Meaning there's now a technological over-ride of the traffic light system available to law enforcement in many places. They already have license-plate scanners that run yours automatically when the police car gets behind you, bringing a plethora of information on you to their in-car display with nary a question about searches or privacy invasion brought up in a court room yet.
Considering these one can better understand how the police have morphed from our protectors to antagonists bringing in government revenue. It's just far easier for them to go along to get along for that sweet retirement package.
Oh...I was pebble sprayed by a big truck the other day. When able to pass I saw on it's side, painted proudly and professionally, "Stone Spitter". I love the Road Warrior movies but don't want to live them.
That has been available to Ambulance a firetruck fo many years in some places. They used to send a incoded flashing signal of some kind, no idea how it is done today.
The way most of this stuff comes about is they sell the great stuff it can do for you and it can but they downplay all the bad stuff it allows them to do. Portable phone/computers are a chief example.