https://practical.engineering/blog/2024/8/19/why-are-texas-interchanges-texas-so-tall
There's a video and a transcript. The author also name-checks Brian Purcell (Texas Highway Man (https://www.texashighwayman.com/about.shtml)).
(the URL name-checks Texas twice :-)
I thought the overview of interchanges was good for a non-enthusiast audience. The ultimate answer of "you need at least 16 feet clearance between levels, and Texas has five levels for frontage roads" seems a bit surface level for me though. It dodges the underlying question of "why is Texas's government willing to spend billions of dollars on overengineered interchanges, just to run frontage roads through them?"