You can build whole cities without cars in Cities Skyline. With mods like TPME banning private cars is easy. You can still allow services (police, fire engines, ambulances, etc), good trucks, buses and taxis but can also disable any of these on a per-road basis.

I like to create areas that have no cars in my cities. Add lots of pedestrian and cycling paths, lots of trains, metro, ferries, etc and just watch oodles of people using public transport or cycling everywhere.

It's such a satisfying game.