OK… It is a pretty common belief (at least amongst most of my friends…) that traffic lights contain sensors which detect sirens, so as to always allow emergency vehicles/cops through the lights with minimal problems. (And I know this is common, as I see people in the middle of the night attempting to trigger this mechanism by flickering their lights. Something I admit I’ve tried… however with not enough success to rule out coincidence.) But there is also a group of people who scoff at this idea saying it would be dangerous if this were true. In fact, as I think about it, I can see how it could be dangerous. My question, I guess, then… is this true? Are there really siren sensors? Is this uniform from city to city? Can you really trigger them by flashing your brights? How?
I don’t know how stupid it is… tell me? (This is stupid, but not, “what does spluge taste like?”) I’ve just always wanted to know… I looked through the archives and stuff… but never found it. Maybe I looked in the wrong place.
That’s what I meant, Screeme. Go to MPSIMS and look at the thread titled “How stupid is this”. They’re referring to a claim on a TV ad, but they get into a discussion on the topic you’re asking about. Sorry about the confusion.
The sensors don’t detect sirens, they detect strobe lights. Fire engines and other emergency vehicles have a strobe mounted on them to get the traffic signals to change to green in the direction their heading. It’s not dangerous because they don’t change instantaneously – the opposing lights go to yellow, then red in the normal sequence. They just go to yellow ahead of schedule.
Attempting to manipulate them by flashing your headlights is unlikely to succeed. It takes more than a single flash (otherwise lightning, for example, would set them off). They are triggered by a short pulse of lights of a particular frequency. You could never match it with your headlights.
I don’t know how widespread these sensors are. They have them in our small town (suburban Seattle) and they are quite obvious. They’re a little box that sits atop the traffic signal.
I’m a vegetarian once removed. I only eat meat from animals that are vegetarians.
I kinda posted this on the other thread, but I’ll put it here too, just to aggrivate everyone else.
The system is called the Opticom, made by 3M. There is a small box with a strobe light in it mounted on the oncoming emergency vehicle. The strobe flashes at a specific rate, and is seen by the sensor mounted on the traffic light. The light sees this, and changes the light to green for the direction the emergency vehicle is going.
In regards to the siren making the lights change, it can. There are systems that will change the light if a certain siren is heard by the sensor, usually a “yelp” type siren. I’ve seen them at gated communities to open the gates up, more so than traffic lights.
Jeremy…
Nobody ever calls me after they’ve done something smart.
Well, in my Petit Ville, they don’t have fancy-pants Strobe Sensors. And, if they did? It might not matter, NYS DOH Laws prohibit blowing a red light, while responding.
That sensor would have to flip the sequence VERY fast, OR sense the strobe from VERY far off, to really give me a green light as I approached. I’d be fascinated to see a link on the product, so I could see how far OFF it “sees” a strobe.
It doesn’t matter if it’s a General Illness, or a CPR call. I would never blow a light. I come to a FULL, albeit quick stop, and LOOK AT all of the drivers who have the light. There are accidents, and then there are senseless tragedies. An accident is hitting another car. A tragedy is the ambulance injuring or killing other people, by responding recklessly to the scene of YOUR accident. Enough preaching. :X
Considering the speeds we sometimes drive, I’d be interested in a device that is keyed by my radio, on my rig- and locks the light to green till I pass. Still, if the strobe sensor can see me coming from far enough off? I’d try to get em installed in my sleepy little burb. A link, a link, my fifedom for a link…
Cartooniverse
If you want to kiss the sky, you’d better learn how to kneel.
Oops… I feel kinda silly. Sorry, I didn’t mean to get defensive or anything, I just misunderstood. OK… two minutes to me for message board misconduct. (Those who are asking yourselves what I mean about the two minutes… ask a hockey fan…)
Thanks for the info… I am now enlightened and with proof.
