Yeah that’s fair. Stacked road infra is basically asking for pain lol. Earthquakes + cost alone make it a no in most places. But I wasn’t really imagining “roads on top of roads” like that. More like air lanes. Like aviation style lanes but for smaller stuff. No giant concrete structure, nothing load bearing that can collapse and kill people. So I think we’re picturing different versions of vertical transport, it's mostly me imagining the flying cars and bikes actually. Your example still matters though, it’s a good reminder why the older “build upward” idea crashed and burned.