Some entities utilize public work channels as mentioned since they are idle most the time. Whether it is PD using as side channels or ops, FD for on scene or fireground or training, pl or different nac varies where you go or same pl used/nac.
Some do rebroadcast traffic to public works departments in areas where public works is used by the PD/FD for clean up of accidents, traffic control deployment, snow plowing or weather conditions, traffic signals that go down and PD calls up technicians over the public works or volunteers whom work for the FD or PD duties but are full time public works persons, etc and so on. While it varies it is most likely one of the above.
Very common in rural areas or smaller cities/towns though larger ones have got out of that. We allow same and all entities have access to another and interops.
You may find in these areas the police or fire department users scanning or monitoring public works or other city departments as they find the traffic on it interesting, vice versa with public works/parks monitoring fire and law enforcement. While interesting they will listen seeing if public works or other services call into central for assistance with traffic, LE presence, or fire department services. Most the time someone on the LE end or fire end is listening to the PW talk and will reply. Not every day you will hear a police officer of fire officer say it is interesting to monitor public works or community services and to know what goes on.
Varies where you go, how systems are setup, and if LE/Fire have the time or ability to monitor other services in its city or county.
