If you're ever in the flatiron district of NYC, I adore the signals at 23rd street. "The walk sign is on across 23rd street," is a simple message, but the gentleman who recorded it sounds like they remembered at the last minute and pulled whoever from the install team wanted to do it (as opposed to some voice actor or something). The gravelly queens accent makes you feel right at home in the city.

Unless they are located in the stairwells at Hogwarts, it does not seem like those names would change often enough to necessitate adding a network connection as a point-of-failure for this sort of technology. (Which I consider the most important aspect. This is life-or-death tech for a subset of our population, and networks are fundamentally unreliable even if you get the security 100% correct.)