Interstate 42 (W)

[splashflash]

Where'd you get that list of improvements from?

Yeah, I count four interchanges in the document referencing the PEL list. Then in the original study, there are seven interchanges and nine overpasses indicated. See references below.

Won't all the other current crossroads be truncated at future I-42? Some would be supplementally connected to the grid road network to the north or south.

Here's a similar list that Swake drew upfrom, I believe.
https://oklahoma.gov/content/dam/ok/en/odot/progress-and-performance/federal-grants/infra/2026/us-412-corridor-priority-improvements/01-grant-application/09%20Project%20Readiness.pdf
From page 1:
 A  Planning and Environmental Linkages (PEL) study completed in
June 2026 identified corridor improvements necessary to upgrade US-412 to Interstate standards,  including the Diamondhead, 4170 Road, and 4190 Road interchanges. The PEL's agency  coordination, stakeholder input, and analysis will be carried forward into project-level NEPA reviews, streamlining environmental documentation and reducing project delivery risk.  Environmental conditions and constraints have already been evaluated through completed NEPA documentation and the US-412 PEL, including the PEL-to-NEPA Transition Report (Appendix D). The PEL established baseline environmental conditions and identified potential corridor constraints, including wetlands, waters of the U.S., threatened and endangered species, and cultural resources. These completed analyses provide a strong foundation for the remaining environmental  reviews and further reduce environmental approval risk.

1. Diamondhead Interchange: Identified in the US-412 PEL and anticipated to qualify for a CE. Environmental clearance is anticipated in Q4 2027.
• US-412 Pavement Reconstruction: Anticipated to qualify for a CE due to its location within an existing transportation corridor. Environmental clearance is anticipated in Q2 2027
2. 265th E. Avenue Interchange: Received an Individual CE in April 2021 and is currently being revised due to a scope change, with completion anticipated in Q3 2028.
3. 4170 Road Interchange: Received a Documented CE in November 2025.
4. 4190 Road Interchange: Identified in the US-412 PEL and anticipated to qualify for a CE. Environmental clearance is anticipated in Q3 2027.
US-412 Frontage Road Easements: Anticipated to qualify for a CE with environmental clearance anticipated in Q2 2028.
4190 Road Reconstruction: Anticipated to qualify for a CE with environmental clearance anticipated by Q2 2027.
5. S. 4200 Road Reconstruction: Anticipated to qualify for a CE with environmental clearance anticipated by Q1 2028.
6. E. 650 Road Reconstruction: Anticipated to qualify for a CE with environmental clearance anticipated by Q1 2028.

An interchange at 412B is in progress and has open houses. https://oklahoma.gov/odot/about-us/newsroom/2026/meeting-set-for-april-7-in-pryor-for-us-412-sh-412b-improvements.html

Anyway, here is the original study. https://media.ark.org/ardot/US-412_Public-Meeting-3_Factsheet_11x17_2024-05-31.pdf

[bugo]

traffic between Tulsa and NW Arkansas will explode

A toll road only for Ford Pintos? Imagine that.

And Corvairs.  We are apparently old.

The Corvair's flaw is that it had swing axles and no rear camber compensator bar. The 1964 added the bar and the 1965-69 had true IRS that eliminated the swing axles. This caused handling issues with the rear wheel tucking under on hard turns. The 1965-69s were reportedly excellent handlers.

[bugo]

It will be painful as hell, but its really looking more and more like they may have to build I-42 over the existing US-412 alignment straight thru Siloam Springs. Commercial property is easier to acquire via eminent domain than residential property. Depending on funding available it might be possible to build a new I-42 as an elevated structure above the US-412 surface street thru at least part of the town.

Zero chance that they will ram an elevated freeway through Siloam Springs. There will 100% be a bypass.

[Bobby5280]

Where'd you get that list of improvements from?

Just by looking at the at-grade intersections along US-412 from the I-44 interchange to the West end of the Cherokee Turnpike. I listed all of the at-grade intersections in order, even numbering them. The overhead imagery makes it pretty obvious what improvements are needed (or intended) at each intersection.

Where I note "grade separation needed" (instead of building a new diamond interchange): it could mean building that intersecting road over the US-412 main lanes via a new bridge. Or the US-412 main lanes could be bridged over intersecting road. The third choice is dead-ending that intersecting road on either side of US-412 so it can no longer cross.

Either way, something has to be done about ALL of those 20+ intersections. The improvement lists others have been mentioning are not complete. They don't mention the full list of at-grade intersections.

Zero chance that they will ram an elevated freeway through Siloam Springs. There will 100% be a bypass.

I sure would not say there's a 100% chance Siloam Springs will be bypassed. There is a 100% chance any new terrain bypass alignment would plow over a bunch of existing residential homes. As time goes on more and more homes are getting built there.

The only way to get a new terrain I-42 bypass built where it doesn't impact a lot of homes is by diverting several miles South, probably along or even South of where the Illinois River runs. There is a bunch of hilly terrain in that area, plus flood zones next to the river. Not great options. A bypass around the North side of Siloam Springs is more problematic. Lots of homes are scattered all over between Siloam Springs and Gentry. Plus there are things like City Lake Park that could be impacted.

Meanwhile, there isn't anything remarkable along US-412 thru Siloam Springs. Lots of chain stores and clutter. Freeway projects in many other parts of the country have bulldozed over that kind of stuff plenty of times before.

[The Ghostbuster]

I'm sure there will be plenty of time to decide what form Interstate 42 will take through/around Siloam Springs.

[Bobby5280]

I'm sure there will be plenty of time to decide what form Interstate 42 will take through/around Siloam Springs.

They probably need to make up their minds about that sooner than later.

It's about 10.5 miles from the West end of the Springdale Bypass to the East edge of Siloam Springs, where US-412 drops from being a 4-lane divided highway down to a non-divided 5-lane city street. AR DOT can probably upgrade that segment of divided highway to Interstate standards without too much trouble. But it will take them I don't know how many years to get that work done. More housing sub-divisions are bound to sprout up in Siloam Springs in the meantime.

Rather than upgrade all 10+ miles of that divided highway to Interstate standards, right to the doorstep of Siloam Springs, they might want to look at bypass alignments that leave existing US-412 farther away from Siloam Springs. That might allow for a more gradual, less curvy and ultimately shorter length bypass.

If they do this upgrade work piece-meal style, pushing the new freeway right to the edge of Siloam Springs their choices of alignment options are going to be far more limited. They'll just have a couple or so very bad, very costly choices. That includes the bad option of plowing straight thru Siloam Springs on the existing US-412 alignment.

[Rothman]

Where'd you get that list of improvements from?

Just by looking at the at-grade intersections along US-412 from the I-44 interchange to the West end of the Cherokee Turnpike.

Oh, so your own opinion.  FHWA can surprise you with other demands.

Prefer lists of such from official sources given how roadgeek assumptions can be far off (e.g., NY 17 to I-86).

[vdeane]

Where'd you get that list of improvements from?

Just by looking at the at-grade intersections along US-412 from the I-44 interchange to the West end of the Cherokee Turnpike.

Oh, so your own opinion.  FHWA can surprise you with other demands.

Prefer lists of such from official sources given how roadgeek assumptions can be far off (e.g., NY 17 to I-86).

Considering this bit:

That list of intersections doesn't take into account any improvements needed along the existing main lanes of US-412.

I think he meant that list to be a minimum of what needs to be done, not a 100% complete list.

[swake]

Where'd you get that list of improvements from?

Yeah, I count four interchanges in the document referencing the PEL list. Then in the original study, there are seven interchanges and nine overpasses indicated. See references below.

Won't all the other current crossroads be truncated at future I-42? Some would be supplementally connected to the grid road network to the north or south.

Here's a similar list that Swake drew upfrom, I believe.
https://oklahoma.gov/content/dam/ok/en/odot/progress-and-performance/federal-grants/infra/2026/us-412-corridor-priority-improvements/01-grant-application/09%20Project%20Readiness.pdf
From page 1:
 A  Planning and Environmental Linkages (PEL) study completed in
June 2026 identified corridor improvements necessary to upgrade US-412 to Interstate standards,  including the Diamondhead, 4170 Road, and 4190 Road interchanges. The PEL's agency  coordination, stakeholder input, and analysis will be carried forward into project-level NEPA reviews, streamlining environmental documentation and reducing project delivery risk.  Environmental conditions and constraints have already been evaluated through completed NEPA documentation and the US-412 PEL, including the PEL-to-NEPA Transition Report (Appendix D). The PEL established baseline environmental conditions and identified potential corridor constraints, including wetlands, waters of the U.S., threatened and endangered species, and cultural resources. These completed analyses provide a strong foundation for the remaining environmental  reviews and further reduce environmental approval risk.

1. Diamondhead Interchange: Identified in the US-412 PEL and anticipated to qualify for a CE. Environmental clearance is anticipated in Q4 2027.
• US-412 Pavement Reconstruction: Anticipated to qualify for a CE due to its location within an existing transportation corridor. Environmental clearance is anticipated in Q2 2027
2. 265th E. Avenue Interchange: Received an Individual CE in April 2021 and is currently being revised due to a scope change, with completion anticipated in Q3 2028.
3. 4170 Road Interchange: Received a Documented CE in November 2025.
4. 4190 Road Interchange: Identified in the US-412 PEL and anticipated to qualify for a CE. Environmental clearance is anticipated in Q3 2027.
US-412 Frontage Road Easements: Anticipated to qualify for a CE with environmental clearance anticipated in Q2 2028.
4190 Road Reconstruction: Anticipated to qualify for a CE with environmental clearance anticipated by Q2 2027.
5. S. 4200 Road Reconstruction: Anticipated to qualify for a CE with environmental clearance anticipated by Q1 2028.
6. E. 650 Road Reconstruction: Anticipated to qualify for a CE with environmental clearance anticipated by Q1 2028.

An interchange at 412B is in progress and has open houses. https://oklahoma.gov/odot/about-us/newsroom/2026/meeting-set-for-april-7-in-pryor-for-us-412-sh-412b-improvements.html

Anyway, here is the original study. https://media.ark.org/ardot/US-412_Public-Meeting-3_Factsheet_11x17_2024-05-31.pdf

I got mine from the new ODOT 8 year plan.

[Rothman]

Where'd you get that list of improvements from?

Just by looking at the at-grade intersections along US-412 from the I-44 interchange to the West end of the Cherokee Turnpike.

Oh, so your own opinion.  FHWA can surprise you with other demands.

Prefer lists of such from official sources given how roadgeek assumptions can be far off (e.g., NY 17 to I-86).

Considering this bit:

That list of intersections doesn't take into account any improvements needed along the existing main lanes of US-412.

I think he meant that list to be a minimum of what needs to be done, not a 100% complete list.

There is no minimum.  There are only the whims and exacting demands of FH-"The Knights Who Say Ni"-WA and they must all be met.

[Scott5114]

There is no minimum.  There are only the whims and exacting demands of FH-"The Knights Who Say Ni"-WA and they must all be met.

Be honest with yourself—do you really think the FHWA Oklahoma office has exacting demands? Given that it's Oklahoma and there's no transit, they have to experience Oklahoma roads at least to get to work and back and they're apparently OK with what they see...

[Bobby5280]

Oh, so your own opinion.  FHWA can surprise you with other demands.

The list of intersections is the full list of intersections. Feel free to check the map for yourself. Every damned one of those intersections has to be dealt with in some manner before Interstate shields can be installed on that stretch of road. That's on top of any improvements needed on the US-412 main lanes.

I don't know what ODOT intends to do with each one of those intersections. But they have to do something. It's pretty obvious where new interchanges are intended. The ROW footprints are visible in Google Earth. Other intersecting roads will either be grade separated with bridges. In some cases, or maybe a bunch of cases, access will get cut off and the roads will dead end on either side of US-412.

The lists swake and others posted covers only a fraction of the work needed to be done:

US-412 and OK-88 - Junction Repairs - 3mm in 2029
4190 Road  - Interchange - 26mm in 2029
US-412 and US-412B - Junction - 26.8mm in 2030
4240 Road - Interchange - 15mm in 2032
289th E Ave - Interchange - 12mm in 2033
4177 Road  - Interchange - 33mm in 2033

Numerous additional phases of work have to be completed in addition to that partial list.

[swake]

Oh, so your own opinion.  FHWA can surprise you with other demands.

The list of intersections is the full list of intersections. Feel free to check the map for yourself. Every damned one of those intersections has to be dealt with in some manner before Interstate shields can be installed on that stretch of road. That's on top of any improvements needed on the US-412 main lanes.

I don't know what ODOT intends to do with each one of those intersections. But they have to do something. It's pretty obvious where new interchanges are intended. The ROW footprints are visible in Google Earth. Other intersecting roads will either be grade separated with bridges. In some cases, or maybe a bunch of cases, access will get cut off and the roads will dead end on either side of US-412.

The lists swake and others posted covers only a fraction of the work needed to be done:

US-412 and OK-88 - Junction Repairs - 3mm in 2029
4190 Road  - Interchange - 26mm in 2029
US-412 and US-412B - Junction - 26.8mm in 2030
4240 Road - Interchange - 15mm in 2032
289th E Ave - Interchange - 12mm in 2033
4177 Road  - Interchange - 33mm in 2033

Numerous additional phases of work have to be completed in addition to that partial list.

Knowing Oklahoma a lot of them will be solved with K-Rails. It looks to me like that ODOT is spacing the interchanges every few miles and I assume, knowing Oklahoma, the rest of the roads that intersect with 412 will just be closed "for now" with barriers until the state gets more money. Which will likely never happen.

[vdeane]

There is no minimum.  There are only the whims and exacting demands of FH-"The Knights Who Say Ni"-WA and they must all be met.

I said minimum, not maximum.  Unless you're suggesting that FHWA would have them leave at least one at-grade alone?

[Rothman]

There is no minimum.  There are only the whims and exacting demands of FH-"The Knights Who Say Ni"-WA and they must all be met.

I said minimum, not maximum.  Unless you're suggesting that FHWA would have them leave at least one at-grade alone?

FHWA doesn't deal with minimums.  They just deal with their edicts.  There is no "good enough" minimum if you ignore their other demands.

[vdeane]

There is no minimum.  There are only the whims and exacting demands of FH-"The Knights Who Say Ni"-WA and they must all be met.

I said minimum, not maximum.  Unless you're suggesting that FHWA would have them leave at least one at-grade alone?

FHWA doesn't deal with minimums.  They just deal with their edicts.  There is no "good enough" minimum if you ignore their other demands.

I think you're interpreting "minimum" in a different sense than what I mean it.  I'm using it to say "they will have to do at least this much work, because the at-grades can't be left there if they want an interstate".  You seem to think I'm meaning "this is what they'd need if they want to do the least amount of work to get the interstate".  Which is interesting because my point was that his list wasn't an all-encompassing, "this is everything they will need to do" list.

[rte66man]

I think in a slightly different political climate in Oklahoma (i.e. one that was focused less on The Government Must Never Spend Money On Anything Ever) you could see local interests in northwest Oklahoma fighting for I-42 to Boise City as an economic/tourism benefit thing. Think of the "Forgottonia" movement that got I-72 in western Illinois, for instance. This is not so far fetched; the current four-lane-divided "Northwest Passage" expressway from OKC to Woodward was borne out of a similar push in the 1980s.

But since that would require the political culture of Northwest Oklahoma to change, that's a big if. And, of course, I-42 has to be be signed in Oklahoma first to give people the idea in the first place.

If the oil business goes through another boom period, then I can see a push for an I-42 extension west from Enid. Without that, the traffic counts don't justify it.

[Scott5114]

I think in a slightly different political climate in Oklahoma (i.e. one that was focused less on The Government Must Never Spend Money On Anything Ever) you could see local interests in northwest Oklahoma fighting for I-42 to Boise City as an economic/tourism benefit thing. Think of the "Forgottonia" movement that got I-72 in western Illinois, for instance. This is not so far fetched; the current four-lane-divided "Northwest Passage" expressway from OKC to Woodward was borne out of a similar push in the 1980s.

But since that would require the political culture of Northwest Oklahoma to change, that's a big if. And, of course, I-42 has to be be signed in Oklahoma first to give people the idea in the first place.

If the oil business goes through another boom period, then I can see a push for an I-42 extension west from Enid. Without that, the traffic counts don't justify it.

Well, if $6 diesel won't do it...

[ObsidianTheFox]

What I can't see ever happening is I-42 going west of Enid. There's so little traffic today on US-412 west of Enid it make no sense to spend billions of dollars to upgrade it. There's just no need.

I think I-42 west of Enid could happen, but only if the I-27 extension gets built, since that would make the theoretical western extension of I-42 into part of a major corridor from Oklahoma (and from points further west along I-40, via "I-343"), to Denver. (Here's hoping ODOT takes a closer look at their plans and renumbers I-343 to I-342.)

[Bobby5280]

I'm more skeptical about any possible I-42 route West of Enid even if I-27 was built up from Amarillo thru Boise City and into SE Colorado. Boise City is a pretty remote and sparsely populated end for an East-West Interstate route. And it would be facing hard 90° turns at the crossing Interstate. Anyone driving to larger destinations that might be connected to I-27 would be taking other routes to get there.

The situation would be similar to the unceremonious North end of I-135 in Salina, KS. But in the case of Salina the US-81 highway continues farther North as a 4-lane divided route (and that route has some freeway exits scattered along the way). US-81 remains as a 4-lane divided highway all the way up to the I-80 corridor and York, Nebraska.

An I-42 ending in Boise City might be more plausible if US-412 was already a 4-lane divided highway from Boise City to Clayton, NM or farther to Springer, NM. Both points are more traveled junction points. As it is, US-412 goes from 4-lane divided to 2-lane not far West of Enid.