"Why?" interchange designs

[Joe The Dragon]

The WI-23 and CTH-Y interchange in Kohler is one of the stranger ones I've ever seen. It includes two seemingly unnesecary loop ramps, both servicing westbound WI-23. This interchange would be safer and take up less space if it were a simple diamond: https://www.google.com/maps/@43.7532204,-87.779378,16.77z

Looks somewhat similar to SB US 41 at Washington Street near Waukegan, IL

looks an bit like the old scissors ramp that used to be on  I-94 / US-41 up in WI

[CoreySamson]

The interchange at Beltway 8 and the Westpark Tollway is probably the most bizarre in Houston. It looks even weirder from the road.

[lepidopteran]

Similar interchange I know of at I-270 and OH 3

Part of that might have been because of the railroad underpass just to the west of the interchange.  Perhaps it was just to save the cost of constructing another overpass, as was done with the WB on-ramp.

Having said that, the railroad tracks that pass through there were abandoned over 30 years ago.

[jay8g]

The Kentucky parkway system has some real oddball interchanges. There are a few where all four ramps are loop ramps for some reason, and when looking for an example of that I also came across this thing, which seems to be an inside-out folded diamond interchange. Maybe I'm missing something, but I can't see any practical reason for these designs.

Closer to home, I've always found I-5/I-405/SR 518 to be a bit perplexing. I get that there are some topographic challenges going on there, but the assortment of left and right exits and one single loop ramp thrown into the mix just seems strange. The surrounding ramps to surface streets are always a bit confusing to use, too.

[CtrlAltDel]

The Kentucky parkway system has some real oddball interchanges. There are a few where all four ramps are loop ramps for some reason, and when looking for an example of that I also came across this thing, which seems to be an inside-out folded diamond interchange. Maybe I'm missing something, but I can't see any practical reason for these designs.

Tollbooths. The idea was to have a single tollbooth in a central location accessible by all traffic. Here's the second one in 1983.

[skluth]

The strangest one I've ever seen is still the one near Perth Amboy.

Ye gads, I believe you've found Cthulhu. It's especially strange when you consider the C/D lanes extend north to the NJ Turnpike.

[tolbs17]

Like why does nj only use toll booths?

[hotdogPi]

Like why does nj only use toll booths?

New Hampshire does, too.

[kphoger]

The Kentucky parkway system has some real oddball interchanges. There are a few where all four ramps are loop ramps for some reason, and when looking for an example of that I also came across this thing, which seems to be an inside-out folded diamond interchange. Maybe I'm missing something, but I can't see any practical reason for these designs.

Tollbooths. The idea was to have a single tollbooth in a central location accessible by all traffic. Here's the second one in 1983.

[img

For a modern and more robust example, see here.

[jeffandnicole]

Like why does nj only use toll booths?

Their system is from the 1950's and 1960's, and pressure to continue taking cash payments have limited its advancement to full ETC.

There are some exceptions - there's a ETC-only plaza on the GSP, and two ramp ETC-only plazas at Interchange 17 of the ACX: https://goo.gl/maps/iP5AaghpUN1zeESj8

[dlsterner]

The Kentucky parkway system has some real oddball interchanges. There are a few where all four ramps are loop ramps for some reason, and when looking for an example of that I also came across this thing, which seems to be an inside-out folded diamond interchange. Maybe I'm missing something, but I can't see any practical reason for these designs.

Tollbooths. The idea was to have a single tollbooth in a central location accessible by all traffic. Here's the second one in 1983.

[img

For a modern and more robust example, see here.

In your example, interesting to see that the ramp network has at-grade crossings among itself.  I personally can't think of any other situations like that.

[paulthemapguy]

I just sent this at-grade nonsense from the Adirondacks to a couple friends last night.  I imagine this leading to a lot of confusion for people making left turns, and therefore crashes.  https://www.google.com/maps/@44.1019636,-73.688917,434m/data=!3m1!1e3

[kphoger]

I just sent this at-grade nonsense from the Adirondacks to a couple friends last night.  I imagine this leading to a lot of confusion for people making left turns, and therefore crashes.  https://www.google.com/maps/@44.1019636,-73.688917,434m/data=!3m1!1e3

Better or worse than IL-15/US-45 on the west end of Fairfield?

[sprjus4]

I just sent this at-grade nonsense from the Adirondacks to a couple friends last night.  I imagine this leading to a lot of confusion for people making left turns, and therefore crashes.  https://www.google.com/maps/@44.1019636,-73.688917,434m/data=!3m1!1e3

I think the yields as opposed to stops along with the lack of "Do Not Enter" or "Wrong Way" signs is another major factor that would lead to crashes.

[GaryV]

I just sent this at-grade nonsense from the Adirondacks to a couple friends last night.  I imagine this leading to a lot of confusion for people making left turns, and therefore crashes.  https://www.google.com/maps/@44.1019636,-73.688917,434m/data=!3m1!1e3

That's close to the previous design of US-41 and the decommissioned business route in Marquette.  Until it got replaced by a roundabout.

[sprjus4]

Then this mess at either end of the 2-lane US-17 Vanceboro bypass in North Carolina.

https://www.google.com/maps/@35.2881952,-77.1289871,530m/data=!3m1!1e3?hl=en
https://www.google.com/maps/@35.3332905,-77.1499587,485m/data=!3m1!1e3?hl=en

[webny99]

I just sent this at-grade nonsense from the Adirondacks to a couple friends last night.  I imagine this leading to a lot of confusion for people making left turns, and therefore crashes.  https://www.google.com/maps/@44.1019636,-73.688917,434m/data=!3m1!1e3

Better or worse than IL-15/US-45 on the west end of Fairfield?

I think the NY one is much worse (having just traveled through it last fall and noticing how weird it was). At least the IL one has only one point of conflict; the NY one has several, and only yield signs instead of stop signs. Here's the Street View; here's another angle (note the second crossing in the background).

[kphoger]

I like it.  Call me weird.

[webny99]

I like it.  Call me weird.

Cool from a visual standpoint, but questionable from a functional standpoint.

[kphoger]

Unless there is an actual high number of crashes there, I'm not questioning its functionality.

[1995hoo]

The intersection of Emmet Street and Jefferson Park Avenue in Charlottesville used to have a similar layout to that and was controlled by yield signs. Unfortunately, the images on Historic Aerials are very grainy and blurry and you can't really see anything. Sometime after 1995, I guess the traffic got heavy enough that they decided to redesign the intersection and use a traffic light instead (except that traffic following southbound US-29 Business from Emmet to JPA can bypass the light). I liked it better the old way, but then, I usually prefer designs that don't use traffic lights when feasible.

[vdeane]

There's half of one where NY 12 and NY 37 meet.  One of the movements is handled with a U turn ramp.

US 9/NY 73 is interesting because it was built pre-Northway for a lot more traffic on US 9 than is there now.  Most traffic these days is probably going to NY 73 from the exit on the Northway a mile south of there.

[webny99]

US 9/NY 73 is interesting because it was built pre-Northway for a lot more traffic on US 9 than is there now.  Most traffic these days is probably going to NY 73 from the exit on the Northway a mile south of there.

Yup, that's what I was doing when passing through this past fall. A standard T-intersection with US 9 to NY 73 as the through movement would be more than sufficient.

[kphoger]

There's half of one where NY 12 and NY 37 meet.  One of the movements is handled with a U turn ramp.

Similar to Mexico 2/29, except that this is the extent of the U turn ramp.

[webny99]

Similar to Mexico 2/29, except that this is the extent of the U turn ramp.

That looks like a leap of faith for large vehicles*.



*See what I did there?