Those roadside radar 'your speed' signs are actually license plate readers

[midnight rambler]

https://qz.com/1400791/that-road-sign-telling-you-how-fast-youre-driving-may-be-part-of-a-us-government-surveillance-network/

[Cebu_4_2]

No front plates around here, not sure how that will work.

[monty]

No front plates around here, not sure how that will work.

Maybe they have rear looking cameras as well.

[ziero0]

I ran across one in Wisconsin that displayed OUTLAW if you were 1 mph over the limit.