I've never had a Mega Drive before working on this, so I wasn't really familiar with a lot of its games.

I took a quick look at F1 just now though. The way it makes use of the nametable and patterns is very similar to what I do. There are precomputed fully solid patterns at a fixed location and the non-solid patterns seem to be bump allocated.

It makes use of both layers though, drawing the street on one and everything else on the other. I think it uses per scanline scrolling to apply correct perspective to the street.

I can't say anything about how it actually renders into the tile map for now. That would require a lot more than looking at the VDP (graphics chip) debugger in an emulator.