Writing fanfic as a non-US citizen like
In case anyone actually wants to know the answer: it’s the plot of Cars.
The difference is literally the plot of Cars.
Highways are usually two-to-four (at the widest) lane roads that meander the US landscape. Think Route 66, dinosaur statues, mom-and-pop diners, southern gothic. There are state-level and national-level highways. Some run for a 100 miles, some, like US HWY-17, run most of the East Coast:
That red line is US HWY 17. If you follow it, you will go through tiny towns. You may hit stoplights. I kid you not, you will see spinning cows on poles. Businesses exist along highways that you are encouraged to pull over and visit. They were designed to let you see America.
Now, interstates were made in the 50s and were made to get people from Point A to Point B. These suckers range from four lanes to eight lanes around big cities. They cut through everything. If you want to get to a business, you have to take an exit ramp and detour. They are great for getting places fast. You can still have weird experiences on them, but usually at night, when your eyes start playing tricks on you. Or there are deer.
I-95 is a massive corridor that runs from the Florida Keys to the Canadian Border. You can see the difference just looking at the maps.
As far as writing goes:
If you want quirky character development inside the car, you’re looking for an interstate. The majority of Americans take interstates to go on road trips.
If you want mysterious and/or supernatural hijinks, you’re looking for a highway. They are weird, weird places, and they’re surprisingly easy to wind up on if you leave the interstate.
(Even in America, no one’s really sure what a freeway is. Just ignore it.)
….Honestly the word you use seem to be dictated by where you live.
To me, everything is a highway. Everything. I’ve never used the word freeway or interstate in my life.
But I’ve found people in/from other regions will use one of the other words as a catch-all.
Yeah pretty much everything to us is “the highway”, even Interstates and freeways. Also, if you’re writing people travelling, most of the time we just refer to the highway/interstate by the number. Like unless you live in the middle of nowhere where “the interstate” is literally the only road that isn’t made of dirt, people will say “Oh, you’ll need to take 376.” or “Which exit is 80 from 79?”. Because between Interstates, highways, freeways, state routes, and every other road that’s numbered, if you just say “the highway”, no one will know which one you mean.
As for freeways, some highways you have to pay to drive on. Those are called tollways and ones you don’t have to drive on are freeways. But that’s also kind of regional because not everyway has tolls so it wouldn’t make sense to differentiate. Also some highways have express lanes in the middle called an expressway.