Here in the UK, almost every set of traffic lights has a little camera on top to receive such transmissions from ambulances etc.
pukey
Isn’t that camera really there so your Orwellian government can follow your every move? 
-Rav
It’s called a “Go box” If you do a search under this term you’ll find I asked this a while back.
Well I’ll be durned. Never woulda thunk it. Thanks for all the links, gang.
One important thing to remember is that any forward-facing flashing white light is illegal for non-emergency use in most US jurisdictions. In most cases, only amber flashing lights can face forward. Mounting a strobe on the front of your car is quite likely to get you pulled over if a police officer observes you using it for any purpose. If you’re not heading to a fire, you’ll probably get a ticket.
In our city, the changers cause a white light (looks like a small floodlight) mounted on the same bar the rest of the traffic signals to blink. This makes it very obvious when the system is being used. Therefore, if no emergency vehicles are in sight and that light starts to blink as the light changes, something would be very suspicious. You might not be caught right away, but I’m sure you would eventually be caught.
I don’t mean to come back to this… well, actually I do, so tough.
But, but, I just now went back and looked at that link that that_darn_cat linked to and noticed the video towards the bottom of the page (It’s the first one of the two).
Pretty cool description on how the thing works. You’ll definitely need a high-speed connection to view it, but if you have one, you get a neat little tour of my fine city.
Well, o.k., it’s only St. Paul Minnesota, it never will be as cool as Minneapolis, Minnesota, but it gives you an idea.
And again, it gives those who’ve never seen this thing a good idea of what we have to deal with every day. Those damn inventions are constantly causing me to be late!
The small city I am a firefighter and paramedic for recently installed a system that causes the lights in town (all 4 of them) green when we approach. The system runs on the high frequency strobe light as discussed above. So yes they really do exist, and yes they do work.
But the system is not perfect, sometimes the light dosen’t change, so we still may run a red light here and there.
I was once curious about this, so i asked a cop on the street if it was real. He told me that yes, it was real, and yes, it was illegal to use them in non-emergencies (i.e., for civilians). He also told me that it worked by flashing strobe lights in a particular frequency. This was back in Austin a few years ago.
Oh, yeah. I meant to add that above.
Just so my example makes some sense way up there, I saw that timing gun thing about fifteen years ago.
I was a kid and the things were new. It’s possible that was the first time I ever saw those things in action, and in person.
Today, from what I saw in that video, they’ve come a long way in defeating the types that like to take advantage of those systems. Good for them- waiting around for the emergency vehicles can be bad enough.
*Just thought I’d add that tid-bit to be upfront and honest.
I deleted two links to companies that appear to be selling to civilians devices intended to defeat the law. This is not tolerated here. The other links appear to be geared toward legitimate users, i.e., emergency services. The OP’s questions have been be answered: Yes, these devices exist, and yes they are illegal for civilians to use. This thread is closed.
bibliophage
moderator, GQ