I am fortunate that for road riding, I can just ride from the house. I'm loathe to drive to ride. But, there are two general types of rides for which I'll put my bike in the car: 1) gravel/mtb rides, and 2) rides on my TT bike.

Luckily, there are two fairly large state parks within a 40 min drive that have reasonable roads and sufficiently low traffic levels that I can comfortably ride the TT bike in the aero position. Within an hour's drive, I can also be far enough out in the country to have pretty good roads to train on the TT bike.

The point: you may have to drive to get what you need.

Use strava heat map. Search your town, click on the bike icon. That is my best place to start to see the most frequently rode routes. Or I'll look for one open road with a wide shoulder that I can ride out and do a U-turn and come back.

I drive to a local road that’s used for a 7.5 mile out and back TT. It’s quiet, little traffic and mostly flat.
I use a 1 mile section in the middle which is totally flat for Notio testing.

Depends a great deal on where you live. In general, you need either a good rails-to-trails option or way out in the rural countryside.

I live near a major city, so I have to drive 60 to 90 minutes to get to an area rural enough that I can do long and steady efforts. My rails-to-trails path is excellent also, but it is about a 45 minute drive to get to the sections suitable for a good TT ride.

If you post an area or city, perhaps we can make a few suggestions.

Strava premium can folter segments in the app by distance. Making them longer than 5mi gets rid of a LOT often revealing the good TT roads.

I’ll second the comments about expecting to drive a ways, and finding an out-and-back.

I’m in southern Connecticut and I have to drive 45 minutes to the one TT spot I’ve found. It’s part a well known motorcycle and cycling route, and I’ve found a flat 4 mile stretch with no stop signs, stop lights, and generally a decent shoulder. Also hills at both ends to aid in turnarounds. I’ve gotten good at both turn-arounds and have averaged 25 mph for 40k in spite of them (the limiter is my fitness and not the course).

It took me several months of looking to find this stretch. It’s far from perfect, but if there’s another road this good within an hour of here I’m yet to come across it.

Point here is, these can be very hard to find, and you’ll almost certainly have to make compromises, as far as requiring turnarounds or other annoyances. Maybe there‘s one intersection where you have to slow down and occasionally stop. Don’t give up but don’t expect perfection, just ride safe within the limits of the course and learn to navigate it better and better over time. You can build riding/racing skills beyond just all-out power & aero.

Also, AllTrails and TrailLink apps can be helpful for finding road-bike friendly routes. (TrailLink focuses on rails-to-trails, though includes other trails as well).

Thanks for all the suggestions so far, this gives me a good place to start.

I live in Minneapolis if anyone knows of some roads around there

Huh, I'd think you'd have good options with all of the rail trails and roads around lakes there -- can you make a right-handed loop around one of the lakes on roads? Or use one of the river parkways? Maybe these are no good because there are too many recreational cyclists or pedestrians or the pavement is not good enough or some combo thereof. Strava heatmaps looks dominated by all the rail trail routes, so might be hard to use if you want something on roads and/or if the rail trails all have stop signs that make a TT effort no dice.

If you're willing to do a lot of repeats of a loop, look for something small with smooth right-handed turns where pedestrian/slow cyclist interference is unlikely. You might search to see if there are any nearby very nontechnical cycling crits with smooth turns. And you can scope out road quality and lights on google maps. Good luck, a little bit of searching on Strava/Google maps suggests this will be trickier in your area than I initially thought!

I drive 30 miles outside of Chicago where there is an 8-mile loop that is free of potholes, has a wide shoulder, is mostly straight, and has few cars. I've done that loop for a century ride, which is its own kind of crazy. But if you want to get real practice holding the aero position and not put your life at risk, what choice is there? I'll say that I discovered that spot by doing lots of group rides with friends. You can use Strava heat maps to give you a general idea of popular spots, but given the very specific conditions one needs to hold aero position safely, I don't know that there is any substitute for simply exploring the roads.

Use the USAT website to find tri or duathlons. Their bike courses might be good bets.

Near you I found the "Maple Grove" tri and then zoomed in and found an 11 mi segment that appears to have a lot of "same day" times on the leaderboard, meaning a race.

https://www.strava.com/segments/24787374

same recommendation from me

i only ride my TT bike on 2 routes....both have really wide shoulders so not mixing with traffic.

1. used for the state 20K TT and multiple Tris and Dus. 2x7.5Miles of rolling hills with a 10 ft shoulder to ride on. My spot for 15 mile or 30 mile "TTs".
2. local flat course used for TTs. Up to 13 miles in each direction with a really wide shoulder to ride on. My spot for 20 mile "TTs".

Both are next to state parks - so somewhere to leave the car; and have restrooms and stuff. Lots of other cyclists do the same here - always others on the course.