A police officer can do some things when off duty, although when off duty the police have limited authority.
When a police officer is off duty the police has some limited authority and most particularly related to public safety.
Off duty police can still often make arrests, use force when necessary and even carry guns, although with some restrictions.
Off duty police cannot use their authority to initiate enforcement for minor crimes like reckless driving or minor property crimes.
Although a police officer can only do these things under their jurisdiction and county.
Even an on duty police officer that is not a state trooper cannot go into another county and do anything as a police officer.
The police even when on duty is limited to their county for jurisdiction and they are only police officers legally in their county.
Although state troopers have jurisdiction when on duty in all counties of the state they are working in.
But as soon as that state trooper leaves their state they are no longer legally a police officer or state trooper in the other state and cannot make arrests or do any traffic stops or act as police.
Police officers only have powers in the jurisdiction they are hired in and not other counties or states.
State troopers have authority in all counties in their state but not in other states.
Off duty police have a general duty to protect public safety and intervene in situations where a crime is being committed or lives and property are endangered.
Off duty officers can also be hired by private employers to maintain order, provide law enforcement functions or provide pedestrian control and traffic control.