Interstates that changed the most from planning stage to building stage

[planxtymcgillicuddy]

As the title implies, what interstates changed the most from when their routes were being laid out to when they actually got built? Could be on a local, state or national level. I guess for North Carolina, the biggest ones would be I-40's extension from Raleigh to Wilmington, as many in the region favored a route that utilized a fully upgraded US-421 to Wilmington instead of the route that parallels/criss-crosses US-117 that ends a few miles north of Wilmington, and the routing of I-77 north of the US-421 interchange in Elkin, with at least two different routings proposed before the Fancy Gap route was selected.....one through Lowgap and Galax, Virginia en route to Fort Chiswell, and one following US-21 up the mountain to Sparta and Speedwell, Virginia enroute to Wytheville

[1995hoo]

I-95 in New Jersey, perhaps?

[ilpt4u]

I-64 across IL&IN between STL and Louisville was originally planned to follow US 50 in IL and US 150 in IN, but some lobbying by Evansville IN and Mt Vernon IL pushed the routing further south to today's route/roughly following old US 460 in IL

[planxtymcgillicuddy]

I-64 across IL&IN between STL and Louisville was originally planned to follow US 50 in IL and US 150 in IN, but some lobbying by Evansville IN and Mt Vernon IL pushed the routing further south to today's route/roughly following old US 460 in IL

I think I-64 on a national level would be the winner for interstate that changed the most from planning stage to building stage, with the US-50/150 routing in Indiana and Illinois, the proposed US-60 routing through Ansted and Rainelle to Sam Black Church in West Virginia, and the Roanoke/Lynchburg/Farmville routing en route to Richmond and Norfolk in Virginia

[Big John]

I-43 was supposed to be I-57 and follow the WI 57 corridor.

[roadman65]

I-75 was to end in Tampa. I-4 was to run from St. Pete to where it is now.

The former got extended to Miami and the latter got truncated to Tampa.

[SkyPesos]

I-70 west of Denver was initially planned to head to Salt Lake City (either via US 40 or US 6), before getting shifted to today's route to provide a more direct routing for Denver to Las Vegas/SoCal traffic.

[Max Rockatansky]

Planned I-5 shifting west from US 99 onto Legislative Route Number 238 was a big one.

[jeffandnicole]

I-95 in New Jersey, perhaps?

Along with I-95 in DC and Boston.

[TheHighwayMan3561]

South of Albert Lea, MN, I-35 was supposed to follow US 69 southwestward into Iowa which is reflected on some official Minnesota highway maps in the late 1950s and early 1960s. Mason City, Iowa successfully lobbied for that part of the interstate to be routed along US 65 instead so they could be closer to the route.

[silverback1065]

I-43 was supposed to be I-57 and follow the WI 57 corridor.

wait why didn't that go through? that would have made a ton of sense!  well the portion west of 94 would have to be another number for that to work though.

[TheStranger]

California ones that really shifted over time:

I-280
North end in SF completely different from pre-1968 designations (with 280 taking over former US 101/Route 82 and planned Route 87)
Segment in San Bruno shifted to follow Junipero Serra Boulevard longer southbound, instead of cutting over to Skyline earlier
South end originally used Route 17 (now I-880 north) to US 101, before the downtown SJ alignment was approved

I-680
North end along former Route 21 replaced the former north end along I-780
South segment was originally along Route 262 and then-Route 17 (now I-880), before being placed on an eastern bypass of Milpitas

I-15 south of Devore
Original southern terminus was in Colton at I-215/I-10 interchange, with I-15 and US 395 concurrent between Devore and Colton, and US 395 continuing south from I-10 to downtown San Diego at Route 75 and former US 101
1969: I-15 extended south to San Diego via today's I-215/former US 395 through Riverside and Escondido to Route 163 (1940s-1969 US 395), then along what was 1964-1969 Route 103 through Murphy Canyon but is now current I-15 to I-8 (and future I-15 to I-5 in Barrio Logan)
1974: I-15 moved between Devore and Temecula to western bypass along Route 31 and 1934-1974 Route 71 corridor, with former US 395 south of Devore (through San Bernardino and Riverside) becoming I-15E
1982: I-15E becomes I-215/Temp Route 215

I-80
Western terminus: cut back to US 101 after the cancellation of the Western Freeway
Sacramento segment: originally via US 50/Business 80 (former US 99E) through downtown and midtown Sacramento and then Arden area, rerouted in 1982 to former I-880 in Natomas due to cancellation of North Sacramento/Arden parallel freeway upgrade

I-580
- portion south of Route 132 was only created after the I-5/US 99 corridor changes of 1957-1958
- started as portion of I-5W pre-1964 then renumbered
- extended west via former Route 17 in 1984

[ilpt4u]

I-43 was supposed to be I-57 and follow the WI 57 corridor.

wait why didn't that go through? that would have made a ton of sense!  well the portion west of 94 would have to be another number for that to work though.

IDOT didn't want to deal with giving the Cheeseheads the 55, 57, or 65 designations and therefore have to do signing work to get one or more of those designations to the Cheddar Curtain

[cwf1701]

I-96 in Detroit was to follow from the eastern end of the M-5 freeway down to I-75 roughly along Grand River, when Built, it was built along Schoolcraft Rd. to I-275.

[SectorZ]

Could you count I-89, given its original plan was to parallel US 7?

[3467]

In very early maps 90 followed US 18 across Wisconsin and Iowa before being moved to the Minnesota route.
The first Interstate 39 though it's not a chargeable route ran along IL 2 IL 26 IL 89 and IL 121 including the now I 155 from Rockford to Decatur.
Then we have myths about 74 . It was going to run through either Kewanee or Monmouth neither is true it always followed the current route.

[ran4sh]

I-43 was supposed to be I-57 and follow the WI 57 corridor.

wait why didn't that go through? that would have made a ton of sense!  well the portion west of 94 would have to be another number for that to work though.

IDOT didn't want to deal with giving the Cheeseheads the 55, 57, or 65 designations and therefore have to do signing work to get one or more of those designations to the Cheddar Curtain

So not only did IDOT oppose the use of 55/57/65 for I-41 in recent decades, but also for I-43 a few decades prior? Of course...

[kurumi]

Could you count I-89, given its original plan was to parallel US 7?

I don't want to pick on SectorZ here; just quoting to ask: if anyone has official docs on this, I'd love to see a copy. It's one of those things that I'd like to be true, but I can't make that call until I've seen some sources.

The closest I've seen to this are:
* VT wanted I-91 to run in the US 7 corridor instead of US 5 (there are more prominent cities there)
* there was a three-state interstate plan for US 7 that would have connected to I-89 (but didn't mention an interstate number for it)

[zzcarp]

I-70 west of Denver was initially planned to head to Salt Lake City (either via US 40 or US 6), before getting shifted to today's route to provide a more direct routing for Denver to Las Vegas/SoCal traffic.

Before planning began on that western extension, I-70 originally was to end in Denver.

[Life in Paradise]

I-75 was to end in Tampa. I-4 was to run from St. Pete to where it is now.

The former got extended to Miami and the latter got truncated to Tampa.

Actually that was the case for many years, as I remember I-75 ending at I-4 in the 70s.  There were no plans for I-75 beyond that point until they made the extension and incorporated what is now known as Everglades Parkway (then known as Alligator Alley).  I guess way too many people move to the Sarasota/Port Charlotte/Fort Myers/Naples corridor that they had to put some sort of interstate there.

[silverback1065]

i've always wondered why 70 ends where it does in utah, it makes sense for it to end in SLC. was 70 always supposed to go where it is in Denver? Skirting the north side of town instead of going downtown?

[planxtymcgillicuddy]

i've always wondered why 70 ends where it does in utah, it makes sense for it to end in SLC. was 70 always supposed to go where it is in Denver? Skirting the north side of town instead of going downtown?

It ends where it does in UT because it forms part of the fastest LA-Denver corridor

[planxtymcgillicuddy]

Could you count I-89, given its original plan was to parallel US 7?

I don't want to pick on SectorZ here; just quoting to ask: if anyone has official docs on this, I'd love to see a copy. It's one of those things that I'd like to be true, but I can't make that call until I've seen some sources.

The closest I've seen to this are:
* VT wanted I-91 to run in the US 7 corridor instead of US 5 (there are more prominent cities there)
* there was a three-state interstate plan for US 7 that would have connected to I-89 (but didn't mention an interstate number for it)

I've heard that about the US-7 corridor for I-91 as well. A few parts of that proposed corridor exist, but I believe only as bypasses of certain towns

[JayhawkCO]

i've always wondered why 70 ends where it does in utah, it makes sense for it to end in SLC. was 70 always supposed to go where it is in Denver? Skirting the north side of town instead of going downtown?

I don't know about original plans, but it's only about a mile and a half away from downtown, so it's not like it's far away.

[abefroman329]

I-43 was supposed to be I-57 and follow the WI 57 corridor.

wait why didn't that go through? that would have made a ton of sense!  well the portion west of 94 would have to be another number for that to work though.

IDOT didn't want to deal with giving the Cheeseheads the 55, 57, or 65 designations and therefore have to do signing work to get one or more of those designations to the Cheddar Curtain

So not only did IDOT oppose the use of 55/57/65 for I-41 in recent decades, but also for I-43 a few decades prior? Of course...

I think there may be some confusion over I-41 vs. I-43. 55, 57, and 65 would all have worked instead of I-41, since you'd just have to run them concurrently with 94 from their current termini (or, in I-65's case, 90 and then 94), but I don't know how you'd justify running any of them concurrently with another Interstate to Rockford.