We have something like those already. Primary and secondary education are free (and compulsory) and one cannot refuse treatment to individuals in the emergency room.
The appeal of free public transportation, to me, is that it allows more people to take advantage of public spaces and works and, marginally, allows people to bring home more money for the same amount of time worked.
Free public transportation fare incentivizes participation not tuning out like I feel many UBI proposals do. No one is going to look at, effectively, a free metro card then think "Sweet! I don't need to work!"
