I disagree with a completely free public transport. Paying creates an entry barrier that suppresses traffic surges and misuse. Instead you can offer free ticket

I disagree with a completely free public transport. Paying creates an entry barrier that suppresses traffic surges and misuse. Instead you can offer free tickets to those who actually need them and subsidize it enough to be a competitive choice regardless of free tickets. An example of what I mean: one time I was returning home from the airport with the bus after a long flight. The bus was already packed at the airport, but as it crossed the city, a bunch of youngsters started entering without tickets, turning a mild inconvenience into a 90 minutes of living hell. Many of them used the bus for a mere 1-2 stops, others took this (more expensive) express bus instead of the regular one, and some were just joining for fun (I think this was after a football match or something). Point being: having to pay optimizes usage.