Oregon only requires a badge be displayed when making a traffic stop.
That being said, contact with citizens off-duty can be considered officious and is discouraged by my department. It is also considered dangerous to make a traffic stop when not wearing a vest and a duty belt.
We reserve off-duty intervention when life and property are in great danger, and even then, we may only stand by as a witness unless a life is in danger.
In time we hate that which we often fear.
Visit nwham.com for accurate Ham Repeater information.