This is an interchange of US-65 at Opportunity Rd in Hollister, MO (just south of Branson). I never see it mentioned in articles about SPUIs, so I was just wondering.
https://maps.google.com/maps?q=hollister,+mo&hl=en&ll=36.610361,-93.232298&spn=0.011161,0.023732&sll=34.751928,-92.131378&sspn=2.924523,6.075439&t=h&hnear=Hollister,+Taney,+Missouri&z=15
Fixed URL
Definitely a cookie-cutter SPUI.
Since this is MO, how about a diverging SPUI?
Quote from: Steve on July 02, 2013, 06:20:04 PM
Since this is MO, how about a diverging SPUI?
I don't think that would be any different from a normal SPUI.
Quote from: ChoralScholar on July 02, 2013, 02:56:29 AM
https://maps.google.com/maps?hl=en&ll=36.610361,-93.232298&spn=0.011161,0.023732&sll=34.751928,-92.131378&sspn=2.924523,6.075439&t=h&hnear=Hollister,+Taney,+Missouri&z=15
Fixed your URL more. See also: https://www.aaroads.com/forum/index.php?topic=5716.0
I don't know if I'd call that "cookie cutter", as every modern SPUI I've seen with the curved, forked ramps has the freeway going
under the intersection.
Quote from: NE2 on July 02, 2013, 07:13:22 PM
Quote from: Steve on July 02, 2013, 06:20:04 PM
Since this is MO, how about a diverging SPUI?
I don't think that would be any different from a normal SPUI.
It would, in the sense that it's only a 2-phase operation, because left turns can go simultaneously with through traffic.
Oops. I meant a normal DDI. Left turn paths already don't cross in a DDI.
A diverging single-point interchange would fail to accommodate left turns exiting the freeway in two-phase mode because there's zero capacity for the cars to wait between the two intersections that are now one. Also, the striping for through traffic would be really weird.
What is different about the Hollister example when compared to a cookie-cutter SPUI? Looks like a SPUI to me.
FWIW, I'm familiar with that interchange. The Spirit Shop just to the north is/was a landmark (is it still in business?) from my wife's childhood, and I've been to a gymnastics meet for my little sister-in-law at the YMCA just to the east of the SPUI.
^ Nothing is different about it. It is a "cookie-cutter SPUI", i.e. a design that can be repeated anywhere.
What is the US 98/ I-4 interchange in Lakeland, FL and the FL 100/ I-95 interchange near Palm Coast, FL classified as? They, too, do are not actual SPUIs, but they function as one with both ramp ends on both sides having the same signal and "passing to the left" is done under the highways at shallow angles. In fact I-4 has a wide median over US 98, yet its able to be done.
https://maps.google.com/maps?q=Lakeland,+FL&hl=en&ll=28.084987,-81.969863&spn=0.004562,0.008122&sll=37.0625,-95.677068&sspn=33.572881,66.533203&oq=lakelan&t=h&hnear=Lakeland,+Polk,+Florida&z=17
Quote from: roadman65 on July 03, 2013, 03:37:11 PM
they function as one with both ramp ends on both sides having the same signal and "passing to the left" is done under the highways at shallow angles.
Yes, that's a SPUI too. The one signalized intersection handling the ramps to and from both sides of the freeway is the "single point" in the acronym.
So the whole "diverging SPUI / DDI" conversation was just a bunch of hogwash? OK. Thread over.
Quote from: roadman65 on July 03, 2013, 03:37:11 PM
What is the US 98/ I-4 interchange in Lakeland, FL and the FL 100/ I-95 interchange near Palm Coast, FL classified as? They, too, do are not actual SPUIs, but they function as one with both ramp ends on both sides having the same signal and "passing to the left" is done under the highways at shallow angles. In fact I-4 has a wide median over US 98, yet its able to be done.
https://maps.google.com/maps?q=Lakeland,+FL&hl=en&ll=28.084987,-81.969863&spn=0.004562,0.008122&sll=37.0625,-95.677068&sspn=33.572881,66.533203&oq=lakelan&t=h&hnear=Lakeland,+Polk,+Florida&z=17
They are definitely SPUIs...just extended a little bit due to the width of the highway. I'm surprised they actually have vehicles passing so close together in such a configuration.
Here is a challenge for all of you. How about the interchanges along Memorial Pkwy in Huntsville, AL (here is an example (http://goo.gl/maps/QPRW4))?
They function as a single intersection at each interchange, but opposing left turns from the service roads can't happen at the same time.
Quote from: codyg1985 on July 03, 2013, 11:43:33 PM
They function as a single intersection at each interchange, but opposing left turns from the service roads can't happen at the same time.
Then it's not a SPUI. If left turns onto the frontage roads can be made simultaneously it's halfway SPUIed.
Quote from: NE2 on July 03, 2013, 11:47:23 PM
Quote from: codyg1985 on July 03, 2013, 11:43:33 PM
They function as a single intersection at each interchange, but opposing left turns from the service roads can't happen at the same time.
Then it's not a SPUI. If left turns onto the frontage roads can be made simultaneously it's halfway SPUIed.
Left turns can be made onto the frontage roads simultaneously. I think of these as ghetto SPUI's but I guess I can now refer to them as half-ass SPUI's.
Quote from: codyg1985 on July 03, 2013, 11:43:33 PM
Here is a challenge for all of you. How about the interchanges along Memorial Pkwy in Huntsville, AL (here is an example (http://goo.gl/maps/QPRW4))?
They function as a single intersection at each interchange, but opposing left turns from the service roads can't happen at the same time.
It's not even an interchange. There are no ramps to/from the highway here.
Quote from: codyg1985 on July 03, 2013, 11:43:33 PM
Here is a challenge for all of you. How about the interchanges along Memorial Pkwy in Huntsville, AL (here is an example (http://goo.gl/maps/QPRW4))?
They function as a single intersection at each interchange, but opposing left turns from the service roads can't happen at the same time.
It's still effectively a SPUI. For the frontage roads, think of it more like a SPUI with split phasing on the ramps. Definitely not the preferred operation, though; surely if geometry were better those left turns would be simultaneous.
Quote from: roadfro on July 04, 2013, 03:01:29 AM
It's still effectively a SPUI. For the frontage roads, think of it more like a SPUI with split phasing on the ramps. Definitely not the preferred operation, though; surely if geometry were better those left turns would be simultaneous.
Go to street view - the left turn paths from the frontage roads cross.
Quote from: jeffandnicole on July 04, 2013, 12:40:40 AM
It's not even an interchange. There are no ramps to/from the highway here.
Apparently I can't say 'what' in response to this, despite being a completely 'what'-worthy post.
Okay, so the one pictured at Memorial & Drake is a half-assed single point urban intersection.
On the other hand, most intersections are given the single-point treatment...
It's a 4-way intersection between an undivided street and a wide-median divided street, with difficult geometry requiring split-phasing from the divided approaches.
Actually, I'm getting a bit tired of this discussion. Can we just say the intersections and interchanges along this stretch of Memorial Blvd are mutants that defy classification?
Quote from: NE2 on July 04, 2013, 06:27:25 AM
Quote from: jeffandnicole on July 04, 2013, 12:40:40 AM
It's not even an interchange. There are no ramps to/from the highway here.
Apparently I can't say 'what' in response to this, despite being a completely 'what'-worthy post.
Allow me:
whatjeffandnicole, you apparently didn't scroll enough north or south to see slip ramps in both directions. The northern ones are south of Bob Wallace Ave, and the southern ones–actually, there are
two sets north of Airport Rd. It's a typical frontage road interchange.
Quote from: NE2 on July 04, 2013, 05:14:56 AM
Quote from: roadfro on July 04, 2013, 03:01:29 AM
It's still effectively a SPUI. For the frontage roads, think of it more like a SPUI with split phasing on the ramps. Definitely not the preferred operation, though; surely if geometry were better those left turns would be simultaneous.
Go to street view - the left turn paths from the frontage roads cross.
And this is what makes it
not a SPUI. It's just a tight diamond with turnarounds.
Quote from: NE2 on July 04, 2013, 06:27:25 AM
Quote from: jeffandnicole on July 04, 2013, 12:40:40 AM
It's not even an interchange. There are no ramps to/from the highway here.
Apparently I can't say 'what' in response to this, despite being a completely 'what'-worthy post.
What you
can say is "Um, no, because..." and then give a reason. As per our forum rules, posts should contribute something to the discussion.
Quote from: kphoger on July 04, 2013, 11:09:07 AM
Quote from: NE2 on July 04, 2013, 05:14:56 AM
Quote from: roadfro on July 04, 2013, 03:01:29 AM
It's still effectively a SPUI. For the frontage roads, think of it more like a SPUI with split phasing on the ramps. Definitely not the preferred operation, though; surely if geometry were better those left turns would be simultaneous.
Go to street view - the left turn paths from the frontage roads cross.
And this is what makes it not a SPUI. It's just a tight diamond with turnarounds.
I disagree. A tight diamond still has two separate intersections, right? This is just one intersection – a "single point" – it's just pinched in such a way that two opposite left turns interfere with one another.
Regarding whether it's an interchange, the ramps for adjacent interchanges seem to be swapped and/or interlaced.
Whatever you call it, this is probably the best interchange / frontage road setup that can be applied to this corridor, unless you make the freeway bridges longer to acommodate non-interfering left turns from frontage roads to crossroads.
Quote from: vtk on July 04, 2013, 03:34:40 PM
I disagree. A tight diamond still has two separate intersections, right? This is just one intersection – a "single point" – it's just pinched in such a way that two opposite left turns interfere with one another.
Yeah, I thought of that after I'd left the house. OTOH, tight diamonds basically function as one intersection anyway. Perhaps you did describe it best a few posts ago.
Quote from: vtk on July 04, 2013, 03:34:40 PM
Regarding whether it's an interchange, the ramps for adjacent interchanges seem to be swapped and/or interlaced.
Those are called X ramps, and are somewhat common in urban environments where frontage roads are present.
Quote from: vtk on July 04, 2013, 03:34:40 PM
Quote from: kphoger on July 04, 2013, 11:09:07 AM
Quote from: NE2 on July 04, 2013, 05:14:56 AM
Quote from: roadfro on July 04, 2013, 03:01:29 AM
It's still effectively a SPUI. For the frontage roads, think of it more like a SPUI with split phasing on the ramps. Definitely not the preferred operation, though; surely if geometry were better those left turns would be simultaneous.
Go to street view - the left turn paths from the frontage roads cross.
And this is what makes it not a SPUI. It's just a tight diamond with turnarounds.
I disagree. A tight diamond still has two separate intersections, right? This is just one intersection – a "single point" – it's just pinched in such a way that two opposite left turns interfere with one another.
I'd agree. The operation is much closer to a SPUI than it is to a TDI.
The arterial lefts can still proceed together at this one, which still lends to being a SPUI from that aspect.
Quote from: kphoger on July 04, 2013, 11:09:07 AM
Quote from: NE2 on July 04, 2013, 06:27:25 AM
Quote from: jeffandnicole on July 04, 2013, 12:40:40 AM
It's not even an interchange. There are no ramps to/from the highway here.
Apparently I can't say 'what' in response to this, despite being a completely 'what'-worthy post.
Allow me: what
jeffandnicole, you apparently didn't scroll enough north or south to see slip ramps in both directions. The northern ones are south of Bob Wallace Ave, and the southern ones–actually, there are two sets north of Airport Rd. It's a typical frontage road interchange.
I did scroll both above and below. The whole definition of a SPUI is a single point urban
interchange. Slip ramps onto a frontage road have nothing to do with a SPUI. The interchanges for the highway are the slip ramps. Below the highway is nothing more than an everyday intersection with a wide median.
Quote from: jeffandnicole on July 05, 2013, 10:19:35 AM
Quote from: kphoger on July 04, 2013, 11:09:07 AM
Quote from: NE2 on July 04, 2013, 06:27:25 AM
Quote from: jeffandnicole on July 04, 2013, 12:40:40 AM
It's not even an interchange. There are no ramps to/from the highway here.
Apparently I can't say 'what' in response to this, despite being a completely 'what'-worthy post.
Allow me: what
jeffandnicole, you apparently didn't scroll enough north or south to see slip ramps in both directions. The northern ones are south of Bob Wallace Ave, and the southern ones–actually, there are two sets north of Airport Rd. It's a typical frontage road interchange.
I did scroll both above and below. The whole definition of a SPUI is a single point urban interchange. Slip ramps onto a frontage road have nothing to do with a SPUI. The interchanges for the highway are the slip ramps. Below the highway is nothing more than an everyday intersection with a wide median.
By those definitions, then, I-35 between San Antonio and Austin (Loop 1604 to TX-45) has no interchanges, because crossroads served by frontage road slips don't count as interchanges. I find that narrow definition of an interchange to be untenable. A diamond interchange doesn't stop being a diamond interchange just because there are frontage roads, so why should a SPUI stop being a SPUI for the same reason?
Quote from: vtk on July 02, 2013, 08:40:21 PM
A diverging single-point interchange would fail to accommodate left turns exiting the freeway in two-phase mode because there's zero capacity for the cars to wait between the two intersections that are now one. Also, the striping for through traffic would be really weird.
Can you draw what you mean by this?
Quote from: johndoe on July 09, 2013, 08:21:46 PM
Quote from: vtk on July 02, 2013, 08:40:21 PM
A diverging single-point interchange would fail to accommodate left turns exiting the freeway in two-phase mode because there's zero capacity for the cars to wait between the two intersections that are now one. Also, the striping for through traffic would be really weird.
Can you draw what you mean by this?
Sounds like a fun challenge. I'll tackle it tonight or tomorrow.
Quote from: kphoger on July 08, 2013, 09:55:08 AM
Quote from: jeffandnicole on July 05, 2013, 10:19:35 AM
Quote from: kphoger on July 04, 2013, 11:09:07 AM
Quote from: NE2 on July 04, 2013, 06:27:25 AM
Quote from: jeffandnicole on July 04, 2013, 12:40:40 AM
It's not even an interchange. There are no ramps to/from the highway here.
Apparently I can't say 'what' in response to this, despite being a completely 'what'-worthy post.
Allow me: what
jeffandnicole, you apparently didn't scroll enough north or south to see slip ramps in both directions. The northern ones are south of Bob Wallace Ave, and the southern onesactually, there are two sets north of Airport Rd. It's a typical frontage road interchange.
I did scroll both above and below. The whole definition of a SPUI is a single point urban interchange. Slip ramps onto a frontage road have nothing to do with a SPUI. The interchanges for the highway are the slip ramps. Below the highway is nothing more than an everyday intersection with a wide median.
By those definitions, then, I-35 between San Antonio and Austin (Loop 1604 to TX-45) has no interchanges, because crossroads served by frontage road slips don't count as interchanges. I find that narrow definition of an interchange to be untenable. A diamond interchange doesn't stop being a diamond interchange just because there are frontage roads, so why should a SPUI stop being a SPUI for the same reason?
Because it's not a single point interchange. If anything it's more like the diamond ramps you mention leading to the frontage road.
This is a SPUI:
http://maps.google.com/maps?ll=27.915947,-82.729427&spn=0.005155,0.007086&gl=us&t=k&z=18
http://books.google.com/books?id=t0jfX9fK5oUC&pg=PA37 (figure 51)
If you disagree you're wrong.
Quote from: jeffandnicole on July 10, 2013, 09:53:52 AM
Because it's not a single point interchange.
Yes it is. The "single point" part is about the intersection above or below the highway. The fact that the frontage roads split off from the ramps doesn't enter into it.
Below is the basic layout of the interchange in question. Look at the bold lines and not the thin lines: if it weren't for the left-turn paths crossing, it would be a normal SPUI with surface-level through movements added.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi1092.photobucket.com%2Falbums%2Fi410%2Fkphoger%2Fspui_zps3ded8efe.png&hash=c9f6af7c3df003790d1489a6b4b47d2f6b05c14f)
Quote from: johndoe on July 09, 2013, 08:21:46 PM
Quote from: vtk on July 02, 2013, 08:40:21 PM
A diverging single-point interchange would fail to accommodate left turns exiting the freeway in two-phase mode because there's zero capacity for the cars to wait between the two intersections that are now one. Also, the striping for through traffic would be really weird.
Can you draw what you mean by this?
Single-Point Diverging Diamond Interchange:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fvidthekid.info%2Fimghost%2Fdivergingspui.png&hash=74cef3cb45345c837ee7ab939c5d839a335fd5b2)
It's really awkward. It can't operate in two-phase mode. It requires a lot of bridge deck. Essentially, this design offers no advantage at all over a standard SPUI or DDI.
Haha, ok. It's just a DCD (doesn't that name make more sense than DDI?) with zero storage. Or a SPUI without concurrent arterial throughs. But still a huge bridge. The worst of both worlds! :sombrero:
What program did you draw that in?
Perhaps you'd enjoy this site, if you haven't seen it before:
http://midimagic.sgc-hosting.com/diamseq.htm
Quote from: vtk on July 10, 2013, 02:55:19 PM
Quote from: johndoe on July 09, 2013, 08:21:46 PM
Quote from: vtk on July 02, 2013, 08:40:21 PM
A diverging single-point interchange would fail to accommodate left turns exiting the freeway in two-phase mode because there's zero capacity for the cars to wait between the two intersections that are now one. Also, the striping for through traffic would be really weird.
Can you draw what you mean by this?
Single-Point Diverging Diamond Interchange:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fvidthekid.info%2Fimghost%2Fdivergingspui.png&hash=74cef3cb45345c837ee7ab939c5d839a335fd5b2)
It's really awkward. It can't operate in two-phase mode. It requires a lot of bridge deck. Essentially, this design offers no advantage at all over a standard SPUI or DDI.
My thought was to offer the same sort of storage as a DDI - shift the crossovers well to the outside, and have the right turn ramps follow along. The difference is having the left turns operate across from each other at a point. It's horribly inefficient compared to a regular DDI, but someone said it couldn't be done, or maybe I just got over-creative.
My thought was that a DDI is already effectively SPUIed, since opposing left turns don't cross.
Quote from: NE2 on July 10, 2013, 10:36:13 AM
This is a SPUI:
http://maps.google.com/maps?ll=27.915947,-82.729427&spn=0.005155,0.007086&gl=us&t=k&z=18
http://books.google.com/books?id=t0jfX9fK5oUC&pg=PA37 (figure 51)
If you disagree you're wrong.
Fine...I'll agree. I may do it kicking and screaming, but I'll agree.
Quote from: johndoe on July 10, 2013, 06:27:57 PM
Haha, ok. It's just a DCD (doesn't that name make more sense than DDI?) with zero storage. Or a SPUI without concurrent arterial throughs. But still a huge bridge. The worst of both worlds! :sombrero:
What program did you draw that in?
Engineered in IMSI TurboCAD Deluxe v10. Illustrated in Jasc Paint Shop Pro 8.
Quote from: johndoe on July 10, 2013, 06:27:57 PM
Perhaps you'd enjoy this site, if you haven't seen it before:
http://midimagic.sgc-hosting.com/diamseq.htm
That site is nifty. I'd like to see practical examples of the different variants described there.
Quote from: Steve on July 10, 2013, 06:54:22 PM
My thought was to offer the same sort of storage as a DDI - shift the crossovers well to the outside, and have the right turn ramps follow along. The difference is having the left turns operate across from each other at a point. It's horribly inefficient compared to a regular DDI, but someone said it couldn't be done, or maybe I just got over-creative.
I think I'd have to call that a triple-point diverging diamond. And it might be worth trying to draw one.
Or, maybe by spreading out the conflict points and timing the signals just right, a 2-phase operation with concurrent movements and no dependence on storage can be achieved. I suppose that would basically be a CFI decked over a freeway with frontage ramps a couple of blocks away...
Quote from: NE2 on July 10, 2013, 07:57:53 PM
My thought was that a DDI is already effectively SPUIed, since opposing left turns don't cross.
wot