leon?

[kphoger]

I've seen at least one directional banner on a federal highway–leaving Monterrey on the free 40, heading for Saltillo.  I found it on GMSV here.

cutouts, no less!  I'd never seen a cutout before in Mexico.  Are they more prevalent in Nuevo Leon?

As I said, this might be the only one I've ever seen; if I've seen more than one (and it's faintly ringing a bell), then I'm sure I've only seen two, and the other one was likely on the same highway.  For all I know, they just took a shield they might otherwise use on a BGS, and pole-mounted it.

PS: what kind of route is this?

BTW, those blue Monterrey route shields are all over the place on newer BGS installations in the metro area, and have been tacked on to many more.  Here are a few samples from a [maybe not so] cursory look at GMSV:
http://goo.gl/maps/YQuYV
http://goo.gl/maps/xo381
http://goo.gl/maps/65Ld1
http://goo.gl/maps/v23M3
http://goo.gl/maps/HKaHb
http://goo.gl/maps/I02pE
http://goo.gl/maps/w0aw7
http://goo.gl/maps/esXvS
http://goo.gl/maps/cKBX6

[NE2]

As I said, this might be the only one I've ever seen; if I've seen more than one (and it's faintly ringing a bell), then I'm sure I've only seen two, and the other one was likely on the same highway.

Rotate the camera left. There's a second one right there

[kphoger]

Wow, that guy has a serious chip on his shoulder.....
Here are some snips from a response to a follow-up email I sent him (copy edited, since it's apparent his mother tongue is not English):

To begin, with the CFI does not exist!  I'm assuming, considering your questions, that you are not a traffic engineer.  There are thousands of copycats by now. I invented the "Two Phase Enhanced INTERSECTION" 2pi in September 1987. It was a 30-year process. Many people see the 2pi and simply conclude they can do it, that it is easy.

If you analyze and take note of the dates on which the copycats designs were built, they were ALL after 1987. The reason is simple: The LA Times published my design in a full-page article; the same happened in the New York Times and the Washington Post and a good number of magazines and papers in Europe and Asia in those years. Try to find one 2pi BEFORE that date.....

Now, you may be referring to the Continuous Flow INTERCHANGE (not INTERSECTION) the one difference is that in order to be continuous it has to be grade separated. Maybe you need to read "The evolution of the Two Phase Enhanced At-Grade INTERSECTION", which is on the net. All your questions can be answered on the net–you just need to investigate, and not believe ALL that you read.

In Mexico, you can NOT sue the government for infringing patents and copyrights.  It is a waste of time. Even in the States, the procedure is so lengthy and so costly that you end up forgetting about suing so many plagiarists.

Please do not feel offended, but I have answered your reasonable questions.  I have work to do, so please, if you require more answers to "opinions", please search the net. It is in there–it just takes a lot of time, effort, and dedication to find answers.

I guess I won't be asking him any more questions. 

[johndoe]

Wow, that is pretty telling!  And 37,000 vph?  I don't think so!  That'd be equivalent to 19 interstate lanes!

Either way, the guy has to feel pretty happy that his idea has become a common principle, and that his designs are saving people time and money.  I mean, how many traffic engineers throughout history can really say that their idea led to a new intersection/interchange type?

[tradephoric]

Thanks for sharing Mr. Romo's replies with us.  He seems insistent that no 2PI existed before 1987.  MetTra Corp's own presentation credits the Detroit Left (more commonly known as the Michigan Left) as a variation of the Two-Phase Enhanced At-Grade Intersection System (2PI).  Dr. Tom Malek invented the Michigan Left turn while working for MDOT in the 1960's with the first Michigan Left being constructed at the intersection of 8 Mile & Livernois in 1967.  Detroit had an entire arterial network of 2PI intersections by 1987.

I do applaud his work in the field of innovative intersection designs and hopefully more catch on.

[NE2]

The Michigan Left is fairly different. But there's Telegraph and Plymouth, a little more stretched east-west than a 'pure' 2PI/CFI: http://maps.google.com/maps?hl=en&ll=42.371184,-83.2753&spn=0.003614,0.008256&gl=us&t=k&z=18
and this one in Camden (mentioned by Steve upthread): http://maps.google.com/maps?hl=en&ll=39.904322,-75.095238&spn=0.005308,0.008256&gl=us&t=k&z=18

[kphoger]

And 37,000 vph?  I don't think so!  That'd be equivalent to 19 interstate lanes!

Is that such a stretch?  The intersection is located on the main highway between México's third-largest city (or fourth, depending on how you count metro areas) and the largest commercial port on the US/Mexican border.  I counted 37 lanes at this intersection on Google Maps; here's how it breaks down:

For 10 years it work like a clock in two phases per cycle. The "new" people in the government without any understanding of traffic engineering decided to "scramble" the phasing "adding" phases....just like that, in order to cause congestion and justify building a cloverleaf and a three leveled overpass.

Interestingly enough, I've been unable to find anything online about redoing this intersection as any sort of grade-separated interchange.  SkyscraperCity is abuzz about redoing the next major intersection to the west (at Av. Sendero & Av. Manuel Barragán), which also started out as a CFI, ummm, 2pi, ummm, one of those funny intersection things.  Maybe I just haven't exerted enough time, effort, and dedication.