Yeah I grew up hearing that "The optimal price of public transit is free".
The one pitfall I was told about was something called a "free-rider problem", which in this specific context doesn't have its normal economic meaning and refers to people taking up public-transit resources while not actually trying to get from Point A to Point B.
Just for example, if your transit is clean, safe, supervised, a moderate temperature, and has long journeys, what fraction of its users will be using it to get somewhere vs. using it because it is a safe place to be?
In the Bay Area, there is "Hotel 22", the Santa Clara Valley Transportation Authority #22 bus from Eastridge Transit Center to Palo Alto Transit Center, about a two-hour ride running 24 hours a day (see e.g. https://www.telegraph.co.uk/news/worldnews/northamerica/usa/... or https://www.mercurynews.com/2013/10/31/homeless-turn-overnig... - a safe warm place to sleep for $6).
In Pynchon's "V" there is Benny Profane "yo-yoing" on the 42nd Street Shuttle from Grand Central to Times Square, but his contemporaries were certainly finding shelter there: https://harpers.org/archive/1956/03/subways-are-for-sleeping...
These aren't necessarily bad side effects but understanding how folks will use the system when it's free is an important part of making the policy decision to make it free.
The one pitfall I was told about was something called a "free-rider problem", which in this specific context doesn't have its normal economic meaning and refers to people taking up public-transit resources while not actually trying to get from Point A to Point B.
Just for example, if your transit is clean, safe, supervised, a moderate temperature, and has long journeys, what fraction of its users will be using it to get somewhere vs. using it because it is a safe place to be?
In the Bay Area, there is "Hotel 22", the Santa Clara Valley Transportation Authority #22 bus from Eastridge Transit Center to Palo Alto Transit Center, about a two-hour ride running 24 hours a day (see e.g. https://www.telegraph.co.uk/news/worldnews/northamerica/usa/... or https://www.mercurynews.com/2013/10/31/homeless-turn-overnig... - a safe warm place to sleep for $6).
In Pynchon's "V" there is Benny Profane "yo-yoing" on the 42nd Street Shuttle from Grand Central to Times Square, but his contemporaries were certainly finding shelter there: https://harpers.org/archive/1956/03/subways-are-for-sleeping...
These aren't necessarily bad side effects but understanding how folks will use the system when it's free is an important part of making the policy decision to make it free.