Your state’s most important highway in each range?

[Quillz]

CA

0-9: I'd pick Interstate 5. Interstate 8 is a close second.
10-19: Again, the interstates. 10 or 15.
20-29: 22 is a heavily traveled Orange County freeway.
30-39: I'd go with 37, along the north side of San Pablo Bay.
40-49: Interstate 40, but 49 is a very scenic highway and quite important.
50-59: US 50, but 55 and 57 are two other SoCal freeways of importance.
60-69: Either 60 or 65.
70-79: Probably 74 or 78.
80-89: Quite a few. 80, 85, 87, 89 all come to mind.
90-99: 99

[hotdogPi]

Massachusetts:

0-9: US/MA 3. Picked over the others for being a freeway, and over MA 2 for going through more urban areas.
10-19: MA 12, a segment of the 4-state New England Route. Picked over 10 as 10 is overlapped with US 5 for a while. 16 is also a contender.
20-29: MA 24, a freeway. A case could be made for US 20 or MA 28, though.
30-39: MA 32, also a New England Route segment.
40-49: US 44.
50-59: MA 57, partially a freeway.
60-69: MA 62.
70-79: MA 79, partially a freeway.
80-89: I-84. While the segment in Massachusetts is short, so are the other routes in this range.
90-95: I-95, picked over the other Interstates for being mostly urban (unlike I-90), being in the Boston metro (unlike I-91), and traveling the entire state (unlike I-93).
100-109: MA 109, a surface road leading in and out of Boston.
110-119: MA 114. While shorter than some other options, it's extremely important for its length.
120-129: MA 128, for obvious reasons.
130-139: MA 138. Again, goes into Boston. (135 gets close.)
140-149: MA 146, a freeway.

Numbers get sparse after this.



New Hampshire, since nobody on this forum lives there:

0-9: US 3. Travels the entire length of the state, All single-digit routes in New Hampshire are relatively important, but US 3 is the most important.
10-19: NH 16, partially a freeway, and travels along the eastern edge of the state almost the entire way.
20-29: NH 28, going through the most populated parts of New Hampshire. Picked over New England Routes 25 and 26.
30-39: NH 33. They're all short (or they don't exist), but 33 serves a crucial role. 32 is part of a New England Route, but it ends at Keene.
40-49: NH 43. No good choices; the even numbers don't exist, and the odd numbers are fairly minor.
50-59: No routes in this range. If 51 didn't become 101, though, it would be important.
60-69: NH 63, the only option.
70-79: NH 77. Not important, but the only two other options are 75 and 78.
80-89: I-89. The only other options (84-88, and 86 being former) are all short routes in Rockingham County.
90-99: I-93.
100-109: NH 101. Partially a freeway, and its non-freeway segment is significant.
110-119: NH 112. A good tourist attraction, and connects both halves of the White Mountains.
120-129: NH 125, a good way to avoid I-95's tolls.
130-139: NH 135, on the New Hampshire side of the Connecticut River.
140-149: NH 140. No good choices.
150-159: NH 155. 153 is longer but overshadowed by NH 16.

Numbers get sparse after this.

[SP Cook]

This is a new one.  I can do WV:

0-9: WV 2, paralleling the Ohio from the very top of the state to Huntington.  One of the few SRs that carry significant thru traffic.

10-19: US 19.   The part not irrelevanted by parallel interstates, is Corridor L, forming part of the route from Toronto-Buffalo-Pittsburgh to Florida.

20-29: WV 20.  Not that significant, but nothing else is either.

30-39: US 35, funneling truck traffic from the Midwest via Cincy, Dayton, Columbus onto 77 and thus the Piedmont Carolinas.

40-49: US 48, Corridor H, if ever completed.

50-59: US 50.  The western two-thirds is Corridor D, the remainder is a serviceable mountain route.

60-69: I-64

70-79: I-77

80-89:  none

90-99: WV 99.  Not that significant, but best of the range.  Unique construction.

100-199: US 119.  The part not irrelevanted by interstates is Corridor G, one of the few good roads in southern WV.

200-299: US 219:  Serviceable mountain route. US 220 close second. 

300-999: I-470.  One of the smallest towns to get a bypass, 470 forms a de facto part of I-70, which is of national significance if not much to WV.

[paulthemapguy]

I really like this idea for a thread!

Illinois...

0-9: Probably US6.  If we're talking state routes, IL-1 is the longest state route we have.
10-19: Perhaps IL-13 across southern Illinois.  It's a very important route from Harrisburg to Murphysboro.  Or US12.
20-29: US20.  Maybe I-24.  Can't decide between IL-23 or IL-29 for state routes.
30-39: US30 or I-39.  IL-38 if we're talking state routes.
40-49: US45 covers more mileage than any other route in Illinois.  US41 is Lake Shore Drive though and that's neat IL-47 if we're talking state routes.
50-59: I-55.  IL-53 or IL-59 if we're talking state routes.
60-69: US67.  US66, historically.
70-79: I-70, though it may not be important to Illinoisans specfically.  IL-72 or IL-78 for state routes.
80-89: I-80.  Can't beat the first transcontinental highway. IL-83 or IL-84 for state routes.
90-99: I-90.  IL-92 for state routes.  Maaaaybe IL-97.

[US 89]

For Utah:

0-9: US 6
10-19: I-15
20-29: this is a tough one, but I’m going to say SR-24. It’s the longest state highway in Utah and pretty much the main drag for Wayne County (which lacks any US or Interstate routes). You could make an argument for SR-28 as well for an important connector from I-15 to US 89. SR-21 is one of only five routes to cross the west desert, but it sees so little traffic I don’t think it should be considered.
30-39: SR-36, Tooele’s only 4-lane connection to an interstate. SR-30 crosses the whole state, but it doesn’t see much traffic.
40-49: US 40
50-59: US 50, though really the only part that means a whole lot is between I-15 and I-70. You could argue for SR-52 as a major urban connector, or SR-56 as one of the few roads to actually cross the west desert.
60-69: it’s a tossup between SR-67 and SR-68. 67 is a freeway, but 68 is six times longer.
70-79: I-70
80-89: I-80, though I-84 and US-89 deserve some recognition
90-99: US 91, Logan’s four-lane connection to the Interstate system

100-109: none of these are all that important, but I’m going to say SR-108. That sees a lot of rush hour traffic.
110-119: same thing. I’ll give it to SR-114 as an alternative to the congested I-15.
120-129: 126 and 129 are the only routes in this group that serve any sizable population. I’ll give the edge to SR-126, because 129 has 74 as a close alternate, and 126 sees a lot of traffic (and much of it is also old US 91).
130-139: once it’s done, SR-131. Currently, I’ll say SR-132, which is an important connector route to the Sanpete Valley and Delta.
140-149: SR-145.
150-159: This was a debate, but I’ll have to go SR-151 for this one. I have never seen that road not crowded at rush hour, as it’s a key connecting route to the west side suburbs.
160-169: SR-167.
170-179: when it’s done, SR-179 (the Tooele Midvalley Highway). But at this point, I’ll have to go with 175 for the same reason as 151. Honorable mention to 171, 172, and 173.
180-189: US 189. Honorable mention to SR-186 though.
190-199: US 191. SR-193 definitely deserves a mention though, as does SR-190.

200-209: SR-201.
210-219: I-215.
220-229: SR-224.
230-239: only two exist, and 232 is more important than 235.
240-249: SR-248.
250-259: SR-252. That western bypass of Logan was definitely needed.
260-269: there are a lot of important urban connector highways in this group. I’ll say 265 is the most important, but 266 and 269 deserve a mention.
270-279: wow, none of these routes are that important. I’ll go with 274, since it’s the business loop to I-15 in Parowan.
280-289: here’s where we hit the state parks and institutions, very few of which are actually signed. I’ll go with 282 as most important, since it is a signed route serving the state's flagship university.
290-299: I don’t think any of the 29x routes are signed. I’ll have to go with 290 or 292, since those serve colleges as opposed to other random state institutions.

300-309: again, very few of these routes are signed. 302 is longest so I guess I'll go with that?
310-319: same thing. I’d say 313 because it’s more than 20 miles long and is the main access to Canyonlands. Honorable mention to 315 though, which is the only route of the 281-320 block signed from the interstate and has usefulness outside of its state park connection.

[hbelkins]

OK, let's do Kentucky

0-9 -- KY 9. The AA highway and it's Grayson spur, links I-64 in the eastern part of the state to the greater Cincinnati area.

10-19 -- KY 15. The southern spur of the Mountain Parkway, also designated an Appalachian corridor, connects much of southeastern Kentucky to the interstate system and the central part of the state.

20-29 -- US 23. The major north-south route through the mountains, called "eastern Kentucky's interstate" by many. I choose it over I-24, which seems to serve more out-of-state traffic than in-state traffic.

30-39 -- US 31E.

40-49 -- US 45. Links the Purchase area to its biggest city, Paducah.

50-59 -- KY 55. Major route through the central part of the state with portions modernized.

60-69 -- I-64, because it connects Kentucky's two largest cities and its capital.

70-79 -- I-75.

80-89 -- KY 80. Kentucky's longest state route across the southern tier; supplanted by parkways along much of its length but improved in the non-parkway links.

90-99 -- KY 90. Major link in the south-central part of the state, an ARC corridor for part of its length.

Three-digit US routes -- US 127. Major north-south link in the central part of the state and will be mostly upgraded when the proposed construction around Lake Cumberland is done.

Three-digit state routes -- KY 114. Part of the Mountain Parkway corridor.

Three-digit interstates -- I-265.

Four-digit state routes -- KY 1747 in Louisville.

This is a new one.  I can do WV:

0-9: WV 2, paralleling the Ohio from the very top of the state to Huntington.  One of the few SRs that carry significant thru traffic.

That would have been my choice.

10-19: US 19.   The part not irrelevanted by parallel interstates, is Corridor L, forming part of the route from Toronto-Buffalo-Pittsburgh to Florida.

Either that, or WV 10, which funnels traffic from the southern part of the state up toward Huntington and is scheduled to get a bunch of improvements between Man and Princeton.

20-29: WV 20.  Not that significant, but nothing else is either.

US 22?

30-39: US 35, funneling truck traffic from the Midwest via Cincy, Dayton, Columbus onto 77 and thus the Piedmont Carolinas.

Honorable mentions, US 30 and US 33.

40-49: US 48, Corridor H, if ever completed.

Now fully signed from Weston to Strasburg. Honorable mention, WV 43 (Mon-Fayette Expressway)

50-59: US 50.  The western two-thirds is Corridor D, the remainder is a serviceable mountain route.

Honorable mention: US 52

60-69: I-64

No-brainer.

70-79: I-77

Honorable mentions: I-70 and I-79

80-89:  none

I-81?

90-99: WV 99.  Not that significant, but best of the range.  Unique construction.

I think a case could be made for WV 92, which runs all the way from I-64 at White Sulphur Springs nearly all the way to I-68 at Morgantown (and in some cases, is still signed along WV 7 from the route's signed terminus into downtown Morgantown). Also, WV 93, which is going to become a fairly important connector route from Corridor H to US 220, and thus on to Cumberland. And WV 97, linking several areas in southern West Virginia to the area's largest town, Beckley. Although I will grant you that WV 99 is an interesting drive.

100-199: US 119.  The part not irrelevanted by interstates is Corridor G, one of the few good roads in southern WV.

200-299: US 219:  Serviceable mountain route. US 220 close second. 

300-999: I-470.  One of the smallest towns to get a bypass, 470 forms a de facto part of I-70, which is of national significance if not much to WV.

Not really much to choose from here, given the way West Virginia haphazardly numbers its three-digit state routes, but I'd nitpick and say that I-470 actually bypasses the tunnel and not Wheeling itself.

[dfilpus]

North Carolina:

0-9: US 1.
10-19: US 17.
20-29: I-26.
30-39: NC 32, which continues as VA 32.
40-49: I-40.
50-59: US 52.
60-69: US 64.
70-79: I-77.
80-89: I-85.
90-99: I-95.

[jeffandnicole]

I'm going to attempt NJ...

0-9: US 1
10-19: 18 may get the edge; 17 is pretty close
20-29: 21, 22, 24, 27 all maybe??!!  There's so many 2x routes near NYC that all are similarly important
30-39: 33, but again, see above.
40-49: US 46
50-59: 55
60-69: 66
70-79: I-78, but 70, 71, 72, 73 and I-76 could all easily come in 2nd.
80-89: I-80
90-99: I-95

[hotdogPi]

North Carolina:

80-89: NC 87, which is longer than I 87.

I-85?

[dfilpus]

North Carolina:

80-89: NC 87, which is longer than I 87.

I-85?

Brain Fart.

[briantroutman]

Here's my take on PA:

0-9: US 1
10-19: US 15
20-29: US 22
30-39: US 30
40-49:
50-59: PA 51
60-69: PA 61
70-79: I-76
80-89: I-81
90-99: I-95

Most of the decades have fairly clear winners. The 40s, 50s, 60s, and 80s are a bit more muddled.

I'm giving PA 51 the nod as a significant route into Pittsburgh that, with the northern routing of the Mon-Fayette now fixed to Monroeville and not Pittsburgh, will remain a major radial into the city for years to come.

If I was answering this question prior to 2009, I probably would have listed PA 60 as the most important route in the 60s because if its vital role in connecting Pittsburgh with its airport and western suburbs–as well as its role as PA Turnpike 60. But now having been truncated to being a local route merely connecting Crafton, Moon, and Robinson, I think the longer route of PA 61, being the transportation spine of Schuylkill County and connecting the Central Susquehanna Valley with Pottsville and Reading, is more important.

The 80s decade also presents a difficult decision. I originally picked I-80 but changed it to I-81. I-80 is clearly the longer of the two and has the fewest nearby alternate routes. Both I-80 and I-81 are significant corridors for cross-country trucking. But what I think tips the scales in I-81's favor is its significance in both the Harrisburg and Scranton/Wilkes-Barre metro areas.

[Eth]

Interesting exercise. Let's see what I can do with Georgia...

1-9: I'm going to say most of the single-digit state routes are disqualified; for instance, nobody actually thinks of GA 3 as being meaningful in any way, they think of the US routes it runs with. Therefore, it's US 1 pretty much by default.
10-19: I-16, though US 19 probably isn't that far behind.
20-29: I-20
30-39: Most significant ones (30, 31, 35, 38) are just US route companions. I'll give it to GA 32 for being an independent route that crosses almost the whole state.
40-49: Probably US 41, even if it is generally overshadowed by I-75.
50-59: Maybe GA 54, though that could be my metro Atlanta bias showing. Would maybe entertain an argument for 57 as well. I-59 really has no importance to Georgia itself.
60-69: I'll go with GA 61. About half of it just rides with US 411, but the rest is a decently important Carrollton-Cartersville link.
70-79: I-75
80-89: I-85
90-99: I-95
100-119: GA 112? It's pretty long, at least.
120-139: US 129
140-159: GA 141
160-179: GA 166
180-199: I-185
200-219: GA 212, with honorable mention to GA 204
220-239: US 221
240-259: GA 247 Connector, which links Robins AFB with I-75.
260-279: GA 260. No, I'm kidding, it's US 278.
280-299: I-285
300-319: I'm going with GA 300 because it's an independent route from I-75 all the way to Albany, whereas most of GA 316 is also US 29.
320-349: US 341
350-399: Not much to speak of, since GA 365 has no independent mileage. I guess US 378?
400-449: GA 400, but only if you include the part that's also US 19. If you're just looking at independent 400, then I'd give the nod to US 441.
450-499: I-475
500-599: Does GA 520 get top billing over US 82? If so, I'd probably go with that; otherwise I-575.
600-699: I-675, which is the only number in this range
700-899: no numbers in this range
900-999: I-985, which is the only number in this range

[jemacedo9]

Here's my take on PA:

0-9: US 1
10-19: US 15
20-29: US 22
30-39: US 30
40-49:
50-59: PA 51
60-69: PA 61
70-79: I-76
80-89: I-81
90-99: I-95

Most of the decades have fairly clear winners. The 40s, 50s, 60s, and 80s are a bit more muddled.

I'm giving PA 51 the nod as a significant route into Pittsburgh that, with the northern routing of the Mon-Fayette now fixed to Monroeville and not Pittsburgh, will remain a major radial into the city for years to come.

If I was answering this question prior to 2009, I probably would have listed PA 60 as the most important route in the 60s because if its vital role in connecting Pittsburgh with its airport and western suburbs–as well as its role as PA Turnpike 60. But now having been truncated to being a local route merely connecting Crafton, Moon, and Robinson, I think the longer route of PA 61, being the transportation spine of Schuylkill County and connecting the Central Susquehanna Valley with Pottsville and Reading, is more important.

The 80s decade also presents a difficult decision. I originally picked I-80 but changed it to I-81. I-80 is clearly the longer of the two and has the fewest nearby alternate routes. Both I-80 and I-81 are significant corridors for cross-country trucking. But what I think tips the scales in I-81's favor is its significance in both the Harrisburg and Scranton/Wilkes-Barre metro areas.

I agree with all of the above. 
I struggled a little with 0-9, as PA 8 is pretty important for a Pittsburgh-Butler connection, and a I-80 to Franklin/Oil City connection, but I think US 1 is slightly more important.
40-49: I'd go with PA 43 since it's a freeway/tollway.
50-59: I thought about PA 56 because for the Johnstown area, but I think PA 51 wins out.
I had the same struggle w/ I-80 vs I-81 and had picked I-81 before I saw your post, for the same reasons.

[briantroutman]

40-49: I'd go with PA 43 since it's a freeway/tollway.

I didn't realize until now that I had just skipped the 40s. But yes, I agree: PA 43.

[Max Rockatansky]

CA

0-9: I'd pick Interstate 5. Interstate 8 is a close second.
10-19: Again, the interstates. 10 or 15.
20-29: 22 is a heavily traveled Orange County freeway.
30-39: I'd go with 37, along the north side of San Pablo Bay.
40-49: Interstate 40, but 49 is a very scenic highway and quite important.
50-59: US 50, but 55 and 57 are two other SoCal freeways of importance.
60-69: Either 60 or 65.
70-79: Probably 74 or 78.
80-89: Quite a few. 80, 85, 87, 89 all come to mind.
90-99: 99

You have me intrigued with this one.  I'll probably do the whole state tonight but I don't know if I would agree in all circumstances that an Interstate/Freeway would trump the importance of a major rural corridor line 25 or 33.  Personally I think I-8 and I-40 are way over valued and don't serve much of an in-state purpose.  I would definitely pick 58 over 50 or 57 given that it is a way more serviceable all year pass in the Sierras. 

[TheHighwayMan3561]

MN:
1-9: Tough call between US 2 and MN 5, because 5 gets the airport and downtown St. Paul.
10-19: US 10
20-29: MN 23
30-39: I-35
40-49: MN 47
50-59: US 52
60-69: Toughest group with three candidates. Probably MN 62.
70-79: MN 77, edging out 71 and 75
80-89: Hard because none in this group are overly significant. MN 89 by default.
90-99: I-94
100-109: MN 100

[froggie]

I'll bite...

Vermont

0-9:  This is probably the most difficult one, as cases could be made for both US 2 and US 7.  Given that what had previously been the main part of US 2 got superceded by I-89, I'll say US 7.
10-19:  I'd give the edge to VT 15.
20-29:  VT 22A.
30-39:  VT 30 by far.
40-49:  VT 44 is the only one that exists.
50-59:  VT 58 is the only one that exists as a state-maintained route (there's also VT 53, but it's entirely town-maintained).
60-69:  VT 62.
70-79:  VT 73.
Last two categories don't apply...there are no VT state routes between 78 and 100.

-------------------

Minnesota

0-9:  To me, it's a toss-up between US 2 and MN 7.  I'd personally go with MN 7. (EDIT:  I didn't go with MN 5 because that's largely local to the Twin Cities area.  MN 7 both serves the Metro and western Minnesota)
10-19:  I'd go with US 10.
20-29:  Definitely MN 23.
30-39:  I-35
40-49:  I'd go with MN 47.  It's the longest of the ten and serves the Twin Cities Metro.
50-59:  A case could be made for US 52, MN 55, or US 59.  I'd go with US 52, as it's the main route between the Twin Cities and Rochester (largest MN city outside the Twin Cities).
60-69:  Cases could be made for MN 60, US 61, or MN 65.  From a historical perspective, definitely US 61.  I'd stick with that today. (EDIT:  didn't go with MN 62 because it's DEFINITELY local to the Metro)
70-79:  US 71.  Though US 75 is longer, US 71 hits higher-population municipalities. (EDIT:  same situation here with MN 77...specifically local to the Metro and not really even in the top 10 within the Metro)
80-89:  MN 89.  None of the other MN 8x routes really amount to anything.
90-99:  I-94

[GaryV]

Michigan:

0-9: M-1 Woodward Avenue
10-19: US-10 (an edge over M-10 for me)
20-29: US-23
30-39: US-31
40-49: US-41
50-59: M-55 (I guess)
69-69: I-69
70-79: I-75
80-89: M-81 (tough to choose)
90-99: I-94 (I-96 would also be a good choice)

[NWI_Irish96]

Indiana

0-9: US 6
10-19: IN 18 (not a lot of good choices here)
20-29: US 20
30-39: US 31 (US 30 a close second)
40-49: US 41
50-59: US 50
60-69: I-65
70-79: I-70
80-89: I-80
90-99: I-94 (since I-90 is mostly duplexed with I-80)

100-199: IN 135
200-299: US 231
300-399: IN 331
400-499: I-465
500-599: IN 550 (western)
600-699: IN 641
700-799: IN 727 (by default)
800-899: I-865
900-999: IN 930 (until 912 is connected again)

[Flint1979]

Michigan

0-9: M-1
10-19: M-10
20-29: M-28
30-39: M-37
40-49: M-46
50-59: M-55
60-69: I-69
70-79: I-75
80-89: M-85
90-99: Probably a tie between I-94 and I-96

[jp the roadgeek]

I'll take a shot at CT:

0-9: 3-way tie between 2, 8, and 9.  All serve essentially the same function: getting traffic from inland cities to the CT shore via expressway

10-19:  CT 15.  The Merritt/Wilbur Cross is an important alternate to I-95 and I-91.

20-29: A slight edge to CT 20 over CT 25 based solely on the significance of the Bradley Connector.   The latter would win if it were a full expressway to I-84, and most would just assume that its designation be eliminated along the 8/25 duplex.


30-39: CT 34.  Important link from upper Fairfield County to the New Haven area

40-49: US 44.  Pretty much by default.  CT 40 is an insignificant expressway and the rest are pretty rural.

50-59: CT 53, with 57, 58, and 59 slightly behind.  Tie goes to the longest length, and they're all Fairfield County North-South arterials.

60-69: CT 63.  Arterial linking New Haven area with the Waterbury/Naugatuck Valley and Litchfield County.  Slight edge over CT 66 and CT 68 (66 would have won in the pre I-691 days)

70-79: CT 72  The expressway between New Britain and Bristol gives it the edge over CT 71 and CT 74

80-89: I-84 (of course).  CT 85 is second based solely on the non-completion of CT 11.

90-99: I-95.  The Main Street of the East Coast.  I-91 is second, CT 99 a distant 3rd, and the rest off the radar

100-109: CT 101.  Part of the most direct link between Hartford and Providence.

110-119: I suppose CT 110 by default, followed by CT 114.  Most of these are rural roads

120-129: None really that major here.  I supposed CT 123 gets the nod over CT 124 because it extends into NY state.

130-139: CT 137.  Serves downtown Stamford.  CT 138, though it's part of an MSR with RI and MA, serves very little function in CT.

140-149: None serve much purpose other than minor arterials or coastal loops, but give me CT 148 if only for the Chester-Hadlyme ferry.

150-159: I'll give it to CT 154 based on length.  While CT 159 is an important link to Six Flags across the MA border, CT 154 gets the nod as a coastal loop and a scenic alternate  (and former routing) to CT 9.

160-169: CT 167 gets a slight edge over CT 160.  Both are arterials in the Hartford area.

170-179: CT 175 slightly over CT 173.  CT 175 is part of a southern bypass of Hartford that I use often when I-84 is clogged.

180-189: CT 187 by a nose over CT 189.  Both serve the same purpose, but the businesses along Blue Hills Ave give 187 the edge.

190-199: CT 190.  Northern tier alternate that can act as a shumpike to the Mass Pike for those going from the Enfield area to eastern MA.  CT 195 is second only because it connects I-84 to the UConn campus.

200-209: I'm going to hold my nose here because of it's frequent redundancy with other routes, but US 202.  The rest of the routes here are out in the sticks.

210-219: CT 218.  The de-facto northwest quadrant of the I-291 beltway

220-229: CT 229.  The road to ESPN and Lake Compounce amusement park from I-84, plus it's becoming an alternate in Southington to the often jammed CT 10 (Queen St.).  CT 220 is multi state and serves Enfield Mall and a prison, but is pretty rural away from the mall.

230-239: CT 234 by default.  No others exist.

240-249: CT 243.  An alternate to CT 34 connecting New Haven with the Naugatuck Valley.

250-259: CT 254 by default. No others exist.

260-264: CT 262, only because it has an interchange with CT 8 and is signed better than the other option, CT 263

270-279: CT 272 over CT 275 based on length.  Neither is significant

280-289:  CT 287, based on it being in a slightly more urban area than CT 286 and CT 289

290-299: I-291 by default.  No others exist.

300-309: CT 305.  Although shorter than CT 302, it has an interchange with I-91 and businesses along it.

310-319: All serve very little purpose, but I'll go with CT 314 as it is a nothern extension of the Berlin Turnpike, and Jordan Lane serves a couple of CT state offices.

320-329: CT 322.  Was CT 320 until CT 322 took over CT 66 through Southington/Cheshire.  Both have truck stops along their paths, but CT 322 has more retail.

330-339: CT 337, only because it connects I-95 with Tweed-New Haven airport

340-349: CT 349, as it serves Groton-New London Airport and Groton City.  CT 341 is longer but rural, and CT 343 is a stub end to NY 343

350-359: CT 354 by default.  No others exist

360-364:  CT 364.  CT 361 is the other choice and would have won if NY hadn't decommissioned its route.  Both are glorified town roads, and CT 361 is intratown.

370-379: CT 372 by default.  No others exist 

380-389: I-384 by default.  No others exist.

390-399: None

NOT DOING SSR's and SR's so none for 400-679

680-689: I-684 by default (even though it's only accessible from NY)  No others exist.

690-699: I-691 by default.  No others exist

[Thing 342]

Here's my take on Virginia:

0-9: US-1 (Also considered: VA-3, VA-6, VA-7)
10-19: US-13 (Also considered: US-11, US-17)
20-29: US-29
30-39: US-33 (Also considered: VA-33)
40-49: US-48 (Also considered: VA-40, VA-48)
50-59: US-58 (Also considered: US-50)
60-69: I-64
70-79: I-77
80-89: I-85
90-99: I-95
100-199: VA-168 (Also: VA-150, VA-164, I-195)
200-299: I-295 (Also: I-264, VA-286)
300-399: I-395
400-499: I-495 (Also: US-460)
500-599: I-564
600-699: I-664
700-799: VA-785 (Also: various secondary routes in Northern Virginia)
800-899: VA-895

[KeithE4Phx]

Arizona
0-9:  I-8, by default, since it's the only single-digit Federal or state highway in Arizona.
10-19:  I-10, the only cross-country highway in the state.
20-24:  AZ 24, our most important off-ramp (Loop 202 to Ellsworth Rd. in Mesa).    Also the only AZ 2x.
30-39:  None exist yet, although AZ 30 will be the only one so far, once it's built.
40-49:  I-40, another default.
50-59:  AZ 51, the Piestewa Freeway in Phoenix. Again the only one.
60-69:  US 60, the only non-Interstate that completely crosses Arizona.
70-79:  US 70, because all state highways in this range are essentially secondary roads.
80-89:  AZ 87, the Beeline Highway.  The main road to the NE from the Valley.
90-99:  US 93, at least for the time being.  It'll eventually become I-11.
1xx:  AZ Loop 101, the freeway around Phoenix.  Honorable mention:  US 191, the former US 666.
2xx:  AZ Loop 202, the freeway around the SE Valley. Honorable mention:  AZ 260, the road on the Mogollon Rim.
3xx:  AZ Loop 303, which isn't a loop at all.

All numbered highways above 400 (what few there are) are secondary roads.  Not worth mentioning here.

[Hurricane Rex]

Oregon:
1-10: I-5
11-20: US 20
21-30: US 26
31-40: OR 35 but you could easily say OR 38
41-50:  OR 42
51-60: OR 58
61-70: OR 62
71-80: OR 74
81-90: I-84
91-100: tie: OR 99(W) and US 97
101-110: US 101
111-130: OR 126
131-140: OR 138
OR 141
151-200: US 197
201-210: I-205
210-220: OR 217
220-230: OR 224
231-240: OR 237
241-250: OR 242
250-300: OR 260
301-399: OR 380
401-499: OR 402
500-599: OR 569

LG-TP260

[oscar]

Alaska's list is really short.

1-10: AK 1
11-20: AK 11 (only route in that range)
91-100: AK 98 (only route in that range)

Nothing 21-90, or over 100 unless you count forest service roads

Hawaii:

1-10: Interstate H-1
11-20: HI 11
21-30: HI 30
31-40: HI 37
41-50: HI 50
51-60: HI 56
61-70: tie between HI 61 and HI 63
71-80: HI 76
81-90: HI 83
91-100: HI 99
100s: HI 130
200s: HI 200 across the Big Island, though Interstate H-201 on Oahu carries much more traffic
300s: HI 360
400s: HI 450
500s: HI 560
600s: no routes
700s: HI 750 (only route in range)
800s: no routes
900s: HI 930
1000s: short, unsigned HI 1370 (service road for Hilo airport; only one other HI 1xxx, which is also unimportant)
2000s: HI 2000
3000s: HI 3000
4000s: no routes
5000s: unsigned 5600 (only route in range)
6000s: no routes
7000s: HI 7101
8000s: HI 8930 (only signed route in range)
9000s and above: no routes