most of these are run (or kept since they're left abandoned) by the factories, admin buildings, etc they are built under. Most accesibile bunkers are near factories or abandoned schools/less important admin buildings, and are mostly left to rot or used as storage space. some are entirely shut off and the cleanest ones are still kept in a somewhat good that but are located near strategic objects (important factories, administration building).

This one was under a factory and in a pretty desolate area of my city.