The most/least vital Interstate to the US as a whole

[OCGuy81]

I know we've done the most vital and the least vital interstates at a state level, but can it be done nationally?

Maybe to make it a bit easier, let's say you can pick one N-S, and one E-W route. 

That said, what's the most vital interstate on a national level?  This should prove tough, I think.

[Brandon]

East-West?
I-80.  New York to San Francisco via Chicago.

North-South?
Debatable.  One could use I-95, or I-5, or even I-55 or I-35.

[briantroutman]

Could we establish criteria on what constitutes the most/least vital? In the other similar threads, people's ideas of importance seem to be all over the map.

Kurumi's 2DI ranking system already established I-95 and I-80 as the two most important Interstates in the country. But a lot of posters seem to think "important"  is synonymous with "no alternative route" , and I-95 could be bypassed by countless other 3DIs, US routes, state routes and local roads throughout most of its length.

I-95 and I-80 would have my votes, by the way.

[OCGuy81]

Could we establish criteria on what constitutes the most/least vital? In the other similar threads, people's ideas of importance seem to be all over the map.

Kurumi's 2DI ranking system already established I-95 and I-80 as the two most important Interstates in the country. But a lot of posters seem to think "important"  is synonymous with "no alternative route" , and I-95 could be bypassed by countless other 3DIs, US routes, state routes and local roads throughout most of its length.

I-95 and I-80 would have my votes, by the way.

I've usually gone with routes that, should they suddenly disappear, would have the most crippling economic backlash, followed by the worst traffic fallout.  Let's use that for this thread. Good question!

[slorydn1]

I would have to agree with I-95 for the N-S route, although a serious argument could be made for I-35 because of its importance for moving freight through the center of the country.

The E-W route is a little more tricky for me. When I lived in the Chicago area I would have supported I-80 hands down, but now that I live down in NC I lean more towards I-40. I guess its the old "me" thing cropping back up, as in "It's the most vital to me" because of my location.

For those of us that are centrally located (in a N-S way) the loss of I-40 would mean that I  (there it is again) would have to travel at least 3 hours out of my way to access I-20 or upwards of 6 hours to get to I-70 to be able to travel west across the country.

Looking at things that way, but removing myself from the equation, I guess I could still support I-80 (or would it be I-90) as the huge population base of the NE US would be severely cut off from points west by the loss of either of those routes.

[Scott5114]

I-40 is a critical part of the route from Los Angeles to anywhere in the east. Alternates like I-70 exist, but I-40 is far enough south that it rarely gets impacted by winter weather, making it preferable to I-70 and I-80, both of which are sometimes closed due to snowstorms.

[Molandfreak]

Least vital: I-97, I-88 IL?

[SteveG1988]

One of the most vital has to be Interstate 81. Helps connect the southeast to Canada and bypasses the northeast metropolis.

Least vital to the US at Whole... Interstate 57, immensely useful to a truck driver, but if it didn't exist i don't think the world would implode.

Interstate 68...definitely useless to the US as a whole, it does not provide an effective bypass.

[hobsini2]

Least vital I-27 as it currently stand from Lubbock to Amarillo. If ever extended to connect to other interstate, then I would take it off the least list.

[noelbotevera]

Most vital
North-South: I-35 intersects with every x0 interstate in the country, and then some, which are important connectors to anywhere towards Mexico or Canada (ex: I-29, I-2 (indirectly))
East-West: I-10, however the only major downside is its isolation for points north (ex. St. Louis, Salt Lake City), and the large 500 mile gap between big cities. I-10 does hit at least five cities that are in the top 25 list of highest population, connecting those cities together (ex. LA to El Paso).

Least vital
North-South: I-27 only connects two small panhandle towns. Not worth it.
East-West: I-86 (NY) has really just replaced NY 17. Nothing new.

[DandyDan]

For most vital: N-S, I'm inclined to say I-95.  E-W, I'll go with I-80, although how much of that has to do with living less than 10 miles away from it is hard to say.

Least vital: N-S I'd go with I-99.  Is anything really important on that route?  E-W, I'd go with I-86 in Idaho.  I'm not sure who exactly is supposed to use that route.  I suppose people going from Pocatello or Idaho Falls to Boise, but who else?

[hobsini2]

Most vital
North-South: I-35 intersects with every x0 interstate in the country, and then some, which are important connectors to anywhere towards Mexico or Canada (ex: I-29, I-2 (indirectly))
East-West: I-10, however the only major downside is its isolation for points north (ex. St. Louis, Salt Lake City), and the large 500 mile gap between big cities. I-10 does hit at least five cities that are in the top 25 list of highest population, connecting those cities together (ex. LA to El Paso).

Least vital
North-South: I-27 only connects two small panhandle towns. Not worth it.
East-West: I-86 (NY) has really just replaced NY 17. Nothing new.

Noel, Amarillo and Lubbock are decent sized cities. Both over 150,000. In fact, Amarillo is the only city of size along I-40 between Albuquerque and Oklahoma City.

[OCGuy81]

Maybe I'm showing a west coast bias here, but I'd put I-5 slightly ahead of I-95, solely for the reason it's the only N-S route that has endpoints at both the Canadian and Mexican border (I-35 comes close)

E-W is tough, as these routes have a lot of isolation in the western states.  I might argue for I-70 here, just because of its central location.

As far as worthless goes, I'd probably nominate the western I-86 and I-27 too.

[ET21]

Least vital: I-88 IL?

Not so much recently, I-88 is becoming a good secondary route to I-80 for QC to Chicago. Recently a lot of people have been using it to avoid I-90 and its expanding construction mess.

However I would say the section from Dixon westward to I-80 has the least amount of traffic

[OCGuy81]

As far as worthless goes, I'd probably nominate the western I-86 and I-27 too.

Again, why? I-86 is short, but far from useless.


iPhone

I'd argue that because it doesn't connect population centers of any real significance.  Idaho is sparsely populated, and even if it does connect one of its larger cities, there still isn't much use for it.

[roadman65]

I-99 for sure, but that we know to well.  I have to say that as far as being worthless, I-74 now east of Rockingham as its long range plans do not have it being a relief route to Wilmington for US 74 but to loop back SW to Myrtle Beach where planned I-73 is going anyway.

[Bickendan]

Gonna go on a limb and say I-5 for N/S. The west coast would be SOL if it disappeared.
E/W... probably I-40 for its southerly crossing of the Rockies but good connections for LA to Chicago (US 66 corridor) and the east.

Least important: I'll note the thread doesn't specifically rule out 3DIs, so IL I-180 ("E/W") and MT I-315 ("N/S")

I'm having a hard time coming up with a useless 2DI short of using one of Hawaii's, Alaska's or Puerto Rico's... Hmm. I-99 and I-74.

[02 Park Ave]

Most vital N/S:  The I-87.  It connects the most important cities in the US and Canada, New York and Montreal.

Most vital E/W:  The I-80.  It includes the most vital segment of the System, the I-80/94.

Least vital N/S and E/W:  Any thing in Hawaii.

[Henry]

Most vital
Even: I-90 (Boston-Seattle via Chicago)
Odd: I-95 (connecting the BosWash corridor to Miami)

Least vital
Even: I-30 (too short for an I-x0 route)
Odd: I-99 (in the middle of nowhere)

[SteveG1988]

Most vital
Even: I-90 (Boston-Seattle via Chicago)
Odd: I-95 (connecting the BosWash corridor to Miami)

Least vital
Even: I-30 (too short for an I-x0 route)
Odd: I-99 (in the middle of nowhere)

There are talks of extending 30 over to where 57 is. it does provide a vital connection as it stands.

[Brandon]

Least important: I'll note the thread doesn't specifically rule out 3DIs, so IL I-180 ("E/W") and MT I-315 ("N/S")

Problem is, I-180 in Illinois is signed north-south, not east-west.

[Mileage Mike]

Most vital no question is I-95.  It serves a larger portion of the US population than any other interstate.

Least vital I'm inclined to say I-74 in NC.  It's almost useless and has very low traffic counts as of right now and even when it's complete it won't be useful since it just will loop back to I-73 in Myrtle Beach rather than go to Wilmington.

[Kacie Jane]

Least important: I'll note the thread doesn't specifically rule out 3DIs, so IL I-180 ("E/W") and MT I-315 ("N/S")

Problem is, I-180 in Illinois is signed north-south, not east-west.

315 isn't signed, but is more east-west than it is north-south, so maybe he could get away with just switching them.

(Although the three routes that are signed the length of 315 are all north-south.... Although two of them are north-south and one is south-north....)

[noelbotevera]

Most vital
North-South: I-35 intersects with every x0 interstate in the country, and then some, which are important connectors to anywhere towards Mexico or Canada (ex: I-29, I-2 (indirectly))
East-West: I-10, however the only major downside is its isolation for points north (ex. St. Louis, Salt Lake City), and the large 500 mile gap between big cities. I-10 does hit at least five cities that are in the top 25 list of highest population, connecting those cities together (ex. LA to El Paso).

Least vital
North-South: I-27 only connects two small panhandle towns. Not worth it.
East-West: I-86 (NY) has really just replaced NY 17. Nothing new.

Noel, Amarillo and Lubbock are decent sized cities. Both over 150,000. In fact, Amarillo is the only city of size along I-40 between Albuquerque and Oklahoma City.

Well, the reason why I nominated I-27 is that it does not connect I-40 to I-20, which would help get I-40 traffic towards Dallas or El Paso rather than having to use a couple hundred miles of  I-35.

[signalman]

Least important: I'll note the thread doesn't specifically rule out 3DIs, so IL I-180 ("E/W") and MT I-315 ("N/S")

Problem is, I-180 in Illinois is signed north-south, not east-west.

I-180 can be the least vital N-S route, I-865 goes to E-W