[Question] Open world roads and AI

Been watching a lot of GTA recently. I’m looking for insight on how the GTA road system works. Would it be best to paint roads on terrain for the most part and only use meshes for overpasses and bridges? If so, can someone point me in the right direction for painting roads quickly onto terrain surfaces? I know you can use splines and static meshes to make roads. I’ve seen tons of those on the marketplace.

For getting AI drivers to drive on the road I’m assuming thats through nav mesh and spline boundaries. I’ve seen some machine learning videos out there on it but I’m curious how they did it efficiently for multiplayer in GTA.

Thanks in advance for any advice or direction! :slight_smile: