It's a tiny part of the center of Stockholm. https://www.svt.se/nyheter/lokalt/stockholm/bensin-och-diese... has a map. Roughly 4x4 blocks.
I really wish we could get more pedestrian focus in the US. While this does still allow cars, it seems like it's a start. Meanwhile in NY some people are all up in arms about the congestion toll. In Boston a certain subset of people are losing their minds at one of our streets going pedestrian only on Saturdays during the summer. the US really has a crazy relationship with cars
They're obviously going to want cars. Walking & cycling are not options (see sedentary).