Fair, I am in Europe, and at the stop, the bus will stop to accept the fares, one by one, there are NFC cards which make a particular noise if you want to fast pass - bad noise if you don't have the money on the card, nice noise if you do.

But I will be the first to admit our public transport would not be the most punctual!

- EDIT: And if someone wont pay, and it delays the driver leaving, the other people on the bus start shouting at the person who wont pay! Or in certain times, pay for them :)