“Before introducing free public transport, the city center was crammed with cars. This situation has improved — also because we raised parking fees. When non-Tallinners leave their cars in a park-and-ride and check in to public transport on the same day, they can’t only use public transport for free, but also won’t be charged the parking fee. We noticed that people didn’t complain about high parking fees once we offered them a good alternative.”
https://popupcity.net/estonia-to-become-the-worlds-first-free-public-transport-nation/