For each state, what is the most important route that never enters it?

[ethanhopkin14]

For Louisiana, I'd think I-65's probably the way to go. One could probably make a case for I-45, though.

I say I-45.

[doorknob60]

(...) WA-14 are just as good of contenders. WA-14 gets points for being a major detour route if I-84 has to close in the gorge. Whether it be for general winter weather, wildfires, derailed trains, etc., I've seen WA-14 used as a detour for I-84 many times.

Just 2 days later, a landslide has closed Eastbound I-84 and proven my point. I'm pretty convinced that WA-14 is the most important out of state highway in Oregon (though I still think I-80 is a strong contender). Here's a fun look at the traffic on the Bridge of the Gods detouring there.




For what it's worth, WA-14 is also closed further east from the bridge (just beyond Stevenson), so all traffic heading east of there (eg. to Hood River/White Salmon or beyond) must cross over to Oregon and can't continue on WA-14. Someone travelling from Troutdale, OR to White Salmon, WA would be required to cross the Columbia 3 times and pay 2 tolls (unless the bridges are waiving them, which I don't think they are).

[MikieTimT]

Interesting topic. I'm doing all the states where I lived.

I never lived in Arkansas, but I'm going to say it's I-69 because they're obsessed with it coming to their state.

I wouldn't say at all that Arkansas is obsessed with I-69.  Funding priorities for the next 20 years indicates that Arkansas is obsessed with its 4 corners with expanding the roads connecting Little Rock to anything else, 4 lanes program, I-49, and I-57.  With the exception of the lightly populated area that I-69 would travel through, the rest of the state could care less other than the thought of interstate traffic that won't traverse I-49 or I-55 having a way to bypass Little Rock.  If there's an obsession in this state, it comes from the capital hoarding the vast majority of the highway funds.

[Avalanchez71]

For Iowa: I-88. Drops you right into downtown Chicago, plus almost any other regionally significant roads that Iowans use would just go through the state.

For Florida: Honestly, I got nothing. This is a tough exercise for a state in the corner of the country with a bunch of road connections to many different places.

Here's my options for FL:
I-24: Part of fastest route from FL to most points northwest of the state, notably cities in the Midwest west of Ohio like Indianapolis, Chicago, St. Louis, Kansas City, Minneapolis, and even a far flung city like Seattle
I-77: Part of fastest route from FL to cities like Charlotte, Cleveland, Pittsburgh, Buffalo and Toronto

It really depends on what part of Florida you're talking about. As for the Panhandle/Emerald Coast area ("Redneck Riviera" ), I would say I-65 and I-85 are the most important out-of-state roads. Those highways meet in Montgomery, Alabama; from there, US 331 takes off heading south through Luverne, Opp, and DeFuniak Springs before eventually meeting US 98 east of Destin. I'm sure that for that reason, the two interstates that I mentioned are rather crowded during spring break, and also throughout the summer. Is that right?

Yes, I-65/I-85 are the choices for the panhandle. I was only thinking of the main penisula part of FL (not sure if there's a better name), which you already have I-75 and I-95 for N-S traffic from there. Of course those two routes aren't as viable for the panhandle compared to I-65 and I-85. I just ended up choosing 2 of the closest main feeders for I-75 and I-95 into FL, which I had as I-24 for I-75, and I-77 for I-95.

Throw in US 31.  The tip of US 31 just barely misses FL.