It's not a binary thing "cars" vs. "not cars at all". Inside the "superblocks" is possible to use the car. Is just that you can't go anywhere except around the super-block and you have to drive in a slow pace.
Parking is also restricted to neighbors and short times for loading and unloading goods or people.
All that, disincentive cars going there except for specific needs. Also a lot of space is take away from cars for common pedestrian spaces and cycling.