[meric]

One example I can imagine you can help with: if your city doesn't have it, you could put its train timetables in an app. There's one for Sydney, it's called TripView. A train timetable available in a convenient manner will help people rely on trains more and reduce CO2 emissions.

[a-fried-egg]

If you develop an API for it and everyone can use the data all over the place freely and easily, that could help.

[quickthrower2]

Google maps does a reasonable job of finding a public transport route. Should work anywhere right?

[y3k]

This sounds pretty nice, sadly the city were I live has no trains, cars only.

Thank you for the suggestion.