Talk:Diverging diamond interchange

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Dates wrong?[edit]

Either the date for the Missouri interchange or Google street view is wrong.,+springfield,+missouri&hl=en&ll=37.214199,-93.311477&spn=0.011381,0.065103&sll=37.0625,-95.677068&sspn=52.240038,133.330078&t=h&hnear=Missouri+13+%26+Interstate+44+Business,+Springfield,+Greene,+Missouri+65802&z=15&layer=c&cbll=37.214186,-93.311469&panoid=wVWxeYT3eBU5UYYYkqLJmQ&cbp=11,262.47,,0,-3.32 says August 2009. It doesn't show the new imagry from the Wikipedia page. — Preceding unsigned comment added by (talk) 02:07, 21 March 2012 (UTC)

The link provided is at the intersection of Business Route I-44, not the intersection at the actual Interstate noted in the article.-- (talk) 13:19, 4 September 2012 (UTC)


I removed the Kansas City link as its shows only a diamond interchange. I do not believe this is helpful to the article and the information provided in the main text is, in my opinion, adequate for providing the proposed location. Just let me know if you disagree. --Thisisbossi 10:28, 28 August 2006 (UTC)

Baltimore Link at Bottom of Page[edit]

The interchange at *39°21′03″N 76°29′48″W / 39.350876°N 76.496601°W / 39.350876; -76.496601 is not a diverging diamond, rather it is a stack modified with left-hand exits, similar to one in Rochester. As a result, I have removed this erroneous entry. Snickerdo 02:49, 30 August 2006 (UTC)

I had added it because the movements are the same, though it is completely grade-separated rather than signalised. I feel it belongs, but I'll let it go unless anyone else feels the same. --Thisisbossi 10:31, 30 August 2006 (UTC)
It is certainly a unique interchange, but kind of goes against the idea of a diverging diamond because all directions are free-flow. A note about this interchange would certainly be a worthwhile addition to the stack article, however. Snickerdo 22:23, 30 August 2006 (UTC)
I am not sure I could call that a stack though. It really doesnt have the lanes stacking on top of each other. Rather it is low lying and offers the advantage of not having a lot of height but able to squeze into it rather easily. In Grand Rapids, MI we have a similar one and it is in the middle of the downtown. Our downtown at the time had very few tall buildings so they used this design to keep it lower. Personally I think if we metion it I would put it in the cloverleaf interchange since it has 8 ramps. --Mihsfbstadium 23:41, 25 January 2007 (UTC)
But then, using your definition of what they are, stack interchanges are merely a subset of the more generic 4-way [semi] directional interchange. e.g. I-64 & I-270 in St. Louis never exceeds 3-levels; I-94/I-90 & I-290 in Chicago is only 2-levels and is more characteristic of a pinwheel. Topology shows that all these interchanges function in the same way. --Millbrooky 06:07, 15 April 2007 (UTC)

Except there are no loops, therefore no cloverleaves. Personally, I've taken to calling these "Diverging Stack Interchanges" and I've since become aware of quite a number of these. They are by no means common, but I wouldn't say that they are particularly rare, either. Another such example is the interchanges of I-20, I-59, and I-65 in Birmingham, Alabama. Might this be an interchange configuration deserving of its own article? --Bossi (talk ;; contribs) 05:42, 15 April 2007 (UTC)

Or another idea for what these interchanges should be called: "Weaving Stack Interchange". They do seem to form a basket weave of sorts. --Millbrooky 06:07, 15 April 2007 (UTC)

The specific interchange is between Interstate 196 and US 131, both freeways, in Grand Rapids, Michigan. US 131 has the weave. Pbrower2a (talk) 06:23, 4 November 2012 (UTC)


GalootRob recently added a mention that a Gilbert Chlewicki "first introduced" this concept. While the paper appears to give the impression that this is correct, I must nonetheless wonder how the Versailles interchange was constructed prior to 2003 if this configuration hadn't been invented yet? Would it be more correct to say "first introduced into the United States", perhaps? ...But even moreso, it may be more accurate only to say that he was first to present a paper on it within the United States, as surely Americans would have been aware of a new interchange configuration in use over in Versailles. We share all sorts of info when it comes to feats of transport engineering. --Thisisbossi 23:12, 17 January 2007 (UTC)

OK, after checking with the author I have a bit more understanding. Yes, Versailles came first; but he's the first one who really got to thinking about potential applications in America. I've modified the history a bit to hopefully better reflect this. --Thisisbossi 05:18, 24 January 2007 (UTC)

The history states there is only one unique example of this type of crossings.. However, I know of at least 2 others in France: exit 19 on the A1 (Seclin) and exit 5 on the A4 (Le Perreux). Might be interesting to change this. (talk) 17:09, 29 January 2008 (UTC)

Thanks! I am not sure which of the three came first and second... I'll add them in and tweak the article accordingly. This is a fine example of how much more communication transportation engineers need both domestic and abroad! I may have to throw these two interchanges onto my sight-seeing list for next year... --Bossi (talkgallerycontrib) 22:49, 29 January 2008 (UTC)


Text under Advantages states, "It reduces the number of lanes for overcrossing or bridges..." What's an "overcrossing" and how exactly would it differ from a bridge? Or is that just redundant? --Wlindley (talk) 01:14, 16 January 2008 (UTC)


Construction has started on the new DDI at I-270 and Dorsett Road in St. Louis County. (talk) 19:02, 29 November 2009 (UTC)

Animation on Youtube[edit]

There are - imho - illustrative animations on youtube, e.g. you tube com/watch?v=VOVcf0xoA0g Maybe someone who's allowed to might want to add it? (talk) 21:55, 7 May 2010 (UTC)

Use in North America[edit]

The "Use in North America" section is bordering on example farm territory. Perhaps this could be broken out to a list of diverging diamond interchanges article? It's the least readable portion of this article, which probably explains why the proposed DDI in Rochester was listed twice. —Mrwojo (talk) 04:25, 20 June 2010 (UTC)

A new diamond has just been completed in Rochester New York, at the intersection of South Winton Road and I-590. ( (talk) 13:51, 11 September 2012 (UTC))

Adjusted content accordingly. --Chaswmsday (talk) 16:37, 11 September 2012 (UTC)

Upon reading this article, I believe that I encountered a diverging diamond at Bangerter Hwy. and UT 201, near Salt Lake City. That is not mentioned in the list; can someone verify? BTW, the highway's intersection with 3100 S. appears to be a continuous-flow intersection. Kudos to UT DOT for implementing improved intersection patterns. — Preceding unsigned comment added by (talk) 02:27, 20 November 2014‎ (UTC)

Yes, that's one. --NE2 05:12, 20 November 2014 (UTC)

Thanks for the quick update. I found a list of DDIs at It's much more extensive than anything given in the article ... though I was able to tell them about one that wasn't on their list yet. {{Ed G.}} — Preceding unsigned comment added by (talk) 05:53, 20 November 2014‎ (UTC)

The interchange between I-196 and US-131 in Grand Rapids, Michigan[edit]

In Grand Rapids, the interchange between I-196 and US-131 resembles a diverging diamond interchange, in that US-131 crosses over itself twice. Unlike a diverging diamond, however, this crossover uses overpasses instead of traffic lights, and the interchange has eight completely separate ramps instead of four Y-shaped ramps. All of the left-turning ramps exit on the left and merge on the left. Should this interchange be mentioned in the article? Here's the interchange on Google Maps:,-85.676794&spn=0.013659,0.036135&t=m&z=15Tanner Swett (talk) 04:35, 25 April 2013 (UTC)

In a way, its seems most similar to what is called in Wikipedia a "diverging windmill" interchange: the former configuration at the northeast I-95/I-695 interchange near Baltimore, MD ([1], [2]). -- Except that US 131 doesn't crossover. One of the roadgeek sites calls the old Maryland example a "twister". IMO, the Grand Rapids interchange is probably best characterized as a hybrid, as it's most likely too rare to be given a formal name. If it merits specific mention, it should probably be made under interchange (road) with the rest of the "freeway" to "freeway" hybrids. --Chaswmsday (talk) 17:43, 4 May 2013 (UTC)
All right, it seems to me like the type of interchange in Grand Rapids is probably neither common enough nor unique enough to be worth a mention. Thanks for your comments. —Tanner Swett (talk) 02:16, 7 May 2013 (UTC)

I-196/US 131 was recently added back to this article as an example of a double crossover merging interchange. It's similar to the Baltimore interchange's current configuration. I don't believe it's a DCMI, either, as DCMIs represent a freeway/minor road interchange and the configuration is different. I don't know what I was thinking above: I meant to say that I-196 doesn't crossover, US 131 does. Per my comments, reverting edit. --Chaswmsday (talk) 14:55, 29 July 2013 (UTC)

Converting North American sections to tables[edit]

I was thinking, rather than lists attempting to be prose, would it not be best to convert the sections listing usages in North America to tables? We may even want to split it off into its own article as the number of DDIs in North America continues to grow. Perhaps something like this:

Missouri (example table)

City Intersection Date opened Notes
Springfield I-44 at Route 13 June 21, 2009 First diverging diamond interchange in the United States
Kansas City Route 150 at Botts Road December 5, 2012 Construction included a new bridge for the interchange

I'd love to hear some feedback on this. This could definitely improve the layout of the article, but I'm sure there's some amount of controversy to be had. Jon (aka Blurred203) holler 03:32, 1 December 2013 (UTC)

I'd love to take work on this project to a subpage for completion, by the way, since mixing tables with prose for the same type content could certainly be jarring to users. Again, any and all feedback will be much appreciated. Jon (aka Blurred203) holler 03:57, 1 December 2013 (UTC)
Do we need a comprehensive list? Why can't a non-exhaustive list of examples be just as educational to readers on what a diverging diamond is. We don't have a list of all of the diamond interchanges, all of the cloverleaves or all of the SPUIs, so such a list here is overkill. Imzadi 1979  20:46, 1 December 2013 (UTC)
This is true...thanks for your input. As the use of DDIs in North America is still relatively new, and there are not that many, I would suggest we keep the list, or perhaps split it off into a "List of..." article. As the use of DDIs becomes normalized, I'd be fine with disposing of the list...but as of now, I almost feel it should be kept for the more adventurous readers. The table would also be much less exhaustive than reading prose on each DDI. Jon (aka Blurred203) holler 23:31, 1 December 2013 (UTC)
Also, I do agree that the "future" list is overkill, especially for stalled projects. At the very minimum, those probably need to be cut, regardless of what happens with the present DDIs. Jon (aka Blurred203) holler 23:35, 1 December 2013 (UTC)
I don't think an exhaustive list is needed, neither as a "List of" split from this article nor as an embedded list here. Michigan left does not contain a full list of them, even though they're still pretty rare outside of Michigan where they are pretty common in the southern part of the state. Imzadi 1979  00:05, 2 December 2013 (UTC)
I still don't see how it's exhaustive. There really aren't that many...the prose just makes it look that way. If we're going to keep the "listing" (if you will), the prose needs to go, in my opinion. Jon (aka Blurred203) holler 03:08, 2 December 2013 (UTC)
Exhaustive = attempts to list every example. This article is trying to have an exhaustive list, which, when, there were only a few cases, was appropriate. Anyway, I agree that this should be cut down a lot. "Uses in North America" should be "Use in North America" and list the notable examples. I'd include the first DDI in Missouri and limit the prose to a discussion of how the concept spread to other states and provinces. I would limit this discussion to the first examples in other jurisdictions, or any that are notable for other reasons. The entire future section should be gutted, unless there are examples notable for some reason. By notable, I'm not employing the Wikipedia definition of coverage in third-party secondary sources, but rather the idea that there is something special that sets them apart, makes them worthy of noting. Imzadi 1979  03:43, 2 December 2013 (UTC)
Apologies for the late response, been busy with school. It might be best to dispose of the future use section altogether, and switch the "Use in North America" section down to known special usages, not only in North America but also abroad. Jon (aka Blurred203) holler 05:30, 11 December 2013 (UTC)

Globalize tag[edit]

The first ones were built in France. This is covered in the History section. A number have recently been built in North America. Unless more have been built outside of North America, I'd like to hear why the tag is warranted. --Triskele Jim 02:14, 15 December 2013 (UTC)

It seems disproportional. There is one mention of the one in France then a huge list of US examples. --AdmrBoltz 02:23, 15 December 2013 (UTC)
If diverging diamonds are being used elsewhere and are not included, then the globalize tag is valid. If all the examples except the few in France are on the US, is it really disproportionate? The list is getting a bit long, but I think they are still uncommon enough that the examples are usefull. --Triskele Jim 03:13, 15 December 2013 (UTC)
The number is still growing. Important to know, France has built minimum 3 pcs in the 1970ies. The better design came up 2009 in the US. It is also important where and how the technic is beeing known and built. Many don't see the benefits and the better performance. --Hans Haase (talk) 01:20, 16 December 2013 (UTC)

RfC: Regarding the North American sections[edit]

There is a clear consensus for option 5. Armbrust The Homunculus 12:57, 22 January 2014 (UTC)
The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Per the two above sections, I feel it is necessary to get some community-wide input on what to do (if anything) with the two sections in the article regarding the uses of DDIs. Should one or both sections be kept and improved, should one or both sections be reduced, or should one or both sections be removed completely? 203 22:20, 16 December 2013 (UTC)

Extra information[edit]

Since there are two issues at hand here, I've created 6 "bold-able" options to keep the discussion easy to follow.

  • Option 1: Take no action; leave both sections as-is.
  • Option 2: Keep all content in both sections and improve the global coverage.
  • Option 3: Keep (and improve global coverage in) the current Uses section as-is, and reduce the Future section to verifiably notable uses.
  • Option 4: Reduce both sections to verifiably notable uses.
  • Option 5: Reduce the current Uses section to verifiably notable uses, and remove the Future section entirely.
  • Option 6: Entirely remove both sections.
  • Option 7: Create a Section "History" and ans sepratated article e.g. "list of DDIs" --Hans Haase (talk) 14:05, 18 December 2013 (UTC)

All input is very much appreciated! To keep the discussion easy to follow, please place your "vote" only in the Survey section below, and if you have additional comments, please place those remarks in the Threaded discussion section. Thanks again!


  • Option 5 203 22:20, 16 December 2013 (UTC)
  • Option 5 --AdmrBoltz 22:58, 16 December 2013 (UTC)
  • Option 4 Dough4872 01:29, 18 December 2013 (UTC)
  • Option 5 which is essentially what I said in previous discussions, oppose creation of any list under Option 7. Imzadi 1979  19:28, 18 December 2013 (UTC)


  • Option 5 - Per the discussion two sections up, the Future uses section seems to contribute very little to the article and is a breeding ground for WP:CRYSTAL violations. In addition, many of the current uses outlined in the article are not especially notable. Therefore, the current Uses section should be reduced to unique construction processes, first occurrences, and other notable interchanges; the Future uses section should be removed entirely. 203 22:20, 16 December 2013 (UTC)
  • Option 4 - Only include notable uses (such as the first diverging diamond interchange in a state) backed by references for current and future diverging diamond interchanges. Dough4872 01:38, 18 December 2013 (UTC)
  • Any list created per the recently added Option 7 would be a mess to maintain, and it wouldn't be terribly encyclopedic. Our job is to describe the concept with a few examples for illustration. To attempt to catalog every instance of a type of interchange is folly. Imzadi 1979  19:31, 18 December 2013 (UTC)
  • here are more references, making a better decission: --Hans Haase (talk) 13:17, 21 December 2013 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Use and disambiguation of locations within citations[edit]

In this version of the article, I had Toledo, Ohio and Wilmington, North Carolina, wikilinked, as location parameters within two citations. @Imzadi1979 changed these to unlinked "Toledo, OH" and "Wilmington, NC", with the reasons "state abbreviations are standard in citations, and the wikilinked publication name will have the full state name if necessary". @Imzadi79 did not show where abbreviations were held as a standard. When I pointed out that Template:Cite news spells out state names in locations in its listed examples. @Imzadi1979 criticized the examples, stating that "cited examples also include locations/publishers for non ambiguous/unnecessary cases". Well, I'm not an editor who tries to bludgeon other editors with the "laws" of Wikipedia.

My contention is as follows: Following @Imzadi1979's argument to its logical conclusion, use of location parameters at all would be unnecessary, since the wikilinked publication name would ultimately allow a reader to find the location. However, the Wikipedia community has determined that locations are relevant when not readily apparent from the publication name. Both Toledo and Wilmington require disambiguation. Use of US-specific state abbreviations such as "OH" and "NC" are unhelpful for non-US readers. Absent the citation of any Wikipedia "law" specifically allowing for such abbreviations, I'll follow the guidance in Cite news and use the full state names. --Chaswmsday (talk) 16:04, 9 April 2014 (UTC)

I commented about this on Chaswmsday's talk page yesterday, where I said,

they are typically abbreviated. The Publication Manual of the American Psychological Association (6th ed.) says to abbreviate them in the reference list (§6.30, p. 187). The MLA Handbook for Writers of Research Papers (7th ed.) says to abbreviate them in "documentation" (§7.3, p. 236). The Chicago Manual of Style (16th. ed.) says they are usually abbreviated in bibliographies while they should be spelled out in running text (§10.28, p. 498).

Now the problem with the examples from the doc page for {{cite news}} is that they are illustrating bad practices contradicted by Help:CS1#Work and publisher. The doc page shows "The Seattle News (Seattle, Washington: The Seattle Times Company)." According to the help page, the location is assumed by the newspaper name, and the publisher is superfluous as it repeats the name of the paper. (Specifically, it says to omit the location and publisher in cases like The New York Times, New York and The New York Times Company.) So as I said, in cases where Wikipedia is contradictory, I will default to established style guides, like the APA, MLA, and Chicago guides. In all cases on-wiki though, there is no "do not abbreviate state names in citations", in fact, MOS:ABBR#Special considerations says this is common practice. In fact, we have several places in the MOS that says we can/should use abbreviations in infoboxes, dates, units of measurement to save space, and both tables and citations are typically given as examples of places to save space. Imzadi 1979  22:09, 9 April 2014 (UTC)

Moving DCMI to talk[edit]

The only sources for this are primary (, patents, and an article written by the "inventor") and an article that ends up referencing Wikipedia. Barring any mention in other sources as a feasible alternative, it looks like self-promotion. --NE2 05:05, 19 November 2014 (UTC)

@NE2: The DMCI ist a Patentes interchange with no known built sample in use. For this reaseon it has no own article. As a variant of the DDI with many similarities and some improvements it became section of the DDI's aricle. I don't know who who expanded it. On the other hand, we are collecting locations SPUIs and removed locations of the more rarely present DDIs from the article. So what is the encyclopedic value of those changes exept of poor infomation content and wasted time of readers an editors? --Hans Haase (talk) 14:24, 19 November 2014 (UTC)
I have no opinion about listing, and that's not what this section is about. --NE2 14:49, 19 November 2014 (UTC)
I support to keep the information about the DCMI in the article. Btw. the box below colapses the talk also. --Hans Haase (talk) 17:14, 19 November 2014 (UTC)
Without any reasons for keeping it, your "support to keep" is meaningless. --NE2 00:35, 20 November 2014 (UTC)
Patents are documents and as a variant of or similar to the DDI it is worth to be mentioned, but not focussed on. It also helps understanding the article. The fact the patent exists only with no practical use was the reason to integrate it into the article. I guess we should stop the libricide here. --Hans Haase (talk) 02:15, 20 November 2014 (UTC)
By calling me a book burner, you've lost any claim to rationality here. --NE2 03:21, 20 November 2014 (UTC)

────────────────────────────────────────────────────────────────────────────────────────────────────Support removal—doesn't appear to be notable. I might support a much-summarized description noting it as a variant, but not the amount of content that's below in the collapsed box. Imzadi 1979  05:38, 20 November 2014 (UTC)

Sumary: We keep a minimalized note about in the article. @NE2: Always see it form the view of readers who have no idea from the stuff they read here and they should be informed what this is. – Done. --Hans Haase (talk) 17:05, 20 November 2014 (UTC)
Reverted. Why should readers be informed about a fringe invention with no real-world examples? --NE2 21:46, 20 November 2014 (UTC)
Let take a closer look on the topic to get a good article: The 1st thought to get a DDI in freeflowing traffic is to replace the 2 intersections by overpasses. This solution causes weaving. The patent confirms a possible solution to eliminate the weaving. In the US weaving is declared as a problem of interchanges. It may affect cloverleaf interchanges without single lane distributor carriage ways. Arround the DDI is not that much finished reserach as about other road junctions. Now back from OR to SOURCES: The patent shows a existing concept for such variant. NICE to know. --Hans Haase (talk) 00:13, 21 November 2014 (UTC)
What you are doing is classic original research. Please stop. --NE2 00:22, 21 November 2014 (UTC)
No, it is exactly not. It is to differ between OR and sourced information. By bringing relevant and sourced information to the article, the reader is enabled to get this or another view on that he/she is reading. It is not to to bring a point of view. It is giving existing information only. Is it wrong? No. Does it not apply? No. What would be a reason to keep it of of the article? One reason to hide such information would be working in a business providing obsolete solutions being replaced by such. Now let's review prices for the reader of including or excluding it. When reading both sections: the created thought is is on the discussion only. It has been created by reading the article, falling under OR. The sourced information is in the article only. It is no OR. It lets the reader decide, to rate it. Another question the reader may ask himself: Why has the patent no practical use? Analyzing the sketch: how large a DMCI most be built to handle what speed of traffic safe, regarding jamming traffic behind overpasses and underpasses? After reading about the DCMI you better understand what a DDI is. The accusation of OR in the article is not true. Read twice! The article provides sourced information only. --Hans Haase (talk) 07:19, 21 November 2014 (UTC)
OK, now it's just word salad that can be used to justify any fact being included in any article. --NE2 07:49, 21 November 2014 (UTC)
Stop wiping and whipping, we are talking about the article. The talks sections above show why the DCMI is a section of this article. What are reasons to keep it out? --Hans Haase (talk) 14:20, 21 November 2014 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Looking at this, it does smell like self-promotion. Iff we include anything about DCMIs, I'd shorten the section down to "Another free-flowing design, for which a patent has been applied, called the "double crossover merging interchange" (DCMI), includes elements from the diverging diamond interchange, the standard diamond interchange and the stack interchange. It eliminates the disadvantages of weaving and of merging into the outside lane from which the standard DDI variation suffers. No such interchanges have been constructed." The rest is fluff. –Fredddie 23:44, 21 November 2014 (UTC)

Double crossover merging interchange

Another free-flowing design, for which a patent has been applied, called the "double crossover merging interchange" (DCMI),[1] includes elements from the diverging diamond interchange, the standard diamond interchange and the stack interchange. It eliminates the disadvantages of weaving and of merging into the outside lane from which the standard DDI variation suffers.

DCMI traffic flow patterns
Three-dimensional computer generated DCMI

The lane configuration allows for high capacity free-flow traffic without the need for costly elevated "flyover" roadway bridges, and uses less lane area and structures than an interchange with large radius flyover(s).[2]

DCMI uses a standard main bridge with two smaller bridges on either side. DCMI lets vehicles cross over conflicting traffic streams while removing weaving maneuvers. This configuration produces an interchange with merging maneuvers.[3][4] By placing two smaller bridges on either side of the main bridge, the traffic signals can be eliminated. Additionally, off-ramp traffic can be crossed over on the same smaller side bridges used by the main traffic patterns. This removes conflicts that would take place with an at-grade traffic signal. The key feature of this type of design is not only the elimination of the conflicts that occur at-grade, but also allowing the off-ramp traffic to cross over without the need for lane changes or weaving.

The double crossover merging interchange introduces a number of new mechanisms to a tight diamond type interchange while producing a free-flow traffic environment interchange.

No such interchanges have been constructed.[5]

DCMI advantages[edit]

  • No weaving sections
  • Free-flow operations
  • Reduced vehicle emissions (no idling vehicles)
  • No right-angle crossing conflicts
  • No traffic signals
  • Less costly to construct than a full free-flow interchange with flyover roadway bridges

DCMI disadvantages[edit]

  • May be more costly than a standard diamond or diverging diamond.


  1. ^ (A1) US 2013011190 (A1), Gingrich, Michael A., Sr., "Double Crossover Merging Interchange", published January 10, 2013, assigned to Gingrich, Michael A., Sr. 
    WO application 2013009704, Gingrich, Michael A., Sr., "Double Crossover Merging Interchange", published January 17, 2013, assigned to Gingrich, Michael A., Sr. 
  2. ^ Cite error: The named reference Alternative_Intersections.2FInterchanges:_Informational_Report_.28AIIR.29 was invoked but never defined (see the help page).
  3. ^ "Double Crossover Merging Interchange". 
  4. ^ Gingrich, Michael A., Sr. (June 2011). "DCMI (Double Crossover Merging Interchange)" (PDF). Institute of Transportation Engineers. Retrieved January 23, 2013. 
  5. ^ Hamilton, Grant (March 4, 2012). "35 Years to Upgrade the Highway?". Brandon Sun. Retrieved January 23, 2013. 

Support removal—No real world example exists and we shouldn't just list hypothetical interchanges until one is being or has been built. --WashuOtaku (talk) 02:12, 22 November 2014 (UTC)

It is not to rate about why but that it has no practical use. Junctions are the major bottleneck of roads. They are subject of civil engineering. I support a diversity of knowledge including there is and design with no practical use only. Even in the US variants of stack interchanges saving contruction costs and bringing performance with less documentation about. Many of these have been built, existing still today, due efficiency. In this point wikipedia is far away from the real world, practical use and existing research. --Hans Haase (talk) 12:03, 22 November 2014 (UTC)

Support removal — This type or sub-type of interchange is not notable unless or until there is a real-world example constructed or placed under construction.  V 15:41, 22 November 2014 (UTC)

Remove—patent hasn't even been granted, just applied for, no real-world application exists. This is the interchange equivalent of a non-notable garage band. —Scott5114 [EXACT CHANGE ONLY] 19:09, 23 November 2014 (UTC)

Removal of {{Example farm}} (re: RfC: Regarding the North American sections)[edit]

A so-called {{Example farm}} was removed from this article per the discussion in Talk section "RfC: Regarding the North American sections". While I don't disagree with the removal of an exhaustive list of examples, I feel that the removal of that content could have been handled in a more collegial manner. As we're all likely aware, much content on WP is unfortunately out-of-sync. It would be helpful to explicitly provide the last version(s) of this article containing the full example list, to allow editors to more easily make sure cited prose about individual diverging diamond interchanges exists in the appropriate road articles. It's also quite conceivable that readers, upon finding this article, might wish to find examples of DDIs. The "What links here" tool, while quite imperfect in the overabundance of links it returns, and probably not well known or used by casual readers, could allow at least some readers to find a list of examples. Thus...

The most complete list of DDIs (existing and planned) can be found at this version of the article.

More up-to-date information about the first DDI in Virginia can be found here.

More up-to-date information about the first DDI in Maryland can be found here.

We should also check that the appropriate road articles found, among other content, here, contain sourced information about individual DDIs. --Chaswmsday (talk) 16:35, 10 January 2015 (UTC)

The reason for removing the list from the article was due planned interchanges, only. Today these interchanges were built. A chronological information can not be linked from other articles. What road or state has the most DDIs is not covered, too. The included template "Streets and roadways" also affects the list of links to the article caused by missing filters. --Hans Haase (有问题吗) 00:50, 13 January 2015 (UTC)
All Coordinates displayed in map material requires to list the coords in the article or separate articles linked to the article or category. By using existing templates, the only solution I see, is to hide or show a text section of use inside the article. The template:Collapse top would fulfill all dicussed requirements. It keeps the visible text small, but if interested, readers can show detailled information of use. --Hans Haase (有问题吗) 12:22, 13 January 2015 (UTC)

Disadvantages: Bike lanes[edit]

In a sequence of edits currently ending here I tried with limited success to convey the idea that using a DDI with a cross-road that has bike lanes is disadvantageous.

Perhaps my troubles are rooted in the 'globalize/North America' template in place for this article.

Please take a look at a classical, urban intersection in Denmark. The blue line indicating a bike lane has a parallel one like it for the opposite direction of traffic. A larger intersection would have blue lines for all four traffic directions, forming a blue square. Fifty years of experience with bike lanes in Denmark have shown that it is exactly in the crossing areas colored blue here that vehicle/bike collisions occur (often fatally), whereas such collisions are rare outside those areas. So for a crossing road that has bike lanes, a DDI intersection that incurs four bike crossings instead of two for a traditional high-way crossing is a disadvantage. I am aware that I did not clearly communicate this in my edit summaries and that this is not explicitly supported by the source cited regarding pedestrians, and that the Danish interest in and experience with bike lanes is not universal.

This is the pedestrian way of Americas 1st DDI. This design migth be the best for bicycles, crossing two roadways in a sigle signal phase. As vehicles moving faster, the bicycles might catch a signal later behind the bridge. --Hans Haase (有问题吗) 15:07, 28 August 2015 (UTC)

But I consider the four versus two necessary bike crossings self-evident, with the necessary crossing of the on-ramp lane looking for example like this (with separate lights and lanes for pedestrians and bicyclists).

My attempt to introduce this bicycle aspect is motivated by a recent article in Ingeniøren, Now you will have to drive on the left side of the road (in Danish), about a planned change of a high-way crossing to use a DDI outside of Odense, Denmark. Incidentally, there the crossing road does not have bike lanes. If someone thinks this can be included in the article, then feel free to help out. Then perhaps one day that 'globalize/North America' template can be removed. Have a nice day. Lklundin (talk) 14:50, 14 April 2015 (UTC)

Your "necessary crossing of the on-ramp lane" is not in fact necessary. This is another way of handling a bike lane at an onramp. --NE2 15:32, 14 April 2015 (UTC)

Reinsert Double Crossover Merging Interchange Section OR Undelete Original Standalone Article?[edit]

I would like to discuss having the Double Crossover Merging Interchange article reinserted back into the Diverging Diamond Interchange article, or having the original standalone article undeleted and updated, as several new secondary references have now become available.

Please note; the secondary references that I have listed below are from highly credible industry sources and reflect experts in their respective fields:


The secondary reference listed below is from the Transportation Research Board (TRB). More information on TRB can be found at the following Wikipedia link:

The following link is to the Final Program for the TRB “Alternative Intersections & Interchanges Symposium”, which was held July 20-24, 2014 in Salt Lake City, Utah. The conference included a formal lecture on the Cost and Constructability Comparison of the DCMI Interchange (see Section 3C). It is important to understand that in order to present at these conferences, there is a strict vetting process that involved the review and acceptance of the subject matter, and this process is completed by transportation engineers with expertise in this particular field; hence, the Double Crossover Merging Interchange was determined to be a valid and credible subject for the Exploring New Concepts session at the TRB conference.

Please See DCMI Interchange in section 3C of final conference program using the TRB website link below:

2. INSTITUTE OF TRANSPORTATION ENGINEERS (ITE) - Technical Conference and Exhibit

The references listed below are from the Institute of Transportation Engineers (ITE); more information on ITE can be found at the flowing Wikipedia link:

In 2012, ITE held their annual “Technical Conference and Exhibit”. As part of this conference, a technical paper was published and presented on the Double Crossover Merging Interchange.

You can search the ITE library for “Double Crossover Merging Interchange” at this page:

It is also reference on the following TRB link:

ITE applies the same standards and vetting process as a TRB conference; ITE requires the application, peer review, and approval of papers and presentations prior to being acceptable to publish and present at the ITE Annual Technical Conference. The peer review by accredited engineering experts in the field of transportation engineers supports the premise that the DCMI Interchange has practical real world applications and benefit.


Every year, ITE reviews all the papers that had been published at all of their conferences, including Annual, Technical, and Regional Conferences, as well as their Peer Review ITE Journal of Transportation, in the previous year and awards a “Best Paper Award” The paper on the Double Crossover Merging Interchange that was presented in 2012 at the aforementioned ITE Technical Conference, it was then reviewed by a committee of transportation engineers and selected for the “ITE 2013 Best Paper Award”. Given that ITE has 17,000 transportation engineering professionals in 60 different countries, I believe their consensus of awarding the Double Crossover Merging Interchange the “Best Paper Award” further substantiates the legitimacy, value, and practicality this type of Interchange.

ITE 2013 Best Paper Award Article Quote: "The new design is unique, original, well documented, and could have an impact on future designs. The paper clearly communicates the benefits of the new design and provides a good foundation for further studies".

Link 1: Scroll down to 12th line.

Link 2: (Bottom right, page 31)


The Double Crossover Merging Interchange was awarded a patent by the United States Patent and Trademark Office on February 10, 2015. The approval process for a patent is very rigorous and requires proof and research of prior interchanges (prior art). This indicated the Federal Government now recognizes the Double Crossover Merging Interchange as a unique, well qualified, and documented interchange.


5. INTERNATIONAL RECONIGTION - Military Academy of Lithuania In this International research paper by Buteliauskas Juozapavičius of the Military Academy of Lithuania, he cites the Double Crossover Merging Interchange (DCMI) and also includes it in a technical comparison to other types of interchanges. This indicates a growing acceptance by the international transportation community as tothe validity and practicality of the Double Crossover Merging Interchange. Link:

Based on the above references from established and highly credible sources, and their acceptance and establishment of the Double Crossover Merging interchange into the professional transportation engineering community, I believe the Double Crossover Merging Interchange warrants it own Wikipedia page. Please provide options on whether you believe the Double Crossover Merging Interchange should be re-inserted into the Diverging Diamond Interchange article, or if it should have the original standalone article undeleted.

Thank you for your assistance, Cliff Shaffer (talk) 07:30, 24 July 2015 (UTC)

SUPPORT: There are many sources listed now that show the interchange is functional. My personal review results there might be speed limits or larger area per interchange necessary to make the roadway ahead visible for stop in time when traffic is jamming or similar incidents hidden by elevations, curves behind underpasses occur. Several patents on other interchange designs fail in the critetia of cost–benefit analysis, but the DCMI shows a realistic design. I understand the position not to notice in the encyclopedia based on a patent only. But the the now existing reviews support the design and awards might not be given to nonfunctional solutions. Also Helium-3 could be deleted by such opinion. The recent given sources should be enough to include the DCMI into the article. --Hans Haase (有问题吗) 09:36, 26 July 2015 (UTC)
Oppose. Nothing new. --NE2 13:28, 26 July 2015 (UTC)
And what is Your statement about the new given sources? --Hans Haase (有问题吗) 16:06, 26 July 2015 (UTC)
When NE2 moved the Double Crossover Merging Interchange (DCMI) to the Talk Page to discuss removal, he stated "The only sources for this are primary (, patents, and an article written by the "inventor").
Reference: Moving DCMI to talk --NE2 05:05, 19 November 2014
Other than the Patent (which has now been granted), all of the new secondary sources now listed are not any of the "primary sources" that NE2 referenced in his November 2014 statement, namely: ", patents, and an article written by the "inventor", so these sources are obviously "Something New". Beyond being many new credible secondary sources, these sources are peer reviewed and published sources from transportation engineering experts and organizations. (verifiability and Reliable Sources). Using our good editorial judgment and common sense, we can conclude that these new secondary sources certainly establishes the Double Crossover Merging Interchange's notability, the new secondary sources are also one step removed from the inventors article, and they directly support the material being presented. The new information and sources are consistent with Wikipedia's article policy, as they are published, attributable, verifiable, and reliable sources secondary sources. Cliff Shaffer (talk) 17:12, 2 August 2015 (UTC)
  • Oppose—as discussed before, I'm ok with a summary statement that notes this as a variant in this article. I don't see the need for a full article, nor do I think we should add too much content to this article about the concept. Fredddie} wrote up a good example of such a summary statement before. Start with that first. We can always expand it as necessary.

    Another comment directed at the proposer: less is more when initiating discussions. Your proposal should have been at least half its length to invite people to actually read it. As it is, I've skimmed it because of the length, and nothing I read in skimming it changed my mind. Imzadi 1979  23:45, 2 August 2015 (UTC)

Based on the various responses, placing a short "Summary Statement" for the Double Crossover Merging Interchange seems to be a fair consensus to reach. I have updated the article with Fredddie's Summary Statement. I removed the reference to the Stack Interchange, as a Stack Interchange usually has at least three levels, whereas the Double Crossover Merging Interchange is a two-level design. I also cited the patent and award sources.

Thank you Hans Haase, NE2, Imzadi1979 for your comments and suggestions, and Fredddie for initially providing the draft summary statement. In the future I will keep my proposals shorter as Imzadi1979 has suggested. Cliff Shaffer (talk) 07:05, 4 August 2015 (UTC)

Great job, Cliff Shaffer! I'm going to do a few copy-edits, as will be explained in my edit summaries. --Chaswmsday (talk) 20:16, 4 August 2015 (UTC)

Per removal of examples[edit]

Could a List of diverging diamond interchanges possibly be appropriate? In the United States at least they are contentious enough to be notable as they fly in the face of a fairly steady convention seen everywhere in the country outside of New York City, which is more comparable to Europe with copious zany and bohemian traffic designs. B137 (talk) 17:37, 1 December 2015 (UTC)

I don't think so, and I'd oppose the creation of such a list. No other interchange type has such a list, and I don't think this type needs one either. Imzadi 1979  19:58, 1 December 2015 (UTC)
B137, Wikipedia does not collect raw data, but there are 3 ways to achieve it:
  1. The engineers website has a collection:
  2. Signup and contribute to: and link Wikipedia to it
  3. In the Wikipedia articles about roads are lists of major intersections and interchanges. In the remarks colmn, add the intersection or interchange type, linking the first to this article (example UT-154)
In OpenStreetMap, maybe some discussions have started about adding junction type properties. --Hans Haase (有问题吗) 12:44, 19 October 2017 (UTC)
I would advise some caution about cluttering junction list tables with lots of notes about interchange types. Frankly, that's an esoteric detail best omitted in most cases. The readers of individual highway articles are typically looking for a more generalist treatment of the topic. Imzadi 1979  13:48, 19 October 2017 (UTC)
Imzadi1979, notes about interchange is a copy of Your own suggestion, see Talk:Single-point urban interchange/Archive 1#Example farm. --Hans Haase (有问题吗) 14:26, 19 October 2017 (UTC)
That was my opinion almost three years ago, and where something is unique or interesting, it still holds. However, we don't need to list the interchange type on every line of a table. Imzadi 1979  14:41, 19 October 2017 (UTC)

Possible resource[edit]

Imzadi 1979  10:16, 12 January 2016 (UTC)

Yes, it shows signal sequences, pedastrian walkways, safety and lots of experience on existing interchanges. --Hans Haase (有问题吗) 22:30, 13 January 2016 (UTC)

Coming soon to Florida[edit]

At Interstate 95 at A1A in Nassau County. Work starts next week. Complete date set for 2020. JenniferRSong (talk) 00:59, 12 January 2017 (UTC)

[1] [2]

Calgary, Alberta[edit]

They built a new DDI in Calgary with a pretty nice fly-through video demonstration. See more at their website Not sure if the Usage:Operational section includes this one for Canada, didn't want to change it in case it was. (talk) 13:49, 14 August 2017 (UTC)