The hospitals in my nearby city have their own BRT which is open to public use, and joined to the city's ticketing system. It shuttles between them and various key locations, and is of course wholly subsidized for the intended users.
Despite being the only BRT here it pretty much goes everywhere it should, skipping the usual traffic, and as a result gets a lot of use.
If the users were limited to the regular transportation I think they would just all drive - while there are a lot of routes here they're not entirely pleasant to use IMO and almost always get stuck in traffic