[mchannon]

The farebox already gathers this information in the case of buses; paper ticket and check-in/check-out systems are less precise (which train are you getting on?) but likewise gather this information. Most of the time this information is not passed along to a server. Duplicating this effort via a voluntary app doesn't seem particularly helpful.

Aside from the agoraphobics among us, most people are in way too much of a hurry to let standing-room-only transit deter them from making a connection. So your target market (people who want to ride an empty bus so much they're willing to wait for one) is already quite limited.

What this information is useful for (and is probably used extensively by some transit agencies) is planning routes, adding buses, trains, and train cars. Evidence (full buses!) suggests that many transit agencies could be doing a much better job coordinating larger bus sizes and more train cars during rush periods. Too bad there's not an app for that that the regular transit rider can employ.