Can you use actual real locations and city layouts in game legaly

This is not a Unity specific question and should be either asked in the forums or somewhere entirely different.

But as an advice: Always assume that everything already created (physical or digital) is copyrighted and not legal to use unless it specifically states otherwise. Do not trust legal advice that says you are allowed to do something unless linked to the specific document/law/ToS that states it explicitly.

but then how does a game like sim city get around the copyright?

As I said: You have to assume you are not allowed. Not that it isn't allowed.

Sim City (EA) is most likely paying the copyright holders to use the assets, or something similar. You always need explicit permission from the copyright holders to use their material.

I can't see how city plans for unplanned cities can be copy-written. Do some research ;)

The other issue here is that even if the layout of the actual streets is considered public domain, are you going to survey it for yourself?

If not then you should check the terms for your data source e.g. OpenStreet$$anonymous$$aps or Google $$anonymous$$aps.