Hi Michał Paluchowski, 

All the streets that you have changed from "living_street" to "residential" are "living_street" because they are signed with the sign S-28 restricting to 20 the max speed and giving all the preference to the pedestrian. Due to this I'm going to revert the Changeset.

Regards, Pau.
https://es.wikipedia.org/wiki/Calle_residencial#/media/Archivo:Spain_traffic_signal_s28.svg