Is this interchange classified as a SPUI?

[ChoralScholar]

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

[NE2]

Definitely a cookie-cutter SPUI.

[Alps]

Since this is MO, how about a diverging SPUI?

[NE2]

Since this is MO, how about a diverging SPUI?

I don't think that would be any different from a normal SPUI.

[vtk]

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. 

[Alps]

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.

[NE2]

Oops. I meant a normal DDI. Left turn paths already don't cross in a DDI.

[vtk]

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.

[kphoger]

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.

[roadfro]

^ Nothing is different about it. It is a "cookie-cutter SPUI", i.e. a design that can be repeated anywhere.

[roadman65]

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

[vtk]

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.

[kphoger]

So the whole "diverging SPUI / DDI" conversation was just a bunch of hogwash?  OK.  Thread over.

[jeffandnicole]

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.

[codyg1985]

Here is a challenge for all of you.  How about the interchanges along Memorial Pkwy in Huntsville, AL (here is an example)?

They function as a single intersection at each interchange, but opposing left turns from the service roads can't happen at the same time.

[NE2]

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.

[codyg1985]

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.

[jeffandnicole]

Here is a challenge for all of you.  How about the interchanges along Memorial Pkwy in Huntsville, AL (here is an example)?

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.

[roadfro]

Here is a challenge for all of you.  How about the interchanges along Memorial Pkwy in Huntsville, AL (here is an example)?

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.

[NE2]

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.

[NE2]

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.

[vtk]

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?

[kphoger]

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.

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.

[Alps]

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.

[vtk]

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.