How many interchanges have you experienced (or know about) that the road levels have been flipped?
For instance, there was an old interchange where Highway A went over Highway B, but in the newly designed interchange, Highway B goes over Highway A.
Some of this info probably can be accessed using USGS.
Here are some I know about.
In Chattanooga, I-75 used to go over I-24 but now the new interchange has I-24 go over I-75.
In Atlanta for the old northern split (mid-1980s and prior), I-75 used to go over I-85 but that was flipped by the late 80s I believe.
In Frankfort, Kentucky, US 60 used to go under Leestown Pike in a trumpet type interchange prior to the late 1970s. Now Leestown Pike goes under US 60 in a SPUI alignment.
In Washington, Pennsylvania, on the Eastern split, I-70 used to go over I-79, but now I-79 flies over I-70.
In St Louis, Missouri I-64 used to go over both I-55 and I-70 on the eastern side of the city. Now I-70 goes over both I-64 and I-55.
I-394/MN 100 in Golden Valley, MN (per froggie) - was I-394 on top and MN 100 on bottom, flipped to MN 100 on top and I-394 on bottom
I-95 at Exit 140 in Virginia - VA-630 Courthouse Road
In the original configuration, Courthouse Road passed underneath I-95 with a traditional diamond interchange. Courthouse Road was widened and relocated a few years back to travel over I-95 with a new diverging diamond interchange.
The original road still travels under I-95 just north of the new interchange and I believe will be used for a direct ramp to the reversible HO/T lanes currently under construction.
I believe this subject has been addressed before basing this on the US 7/I-189 interchange in Burlington, VT where I-189 overpassed US 7 when first completed. Now US 7 overpasses I-189. Some other member may know when the reconstruction occurred for the change (late 1970's, early 1980's?).
US/I-41 at WI 21 and US/I-41 at US 45 in Oshkosh WI.
Quote from: amroad17 on July 23, 2022, 06:01:23 AM
I believe this subject has been addressed before basing this on the US 7/I-189 interchange in Burlington, VT where I-189 overpassed US 7 when first completed. Now US 7 overpasses I-189. Some other member may know when the reconstruction occurred for the change (late 1970's, early 1980's?).
1988-ish.
Quote from: sprjus4 on July 23, 2022, 03:01:36 AM
I-95 at Exit 140 in Virginia - VA-630 Courthouse Road
In the original configuration, Courthouse Road passed underneath I-95 with a traditional diamond interchange. Courthouse Road was widened and relocated a few years back to travel over I-95 with a new diverging diamond interchange.
The original road still travels under I-95 just north of the new interchange and I believe will be used for a direct ramp to the reversible HO/T lanes currently under construction.
This is correct. The ramp will pass underneath the I-95 NB lanes and the new I-95 NB ramp.
Another Virginia example is I-95 at SR 644 in Springfield. Up until ~1970 SR 644 went over I-95. The new construction changed this to the current half-and-half with SR 644 going over I-95 SB but under I-95 NB.
A sort of in east Baltimore: I-95 SB used to go over both directions of I-895 at Exit 62, but now I-895 NB goes over both directions of I-95.
The partial interchange of I-96 and I-196's eastern terminus in Grand Rapids: Wbd I-196 used to go over ebd I-96 but it now goes under.
In downtown Detroit, I-94 currently goes under M-10. When that interchange is rebuilt as a stack, I-94 will go over M-10.
The I-27/I-40 interchange in Amarillo used to have I-27 going over I-40, until a few years ago when the interchange was partially redone. Now, I-40 goes over I-27.
The "High Five" (I-635/US 75) in Dallas was a partial flip. Originally when I-635 was built, its interchange with US 75 had I-635's EB lanes under US 75, while the WB lanes were over it. Since the High Five was done, I-635 in both directions goes over US 75.
As part of the recent US 175 realignment and "Dead Man's Curve" fix in Dallas, US 175 (Hawn Frwy.) goes over TX 310 (S.M. Wright Frwy.) now. Previously, when US 175 curved EB, it went undeŕneath TX 310 at the old interchange.
The Blue Mountain interchange on the PA Turnpike: the ramps to/from I-76 WB used to pass under the mainline, but following a widening project in that area the ramps were realigned and now cross over the mainline.
Question. Would it be, for most if not all these projects cited, that the need to maintain 1 or 2 thru lanes of traffic in each direction during reconstruction, that the "flip" became almost the default alternative in the interchange reconstruction projects?
I-285 & SR 400 will partially flip when the current construction project is complete. The old configuration had 400 SB over I-285 while 400 NB went under I-285. The new configuration has both NB and SB 400 under I-285.
I-91 southbound used to pass over the Founders Bridge approach (CT 2) in Hartford. As part of the Riverfront Recapture work c. 1990, I-91 SB was lowered to pass under the bridge approach, improving vistas and access to the river.
Quote from: ran4sh on July 23, 2022, 10:04:40 PM
I-285 & SR 400 will partially flip when the current construction project is complete. The old configuration had 400 SB over I-285 while 400 NB went under I-285. The new configuration has both NB and SB 400 under I-285.
And... the first new design had 400 going over 285, but the second, adopted after construction had begun, has 400 going under. :awesomeface:
Quote from: Georgia Guardrail on July 23, 2022, 12:59:41 AM
How many interchanges have you experienced (or know about) that the road levels have been flipped?
For instance, there was an old interchange where Highway A went over Highway B, but in the newly designed interchange, Highway B goes over Highway A.
In Washington, Pennsylvania, on the Eastern split, I-70 used to go over I-79, but now I-79 flies over I-70.
I-79 NB to I-70 WB is now a flyover that goes high above I-70, but I-70 WB to I-79 SB still follows its original route underneath I-70.
Quote from: Georgia Guardrail on July 23, 2022, 12:59:41 AM
In Frankfort, Kentucky, US 60 used to go under Leestown Pike in a trumpet type interchange prior to the late 1970s. Now Leestown Pike goes under US 60 in a SPUI alignment.
I had no knowledge or memory of this, despite the fact that US 421 (not US 60) was my dad's preferred route to travel between Lexington and Frankfort before I-64 was finished in 1971.
I would love to see a picture of that intersection. I had always figured it was an at-grade intersection.
The SPUI there came about because of the construction of the East-West Connector (KY 676). My first encounter with the SPUI was in either 1982 or 1983, I can't remember which.
Historic Aerials has a good 1960 picture of the trumpet interchange.
Two different at-grade configurations are shown in 1952 and 1957.
The Cahuenga-nee-Hollywood Freeway interchange with Highland Avenue was built in 1940 with southbound Cahuenga passing under northbound Highland and the Pacific Electric tracks via a retained cut and a cut-and-cover tunnel, but in 1954 or so the tracks were removed, northbound Highland was dropped in elevation, and the below-grade ramp to Cahuenga was superseded by a bridge onto the Hollywood Freeway.
This is the original layout, photographed in 1948.
(https://scontent-atl3-1.xx.fbcdn.net/v/t31.18172-8/13497889_10207945816457490_2403300730559016377_o.jpg?_nc_cat=106&ccb=1-7&_nc_sid=825194&_nc_ohc=8AzHmrenFqkAX-NXyHo&_nc_ht=scontent-atl3-1.xx&oh=00_AT_TVuR_8p2Yec21r4otyAnaJGdyestzyAXj4Un-rHGv-w&oe=630A42EF)
May need confirmation on this one, but originally (the then-unsigned) I-695 in DC went over the SB lanes of I-295 where they merged. When the interchange was reconstructed to include the long-overdue missing movements, the I-295 SB lanes were raised up to go over the I-695 on-ramp.
Not an interchange, but an ordinary overpass. On the NJTP, in Edison, Woodbridge Ave./NJ-514 originally went underneath the turnpike. Some 50 years ago, it was rerouted over a newly constructed overpass. (I quietly watched this take place as a small child!) The underpass remains in use as an "official use only" U-turn (https://goo.gl/maps/tLTrJHF2YHLefFqo6), though the NB bridge is at a different angle -- the overpass was built just before the 9-10 truck lanes came about.
Near Peoria, IL, I-155 used to go under I-74 at its terminus. After reconstruction a few years ago, 155 goes over 74.
There are several on I-35 between Austin and the 35W-35E split.
I-25 and County Road 44 between DENVER and Loveland is in the process of getting flipped. I-25 used to go under CR-44, but after it is finished, CR-44 will go under I-25.
When the I-680 / CA-24 interchange was originally built, to continue south on I-680 through the interchange, one had to exit and pass over the interchange. Similarly, to continue north on I-680 through the interchange, one had to exit to the right, while the mainline transitioned onto CA-24 West. The modern configuration which was built in the 1990's is more typical, moving the CA-24 feeding movements to the exit position.
Here is a side-by-side of the old configuration in 1963 vs the current, the view is from the south, with North I-680 continuing towards the right, and CA-24 West continuing towards the top of the frame:
(https://i.imgur.com/oNq5a3m.png)
I-35E, Corinth Parkway, Exit 460, Corinth, TX
It's not an interchange but I always found it fascinating how I-70 in Indianapolis changed from going under Sherman Drive and a railroad track to going over it in 2008. It required a lot of filling in. Surprisingly perhaps, the bridges for Sherman and the railroad are still there going over nothing but fill.
https://goo.gl/maps/yfM76W6jnS9tYnZx6
If you poke around, you can look east from Sherman in modern day to see the railroad bridge still there, now under I-70 but still carrying the tracks.
The interchange with Jefferson Highway and the Huey P. Long Bridge got flipped when the bridge got widened. The bridge approach over Jefferson Highway now, but previously Jefferson went over the bridge approach and Clearview Parkway