How do traffic department personnel detect a car going over speed limit ? [I Obey the Speed Limit]

What sensors do they use ?

And if anybody knows what data the sensors gather and how they calculate instantaneous speed, that would be great too ?

Or do they use a pair of sensor located close to each other ? That would make it easier. IDK

This is NOT a homework question, BTW

And most importantly, can bluetooth sensors be used to do that?

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Elevatorpitches · F

electronic sensors on the traffic light apparatus, and many other places.

MasterofNone · 26-30, M

@Elevatorpitches Yes! But which electronic sensors ?

Elevatorpitches · F

@MasterofNone I don't know, I just know they are there and they do catch speeders and on the lights everyone is stopped so who knows how they work... I think they are all over the place on the roads...