Strange Interchanges

[roadman65]

There is the one interchange near San Antonio where I-35 and I-410 meet at the northeast end of the two route overlap.  I-410 through traffic not only gets substandard ramps but make basically a hook instead of utilizing the land in the southwest quadrant to build much better (and direct) ramps or better through alignment.

[rbt48]

Slightly off-topic, but I doubt there is a much cooler looking interchange than the I-787 / US 20 meeting in Albany, NY.

[empirestate]

Slightly off-topic, but I doubt there is a much cooler looking interchange than the I-787 / US 20 meeting in Albany, NY.

You mean this one?

[johndoe]

I've always loved the Interchange between I-5, I-405, US 26, OR-99W, and OR-43.  It is like a gigantic round about connected via surface streets to other roadways, and partially screwed up due to removal of Harbor Drive.

There's also the Paper Clip interchange between I-5 and OR-99E:

That's pretty nifty!  Check this out if you haven't seen it yet: http://www.kurumi.com/roads/interchanges/oddities.html

One interesting thing, as he says on his page, is that making a through movement from an off-ramp results in a "u-turn" on the mainline.  To rejoin the mainline in the same direction you could make a u-turn.  I'd like to see a sign describing that!

I guess I'm a bit confused why he calls this geometry "spupclo".  If I'm looking at this right it's the same (operationally)  as what he calls a "paperclip".  To me anything with "single point" in the name should have the ramps aligned in a normal diamond pattern.  Isn't he a user here?  Maybe he'll explain this... my brain hurts! 

[kurumi]

Two things occurred to me long after I wrote the "Strange interchanges" page:
* some of those interchanges really exist
* paperclips and spupclos are more similar than different

All ramps intersect at a single point, but loop ramps are used to avoid the large left turn geometry that a SPUI needs. If we should be distinguishing paperclips and spupclos (we'll leave that to the PhDs in civil engineering :-) then we could do so based on either:
* whether the surface street crosses the freeway or stays parallel
* whether an inner loop exit ramp becomes an outer loop entrance ramp (spupclo example) or stays inner (as in I-5/OR 99E)

[roadman65]

Though old,  it fits the topic as it is a strange interchange.

https://goo.gl/maps/bMrTYEuGoKs1YK1z9
The I-91 and VT 9 exchange in Brattleboro is got unusual ramps for a folded diamond. They are way too long for any interchanges IMO.

[MCRoads]

Though old,  it fits the topic as it is a strange interchange.

https://goo.gl/maps/bMrTYEuGoKs1YK1z9
The I-91 and VT 9 exchange in Brattleboro is got unusual ramps for a folded diamond. They are way too long for any interchanges IMO.

Hooo boy, I immediately thought of something dirty when I saw that, lol.

[dlsterner]

Though old,  it fits the topic as it is a strange interchange.

https://goo.gl/maps/bMrTYEuGoKs1YK1z9
The I-91 and VT 9 exchange in Brattleboro is got unusual ramps for a folded diamond. They are way too long for any interchanges IMO.

Looking at the satellite view, that design might have been the only one to maintain all movements and to not destroy whole streets worth of houses on Brattle St. and Allerton Ave.

There aren't too many alternatives for northbound I-91 traffic to exit onto VT 2.  Just think of them as glorified frontage roads with a RIRO exit on either side.

[Terry Shea]

I-95 and I-695 north of Baltimore used to do that when they met, but now it's a conventional stack interchange.

Not completely true.  The I-695 carriageways still cross each other through the interchange.

US-131 does the same thing at I-196. Also, the carriageways for I-196 are at different levels, one going over US-131 and the other going under.

I refer to that portion of US-131 as The Corkscrew.

[roadman65]

Though old,  it fits the topic as it is a strange interchange.

https://goo.gl/maps/bMrTYEuGoKs1YK1z9
The I-91 and VT 9 exchange in Brattleboro is got unusual ramps for a folded diamond. They are way too long for any interchanges IMO.

Looking at the satellite view, that design might have been the only one to maintain all movements and to not destroy whole streets worth of houses on Brattle St. and Allerton Ave.

There aren't too many alternatives for northbound I-91 traffic to exit onto VT 2.  Just think of them as glorified frontage roads with a RIRO exit on either side.

My thoughts exactly.  It makes me wonder how many other homes got razed to build the freeway in the first place.

[ztonyg]

Though old,  it fits the topic as it is a strange interchange.

https://goo.gl/maps/bMrTYEuGoKs1YK1z9
The I-91 and VT 9 exchange in Brattleboro is got unusual ramps for a folded diamond. They are way too long for any interchanges IMO.

Kansas has a similar one here, although the large interchange directly south of it is my nominee for strangest interchange:

https://goo.gl/maps/SpXQqb6WQ1o46Rek6

[Occidental Tourist]

Presented without further comment:

[Tom958]

US 45E, TN 22, and TN 431 near Martin, TN. TN 22 has priority and two-lane ramps as it passes through the interchange. It's a TOTSO north/westbound but not south/eastbound, since the ramps carrying US 45E are on the right (and one lane). And there's a left lane exit only for the northbound exit to TN 431 as a way to killing off the unneeded second northbound lane.

The bridges are similar in design, but the one for TN 22 was built in 1985, while  the ones for US 45E are from 1994, which pretty much explains the layout. That section of US 45E provides a marginally-useful second bypass of Martin, which was likely an afterthought.

[achilles765]

Presented without further comment:

Oh COME ON NOW. lol. I almost think that must have been intentional.

[jakeroot]

Oh COME ON NOW.

[TheHighwayMan3561]

Oh COME ON NOW. lol. I almost think that must have been intentional.

https://www.youtube.com/watch?v=wzCwYJZfqik

[snowc]

Exit 79 is a GOOD example of a weird interchange.
I95 in Benson NC.
In 1957, exit 79 had NO direct intersection with NC 50. Signs said TO NC 50 instead of NC 540.
However, on NB sides of Exit 79, exit 79 has NC 242 signs rather than TO NC 50.
This was rebuilt in 2005 to a folded diamond interchange, as well as replacing the old 1950s bridge (the bridge was in process of being replaced as seen in sat view)

[milbfan]

Most of I-240 is odd, but especially between Exit 3/Patton Ave. and Exit 4 to the east in Asheville.

[DJDBVT]

Though old,  it fits the topic as it is a strange interchange.

https://goo.gl/maps/bMrTYEuGoKs1YK1z9
The I-91 and VT 9 exchange in Brattleboro is got unusual ramps for a folded diamond. They are way too long for any interchanges IMO.

Looking at the satellite view, that design might have been the only one to maintain all movements and to not destroy whole streets worth of houses on Brattle St. and Allerton Ave.

There aren't too many alternatives for northbound I-91 traffic to exit onto VT 2.  Just think of them as glorified frontage roads with a RIRO exit on either side.

My thoughts exactly.  It makes me wonder how many other homes got razed to build the freeway in the first place.

When constructing 91 in that area, the entirety of Northern Ave. was eliminated. Northern Ave. was another short residential dead-end off VT 9, about halfway between Brattle and Allerton, or roughly where the 91 mainline now sits. To build a "normal" interchange, they would probably have had to take all three streets.

[vtk]

Looking at Street View, I can see hints of former grading for a simple half-diamond interchange at I-91 & VT-9. My guess is the current configuration is a result of upgrading that partial interchange to accommodate all movements, without needing to take more residences.

[froggie]

^ You're seeing things.  Exit 2 (I-91/VT 9) was built in its present configuration from the get-go.  Here is a photograph showing an aerial view of the interchange from 1962, a couple years after it opened

[RoadRebel]

There are a lot of old, substandard grade separated intersections in South Carolina.

US-21 and SC-9
This one is pretty odd; it comes complete with a gas station! If you look closer, the ramps have road names too! Boundary Road used to be US-21 before the overpass was built.
https://www.google.com/maps/@34.7020978,-80.8945192,16z/data=!3m1!1e3?gl=us

US-521/US-521BL/SC-9/SC-200
Strange layout due to SC-200 forking off just south of where the bypass was built:
https://www.google.com/maps/@34.7344457,-80.7761042,15z/data=!3m1!1e3?gl=us

US-17 at Harrelson Blvd in Myrtle Beach has an unusual underpass loop ramp pair.
https://www.google.com/maps/@33.7032302,-78.9313204,16z/data=!3m1!1e3?gl=us


In North Carolina:

I-85 at US-321
Recently rebuilt with new underpass ramps using an old railroad underpass.
https://www.google.com/maps/@35.2837416,-81.1877174,16z/data=!3m1!1e3?gl=us

I-85 at US-29/US-74 near Kings Mountain is an interesting weave interchange
https://www.google.com/maps/@35.2483202,-81.3032547,14z/data=!3m1!1e3?gl=us

An odd set of weaving ramps on I-240:
https://www.google.com/maps/@35.5953033,-82.5295594,16z/data=!3m1!1e3?gl=us

I-485 at Prosperity Church Road is a diamond with three overpasses and six roundabouts:
https://www.google.com/maps/@35.367645,-80.7844703,15z/data=!3m1!1e3?gl=us

Of course, there's the infamous I-77/I-85 interchange:
https://www.google.com/maps/@35.2717497,-80.8458006,15z/data=!3m1!1e3?gl=us

[vtk]

^ You're seeing things.  Exit 2 (I-91/VT 9) was built in its present configuration from the get-go.  Here is a photograph showing an aerial view of the interchange from 1962, a couple years after it opened

Whatever I'm seeing is visible from multiple angles.

[Skye]

In suburban Cincinnati, I-75 SB exit to Lockland (Exit 12) is nearly a 90 degree right turn.

Toll roads are a haven for strange interchanges. My "favorite" is NB I-65 to WB I-90 (Indiana Toll Road) in Gary, IN. It's a 360 degree loop from I-65 to the toll plaza then onto I-90.

[froggie]

^ You're seeing things.  Exit 2 (I-91/VT 9) was built in its present configuration from the get-go.  Here is a photograph showing an aerial view of the interchange from 1962, a couple years after it opened

Whatever I'm seeing is visible from multiple angles.

I'm aware of what you're seeing at that location.  Especially on the southbound side, I can see what one might perceive as flat grading.  But I'm pointing out again that the current interchange configuration is what was built from the get-go.