This is really where OLED is the right answer, I think. On smaller devices it's more or less entirely replaced 7-segs and similar displays. High contrast, high legibility, high resolution, but high cost. But if you're considering the cost of a monochrome/limited-colour OLED vs an LCD against the rest of the cost of upgrading a bus stop signage display the differential won't be a huge factor - labour, metalwork, etc will be. I've also seen high-resolution signage-oriented LED/LCD displays used for this sort of thing successfully.

Oxford's travel signage has always been a bit crap, though (and not alone, of course, in this - lots of places in the UK and Europe (and I'm sure US) have crap signage following similar patterns).

The amber matrices were at least clearly readable, but the presentation of information left a lot to be desired. Even on legible displays, constant scrolling displays that alternate between scrolling directions for different text displays for no good reason, and other such madness make it so hard to actually get information about stops that I ended up writing my own wrappers around APIs/website scraping to make a legible display on my phone.

This sort of thing should really be considered in terms of accessibility - for able-bodied people with good eyesight and a quick mind these displays may be legible, but a good % of your users are disabled, elderly, etc - none of the moving display, low-viewing-angle, small-text displays will be usable, but partially sighted/elderly people will generally make do with big friendly text that doesn't change except when it needs to.