https://www.thenational.ae/uae/transport/drivers-should-use-dash-cams-to-resolve-car-crash-disputes-police-boss-says-1.615774
I have a dash cam, infact 2 in my car. One on the front and one at the back.
I remember reading an article in gulf news that stated it was OK as long as the footage is not posted on social media and can only be used to show the police in case of an accident.
Not sure about recording someone on the street breaking the law when no accident involved, that gets classed as invasion of privacy. ( edit: Link below states it is ok to record and share with the police only) Remember the guy who bought the number plate D4 for some millions, someone recorded him parking in a no parking space, he was fined but also filed a complaint against the person who recorded the video for invasion of privacy and that guy was fined too because he shared it on Facebook.
Just found this link.
https://m.khaleejtimes.com/dubai-police-clarify-owning-dash-cams-not-iilegal