The "Mount Rushmore" of roads in every state.

[US 89]

Arizona:

I-17: Arizona's 2DI intrastate interstate, connecting Phoenix with Flagstaff. Major shift in elevation, scenery and culture.

I-15: Arizona's 2DI pene-enclave, basically only accessible by car through Utah or Nevada. Beautiful drive through the rugged Virgin River Gorge

US 191: Over one mile gain in elevation, 400+ slow curves, traversing some of the most remote terrain in the USA along with one of the largest copper mines in the world.

AZ-64: Gateway to the Grand Canyon.

I'd take out I-17 from that list and put in AZ 89A. Awesome and historic drive through the Oak Creek Canyon and Jerome area.

[Max Rockatansky]

Arizona:

I-17: Arizona's 2DI intrastate interstate, connecting Phoenix with Flagstaff. Major shift in elevation, scenery and culture.

I-15: Arizona's 2DI pene-enclave, basically only accessible by car through Utah or Nevada. Beautiful drive through the rugged Virgin River Gorge

US 191: Over one mile gain in elevation, 400+ slow curves, traversing some of the most remote terrain in the USA along with one of the largest copper mines in the world.

AZ-64: Gateway to the Grand Canyon.

I'd take out I-17 from that list and put in AZ 89A. Awesome and historic drive through the Oak Creek Canyon and Jerome area.

That's why I had US 89 on my list.  AZ 89A was US 89A and even has a signed historic segment.  The other US 89A through the Vermilion Cliffs is another top level scenic road.  Either way all of these roads owe their existence to US 89. 

[JKRhodes]

Arizona:

I-17: Arizona's 2DI intrastate interstate, connecting Phoenix with Flagstaff. Major shift in elevation, scenery and culture.

I-15: Arizona's 2DI pene-enclave, basically only accessible by car through Utah or Nevada. Beautiful drive through the rugged Virgin River Gorge

US 191: Over one mile gain in elevation, 400+ slow curves, traversing some of the most remote terrain in the USA along with one of the largest copper mines in the world.

AZ-64: Gateway to the Grand Canyon.

I'd take out I-17 from that list and put in AZ 89A. Awesome and historic drive through the Oak Creek Canyon and Jerome area.

That's why I had US 89 on my list.  AZ 89A was US 89A and even has a signed historic segment.  The other US 89A through the Vermilion Cliffs is another top level scenic road.  Either way all of these roads owe their existence to US 89.

Let me preface  my response by saying I based my decision on current routes of 2019, not former routes that have been truncated or broken up.

Since Route 66 is mostly decommissioned, and more of a national icon, I excluded it.

I'll defend I-17: It traverses part of the major population corridor in the heart of Arizona, and transitions through the majority of climate zones the state has to offer. The juxtaposition of old freeway design (Durango Curve, old Phoenix) against new (North Phoenix, Anthem) is obvious, as well as the cultural shift, from the blue collar inner neighborhoods of Phoenix, to the suburbs of North Phoenix, to the college/hippie/Native culture in Flagstaff. One can get a good picture of what Arizona is all about in a 2-hour drive.

I thought of including 89 but thought better of it due to its close proximity to I-17.

I-15, upon reflection, is more of an interesting oddity than an Icon, so I guess I'll scratch it. In its place I would include 163 in Monument Valley, since it's in so many movies with its images commonly associated with the Arizona Old West. Ironically, the part commonly used in movies is actually in Utah.

[Beltway]

Since Route 66 is mostly decommissioned, and more of a national icon, I excluded it.

Are any segments still posted as US-66?

[Max Rockatansky]

Since Route 66 is mostly decommissioned, and more of a national icon, I excluded it.

Are any segments still posted as US-66?

Most of AZ 66, the Oatman Highway and most I-40 Business routes have US 66 Historic signage in Arizona.  Decommissioned or not the route is very much alive because people want it to be. 

[Konza]

Something has to be said for I-10 and/or Historic US 80.  The railroad that parallels I-10 is the main reason for the Gadsden Purchase, which brought most all of the land south of the Gila River into the United States.

I'd go:

I-10/Historic US 80
I-40/Historic US 66
One of the roads that connects Phoenix with Flagstaff, so either I-17 or Historic US 89
AZ 64 to the Grand Canyon

[vdeane]

I-15, upon reflection, is more of an interesting oddity than an Icon, so I guess I'll scratch it. In its place I would include 163 in Monument Valley, since it's in so many movies with its images commonly associated with the Arizona Old West. Ironically, the part commonly used in movies is actually in Utah.

I don't think I-15 is as illogical as it would seem at first glance.  I think even non-roadgeeks are aware of the scenic nature of Virgin River Gorge on I-15 through Arizona!

[roadman]

Iconic and important - I will argue - are very different!

Iconic for Jersey - the NJ Turnpike and Garden State Parkway are obviously state icons. I'll argue for two lesser ones, though, for their historic value...

- the Pulaski Skyway, a literal landmark and one of the first "superhighways"  in the country.
- The LINCOLN HIGHWAY - now a few different routes in NJ, but we can pull out US 1, famous for many reasons, including it (and its US 9 concurrency) being the site of the first cloverleaf interchange.

The Pulaski Skyway was also mentioned in Orson Welles' 1939 radio adaptation of The War of The Worlds, which is historic for its own reasons.

[FrCorySticha]

A couple thoughts for Montana:

Most important:
US 2: the northern Hi-Line for east/west traffic along the Canadian border (admittedly, a bit of personal bias on this one)
I-94/I-90 west of Billings (Historic US 10): main east/west corridor, connecting the most important population centers.

Most iconic:
Going-to-the-Sun Highway in Glacier National Park: an amazing feat of road-building, and extremely scenic
US 212/Beartooth Highway over Beartooth Pass: arguably one of the most scenic and breathtaking stretches of highway in the US.

[7/8]

If people don't mind me including Canada...

For Ontario:

• The 401: The busiest highway in North America, travels the length of Southern Ontario (along the populated Windsor-Quebec City corridor), the longest freeway in the province. The easiest choice of the four.
• The QEW: Connects the Golden Horseshoe (Ontario's most populous region) and it's one of the earliest divided highways.
• Highway 17: The longest highway in the province, passes through both Northern and Southern Ontario and Canada's capital (Ottawa), the primary route of the Trans-Canada Highway, and the Lake Superior portion is among the most scenic drives in the province.
• Highway 11: A continuation of Yonge St in Toronto that extends all the way to the Lake of the Woods, a majority of the route is part of the Trans-Canada, and the southern portion is an important highway for cottage country traffic.

Honourable mentions:

• The 407: One of the first all-electronic toll roads and an important bypass and relief freeway for the GTA.
• Former Highway 2: Almost entirely decommissioned, Highway 2 was Ontario's main street following a similar route to the current 401.
• The 400: One of the earliest freeways in the province, it's a vital highway for cottage country traffic and will eventually reach up to the northern Ontario city of Sudbury.

[stevashe]

I don't think WA is done yet, so here are the top four:

I-5: The West Coast's Main Street
I-82: Shortcut from Seattle to Salt Lake/Denver
I-90: The longest 2di ends in Seattle
WA 99: Historic N-S route through the state that was taken over by I-5, but still exists in Seattle-Tacoma area, including historic Alaskan Way viaduct and its tunnel replacement

I'd take out I-82 and replace it with WA-20 personally. It's certainly not very iconic and importance is definitely 3rd place to I-90 and I-5. WA-20 as the North Cascades Highway highlights a more scenic route, which is missing from your list.

I'd also maybe consider WA-410 over Chinook Pass which is also very scenic and also offers views of Mount Rainier, the state's highest mountain, to replace either I-5 or WA-99 since they're just different iterations of the same route.

[ipeters61]

I'll do Delaware:

• DE-1 - The route serving every major region of the state: Wilmington/Newark, Middletown, Dover, and the beaches.  It contains two of Delaware's "major" bridges (Indian River Inlet/Cullen and C&D Canal/Roth), is relatively modern, and handles tons of traffic.  When I was doing my MS in Economics at UD, one of my professors (who specialized in Delaware economic history) credited DE-1 to the massive population boom in Sussex County.
• US-13 - Basically the "Main Street" of Delaware, it serves Wilmington, Middletown(ish), Dover, and inland Sussex County.  Until the 1990s, this was pretty much your route between Wilmington and the beaches until you split onto US-113 in Dover.  Now, it mainly serves local traffic north of Camden/Puncheon Run Connector, but I live within 1000 feet of it in Dover and can tell you it is one busy highway.  South of the Puncheon Run Connector, it also connects to Salisbury MD (the other "major city" on the Delmarva peninsula) and eventually to Norfolk/Virginia Beach via the Chesapeake Bay Bridge Tunnel.
• Delaware Turnpike (I-95 MD line to I-295, continuing onto I-295 to NJ) - Forms part of a major route between Washington/Baltimore and points south and New York/New Jersey/New England.  Incredibly busy and important route.  Includes the Delaware Memorial Bridge, the only fixed crossing between Delaware and New Jersey and also the southernmost fixed crossing of the Delaware River.
• I-495 - Serves as a more local alternate to I-95 for Washington/Maryland/Delaware traffic to Philadelphia (I-295 serves as a longer distance alternate, as it's essentially the eastern bypass of Philadelphia).  Also serves the Port of Wilmington.

Yes, I am aware I didn't include I-95 between I-295 and the PA line (i.e. I-95 through Wilmington).  While it is an extremely important local route and I have sat in its traffic during rush hour before, I feel that these roads are really the ones that out of staters would associate with our state.  Also, outside of rush hour, I haven't really noticed much traffic on I-95 through Wilmington.

I'll do Maryland:
...
I-68 or I-70- Gotta give Western Maryland some love too!

Don't forget about the Sideling Hill Rock Cut on I-68!  When I went to Cumberland for the first time I stopped at the rest area at the cut.  I nearly cried (noting that I was 24 at the time).  Not even joking.

[sprjus4]

• US-13 - Basically the "Main Street" of Delaware, it serves Wilmington, Middletown(ish), Dover, and inland Sussex County.  Until the 1990s, this was pretty much your route between Wilmington and the beaches until you split onto US-113 in Dover.  Now, it mainly serves local traffic north of Camden/Puncheon Run Connector, but I live within 1000 feet of it in Dover and can tell you it is one busy highway.  South of the Puncheon Run Connector, it also connects to Salisbury MD (the other "major city" on the Delmarva peninsula) and eventually to Norfolk/Virginia Beach via the Chesapeake Bay Bridge Tunnel.

For thru traffic, US-113 is the overall better thru route rather than US-13, IMO.

[ipeters61]

• US-13 - Basically the "Main Street" of Delaware, it serves Wilmington, Middletown(ish), Dover, and inland Sussex County.  Until the 1990s, this was pretty much your route between Wilmington and the beaches until you split onto US-113 in Dover.  Now, it mainly serves local traffic north of Camden/Puncheon Run Connector, but I live within 1000 feet of it in Dover and can tell you it is one busy highway.  South of the Puncheon Run Connector, it also connects to Salisbury MD (the other "major city" on the Delmarva peninsula) and eventually to Norfolk/Virginia Beach via the Chesapeake Bay Bridge Tunnel.

For thru traffic, US-113 is the overall better thru route rather than US-13, IMO.

My personal experience says the same, as well.  Going from New York/Philadelphia/Wilmington/Dover to Norfolk?  Take DE-1 to US-113, then get on US-13 at the end of US-113.  If I'm going to Trap Pond in the Laurel DE area or even Salisbury MD, I usually take that route (taking East Trap Pond Road from Georgetown down to DE-24) since I honestly can't stand driving US-13 for that long.

However, US-13 serves more significant towns in DE than US-113, which is why I chose it instead.  And I wanted to include one route with more local significance.

[Buck87]

My version of Ohio:

1. I-71
2. The Ohio Turnpike
3. I-75
4. US 23

[nexus73]

Oregon is known for its beauty.

US 101: Some stretches are right on the coast and they have the best views of the ocean.

US 30/I-84: From Astoria to Ontario one can sure see a lot of different natural scenes from the longest bridge on US 101, the Columbia Gorge, NE Oregon's Wallowa Mountains and finally end up crossing the Snake River.  Interesting towns along with PDX await the traveler.

SR 126: Coast Range seasonal changes, Eugene-Springfield, the McKenzie River, the Cascades and Central Oregon lay along this route. 

US 26: From the coast to Ontario, this E/W route offers more to see than US 20, especially in Eastern Oregon.  Some of the types of terrain and natural growth will surprise you out there!  Heading east of PDX you get to see "ski country" and Mt. Hood up close.  For the best stocked high variety general store, stop in John Day.  It is the only town around for a long ways, thus the evolution of that store's inventory.  Believe it or not, you can get a decent catfish dinner at one of the downtown restaurants....in the middle of Eastern Oregon? 

Rick

[Max Rockatansky]

I'd say US 30 has a lot more brand equity as a iconic route given that it was part of the Historic Columbia River Highway.  Not many people drive I-84 for scenery but definitely do on Historic US 30. 

[TheHighwayMan3561]

Heh, no one's tried MN yet.

I-94
I-35
US 169
US 61

[thspfc]

Heh, no one's tried MN yet.

I-94
I-35
US 169
US 61

I'd swap out 169 for MN-61, unless you're counting US and MN 61 as the same route.

[TheHighwayMan3561]

Heh, no one's tried MN yet.

I-94
I-35
US 169
US 61

I'd swap out 169 for MN-61, unless you're counting US and MN 61 as the same route.

For this purpose I was combining the two 61s. 169 is easily the flimsiest of the four anyway and there are a few routes it could probably be swapped with.

[Charles2]

Alabama:

I-65:  Connects the four largest metro areas (Mobile, Montgomery, Birmingham and Huntsville)
I-20:  Not all roads lead to Atlanta, but I-20 connects Tuscaloosa (metro area #5) and Birmingham with Atlanta
U.S. 280:  Not as iconic for the rest of the state, but definitely iconic for the Birmingham area
U.S. 231:  The stretch between Montgomery and the Florida state line is vital to tourism