The tl;dr to the article is "Texas freeways have frontage roads, which add at least one additional level to a traditional stack interchange, and that makes them taller than interchanges in e.g. California.
The broader question I've always had, that's not addressed in the article, is "so why do California and Texas build so many stack interchanges while the rest of the country mostly does not?"
> And the design that generally provides the most capacity, on the smallest footprint, (often for the highest cost), is the stack.
This would explain why there are plenty in coastal California, where there are tons of people to move around and where space is very much at a premium.
That's an interesting thought. Are there statistics out there for "percentage of interchanges that are stacks"?
I've lived in CA and the Northeast. I didn't get the impression that either region uses them preferentially. Certainly I see them more in CA, but I feel like that is probably because the number of interchanges is higher, ha!
The broader question I've always had, that's not addressed in the article, is "so why do California and Texas build so many stack interchanges while the rest of the country mostly does not?"