Hard disagree there. Driving on the interstate south of San Antonio, there are these overpasses that are, inexplicably, on the highway itself. These are artificial hills that are steep enough at highway speeds, that your visibility is made shorter than your stopping distance. You can’t see past the top until you’re there, and they completely obscure the entire highway on the other side because it’s so straight. Obstructions, stopped vehicles, pile ups, anything could be on the other side and you wouldn’t know. Anyone on cruise control or driving a semi has their trip peppered with these possibly lethal moments at regular intervals.
Everywhere else I’ve been in the lower 48, (slower) local roads pass over freeways, because it literally takes less dirt to make that safe.