Open world racing game optimization strategies?

I wasnt quite sure where to put this, but i guess here is fine.
I’m planning to make a racing game, and im gonna be busy with the physics and systems for a while, but Ive been wondering how you best build an environment/city for a racing game.
It has to be quite big of course, because of the speed and has to look good enough, but i expect you can cut corners (wow unintended racing game pun) because of the speed too, when you go past everything so quickly. Has anyone had experience with that, just some general advice, what kinda assets to use, how to set up level streaming etc. just some general stuff on how to make a big map for a racing game without sacrificing too much detail or performance.

It would vastly depend on the game.

if you are racing in the streets, then buildings with multiple LODs are a prerequisite. They just cannot pop at all or they destroy the feel of the game.
you may be able to get away with only using impostors if you have a MonteCarlo type race, where the buildings are separated form the tarmac.

if you have a large enough map sectoring and streaming may help, but ultimately, if the speed and size is right, a single map may be best for player experience.

Personally, I think those are all determinations I would make after the alpha is done with, based on the lowest tear PC or whatever I’m interested in supporting.
Afterall, there are tons of tricks one can employ later on, like converting the whole landscape to static meshes and gain a ton of performance…