580 is unconstructed from Vernalis to Hallelujah Junction/South Lake Tahoe

[bootmii]

Now that Nevada 580 is a thing, and given that the freeway continues all the way into California for a few miles, we should think about a traversable route to 5/580 in San Joaquin County and upgrading it to Interstate standards.

[Max Rockatansky]

I-70 being rejected over Minaret Summit, Sonora Pass and Echo Summit not enough to tell you that it ain't happening?  There is a less of need for a full limited access highway in South Lake Tahoe now than there was circa 1965-1973.

[gonealookin]

My thought was, why doesn't Nevada change the numbering of its I-580 to "I-380"?  That way, the connection would logically be to I-380 near SFO Airport, which would require California to construct that long-awaited "Southern Crossing" bridge across the Bay!   

(NOBODY at Tahoe wants to make it easier for even more visitors to pile into this over-taxed area by upgrading US 50 through the Sierra.  Yeah, it's also more difficult for me to get to Sacramento, but we have all the visitation we can handle.)

[The Ghostbuster]

The Interstate 580 designation in Nevada was set in stone decades ago. If it were to have had a different Interstate designation, it should have been 180 (since California doesn't have one due to a state highway of the same number existing). I don't see 580 being extended in any direction. US 50 is already a four-lane undivided roadway, so I don't think any further upgrades will come to that corridor.

[Max Rockatansky]

There is plenty of two lane segments of US 50 between Carson City and Placerville. 

[gonealookin]

The Interstate 580 designation in Nevada was set in stone decades ago. If it were to have had a different Interstate designation...

US 50 is already a four-lane undivided roadway, so I don't think any further upgrades will come to that corridor.

Actually NDOT was proposing a "downgrade" in the form of a road diet along the east shore of Lake Tahoe, going from four-lane undivided to two lanes with a center turn lane and bike lanes.  The proposal got a lot of pushback from the local community, the Douglas County political leadership formally opposed it and NDOT withdrew the road diet idea.  That section of road could stand some safety improvements as we've had a number of fatal head-ons over the years, but improved safety will require some plan other than the road diet.

"I-380" was a joke.  I think the OP might be better served by posting ideas like this in Fictional Highways.

[Plutonic Panda]

Wasn't there a bridge proposed over Lake Tahoe at one point?

[gonealookin]

Wasn't there a bridge proposed over Lake Tahoe at one point?

Not involving US 50.  The bridge would have been on California's SR 89, crossing the mouth of Emerald Bay at the southwest portion of the lake and avoiding the hogback and north-facing avalanche zone on that road which are closed quite often during the winter.  It was rejected on the grounds of aesthetics in a beautiful natural area.

[Max Rockatansky]

89 had an entire freeway corridor alignment adopted by the CHC along western Lake Tahoe. 

[Plutonic Panda]

89 had an entire freeway corridor alignment adopted by the CHC along western Lake Tahoe. 

So this bridge would have been part of a freeway corridor then?

[Max Rockatansky]

89 had an entire freeway corridor alignment adopted by the CHC along western Lake Tahoe. 

So this bridge would have been part of a freeway corridor then?

Yes.

[Plutonic Panda]

89 had an entire freeway corridor alignment adopted by the CHC along western Lake Tahoe. 

So this bridge would have been part of a freeway corridor then?

Yes.

Wow that would've been some freeway if it had actually been built. As much as I love freeways and bridges I'm glad this one didn't get built. Lake Tahoe is extremely pristine and beautiful.

If anything since we're in fantasy land a LRT would be better. I'd certainly utilize it.

[gonealookin]

The US 50 freeway project within the Tahoe Basin that would have made sense, many years ago, would have been the Meyers to Stateline bypass.  It would have bypassed the main commercial corridor which is several miles of the current US 50 through the City of South Lake Tahoe, running through the forest from the small town of Meyers, at the eastern foot of Echo Summit, just into Nevada, passing the Heavenly ski area's California lodge and connecting to the major casinos at Stateline.  More or less along the alignment of the current Pioneer Trail, an El Dorado County road.  That alignment would not have impacted any particularly scenic area.



That proposal was floated around the 1960s, at the same time some similar freeway bypasses of smaller towns were being constructed in California (for example, SR 29 around Lakeport and SR 20/49 through the Grass Valley/Nevada City area).  I'm not certain whether there was a formal freeway route adoption for Meyers-Stateline.  It couldn't be built now because there has been too much residential development along that alignment.  Two-lane Pioneer Trail does exist and serves the bypass function as it avoids that often very congested in-town stretch of US 50, but as a moderately high speed road through residential areas including a school zone it's less than ideal.

Heck, nowadays we can't even get a short surface street bypass of the immediate Casino Corridor right at the state line.  I have lived here for 15 years and that "Loop Road" issue just goes endlessly in circles with zero progress.

[Max Rockatansky]

That corridor was also explored as part of the 1973 Federal Aid Highway Act.  The alignment over Echo Summit included a tunnel.

[pderocco]

I think a suspension bridge across the mouth of Emerald Bay could be quite beautiful, especially if it had some decorative lights on it. It would be visible in the distance at night from the eastern shore in Nevada.

I wouldn't call Lake Tahoe "pristine", since there's quite a bit of development along its shore in places. But I've always felt that lights reflected in water at night were among the most scenic things.

[Max Rockatansky]

I've been fascinated at how most of the trees around Tahoe are approximately the same age.  The whole area used to be heavily logged and worked.

[mgk920]

The only way that I can envision I-580 ever being extended southward is for it to somehow feed into US 95 and ultimately I-11 (via Yerrington, NV?).

Mike

[heynow415]

That corridor was also explored as part of the 1973 Federal Aid Highway Act.  The alignment over Echo Summit included a tunnel.

If you rummage around with SLT parcel maps, such as the GIS maps on this site: https://see-eldorado.edcgov.us/ugotnet/ , it sure looks like not only was a corridor identified and/or adopted but future right of way was acquired or otherwise reserved at one time.  There is a broken chain of parcels that have the characteristics of a future freeway, including flaring out at certain intersections for interchanges. 
For example, between the airport and Onnontioga Street there is a strip parcel that flares where Washoan Blvd. dead-ends. Another runs parallel to Barbara Avenue and northeast of that on either side of Al Tahoe Blvd is another segment that flares for what would have been another interchange.  There are then several property lines diagonal to the underlying block layout that would reflect the corridor sweeping across Pioneer Trail at Needle Peak Road, with another potential interchange at Ski Run Blvd., and then an large strip parcel that runs behind the Raley's shopping center and Heavenly Village that flares out again for another potential interchange at stateline. 
Coincidence?  Perhaps but being in the land planning business, having property lines and parcels like this is very suggestive of a planned transportation corridor, particularly in an area where property lines tend to be straight and square or follow natural features like a creek.  Zooming out a bit on the map it is easy to see how these could link together to provide that once-planned freeway corridor that would wind around more developed areas.

[gonealookin]

^^^

Over here on the Nevada side, the State still owns this parcel on the south side of SR 207 just east of US 50.  It's fairly wide, about 436 feet of frontage on SR 207 and clearly shaped to provide for on and off ramps.  The freeway would have continued north across SR 207 through what is now Kahle Community Park, bent a bit west and joined existing 4-lane US 50 a bit to the north of here.



Looking this up last night, on the CAHighways.org US 50 page you can scroll down a ways and see the alignment including the tunnel under Echo Summit, and further down another map showing the California portion of the Meyers to Stateline bypass.

[Henry]

Besides, the presence of I-580 in the East Bay guarantees that the NV version will end in Carson City. So if anything, the bypass would've been better off as a reroute of US 395.

[oscar]

Now that Nevada 580 is a thing, and given that the freeway continues all the way into California for a few miles, we should think about a traversable route to 5/580 in San Joaquin County and upgrading it to Interstate standards.

580 in California and 580 in Nevada are completely unrelated routes. Out east, it's common for 3-digit Interstates in close proximity to have the same number, such as I-291 in the Hartford CT area and I-291 in the Springfield MA area. Also, I-695 beltway around Baltimore (for now interrupted by the Key Bridge closure) and I-695 in D.C. (being renumbered to part of I-395). No intention (or need) to connect the routes, except as a fantasy exercise.

[The Ghostbuster]

I don't see Interstate 580 ever being extended in any direction. The four-lane divided highway on existing US 395 between Carson City and Minden is probably sufficient for existing traffic needs. Any upgrades, if necessary, can be made to the existing roadway.

[Max Rockatansky]

Probably also worth noting that the California iteration of 580 was part of I-5W before the 1964 Renumbering.  There was even some shields posted in Oakland.

[Voyager]

I think a suspension bridge across the mouth of Emerald Bay could be quite beautiful, especially if it had some decorative lights on it. It would be visible in the distance at night from the eastern shore in Nevada.

I wouldn't call Lake Tahoe "pristine", since there's quite a bit of development along its shore in places. But I've always felt that lights reflected in water at night were among the most scenic things.

A large arch bridge like the Bixby would have been perfect for that location.

[tawnuskgrevy]

That corridor was also explored as part of the 1973 Federal Aid Highway Act.  The alignment over Echo Summit included a tunnel.

If you rummage around with SLT parcel maps, such as the GIS maps on this site: https://see-eldorado.edcgov.us/ugotnet/ , it sure looks like not only was a corridor identified and/or adopted but future right of way was acquired or otherwise reserved at one time.  There is a broken chain of parcels that have the characteristics of a future freeway, including flaring out at certain intersections for interchanges. 
For example, between the airport and Onnontioga Street there is a strip parcel that flares where Washoan Blvd. dead-ends. Another runs parallel to Barbara Avenue and northeast of that on either side of Al Tahoe Blvd is another segment that flares for what would have been another interchange.  There are then several property lines diagonal to the underlying block layout that would reflect the corridor sweeping across Pioneer Trail at Needle Peak Road, with another potential interchange at Ski Run Blvd., and then an large strip parcel that runs behind the Raley's shopping center and Heavenly Village that flares out again for another potential interchange at stateline. 
Coincidence?  Perhaps but being in the land planning business, having property lines and parcels like this is very suggestive of a planned transportation corridor, particularly in an area where property lines tend to be straight and square or follow natural features like a creek.  Zooming out a bit on the map it is easy to see how these could link together to provide that once-planned freeway corridor that would wind around more developed areas.

The Tahoe Conservancy owns a good portion of those parcels and has all their properties highlighted on a GIS map that makes the planned corridor really easy to see (especially at the northeast end); it's very neat to have this level of evidence for a planned-and-abandoned project like this: