"Why?" interchange designs

[thspfc]

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

[kphoger]

Might as well cross-post this here:

I found one that surprised me the other day. It's a junction if what are basically two farm roads in a plains state.

SW Ohio Street Road & SW 20th Street in rural Kansas, just west of El Dorado.

Might be because of terrain, so the north-south road doesn't have to dip down too much.

I discovered this one a few weeks ago as part of my ongoing exploration of paved county roads in Sedgwick and the surrounding counties.  At the time I suspected the grade separation was built when this length of SW 20th Street was still part of K-254.  However, while HistoricAerials.com is not being cooperative at present, I can find no evidence this intersection was ever on K-254.  The 1959 aerial photo (oldest available) shows it as a flat intersection while, just to the west, the road that Google Maps now shows as "Old K-254" swings north to converge on the current expressway alignment of K-254.

In the old days, when it was still a two-lane state highway, K-254 was on top of the east-west section line road known as 61st Street North in Sedgwick County and SW 20th Street in Butler County, and ran straight through Benton and Towanda.  This is largely still true of the expressway relocation, which was built in the mid-1990's, except that both Benton and Towanda are now bypassed with "Old K-254" former alignments.  However, the 1959 aerial shows that K-254 swung north in Towanda (well west of Ohio Street Road) to enter El Dorado along Central Avenue, and I suspect this was its original alignment since the K-254 designation was created in the mid-1950's.  (Side observation:  east-west county road numbering in Butler County is based on north/south distance to Parallel Street, which overlaps the Fifth Standard Parallel South and continues in Sedgwick County as 77th Street North.  The bulk of K-254 runs parallel to it but two miles south, while Central Avenue in El Dorado is also parallel to it but runs half a mile south.)

As for the grade separation at SW 20th Street and Ohio Street Road, this can have been built only by Butler County, though why it was done is a bit of a mystery.  There are a few clues, though.  The 1959 aerial shows Ohio Street Road making a spread-out wye on the south side of SW 20th Street, while the 1979 topographic map shows pavement on Ohio Street Road ending at the wye--north of it, it was just gravel.  The 2002 aerial shows the grade separation in its current configuration and Ohio Street Road paved all the way north to its current intersection with relocated K-254.

I suspect that the northern mile and a half of Ohio Street Road was paved as a complement to the K-254 relocation and widening.  It is uncharacteristically extravagant for Butler County to put in a grade separation instead of a four-way stop, and this may have been done to avoid creating new stop conditions for straight-through traffic on SW 20th Street.  (There would have been pre-existing stop signs on either arm of the wye for northbound traffic going from Ohio Street Road to SW 20th Street in either direction, but these would have affected turning traffic only.)

Ohio Street Road gets its internally redundant name from the fact that it is the county road extension of Ohio Street in Augusta.  It is currently a convenient paved shortcut between US 54 and K-254, though using it entails some knowledge of Augusta streets since it passes under the US 54 railroad viaduct instead of intersecting it on the level.  In time it will become much less convenient because Augusta has no meaningful planning control and is sprawling north along Ohio Street.

While detouring due to a bridge that was out for reconstruction on Saturday, I ended up using the craziest path through this interchange while my wife and I were out running deliveries.  This path totally defies common sense and, at each turn along the way, I was never quite sure if my next turn was even a possibility.

[webny99]

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

My suspicion is that, since most of the development in the area is south of the interchange, they wanted to make all the primary turns right turns. This will allow for a lot more growth before traffic signals or intersection upgrades are needed.

This interchange, for example, carries an incredible amount of traffic with no traffic signals because all the primary turns are right turns; I've mentioned it as possibly the busiest such interchange in the country.

[SkyPesos]

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

[kphoger]

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

That's nearly identical to...

The situation Kphoger is talking about is a compromised design dating from completion of the I-135/US 54 turban interchange in the late 1970's.  This involved the upgrading of Kellogg from a surface arterial to a (relatively) modern freeway between Topeka (east fringe of downtown) and Bluff (a north-south road midway between Hillside and Oliver that was basically a collector but, at the time, functioned as a signalized access point to Kellogg).  Putting in loops instead of link ramps for Hillside on eastbound Kellogg avoided taking Sunnyside, still an elementary school at the time but now an apartment building, as well as part of Calvary Cemetery.  Even so, this decision still necessitated shifting the Kellogg centerline to the north--Kellogg Drive, which borders the cemetery, is actually in the footprint of the old road.  The loops do create a weaving section, but to put in links would have created a weave between traffic entering from I-135 and traffic exiting onto Hillside that would arguably have been worse, and until the freeway was extended to Oliver and beyond, mainline traffic tended to slow down for a signal at Bluff.  (It still slows down to a degree because this is the point at which eastbound Kellogg climbs out of the Arkansas River floodplain, with a gentle uphill grade that drivers almost uniformly fail to anticipate.)

Absent travel demand management, the logical fix would appear to be to braid ramps so that traffic exits for Hillside before the merge point for cars coming from I-135.  I don't see this entering the development pipeline except as part of a widening of Kellogg that would displace its centerline further to the north and probably also involve the closure of the restricted-access interchange with Grove.

location here

[webny99]

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

That's nearly identical to...

location here

The Ohio example is better than both the Kansas one and the OP one because it has a C/D lane, shown here.

[Hwy 61 Revisited]

The Columbia-Portland Interchange in New Jersey is way overbuilt for the traffic it carries and the town it serves.

[kphoger]

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

That's nearly identical to...

location here

The Ohio example is better than both the Kansas one and the OP one because it has grade separation, shown here.

Huh?  Both are grade-separated interchanges.

[SkyPesos]

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

That's nearly identical to...

location here

The Ohio example is better than both the Kansas one and the OP one because it has grade separation, shown here.

Are you referring to the C/D lane? All 3 interchanges have grade separation.

[vdeane]

Reminds me of this interchange on the Northway, which is built to allow for all right turns going to/from the Saratoga Racetrack.

[webny99]

Huh?  Both are grade-separated interchanges.

Are you referring to the C/D lane? All 3 interchanges have grade separation.

Sorry, brain freeze. I was going for "separate from the main lanes" and it came out wrong. The C/D lane is what I was referring to.

[Hwy 61 Revisited]

Reminds me of this interchange on the Northway, which is built to allow for all right turns going to/from the Saratoga Racetrack.

Which reminds me of this at Route 54 and Interstate 80, which is even more egregious because there's nothing there!

Well, aside from the National Guard, but still!

[1995hoo]

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

[Hwy 61 Revisited]

I legitimately feel like we could have a RiffTrax-style game about the worst interchanges. But Perth Amboy may very well win that.

[SkyPesos]

Seems like a common theme with a lot of weird, overbuilt interchanges coming from New Jersey from what's in this thread already.

[Mark68]

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

I think it's set up that way due to the interchange being too close to the WI-23 & I-43 interchange. I think it would've been a better design as a folded diamond, with all ramps being west of CTH-Y.

[jeffandnicole]

This interchange in NJ looks relatively innocent compared to the Perth Amboy interchange, but it still involves interchanges for 3 roadways. Maybe more significant: None of them are limited access highways.  https://goo.gl/maps/hMtBgdd3XSFg58Nv7 

Two of the movements: 73 North to 41 North and and 41 North to 38 West involves using the 3rd route to complete the movement.  73 South to 38 West can be done 2 different way, with the indirect way (73 to 41 to 38) being the shorter and quicker option.

[1995hoo]

Seems like a common theme with a lot of weird, overbuilt interchanges coming from New Jersey from what's in this thread already.

I saw a comment once, don't remember where other than that it wasn't on this forum (though I may well have repeated it here), that described New Jersey's interchange design strategy as to start with a relatively basic standard design and then just arbitrarily throw in as many extra ramps as you need to achieve the desired result. I'm not sure Perth Amboy qualifies for that, but Exit 10 on the Turnpike does with the combination of a trumpet and something based on a partial cloverleaf, and the interchange outside Short Hills Mall similarly demonstrates cloverleaf underpinnings with various extra ramps tossed into the mix. Even the mess near Newark Airport reflects a combination of a trumpet and aspects of cloverleaf designs.

[Hwy 61 Revisited]

Not as egregious as other examples, but the lack of two movements makes this interchange in Reading somewhat clustery, especially considering how both routes leave the freeway to make way for a route that doesn't even end up being a freeway after a few moments.

[kphoger]

And, of course, there's always this one in Mexico, which actually seems to work pretty well in my experience:

https://goo.gl/maps/8k5PfoaqoFCZLqMY9

[jeffandnicole]

Seems like a common theme with a lot of weird, overbuilt interchanges coming from New Jersey from what's in this thread already.

I saw a comment once, don't remember where other than that it wasn't on this forum (though I may well have repeated it here), that described New Jersey's interchange design strategy as to start with a relatively basic standard design and then just arbitrarily throw in as many extra ramps as you need to achieve the desired result. I'm not sure Perth Amboy qualifies for that, but Exit 10 on the Turnpike does with the combination of a trumpet and something based on a partial cloverleaf, and the interchange outside Short Hills Mall similarly demonstrates cloverleaf underpinnings with various extra ramps tossed into the mix. Even the mess near Newark Airport reflects a combination of a trumpet and aspects of cloverleaf designs.

One of the least common interchange designs in NJ is the most common elsewhere: The standard diamond interchange.  Even at sparsely, low volume interchanges like I-295's Exit 4, they create something that seems very exaggerated for what is needed, and then there's a cloverleaf ramp thrown in when a simple left turn onto the other ramp would've done the job: https://goo.gl/maps/2XfoUfQ4qShKwAfaA .  The AC Expressway is probably the only roadway in the state that consistently used diamond interchanges, even with the 2 lane toll plazas necessary on specific ramps.

[Brandon]

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

Here's another of that style with another, extra ramp, I-74 and Main Street, Galesburg, IL: https://goo.gl/maps/coNuLEHZf8yPMcCr6

And, of course, there's always this one in Mexico, which actually seems to work pretty well in my experience:

https://goo.gl/maps/8k5PfoaqoFCZLqMY9

Reminds me a bit of this one, Lake Shore Drive and 47th Street: https://goo.gl/maps/cTrwnbdQbHoHeLJs9
It was even more interesting when the exit/entry lane northbound was separated by only paint.

[thspfc]

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

My suspicion is that, since most of the development in the area is south of the interchange, they wanted to make all the primary turns right turns. This will allow for a lot more growth before traffic signals or intersection upgrades are needed.

This interchange, for example, carries an incredible amount of traffic with no traffic signals because all the primary turns are right turns; I've mentioned it as possibly the busiest such interchange in the country.

That's a possibility.

[sprjus4]

I-264 and Witchduck Rd in Virginia Beach, VA.

This interchange is currently being overhauled apart of the I-64 / I-264 Interchange Improvement Project Phase 2 which will be complete by the end of the year. Once complete, the double loops will be removed and replaced with a more traditional design that eliminates the mainline weaving.

[Revive 755]

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