Holy crap. Now you're digging really deep. lol
the internet man .. once there, there forever.
This kinda bus .. all the rage, everywhere, then gone. everywhere (except down unda -- lasted till 1984, some into the 1970's in a few places is Asia, and still today in South Africa).
could be as simple as the single chassis designs were (1) more economical inherently or by regulation (no passengers can ride in the trailer), and/or (2) the truck/trailer designs were "unsafe" or somehow less economical to large scale commercial carriers, or (3) they just went outta style?
but ..everywhere in less that a decade? its like the Rock that hit the Yucatan and killed all the dinosaurs. everywhere. except in australia where they turned into "budgies"
.
anyway, seems like the tractor/trailer models are coming back? California got it figured out?
2006 - OCTA (Orange Country Transportation Authority)
In the late 80s early 90's, OCTD/OCTA, had some tractor trailer based buses called the SuperBus, which had a White cab over, pulling a coach like low floored trailor. These SuperBuses, ran on the OCTAs Orange County to Downtown Los Angeles route.
I know that Palm Spring based, Sun Transit used them fo a time also, and I believe Disney World also bought so of these SuperBuses.
2014 - Sunline Transit Agency, Thousand Oaks, CA