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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Pfuzylogic · M

They don’t need sensors.
It is Doppler principles used in radar.

MasterofNone · 26-30, M

@Pfuzylogic Ah good. Makes sense.

I actually had data on vehicles from bluetooth sensors and was wondering if there was a way to find out instantaneous speeds of various vehicles from it.

Pfuzylogic · M

@MasterofNone
Doppler has a shift in frequency dependent on speed.