Madison Metro has fitted at least some of the buses with GPS systems and automatic bus stop announcements. As the bus gets close to a stop point, a cheerful male voice gives the intersection name, and maybe a little extra info: ("East High"). I guess they did this for the blind, though I'm learning the names of a lot of streets I never bothered to learn before.
The installers got the voice and the volume right. You can hear the voice if you want to, or ignore it--it doesn't demand attention. My stop is a left turn across East Washington, so the GPS unit doesn't get close enough to make the announcement until we're already there. I don't think that matters, since the turn is dramatic enough that you can recognize it without seeing it. Or hearing it.
The voice was a bit disconcerting the first day, but now I approve. I hope it was inexpensive. (Found the announcement--display is munged up, though)