Hierarchy of Interstates in Your State (from Most Vital Highways thread)

[nwi_navigator_1181]

Here's a tough one...

OHIO: 

- I-71
- I-75
- I-70
- I-90
- I-80
- I-76
- I-74
- I-480
- I-270
- I-280
- I-275
- I-475
- I-670
- I-675
- I-680
- I-470
- I-490
- I-277

I 471?

RE-REVISED OHIO:

- I-71
- I-75
- I-70
- I-90
- I-77
- I-80
- I-76
- I-74
- I-480
- I-270
- I-280
- I-275
- I-475
- I-670
- I-675
- I-680
- I-470
- I-490
- I-471
- I-277

I really hate to make you do this, but you also omitted I-271. While it's very short, it serves as an excellent connection from Columbus to Erie and points east while completely avoiding Cleveland, the heavy traffic downtown, the "Dead Man's Curve," and a huge influx of Turnpike traffic.

Again, sorry about that, but I had to point it out.

[empirestate]

Here's my shot at a ranking for NY:

1. 87 - The NYC-to-Albany route, yet most of its ranking comes from the E-W Rockland County and Tappan Zee segment, which is critical and has few practical alternates. A vital link between downstate and upstate.

2. 90 - The east-west backbone, cutting into the interior U.S. through the water level route, one of the nation's oldest and most important trade routes.

3. 81 - A near-tie with I-90, it connects both to Canada and Appalachia and is another route to NYC, but it serves less population in the state than I-90.

4. 287 - The northern bypass of NYC. Also including the Tappan Zee link, its ranking would drop if the I-87 overlap were discounted (but not by much).

5. 495 - The only Interstate serving Long Island, a region of comparable area to some states.

6. 95 - You may be surprised to see this here instead of at #1, if you've followed the parent thread. My criteria here are a little different, being based more on the routes as they actually are, versus the other thread which is about the routes as if they suddenly were not. Still, it's the middle of three routes through or around NYC and is a corridor of huge economic importance.

7. 278 - Several major water crossings and the third of the trans-NYC routes, in addition to having great local importance in that city.

8. 190 - Mainline of Buffalo and a major international port of entry.

9. 684 - I'm surprised it made it this high, but it carries a lot of traffic between NYC and its "suburbs" in New England.

10. 84 - An important Hudson crossing, but a bit far from NYC to be a practical bypass. It seems to be more important in PA and CT than it is in NY.

11. 490 - Picks up I-90's slack by serving Rochester, giving it a little more weight than other upstate 3dis.

12. 86 - An important route through a more lightly-traveled corridor. Upon completion it will go up a little, perhaps just into the top ten.

13. 390 - Part of the route between Buffalo/Rochester and downstate for many travelers.

14. 678 - Important route within NYC (airports), but the redundancy of upper East River crossings gives them individually a little less weight.

15. 78 - Short as it is in the state, it's the Holland Tunnel and brings in lots of commercial traffic to lower Manhattan and Brooklyn.

16. 290 - Short but highly developed bypass of Buffalo.

17. 787 - Serves a busy corridor between several Capital District cities.

18. 690 - Important route through Syracuse, but is closely parallel to I-90.

19. 88 - Convenient route for some, but not vital for most purposes.

20. 890 - Like 490 and 690, but serving a yet smaller population.

21. 481 - A bypass with limited applicability; suitable, but not a slam-dunk.

22. 295 - Again, one of several Bronx/Queens crossings, and a redundant N/S route (actually, I feel it's under-utilized and should rank higher, but that's OK with me).

23. 590 - Handy little route, just very limited in scope.

24. 478 - Brooklyn-Battery tunnel. Important as such; less important as an Interstate. Actually, this ranking seems low, but what're ya gonna do. :-)

25. 790 - Yeah, yeah, I know, but it is the only way into Utica from the Thruway, after all...

26. 990 - I never use this route. Maybe it's more important than I think, but I dunno.

27. 878 - Actually gets a lot of traffic as part of the JFK airport network, but there's just so much redundancy in the area.

28. 587 - Hey, it makes getting into Kingston just a little faster...

29. 781 - While there's certainly some value in moving people and things in and out of an army base in the middle of nowhere, it just feels like a one-trick pony.

30. 695 - Doesn't do anything that a couple extra ramps at the Bruckner Interchange couldn't do.

31. 895 - Yeah, it really doesn't go anywhere. It cuts a corner that nobody needs cut; otherwise, it's a way to get to a couple streets in the middle Bronx.

[thenetwork]

I really hate to make you do this, but you also omitted I-271. While it's very short, it serves as an excellent connection from Columbus to Erie and points east while completely avoiding Cleveland, the heavy traffic downtown, the "Dead Man's Curve," and a huge influx of Turnpike traffic.

Again, sorry about that, but I had to point it out.

RE-RE-REVISED OHIO

- I-71
- I-75
- I-70
- I-90
- I-77
- I-80
- I-76
- I-74
- I-480
- I-270
- I-271
- I-280
- I-275
- I-475
- I-670
- I-675
- I-680
- I-470
- I-490
- I-471
- I-277
[/quote]

[vdeane]

As someone who went to college in the North Country, I'd rank I-781 higher.  It didn't shorten the distance (it actually lengthened it by a tiny amount), but the moment it was built I could suddenly get to/from Potsdam 15 minutes faster each way, and unlike I-587, it actually serves long-distance traffic (pretty much anyone who's going on a long trek up US 11 to NY's final frontier).  I'd guess that most of the traffic is going to US 11 and not the fort, though I don't think Region 7's done any traffic counts there yet to find out.

[Brandon]

I omitted I-10 in Alabama because east of Mobile, the next major city it directly connects is Tallahassee, which is 245 miles away.  (Sorry, Pensacola, but are you really a major city?)

Considering that Pensacola has a metro area of over 460,000 and Tallahassee has only about 375,000 in its metro area, I'd say Pensacola (it's area at least) is a major city along I-10.

[empirestate]

As someone who went to college in the North Country, I'd rank I-781 higher.  It didn't shorten the distance (it actually lengthened it by a tiny amount), but the moment it was built I could suddenly get to/from Potsdam 15 minutes faster each way, and unlike I-587, it actually serves long-distance traffic (pretty much anyone who's going on a long trek up US 11 to NY's final frontier).  I'd guess that most of the traffic is going to US 11 and not the fort, though I don't think Region 7's done any traffic counts there yet to find out.

OK, I can see that. I tried to use it once on a trip down from Hammond, but on NY 37 it's no use to me. As a Watertown bypass, I can see it moving up to around #26 or so.

[cl94]

I'm going to do my version of the New York hierarchy. Having lived all over the state, I have a few things that would be different:

1. I-87
2. I-90
3. I-495
4. I-81
5. I-95
6. I-190: Serves 2 of the busiest US-Canada border crossings, route between Toronto and the east coast
7. I-287
8. I-86 (current and future): major east-west route that gets a surprising amount of long-distance intrastate traffic
9. I-278
10. I-390: connection between Buffalo, Rochester, and Ontario and the southern part of the state, Pennsylvania, and the rest of the east coast south of Connecticut
11. I-84: only high-speed crossing of the Hudson between Tappan Zee and just south of Albany, northern leg of "golden triangle
12. I-88: part of well-used shunpike between Albany and Ohio
13. I-684: only limited-access road in the eastern Hudson Valley open to all vehicles
14. I-295: Best truck route to LI
15. I-678
16. I-490
17. I-290: one of the busiest Interstates upstate not already mentioned, if not the busiest
18. I-78
18.5. I-99: doesn't deserve a real number, but it and US 15 are the main connection between Central PA and the southeast with Western New York
19. I-781: might seem insignificant, but it's a very important shortcut between I-81 and US 11 that gets much use
20. I-690: connection between I-90 and downtown Syracuse
21. I-787
22. I-890: GE plant
23. I-590
24. I-990: surprisingly useful. Accesses a couple of large office parks and UB while bypassing congested sections of NY 78 and NY 263
25. I-478
26. I-695
27. I-878
28. I-790. Depending on where you're going, it might be faster to take local roads
29. I-895
30. I-481. Candidate for "most useless bypass".
31. I-587: likely did nothing other than kill Downtown Kingston's shopping district as all traffic now bypasses it

[Ned Weasel]

Either no one has taken Kansas yet, or I scrolled through the replies way too quickly--

1) I-70
2) I-35
3) I-135
4) I-335
5) I-435
6) I-235
7) I-470
8) I-635
9) I-670

This is guesswork, though.  I-335 isn't important as a number, but it is important as a roadway.  I-135 and I-335 were chosen over I-435 because of their positions in the state's freeway network, despite the traffic volumes and width of I-435.  If I-470 didn't exist, that portion of the Kansas Turnpike could easily be another five miles of I-335.  I-235 serves a bigger city than does I-470, but the connection provided by the western leg of I-470 is harder to duplicate than those provided by I-635 and I-670.

[NWI_Irish96]

Here's Indiana:

1. Tie: I-80 and I-90: As I stated in the "Most Vital Highway" thread, this duplex is the only one in Northern Indiana that feeds into Ohio, and serves as a bigger part of a connection from Chicago to NYC. Being two of the longest east-west interstates in the country and a major part of Midwest travel, few can go far quickly without them. Worth the toll to zip through.

2. I-65: The only north-south interstate serving Northwest Indiana, it's the optimal route from Chicago to Indianapolis, and a major component to linking with other major Southeastern cities, whether directly (Louisville, Nashville), or indirectly (Cincinnati, Atlanta). That's a big reason why many here are advocating a full-state widening of I-65 in Indiana; traffic can be heavy in pockets.

3. I-70: The major east-west Interstate of Central Indiana, connecting Indianapolis to major cities such as St. Louis, Denver, Baltimore, and (almost) Pittsburgh. Unlike the Toll Road and I-65, there is a decent alternate route in I-74.

4. I-69: While not yet built to its fullest potential (the southwest portion from Indianapolis to Evansville is still under construction), this road is integral to linking Northeast Indiana to Indianapolis, Lansing, and Canada. If the rest of this highway is ever built, the vitality of this highway will be increased exponentially.

5. I-94: The biggest reason it's so low on the list is because it covers a very short distance in Indiana (46 miles). However, it plays a large role in connecting the Lake Michigan shore cities (Chicago, Milwaukee, Grand Rapids indirectly), as well as serving the Upper Midwest. It also serves as a good segue into other portions of the country due to its duplex with I-80.

6. I-74: While not as heavily prominent as the above Interstates, it serves well as a quick connection from Cincinnati to the Quad Cities and beyond while completely taking Chicago out of the equation.

I really don't rate the bypasses since I'm not familiar enough with them to rate. However, I'd rate I-465 well above I-469 because of how the major interstates converge near the circle.

I would put I-65 above 80/90 by a slight amount, if for no other reason than the sheer volume throughout the length of the state.  Agree with 70 being third and 69 being fourth.  I would actually put 465 fifth.  I would also put 74 above 94 just because of the length.  After 94 I would round out the state with 64, 265, 469, 869 and 275. 

[Pink Jazz]

Not my state, but I will do one for New Mexico:

1. I-25 - Connects the three largest metro areas of the state (Las Cruces, Albuquerque, and Santa Fe).
2. I-40 - Major truck route for the state, although I would put it below I-25 due to the cities served being smaller.
3. I-10 - Has the least mileage through the state and the only significant metro area served in the state is Las Cruces, although nationally I-10 is probably more important than both since it serves a lot more major cities in its entire length.

[epzik8]

Maryland, my Maryland!

• Interstate 95 - the East Coast's most major Highway; need I say more?
• Interstate 70 - the gateway "out west"; it connects Baltimore with Frederick, Hagerstown and Hancock.
• Interstate 68 - picks up where I-70 leaves off. Goes the rest of the way to Garrett County.
• Interstate 97 - connects Baltimore (Maryland's largest city) with Annapolis (the state capital) and the Bay Bridge.
• Interstate 83 - not much scenery as it emerges from Baltimore into Pennsylvania.
• Interstate 81 - only about 12 miles through Maryland. Doesn't give out-of-staters time to realize that Maryland is more than just Hagerstown.

[mapman1071]

Here's my shot at a ranking for NY:

1. 87 - The NYC-to-Albany route, yet most of its ranking comes from the E-W Rockland County and Tappan Zee segment, which is critical and has few practical alternates. A vital link between downstate and upstate.

2. 90 - The east-west backbone, cutting into the interior U.S. through the water level route, one of the nation's oldest and most important trade routes.

3. 81 - A near-tie with I-90, it connects both to Canada and Appalachia and is another route to NYC, but it serves less population in the state than I-90.

4. 287 - The northern bypass of NYC. Also including the Tappan Zee link, its ranking would drop if the I-87 overlap were discounted (but not by much).

5. 495 - The only Interstate serving Long Island, a region of comparable area to some states.

6. 95 - You may be surprised to see this here instead of at #1, if you've followed the parent thread. My criteria here are a little different, being based more on the routes as they actually are, versus the other thread which is about the routes as if they suddenly were not. Still, it's the middle of three routes through or around NYC and is a corridor of huge economic importance.

7. 278 - Several major water crossings and the third of the trans-NYC routes, in addition to having great local importance in that city.

8. 190 - Mainline of Buffalo and a major international port of entry.

9. 684 - I'm surprised it made it this high, but it carries a lot of traffic between NYC and its "suburbs" in New England.

10. 84 - An important Hudson crossing, but a bit far from NYC to be a practical bypass. It seems to be more important in PA and CT than it is in NY.

11. 490 - Picks up I-90's slack by serving Rochester, giving it a little more weight than other upstate 3dis.

12. 86 - An important route through a more lightly-traveled corridor. Upon completion it will go up a little, perhaps just into the top ten.

13. 390 - Part of the route between Buffalo/Rochester and downstate for many travelers.

14. 678 - Important route within NYC (airports), but the redundancy of upper East River crossings gives them individually a little less weight.

15. 78 - Short as it is in the state, it's the Holland Tunnel and brings in lots of commercial traffic to lower Manhattan and Brooklyn.

16. 290 - Short but highly developed bypass of Buffalo.

17. 787 - Serves a busy corridor between several Capital District cities.

18. 690 - Important route through Syracuse, but is closely parallel to I-90.

19. 88 - Convenient route for some, but not vital for most purposes.

20. 890 - Like 490 and 690, but serving a yet smaller population.

21. 481 - A bypass with limited applicability; suitable, but not a slam-dunk.

22. 295 - Again, one of several Bronx/Queens crossings, and a redundant N/S route (actually, I feel it's under-utilized and should rank higher, but that's OK with me).

23. 590 - Handy little route, just very limited in scope.

24. 478 - Brooklyn-Battery tunnel. Important as such; less important as an Interstate. Actually, this ranking seems low, but what're ya gonna do. :-)

25. 790 - Yeah, yeah, I know, but it is the only way into Utica from the Thruway, after all...

26. 990 - I never use this route. Maybe it's more important than I think, but I dunno.

27. 878 - Actually gets a lot of traffic as part of the JFK airport network, but there's just so much redundancy in the area.

28. 587 - Hey, it makes getting into Kingston just a little faster...

29. 781 - While there's certainly some value in moving people and things in and out of an army base in the middle of nowhere, it just feels like a one-trick pony.

30. 695 - Doesn't do anything that a couple extra ramps at the Bruckner Interchange couldn't do.

31. 895 - Yeah, it really doesn't go anywhere. It cuts a corner that nobody needs cut; otherwise, it's a way to get to a couple streets in the middle Bronx.

LI Interstates
278, 478 (Unsigned), 678, 878 (Unsigned), 295 & 495

[TravelingBethelite]

Connecticut:

1. I-95...unquestionable. Main Street of the East Coast, Boston-New York, Metropolis, commuters, etc., etc., etc.
2. I-84...Doesn't join big regional cities, but is a major trucking corridor from the Mid-Atlantic & points south to New England; connects to Mass Pike. Runs through smaller cities-DB, WB, HFD.
3. I-91...not as important as a trucking corridor, but goes to Canada. Does run through both Hartford and New Haven.
4. I-395...Also meets Mass Pike, but is more for local access. See: Norwich, Putnam, Thompson, and so on.
5. I-691...Connector of I-84, U.S. 5, and I-91. Important for trucking.
6. I-384...Would have far more significance if it eventually became I-84, but all it does now is: I-84 >> U.S. 6 east to Willimantic, U.S. 44 east to Putnam.
7. I-291...poor I-291...really is not anything besides a back-up for accessing I-91 from I-84 and vice versa. If it turned into the beltway, well...
8. I-684...need I-explain? Provides background noise and very little scenery to northern sections of Greenwich. 

Also see kurumi's ranking of all the 2-digit interstates, back from 3 presidents ago, the long-ago days of January, 2001: http://www.kurumi.com/roads/rank2di.html

[empirestate]

Here's my shot at a ranking for NY:

1. 87 - The NYC-to-Albany route, yet most of its ranking comes from the E-W Rockland County and Tappan Zee segment, which is critical and has few practical alternates. A vital link between downstate and upstate.

2. 90 - The east-west backbone, cutting into the interior U.S. through the water level route, one of the nation's oldest and most important trade routes.

3. 81 - A near-tie with I-90, it connects both to Canada and Appalachia and is another route to NYC, but it serves less population in the state than I-90.

4. 287 - The northern bypass of NYC. Also including the Tappan Zee link, its ranking would drop if the I-87 overlap were discounted (but not by much).

5. 495 - The only Interstate serving Long Island, a region of comparable area to some states.

6. 95 - You may be surprised to see this here instead of at #1, if you've followed the parent thread. My criteria here are a little different, being based more on the routes as they actually are, versus the other thread which is about the routes as if they suddenly were not. Still, it's the middle of three routes through or around NYC and is a corridor of huge economic importance.

7. 278 - Several major water crossings and the third of the trans-NYC routes, in addition to having great local importance in that city.

8. 190 - Mainline of Buffalo and a major international port of entry.

9. 684 - I'm surprised it made it this high, but it carries a lot of traffic between NYC and its "suburbs" in New England.

10. 84 - An important Hudson crossing, but a bit far from NYC to be a practical bypass. It seems to be more important in PA and CT than it is in NY.

11. 490 - Picks up I-90's slack by serving Rochester, giving it a little more weight than other upstate 3dis.

12. 86 - An important route through a more lightly-traveled corridor. Upon completion it will go up a little, perhaps just into the top ten.

13. 390 - Part of the route between Buffalo/Rochester and downstate for many travelers.

14. 678 - Important route within NYC (airports), but the redundancy of upper East River crossings gives them individually a little less weight.

15. 78 - Short as it is in the state, it's the Holland Tunnel and brings in lots of commercial traffic to lower Manhattan and Brooklyn.

16. 290 - Short but highly developed bypass of Buffalo.

17. 787 - Serves a busy corridor between several Capital District cities.

18. 690 - Important route through Syracuse, but is closely parallel to I-90.

19. 88 - Convenient route for some, but not vital for most purposes.

20. 890 - Like 490 and 690, but serving a yet smaller population.

21. 481 - A bypass with limited applicability; suitable, but not a slam-dunk.

22. 295 - Again, one of several Bronx/Queens crossings, and a redundant N/S route (actually, I feel it's under-utilized and should rank higher, but that's OK with me).

23. 590 - Handy little route, just very limited in scope.

24. 478 - Brooklyn-Battery tunnel. Important as such; less important as an Interstate. Actually, this ranking seems low, but what're ya gonna do. :-)

25. 790 - Yeah, yeah, I know, but it is the only way into Utica from the Thruway, after all...

26. 990 - I never use this route. Maybe it's more important than I think, but I dunno.

27. 878 - Actually gets a lot of traffic as part of the JFK airport network, but there's just so much redundancy in the area.

28. 587 - Hey, it makes getting into Kingston just a little faster...

29. 781 - While there's certainly some value in moving people and things in and out of an army base in the middle of nowhere, it just feels like a one-trick pony.

30. 695 - Doesn't do anything that a couple extra ramps at the Bruckner Interchange couldn't do.

31. 895 - Yeah, it really doesn't go anywhere. It cuts a corner that nobody needs cut; otherwise, it's a way to get to a couple streets in the middle Bronx.

LI Interstates
278, 478 (Unsigned), 678, 878 (Unsigned), 295 & 495

Yeah, they're all in my list...?

[Life in Paradise]

Indiana:

Although should be lower than I-74 on the list, you forgot I-64 through Southern Indiana.  Not unusual in that most people north of a line running from Terre Haute to south of Bloomington forget that part of the state.  Also I-265 on the Indiana side of the Louisville, KY metro is a fairly busy interstate as well, especially between I-64 west and I-65 north.

[PHLBOS]

7. I-291...poor I-291...really is not anything besides a back-up for accessing I-91 from I-84 and vice versa.

Such does provide northeastern/eastern CT better access to Bradley Airport (BDL).

[TravelingBethelite]

7. I-291...poor I-291...really is not anything besides a back-up for accessing I-91 from I-84 and vice versa.

Such does provide northeastern/eastern CT better access to Bradley Airport (BDL).

This is true, and so does I-91. This makes I-91 a bit more important in the CT road network than I may have considered. Oops! 

[bzakharin]

Connecticut:

1. I-95...unquestionable. Main Street of the East Coast, Boston-New York, Metropolis, commuters, etc., etc., etc.

Isn't it actually faster to take I-91 to I-84 for NY to Boston and points north? Of course you'd still be taking 95 from points south (unless it's CT 15 instead)

[CtrlAltDel]

Here is my listing for Illinois. I left off the 3DI's since there's so many of them (11), and I don't really know all of them that well.

I-80
I-94
I-90
I-55
I-57
I-39
I-74
I-72
I-64
I-70
I-88
I-24
I-41

I appreciate the efforts other have made, since making this list turned out to be pretty hard. So many of the routes in Illinois come in roughly equivalent pairs, like I-64 and I-70. Both connect Saint Louis to cities east of the state, passing through few populated areas of the state itself. Or I-72 and I-74, which both connect medium-sized cities across the state. Or I-90 and I-94, which are both essential arteries through Chicago. Or even I-80 and I-88, which go east-west across pretty much the same area. I'm pretty happy with the ranking I came up with, although I'm not sure if I'd come up with the same one consistently, if I had to do so again and again.

[stwoodbury]

I THINK I got em all. I know, I know, 905 WILL be signed someday, and 305 is hidden, so I left them off.

What, no I-40?  I'd put it right after I-10 in importance to California.

Washington:

I-5 and I-90 tie for first
I-82
I-405
I-205
I-705
I-182

I'd agree with that if you switched I-705 and I-182. As someone who used to live in Richland, I-182 is very important in the Tri-Cities, and the road network there would fall apart without it. Tacoma could survive fine without I-705 (assuming a surface street with connection to I-5 in its place).

I would put 5 ahead of 90 in Washington because it connects Seattle to other major WA population centers like Tacoma, Olympia (the state capital) , Everett, and Vancouver WA, as well as Vancouver BC, Portland and other more distant major West Coast metro areas in California. Also it carries a lot more traffic than 90 and the mileage in Washington for both is almost the same (276 versus 299). 90 has considerable credibility because it is the longest of the interstates in the USA, but it only leads to Spokane and eventually to Chicago and other points East after a long trek through the very sparse Northern Rockies and Great Plains. I prefer driving on 90 because of the scenery and the lighter traffic, but I believe that it ranks behind 5 for overall importance in Washington.

[Super Mateo]

I appreciate the efforts other have made, since making this list turned out to be pretty hard. So many of the routes in Illinois come in roughly equivalent pairs, like I-64 and I-70. Both connect Saint Louis to cities east of the state, passing through few populated areas of the state itself. Or I-72 and I-74, which both connect medium-sized cities across the state. Or I-90 and I-94, which are both essential arteries through Chicago. Or even I-80 and I-88, which go east-west across pretty much the same area. I'm pretty happy with the ranking I came up with, although I'm not sure if I'd come up with the same one consistently, if I had to do so again and again.

I would argue that I-55 is the most important, mainly because it connects the following areas:  St. Louis, Springfield, Bloomington, Joliet, and downtown Chicago.

[7/8]

I'll rank the 400-series highways of Ontario, since they're our equivalent of the Interstate system, and I don't feel like making my own thread for this post. I'll probably change my mind on a few of them, but I think the general order is reasonable

401: Spans from Windsor to the border near Montreal, connecting a majority of Ontario's population. The portion in Toronto is also one of the busiest highways in the world!
QEW: Connects the Golden Horseshoe, from Toronto to Fort Erie
427: An important north-south corridor that helps connect Toronto with cities to the west and north
400: Connects Toronto with Cottage Country and Northern Ontario, and gets incredubly congested on summer weekends
417: Connects Ottawa and points west to Montreal, and serves as an important highway within Ottawa
403: An important truck corridor from Woodstock to the QEW, and heavily used by commuters from the QEW to the 410
404: Busy commuter route for Durham region, though it also helps with reaching Cottage Country
410: Connects Brampton and points north to Mississauga/Toronto and the rest of the 400-series highways
402: Important trade corridor connecting the Bluewater Bridge to London. Gives a useful alternative to passing through Windsor-Detroit
407: Useful (but expensive ) bypass of the 401 around Toronto
405: Connects the QEW with I-190 through the Queenston-Lewiston Bridge, another important trade corridor.
409: Serves Pearson Airport in Toronto, and bypasses the busy 401-427 interchange
420: Connects the QEW with downtown Niagara Falls, and leads to the Rainbow Bridge
416: Connects Ottawa to Toronto and I-81. I'm ranking this one rather low since I found taking the 401>37>7>417 was similar in travel time to the 401>416>417. Also, I've heard traffic counts are fairly low on the 416. However, I'll admit that having an all-freeway route is still important
412 (and future 418): Connects the 407 with the 401 on the east end, finally completing the Toronto bypass. I've personally found that using the 404 between the 407 and 401 hasn't been too bad, but the 412/418 are definitely nice to have. I rate them lower simply because they're move of a luxury than a necessity in my mind
406: Connects the QEW with St. Catharines and Welland. Traffic in my experience has always seemed rather low to me along here, and it serves mostly local traffic

[mvak36]

Nebraska:

I-80
I-680
I-76
I-480
I-180
I-129

I debated between 680 and 76 because they're both pretty important links, but 680 won out because it's used a lot more.

[JCinSummerfield]

I haven't seen Michigan yet.

I-94
I-75
I-96
I-696
I-275
I-69
I-196
I-496
I-475
I-675
Edit:  I-375
I-194
I-296 (if it were signed, I'd move it up 3 or 4 places)

I've never been to Michigan, but shouldn't I-96 be at the top of the list? It connects the state capital with the two largest cities.

No, that's about right.  There is so much more Detroit-Chicago traffic on I-94 and I-75 the major north-south link.  Much of I-96 west of say Brighton/US-23 is an easy drive with hardly the traffic you'd find on I-94 or I-75 at least in SE Michigan.

I'd make two changes:

First, I'd make I-75 #1, since it is the only road to connect both peninsulas.
Second, I would probably flip-flop I-69 & I-196.

[Roadgeekteen]

From most to least, 2di only for mass
90
95
93
91
84