Long, but not important

[webny99]

What is US 36 like between I-35 and Hannibal (MO)?

4 lane divided expressway with some cross traffic segments. In all, not a bad way.

It is expressway with occasional interchanges and (I think) no traffic signals except at I-35.  However, it was developed from the original two-lane US 36 by laying down a new carriageway without revising the geometry of the existing one, so as you travel in a given direction, there is a noticeable alternation between modern and less modern alignments.  The speed limit is also lower--65 versus 70 for a typical rural Interstate in Missouri.  Overall, it is a very capable alternative to I-70 for Chicago-Kansas City trips, though to an extent this says more about how awful I-70 is.  ("Missouri loves company.")

The timings people have been quoting for this itinerary are variable and I-35/US 36/I-72/I-55 has less of an advantage over I-35/I-80 at some times of day than at others.  For example, Google Maps just now quotes 7 hours 54 minutes/510 miles for the former and 8 hours 3 minutes/526 miles for the latter.  There is also more slack to the design of I-80 in both Illinois and Iowa, so there is more scope for speeding; the tradeoff is having to deal with transcontinental truck traffic.

Interesting. Coming from a state (and part of the country) where nothing higher than 55 mph is posted except on full freeways, that sounds like the kind of road I wish we had more of, which is to say a very reasonable route even for a long distance trip. The main issue with divided non-freeways is traffic signals, and if there aren't any of those, there wouldn't seem to be much downside to that route considering it's almost 30 miles shorter.

Besides the fact that I-70 in Missouri goes a bit out of the way, what are its issues? Pavement quality, truck traffic, or both (or perhaps something else)?

[kphoger]

Besides the fact that I-70 in Missouri goes a bit out of the way, what are its issues? Pavement quality, truck traffic, or both (or perhaps something else)?

Saint Louis traffic.  Truck traffic.  Traffic, traffic, traffic.

[SEWIGuy]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

[hobsini2]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

[SEWIGuy]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000. 

[Max Rockatansky]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It's hard for me to call a highway that has so much scenery National Park lane as "not important"  subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

[J N Winkler]

Interesting. Coming from a state (and part of the country) where nothing higher than 55 mph is posted except on full freeways, that sounds like the kind of road I wish we had more of, which is to say a very reasonable route even for a long distance trip. The main issue with divided non-freeways is traffic signals, and if there aren't any of those, there wouldn't seem to be much downside to that route considering it's almost 30 miles shorter.

The main drawback is roadway geometry on the older sections--65 feels uncomfortably fast on them and you have to keep your eyes peeled for traffic making ill-judged right turns out of side roads, since the much shorter sight distance translates to reduced time to react.

Besides the fact that I-70 in Missouri goes a bit out of the way, what are its issues? Pavement quality, truck traffic, or both (or perhaps something else)?

To add to Kyle's answer:

*  Most (all?) of rural I-70 in Missouri was built with its median at the 40-foot minimum width allowed by standards, so headlamp glare at night is bad.

*  Many lengths have two-way frontage roads ("outer roads" in MoDOT-speak) with grossly deficient horizontal and vertical alignment that are too close to the traveled way of I-70 proper.  This, too, contributes to glare at night.

*  Ramp geometry used to be, and may still be, especially unforgiving in Columbia, one of the first segments to be built (open by 1960).  (Some interchanges have been redeveloped--e.g., there are now dumbbell roundabouts at Exit 125 and a dogbone at Exit 127--so the situation in terms of tight merges may be improved.)

*  Between Columbia and St. Louis, there are curves sharp enough to require signs, as well as long grades in the vicinity of Mineola Hill.  I suspect this has been somewhat mitigated by a recently completed design-build project to add climbing lanes.

Overall, despite recent improvements--all of which have necessarily been modest owing to MoDOT's funding issues--I-70 in Missouri is still (to adapt the famous children's book title) terrible, horrible, no good, very bad.

[paulthemapguy]

How about US385?

[Rothman]

How about US385?

Main acceas to Big Bend.

[kphoger]

How about US385?

Main acceas to Big Bend.

Not just that.  Yes, I've driven US-385 from Fort Stockton to Big Bend, but that stretch isn't what really makes it not unimportant.

I've also driven US-385 from Brownfield to Odessa, and that stretch is important enough to be a four-lane divided highway.  In fact, I've used the Brownfield—Seminole portion not only driving to and from Big Bend NP, but also on last year's family road trip from Wichita to Guadalupe Mountains NP (the Lubbock—Carlsbad portion).  It's quite a useful corridor, although the latter smaller portion is admittedly multiplexed.

Then I've also driven US-385 from Hereford to Dalhart, which has frequent passing lanes in the hills north of Vega and a four-lane divided stretch north of Hartley.

It's been forever since I was up in the Black Hills of South Dakota, so I'm not sure how important US-385 is there, but I see it's four lanes from the Nebraska line up to Hot Springs, and the portion north of Custer also appears to be well trafficked.

[webny99]

Besides the fact that I-70 in Missouri goes a bit out of the way, what are its issues? Pavement quality, truck traffic, or both (or perhaps something else)?

To add to Kyle's answer:
...

Overall, despite recent improvements--all of which have necessarily been modest owing to MoDOT's funding issues--I-70 in Missouri is still (to adapt the famous children's book title) terrible, horrible, no good, very bad.

Wow! I see now that the median in many sections is very narrow compared to what I'm used to on rural interstates, but unlike the similarly-narrow PA Turnpike, is often a grass median instead of jersey barrier. Between that and the heavy truck traffic I think I might find it mildly interesting to drive during the day, but can imagine it would be almost intolerable at night.

[webny99]

It's been forever since I was up in the Black Hills of South Dakota, so I'm not sure how important US-385 is there, but I see it's four lanes from the Nebraska line up to Hot Springs, and the portion north of Custer also appears to be well trafficked.

The section between Needles Highway and Custer seemed like a major through route and was plenty busy when I was on it in summer 2018.

[Max Rockatansky]

It's been forever since I was up in the Black Hills of South Dakota, so I'm not sure how important US-385 is there, but I see it's four lanes from the Nebraska line up to Hot Springs, and the portion north of Custer also appears to be well trafficked.

The section between Needles Highway and Custer seemed like a major through route and was plenty busy when I was on it in summer 2018.

US 385 in the Black Hills is one of the primary highways in the area.  It gets a bunch of the tourism traffic during the busy months of year.

US 191 is going to be a tough one to beat if we are looking for the most consistently remote US Route. 

[SEWIGuy]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It's hard for me to call a highway that has so much scenery National Park lane as "not important"  subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

Ah. Good call.  That's what I get for thinking I know where a route goes, when I just need to look at a map.  (I thought it went through SLC.)

[US 89]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It’s hard for me to call a highway that has so much scenery National Park lane as “not important” subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

Ah. Good call.  That's what I get for thinking I know where a route goes, when I just need to look at a map.  (I thought it went through SLC.)

Pre-interstate US 191 got kind of close - it went southwest from West Yellowstone basically along what’s now US 20 and I-15 to Brigham City, UT.

At any rate, today’s US 191 does have some semi-important segments, but almost all of them are concurrent with something else. One exception might be the part between I-70 and US 491, which doesn’t have a huge amount of traffic but is part of the Salt Lake City-Albuquerque route (and by extension, the long distance corridor from the Pacific Northwest to Texas and points beyond).

[Max Rockatansky]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It's hard for me to call a highway that has so much scenery National Park lane as "not important"  subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

Ah. Good call.  That's what I get for thinking I know where a route goes, when I just need to look at a map.  (I thought it went through SLC.)

Pre-interstate US 191 got kind of close - it went southwest from West Yellowstone basically along what's now US 20 and I-15 to Brigham City, UT.

At any rate, today's US 191 does have some semi-important segments, but almost all of them are concurrent with something else. One exception might be the part between I-70 and US 491, which doesn't have a huge amount of traffic but is part of the Salt Lake City-Albuquerque route (and by extension, the long distance corridor from the Pacific Northwest to Texas and points beyond).

US 191 also has the distinction of being the only US Route signed in the boundaries of Yellowstone National Park.  It is in fact signed through the Gallatin Mountains in the western park boundary. 

[thspfc]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It's hard for me to call a highway that has so much scenery National Park lane as "not important"  subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

Ah. Good call.  That's what I get for thinking I know where a route goes, when I just need to look at a map.  (I thought it went through SLC.)

Pre-interstate US 191 got kind of close - it went southwest from West Yellowstone basically along what's now US 20 and I-15 to Brigham City, UT.

At any rate, today's US 191 does have some semi-important segments, but almost all of them are concurrent with something else. One exception might be the part between I-70 and US 491, which doesn't have a huge amount of traffic but is part of the Salt Lake City-Albuquerque route (and by extension, the long distance corridor from the Pacific Northwest to Texas and points beyond).

US 191 also has the distinction of being the only US Route signed in the boundaries of Yellowstone National Park.  It is in fact signed through the Gallatin Mountains in the western park boundary.

Though not necessarily reflective of its importance relative to its length, US-191 is at least one of the few 3di routes that are more important than their parent.

[Max Rockatansky]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It's hard for me to call a highway that has so much scenery National Park lane as "not important"  subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

Ah. Good call.  That's what I get for thinking I know where a route goes, when I just need to look at a map.  (I thought it went through SLC.)

Pre-interstate US 191 got kind of close - it went southwest from West Yellowstone basically along what's now US 20 and I-15 to Brigham City, UT.

At any rate, today's US 191 does have some semi-important segments, but almost all of them are concurrent with something else. One exception might be the part between I-70 and US 491, which doesn't have a huge amount of traffic but is part of the Salt Lake City-Albuquerque route (and by extension, the long distance corridor from the Pacific Northwest to Texas and points beyond).

US 191 also has the distinction of being the only US Route signed in the boundaries of Yellowstone National Park.  It is in fact signed through the Gallatin Mountains in the western park boundary.

Though not necessarily reflective of its importance relative to its length, US-191 is at least one of the few 3di routes that are more important than their parent.

In a modern sense yes, but in a historical sense I could make a strong argument for US 91 as being the most overlooked US Route. 

[thspfc]

US-63

Serves Rochester, a pretty decent sized city.

Also serves Waterloo Iowa, Columbia Mo, and Jonesboro Ark. Relative to their states, all important cities.

I believe that US-63 is the longest US route that doesn't serve a city of over 150,000 people.

US 183, had it not been for Austin TX, doesn't serve any other cities over 70k. At least US 63 does.

LOL, ok...  So outside of a city of a million people, US-183 doesn't go anywhere important.   

You did dismiss US 63 in Rochester for the same thing. 183 is not the important highway in Austin. That's 35 and 290. Just saying.

Comparing Austin to Rochester is an interesting choice.

Just saying you dismissed 63 in Rochester for the exact same reason I dismissed 183 in Austin. It's the principle. That's all. Not saying Austin is not an important big city. But be honest with your assessment. Can you even name another city over 70k that 183 goes through? I can't. At least 63 does have a few 70k+ cities it connects. And before it was rerouted to Louisiana in 1999, it did go to the Memphis area.

I'm not dismissing either one.  I'll include both.  US-63 is the longest route in the US system that doesn't serve a city over 150,000.

Is it though? 

https://en.m.wikipedia.org/wiki/U.S._Route_191

To that end I thought of US 191 when I did the original post.  It's hard for me to call a highway that has so much scenery National Park lane as "not important"  subjectively.  But sure, if population is the only criteria we are going to use then US 191 would fit the bill.  The Coronado Trail in Arizona I believe has the lowest traffic count of any US Route segment. 

Ah. Good call.  That's what I get for thinking I know where a route goes, when I just need to look at a map.  (I thought it went through SLC.)

Pre-interstate US 191 got kind of close - it went southwest from West Yellowstone basically along what's now US 20 and I-15 to Brigham City, UT.

At any rate, today's US 191 does have some semi-important segments, but almost all of them are concurrent with something else. One exception might be the part between I-70 and US 491, which doesn't have a huge amount of traffic but is part of the Salt Lake City-Albuquerque route (and by extension, the long distance corridor from the Pacific Northwest to Texas and points beyond).

US 191 also has the distinction of being the only US Route signed in the boundaries of Yellowstone National Park.  It is in fact signed through the Gallatin Mountains in the western park boundary.

Though not necessarily reflective of its importance relative to its length, US-191 is at least one of the few 3di routes that are more important than their parent.

In a modern sense yes, but in a historical sense I could make a strong argument for US 91 as being the most overlooked US Route.

Hmm, I had no idea that US-91 once ran all the way up and down the country. Interesting

[DJ Particle]

What about multistate (ID/MT/ND/MN) 200?

[SeriesE]

Does I-40 in California count? 150+ miles but serves no major population centers.

|Max Rockatansky| would have to say for sure.  But, considering that this thread started as a companion to one whose OP specifically states So, please do not include "a portion of"  a highway as part of this, I think it doesn't really fit the spirit.

Oh I interpreted that requirement having to consider everything within a state only. If it must apply to the entire route regardless of state boundaries, then yeah I agree it doesn't count.

[FrCorySticha]

What about multistate (ID/MT/ND/MN) 200?

I'd almost agree with MSR 200, that large parts of it really aren't an important through route. I doubt a lot of traffic crosses ND and eastern MT on 200. However, the part of MT 200 that duplexes with US 87, 89, and 191 is a major corridor for central MT. Also, 10 Ave. S and I-315, which is MT 200's route through Great Falls, is the busiest highway in MT.

I'd also point out that Rogers Pass on MT 200 is the first crossing of the Continental Divide south of Marias Pass on US 2, at a distance of almost 100 miles! That definitely makes it important.

[SeriesE]

Another I thought of is US-6.

To quote the Wikipedia article:

US 6 does not serve a major transcontinental corridor, unlike other highways. George R. Stewart, author of U.S. 40: Cross Section of the United States of America, initially considered US 6, but realized that "Route 6 runs uncertainly from nowhere to nowhere, scarcely to be followed from one end to the other, except by some devoted eccentric".

[FrCorySticha]

Hmm, I had no idea that US-91 once ran all the way up and down the country. Interesting

Yep, it followed the route that is today I-15.

[Rothman]

Hmm, I had no idea that US-91 once ran all the way up and down the country. Interesting

Yep, it followed the route that is today I-15.

Teton Dam flood did a number on it.