Talk:Interchange (road)

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Should not have been split from Road junction[edit]

The split of this article from Road junction was a bad idea. The original article was compact and informative. Both parts are now ugly stubs. We should merge (and rename) back. −Woodstone 20:04, 19 September 2005 (UTC)

Since your comments, both articles have been tidied up to better reflect their titles. This article is now no longer a stub, but a fully fledged article. Ae-a 18:35, 20 September 2005 (UTC)

merge Interchange (road), Junction (traffic) and Intersection (road)[edit]

Both articles Junction (traffic) and Intersection (road) are still pretty lame stubs. This one "Interchange (road)" is good, but still lost from its separation from the general idea of junction. The most neutral name for the new 3-way merged page could be Junction (traffic) or Junction (road). −Woodstone 16:33, 12 January 2006 (UTC)

I disagree. Frankly, the old interchange article was a mess in terms of structure. An interchange is inherently different from an intersection due to the presence of a grade separation and ramps. A basic intersection might cost only $100,000 (the cost of paving the intersecting roads and adding a stop sign, limit lines, and perhaps a few other safety signs), while a full-fledged interchange costs anywhere from $20 million to $1 billion (e.g., the Macarthur Maze reconfiguration in Oakland after the 1989 Loma Prieta earthquake), depending upon the size and number of roads to be connected.
I supported the split, and I prefer to keep interchange and intersection separate. Pardon my bluntness, but this merge proposal is one of the dumbest I have ever seen on Wikipedia. I am also posting this response to the other articles' talk pages.--Coolcaesar 04:53, 13 January 2006 (UTC)
The Interchange (road) and Intersection (road) pages should remain separate in my opinion. There is plenty scope for addition to both and they complement one another nicely. Junction (traffic) is the problem - it's not much of an article and I'm lost as to what it could possibly provide that isn't covered in the Interchange and Intersection articles. All it can really do is point to them both... right now it's a mish-mash of nonsense. Erath 23:16, 13 January 2006 (UTC)
And now of course, I've defied myself by making just such an attempt. Thoughts please on the new Junction (traffic) article. I'm also considering moving it to Junction (transport) to alleviate the confustion over exactly what constitutes "traffic". Erath 00:07, 14 January 2006 (UTC)
See Talk:Junction (traffic)#Merge proposal revived for my response. Ae-a 15:55, 14 January 2006 (UTC)

Just place them back together and give them seperate sub headers. --Storms991 06:37, 5 March 2006 (UTC)

So, it looks to me like the conclusion is to keep Interchange (road) seperate, but that the merger of Junction (traffic) and Intersection (road) is still undecided. In view of this I propose to remove the merge tag from Interchange (road) so the dicsussion can be focussed at Junction (traffic) and Intersection (road) in relation to those articles. Kcordina 09:36, 10 March 2006 (UTC)

An unusual Interchange[edit]

I have seen a total of 2 of what I am going to arbituary call a Diverging Complete Interchange. It is when either 1 or both freeways flip thier normal flow of traffic by going over each other with ramps before and after the flip. This type of interchange is shown in Grand Rapids, Michigan at US 131/I 196 Interchange and in Maryland at I 695/I 95 Interchange and possible several others when I get a chance to find them. In anycase it offers significant space savings and has a height similar to a cloverleaf. --Mihsfbstadium 09:18, 26 January 2007 (UTC) Birmingham, Alabama's Malfunction Junction is another example of said interchange. —Preceding unsigned comment added by (talk) 20:04, 3 September 2007 (UTC)

The I-695 and I-95 before redesign in 2008 to a „Stack” (4-level) was called a „Double Diverging Diamond“, taken from WP-Refereces/Kurumi, the German call it „Gothic Cross“ing, (the old one), the new one „Maltheser” Cross (bird view), equals a 4level stack. --Hans Haase (talk) 09:29, 7 October 2012 (UTC)

Here's a completely different design that also doesn't fall in any of the categories in the main article. Just like some of the "Double Diverging" ones mentioned above, the local authorities decided to overhaul it on account of unusually high accident rates... OneAhead (talk) 00:42, 22 January 2009 (UTC)

This sample in Lummen, BE is a equals a highspeed roundabout or traffic circle (!neologism!, w/o reference, AFAIK). These were redesigned to a „turbine“, see in google maps DE. The short weaving zones caused many accidents. An other one is/was in « 48.706051,9.166802 » Leinfelden-Echterdingen, near Stuttgart intl. Airport, DE (paste it in google maps or other map service). --Hans Haase (talk) 09:29, 7 October 2012 (UTC)

British Columbia terminlogy[edit]

Here, we call the three looped intersections cloverleafs, and a full four looped version "Dogwood". I was surprised to find out that the "dogwood" terminology was used exclusvely here and probably has something to do with the fact that the Dogwood flower is the provincial flower. 07:23, 6 September 2007 (UTC)

Left/Right terminology[edit]

Would it make sense to talk about the inside and outside of the road rather than the left and right? Or to pick some words other than inside and outside to again be able to use language that's not specific to the US way of doing things? JNW2 05:55, 9 November 2007 (UTC)


I'm a traffic engineer who's designed 100s of interchanges, and I must say this is just a horrible, horrible article. —Preceding unsigned comment added by (talk) 12:11, 2 May 2009 (UTC)

Excellent. Go ahead and use your knowledge to improve it. This is the encyclopedia anyone can edit. −Woodstone (talk) 13:25, 2 May 2009 (UTC)
I doubt he/she will, for the same reason I've been gradually cutting back on Wikipedia contributions. It's simply too damned time-consuming for experts in fields to attempt to make major contributions to articles because then one gets into nasty edit wars with children, teenagers, vandals, and other idiots. The few articles where my edits have actually stuck are those that are relatively obscure, such as Duty of care. Even on Lawyer, I waste more time on fighting edit wars then on making substantive contributions to the article nowadays. --Coolcaesar (talk) 07:06, 4 May 2009 (UTC)


Sliproad redirects here, but the term doesn't appear in the article. For example, the appearance in the article Motorways of Switzerland is unintelligible: The article tells the reader that "the exit sliproads appear much more often than in other countries" but the reader who clicks through is left to infer that a sliproad is a synonym for a road interchange. - Regards, PhilipR (talk) 06:31, 28 December 2009 (UTC) (EDITED)

Yeah, I got the same thing, only it says "slip road" in Bridge to Nowhere. This article isn't much help in figuring out what that means, which is the whole reason I clicked on it. AnnaGoFast (talk) 17:01, 22 January 2016 (UTC)

Interchanges on Kentucky Parkway System[edit]

On former Kentucky toll roads, the parkways seem to have some odd interchanges at original intersections. They look like the circular segments of cloverleaf interchanges, but lacking the diagonal ramps, as at this location: N 37.28194 W 87.10907 at which the Western Kentucky Parkway meets Kentucky State Highway 70. The circular on-ramps and off-ramps built to accommodate toll plazas seem more complicated than the usual diamond interchange that the highway department has either used for newer interchanges or that have replaced older ones on the now toll-free highway and very different from the trumpet-shaped interchanges more normal for closed-system toll roads.

Is there a name for such interchanges? — Preceding unsigned comment added by Pbrower2a (talkcontribs) 04:27, 13 February 2011 (UTC)

Another such interchange is to be found on the H.E. Bailey Turnpike at N 34.36209 W 98.40986, so this is not simply a quirk of the Kentucky Parkway system. Can someone explain why this sort of interchange works better (even if solely for the collection of tolls) than a diamond interchange which is more common and not so counter-intuitive? Is there a name for such an interchange? Pbrower2a (talk) 06:11, 10 November 2014 (UTC)

Unconventional junctions[edit]

There used to be an interesting wikiarticle about unconventional junctions on UK motorways (used for works vehicles, police or military purposes, or farm access). Where is it, or was it suppressed for some reason? Deipnosophista (talk) 14:56, 20 February 2011 (UTC)

Funny quasi double diamound roundabout/circle ,traffic light controlled - strange! „Volleyball“, see
See also the east part of the doubleintersection (de:Doppelanschlussstelle) Duesseldorf-Stockum, DE at 51.271362,6.750503 - interchnge A44/B8 taken from de:Autobahnkreuz#Kreisverkehr (I am the contributor in DE WP) --Hans Haase (talk) 09:42, 7 October 2012 (UTC)

Trumpet and tool booths[edit]

The origin hint was published in the German WP and describes the connections between a freeways and tollroads. That means to interconnect these roads by instead of the X by a H arranged road. Place the toll booth on the - of the H. The roads may somewhere else cross each other but without ramps at that point. Sure, the trumpet can be used in smaller build for lower speed operations for this. The real benefit of saving space results by these (ear ramps) 270° and 180° turns are placed like rings in each other for both directions. Sure, single trumpets are in use on tollroads from Ohio to the east coast, reviewable of all maps. An other useful hint of a 3-way tollroad intersection is to merge all directions off traffic sharing the toll queues. The on traffic is handled as well.

Other Trumpets[edit]

In the WP I'm missing reports of futher usages and modifications of trumpet intersections like these kind of double trumpets:

Also read the article in the German WP There are examples where the information can be reviewed including geo coordinates. Please help out with correct expressions and meanings.

Name of this ?[edit]

Unknown, but used interchange.

Does anybody know the official name for this kind of interchange? --Hans Haase (talk) 22:17, 18 July 2012 (UTC)

That would be a cloverstack. 2602:304:CE27:4959:F13E:FF4C:F442:7213 (talk) 15:14, 11 May 2014 (UTC)
With the left-hand ramps, I don't think it can be classifed as a pure cloverstack. "Hybrid cloverstack", perhaps. --Chaswmsday (talk) 21:48, 12 May 2014 (UTC)

Neologism template[edit]

People have questioned my use of the neologism template on the article, so let me transcribe my words from my talk page:
I know for one that "volleyball" is a neologism, since its creator admits to it. "Trumpet" and "diamond", on the other hand, have been identified in engineering documents. I'm not sure of others, like "turbine", which is why I applied the template to the whole article. I thought about putting inline templates, but there were so many instances that I felt that it would make a cluttered appearance, in addition to the ones of which I'm uncertain. I also didn't see a "reason" parameter available for the header template, or otherwise I would have thought of one to add. (User:Chaswmsday in the meantime has added a note in the source code.) Mapsax (talk) 12:34, 19 August 2012 (UTC)

„Volleyball“, see
I have not a solution, but there's an other controversial meaning in the description „windmill“. In w:de is made of flyoverramps ending before the common bridge to use it with other lanes together. In the w:en a „windmill“ describes a left turn scenario as an unfinished cloverleaf (kurumi refers a sample in Ohio, see, redirected to google maps), what saves amount of asphalt only. Hint: German freeways (=Autobahn) requires non-crossing intersections by law or equal policy (called „RAA“ (de:Richtlinien für die Anlage von Autobahnen) which means: policy for highway design, while there's the „RAS“ for Steets / roads (Richtlinien für die Anlage von Straßen)). When two freeway are crossing each other no left turn design is allowed. An other hint in theory is the windmill in bird view, what returns a symbol similar to an other one, used by the Germans between 1933 and 1945 to explain it carefully. --Hans Haase (talk) 20:32, 6 October 2012 (UTC)

See also:


Copied from user talk:Woodstone:
In Interchange (road), you restored a bullet point about U-turn ramps in this diff. I placed a "citation needed" tag on the sentence "The use of U-turn ramps is common in less wealthy countries." While this may be true, there is no citation behind it. Was the intent to refer to divided highways that have been converted to so-called RIRO expressways or Jersey freeways with some, but not expressway-standard, access control? Please let me know your thoughts on this. Thanks! --Chaswmsday (talk) 16:11, 20 August 2012 (UTC)

Using u-turns instead of left turn ramps is not that common in rich countries, as is evidenced by the removal of the u-turn from this article. In less wealthy countries they are common practice (often left driving, but I will stick to explanation in right-driving terms).
The simplest form is one major through road that cannot be crossed. To both sides of the intersection (often a km away) there is a u-turn fly-over. Any side traffic needs to turn right into the main road. For a left turn take the u-turn afterwards. For going straight turn back and leave the road to the right. Traffic from the main road wanting to turn left needs to pass the crossing first, u-turn and turn right.
A more advanced form has an elevated crossing, so going straight is possible on both roads, but a left turn from the main road still needs the u-turn. If the minor road has no divider, sometimes a left from the minor road is possible.
Woodstone (talk) 11:37, 21 August 2012 (UTC)
Your examples seem to be forms of "RIRO expressways", a road type not well covered in Wikipedia, which I plan to remedy. And you still need some citation for your rich country/poor country claim. New Jersey in the U.S. has a number of such roads, commonly called "Jersey freeways". I don't know how many have U-turn ramps. --Chaswmsday (talk) 11:36, 24 August 2012 (UTC)
This is called „Michigan Left“, see and,4616,7-151-9620_10694-161777--,00.html --Hans Haase (talk) 11:59, 7 October 2012 (UTC)

Scissor interchanges[edit]

Why isn't there any information on "Scissor" interchanges? Two examples of this are Interstate 95 with US 1 in Lorton, Virginia, and the formerly proposed interchange between Seaford-Oyster Bay Expressway and the Bethpage State Parkway extension in Bethpage, New York. ----DanTD 19:11, 7 September 2012 (UTC)

Interstate 95 in Virginia lists the Lorton example as "US 1 north – Fort Belvoir, Mount Vernon: Northbound exit and southbound entrance" & "US 1 south – Woodbridge: Southbound exit and northbound entrance". Looking at the aerial, this appears to be a kind of a hybrid of the "partial y interchange" listed under Interchange (road)#Between two motorways (System Interchange)#Two-way interchanges, except that US 1 is a non-motorway, and the road continues in each direction. (And with the added complication of what seem to be ramps to & from reversible HOV/HOT lanes on I-95.) Do such scissor interchanges also exist betweeen two motorways? If citations can be located for motorway-to-motorway and/or motorway-to-non-motorway, it would probably make sense for you to add these types to the article. --Chaswmsday (talk) 18:33, 10 September 2012 (UTC)
Good question, nice theory in giving a name to it. One is a German called „Fork“, requires one bridge in one direction, while no U-turns and not left turns are allowed, simply and Y with no way from top to top. The US-1 and US-95 intersection is a „parclo” (partial cloverleaf) or „folded diamond“, see: . These are not made for high occupancy, but allow to use the bridge for other traffic, see also: de:Autobahnanschlussstelle

This sample located near Darmstadt, DE has 4 ramps only, few miles ahead other interchanges will allow the directions of those missing ramps. With roads to highways in Germany this also known as „Half Interchange”, or even „incomplete”, if not all directions are allowed. --Hans Haase (talk) 21:10, 6 October 2012 (UTC)

Finally i see a result of missing soucres or incomplete research or simply missing communication. I also found based on my research about German road design: Focussed on speed, cost of construction only, but horrible hurts of issues like fuel consumption, energy efficiency use, comfort, capacity, future use, travel time in relation to travel speed. --Hans Haase (talk) 10:12, 7 October 2012 (UTC)

None of those are even close to what you find at Exit 161 on I-95 in Virginia. ---------User:DanTD (talk) 19:27, 31 October 2014 (UTC)

Dumbbell interchange[edit]

See Talk:Bowtie (road)#Dumbbell interchange. --Chaswmsday (talk) 14:18, 8 October 2012 (UTC)

Thank you for refering this. I do not totally agree in two things:

# The name "bowtie" is from these .info and .org pages. The DoTs do not write "bowtie", a former name was "bone", I also find no common source for this word. I would prefer the DoTs publications first.

  1. In diamond configuration of the ramps you will not need 2 roundabouts. Simply squeeze the single roundabout to fit it over the bridge and the touch a ramps. There will not traffic flow using two separate roundabouts, except heavy duty and oversize. The single direction of priority traffic makes drivers comming from the hwy feel more safe. Two separated roundabouts are neccessary when using cloverleaf arranged ramps, ending and beginning same side.

You will find this interchange sometimes in US, newer builds or modifications, often in Emirates and sometimes in France. A very tiny one is in Switzerland at 47.547722,7.633528 --Hans Haase (talk) 21:10, 8 October 2012 (UTC)

Arrrrr, stupid me, now i got it:
Reviewing the article "bowtie" and the the technology: Bowtie and dumbbell are different. The dumbbell has a bridge and is an intersection. The bowtie is a simple streetcrossing and has no bridge at all. This is totally different. The only thing in common they have is the similar bird view. Remove the dumbbell image from the bowtie and have de dumbbell it's on article, but still add each other: "Do not to be confused with ..." --Hans Haase (talk) 22:36, 8 October 2012 (UTC)


Are there examples for:

  • Diverging windmill
  • Divided volleyball

What is a „half trumpet”? I only know about „trumpet”, „double trumpet“ and „paperclip“ (see former talk sections). Helping out with the definition would be a parcial cloverleaf when road and motorway crossing in an acute or obtuse angle like the Putzbrunn Intersection near Munich, Germany

Missing DDI (Diverging diamond interchange) and in and DCMI (Double Crossover Merging Interchange) as a patented and grade separated DDI. Are there there examples for the DCMI? --Hans Haase (talk) 10:05, 24 October 2012 (UTC)

Service Road/Frontage Road[edit]

Should not a frontage road be considered a type of interchange as it provides exit and entrance to and from a local parallel road and its perpendicular junctions. If not, at least a short word with a link to the Frontage road article. In fact, in that article, the word interchange is used several times to describe the interaction between the main road and the parallel frontage road. --@Efrat (talk) 10:45, 30 October 2012 (UTC)--@Efrat (talk) 10:43, 30 October 2012 (UTC)--@Efrat (talk) 10:35, 30 October 2012 (UTC)

Don't think in this way. The frontage / service rd is a way to prevent weaving traffic and jamming flow on the hwy. Even keep the the hwy running. These itself are special roads making the interchange to other non hwy road. The exchange with the hwy are common ramps and parts, some times grade separated to kill the weaving traffic or in both directions traffic, if the single frontage rd serves both directions. See the Timpanogos Hwy (UT-SR-92) in SLC at 40.432706,-111.861433 . There are publications from the UDoT on their site or youtube. For the direction separated forntage rds, see the Dallas and Huston in TX. There's not a single mile to the next on and off traffic ramp. This saves miles. So the interchange between the frontage and the hwy may really fit into the frontage road's article. F.e. a clover leaf would be spread up with frontage roads. Some frontage rds pass the cloverleaf outside from it as all other traffic. I need to look for expamples having the frontage configured in a cloverleaf and the hwy as a stack inside the same interchange, using more than 8 ramps to serve frontage and hwy traffic separated. I have seen one in an us east cost state. --Hans Haase (talk) 16:22, 30 October 2012 (UTC)

See: and in Dallas, TX here 29.783841,-95.479434 (use google maps an paste the coorinates) --Hans Haase (talk) 16:31, 30 October 2012 (UTC)

I was thinking about something like this:
Frontage Road Interchange.png
Frontage/Service road
While a Frontage/Service road in and of itself is not an actual interchange,it does provide "interchange" access between motorway and a non-motorway roads with entrance and exit ramps.
It would go just under the last gallery at the end of the "Between a motorway and a non-motorway road" section, before the"See also" section and include a diagram. --@Efrat (talk) 12:36, 13 November 2012 (UTC)
I am in full support of your proposal. Sincerely, -- Gareth Griffith-Jones/The Welsh Buzzard 18:19, 13 November 2012 (UTC)
I'm with you. But this frontage rd has a huge mistake in contruction. The right lane on the hwy needs to leave the hwy. It needs to use weaving on the frontage and return with weaving to the hwy. In the shown sketch is correct. It provides weaving to the frontage rd only. This would jam the hwy on higher occupancy. If you can't merge into the hwy you stay on the weaving lane and exit once more, within the next mile you will try merge again. But there's no ending lane. The example in US-TX : Katy Fwy (I-10) you will find both of the solutions. --Hans Haase (talk) 13:47, 14 January 2013 (UTC)
Hi Hans!
I take it that you are referring to this section
 – Gareth Griffith-Jones – The WelshBuzzard – 15:52, 14 January 2013 (UTC)
Yes, but more to west. Just google maps for "katy freeway". --Hans Haase (talk) 14:50, 4 April 2013 (UTC)
Just done that ... quite amazing ... they have so much space in The States. Being hindered by so little of it, we are always struggling to improve –
 – Gareth Griffith-Jones |The Welsh Buzzard| 19:35, 4 April 2013 (UTC)

Proposed deletion of Double Crossover Merging Interchange[edit]

Copied from User talk:Cliff Shaffer#proposed deletion of DCMI

Ambox warning yellow.svg

The article Double Crossover Merging Interchange has been proposed for deletion because of the following concern:

This article should be deleted as its subject fails to meet the GNG. The only citation referring to DCMIs seems to be promotional and would probably fail RS. Furthermore, no interchanges of this type have been built.

While all contributions to Wikipedia are appreciated, content or articles may be deleted for any of several reasons.

You may prevent the proposed deletion by removing the {{proposed deletion/dated}} notice, but please explain why in your edit summary or on the article's talk page.

Please consider improving the article to address the issues raised. Removing {{proposed deletion/dated}} will stop the proposed deletion process, but other deletion processes exist. In particular, the speedy deletion process can result in deletion without discussion, and articles for deletion allows discussion to reach consensus for deletion. Above others (talk) 03:28, 20 January 2013 (UTC)

End Copy --Chaswmsday (talk) 19:53, 23 January 2013 (UTC)

the pictures on the japanese page[edit]

I posted this same question on the japanese version of this talk page: Could the pictures from the japanese page be added to the english page? They are much better69.161.17.114 (talk) 05:21, 28 February 2013 (UTC)

Diverging windmill[edit]

Is this or? It apersts having no weaving probs but ether speed limit or large areal due making drivers see jamming traffic early. Where is/was a bult sample? --Hans Haase (talk) 12:30, 3 April 2013 (UTC)

Identify Y, partial Y, U-turn hybrid interchange[edit]

Copied from User talk:Chaswmsday#Name of intersection:

What's that kind of interchange? Is there a name for it?

Technically this is a grade separated HIGH-T / CGT / Seagull or sealed trumpet?

* 27.552055,-82.562985 US-19 / US-41

* 39.077387,-108.576782 US-50 / US-6

it can also be found at I-10 to I-20 intersection next to west end of Texas. --Hans Haase (talk) 11:44, 30 August 2013 (UTC)

End copy. --Chaswmsday (talk) 21:46, 9 September 2013 (UTC)

Hans, to my eyes these very interesting interchanges appear to be hybrids of full Y's, partial Y's, a little bit of trumpet interchange, and with U-turn ramps like the "interchanges with U-turns" described in this article. They sort of "do" look like a grade-separated version of seagull intersections except that whichever highway you pretend is the "top bar of the T", the left entrance ramp merges onto that roadway before the left exit ramp departs. I'm not sure they're a common-enough type to have their own name, other than just describing them as hybrid-"somethings". Does anyone else here have an opinion? Thanks. --Chaswmsday (talk) 21:46, 9 September 2013 (UTC)

"Barring U-turns, a complete interchange between two freeways requires eight ramps"[edit]

This claim is made in the article. But couldn't you technically have a complete freeway-freeway interchange with only four ramps (for example, a cloverleaf with only the inner loop ramps)? It would be inefficient and cause even more weaving, but it would still allow all movements and give both roads freeway status.

Just saying... (talk) 20:30, 23 November 2013 (UTC)

Kathipara interchange
Nice, let's eliminate misunderstandings. We are talking about a 4-arm interchange in freeflowing traffic on all roadways. All of these require 8 ramps to allow the change from any arm in all other directions. Roundabouts and cloverleafes allow the u-turn also but cause weafing traffic in the interchange. Stacks move the weaving out from the interchange to the roads before and behind the interchange. There's not that limited section to change the lanes. A ramp is a one-way road. A flyover-ramp is a ramp on a bridge. See stack interchanges or as a unique feature: the loop ramps (missing WP-article, or section!) of the Kathipara interchange. In a doubletrumpet (→ see the german artice of 3-arm based interchanges and click the map exaples, e.g. US-501 - Carolina Parkway / SR-31 @ 33.740543,-78.951788 ), the loop ramps are located in each other like Matryoshka dolls. If the interchange has more or less arms or roadways (like local and express lanes, also known as collector and distributor roads, also a tollroad and a freeway in the same path) an other number of ramps is needed to allow the changing from any into any other direction. If an interchange has less ramps installed, there are 2 possible causes: either no freeflowing traffic on one or some roadways (typical for the crossstreet of intersections, →see parclo) or there's no way to change into one or some directions. This can be found in 5-arm interchanges or if the not connected arms have the nearly same direction and no demand for ramps. If you have better words for the article, feel free to edit it. --Hans Haase (talk) 13:26, 24 November 2013 (UTC)
I don't see how this discourse relates to the IP's question. If an intersection has just 4 ramps of 270°, a car wanting to go right could pass the crossing first and then make 3 left turns by circling 3 of the ramps to finish up on the road to his original right. So indeed it seems that 4 ramps are enough to connect all directions. Admittedly inefficient and needing a lot of weaving. −Woodstone (talk) 15:08, 24 November 2013 (UTC)
Yes, it takes 2 weaving operations and has effect of a 3rd one per right turning car and more than one minute driving time, unneccessary fuel, more decelerating and accellerating. Example for the above described roundabout is here. --Hans Haase (talk) 19:20, 24 November 2013 (UTC)
I've updated the article in light of these details (so having eight ramps is not required, but reducing the number would cause problems). How does it look? (talk) 18:53, 25 November 2013 (UTC)
Well, but 4 arm standard interchanges only require 8 ramps, 3 arm or 5 arm interchanges differ! The case of a 3-arm interchange is not covered in the article's section. A special constuction can be found at the I-10 / I-20 in west Texas, also applied at some interchange constructions in Florida. This example shows how costs of flyover ramps and bridges are increased, compared to a simple at-grade ramp/road. To save the huge costs of bridges, see the I-10 / I-20 interchange, it uses just one bridge to separate one single roadway to a single other one. 4-arm stack interchanges can be built as well by using smaller bridges. See that stack interchanges refered in de:Autobahnkreuz#Gotisches Kreuz and de:Autobahnkreuz#Gotisches Kreuz mit reduzierter Br.C3.BCckenfl.C3.A4che (Gothic cross stack interchanges with reduced bridge areas), but please refer a historical picture proir 2005 of the Baltimore interchange of I-95 / I-695. To apply this on cloverleafes to eleminate the weafing, lefthand located ramps are installed and the main bridge is beeing spitted into 4 bridges. It can be found in this talk, section "#Name of this ?", picture "Unknown, but used interchange". --Hans Haase (talk) 01:10, 26 November 2013 (UTC)


Satellite photograph
Would this interchange be considered a "STACK" or a "CLOVERSTACK"? It looks complicated.

— Preceding unsigned comment added by 2602:304:CE27:4959:F13E:FF4C:F442:7213 (talk) 15:12, 11 May 2014 (UTC)

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A Wikipedia talk page is for discussions among editors in relationship to editing the corresponding article, not for use as a general forum for asking questions about the subject of the article. You could, however, try asking at Wikipedia:Reference desk. The editor who uses the pseudonym "JamesBWatson" (talk) 08:13, 23 May 2014 (UTC)

Answer: This is a undenfined interchange type. Such is called a Spaghetti Junction (←this article contains some horrible original research. The following can be verified: It is a 5-leg interchange, it contains parts from other interchanges like Loop ramps (←an orphaned redirct in Wikipedia) used in Cloverleaf interchanges, 2 directional T interchanges, and braided ramps. It is built on a large areal. --Hans Haase (talk) 08:06, 10 November 2014 (UTC)

"Carriageway" is not used in North America[edit]

The term "carriageway" is not used in North America, but it appears, e.g., in the discussion of the I-196/US 131 interchange in Grand Rapids. The US equivalent would be "roadway", "lanes", or "traffic lanes". I grant that "carriageway" is more specific, but it's just not used in the US, or, as far as I know, in Canada.

Edgy4 (talk) 01:32, 26 February 2017 (UTC)

External links modified[edit]

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Loop ramp ...[edit]

... leads to this article, but is not explained here as such. (See also Redirects for discussion#Loop ramp and, previously, Reference desk/Archives/Miscellaneous/2018 October 26.) Can somebody in the know maybe provide an appropriate definition of the term in question?--Neufund (talk) 16:34, 11 November 2018 (UTC)