What sort of system do the firemen use to change the traffic lights to all red?

Question

I noticed today at an intersection that was next to a fire station that all the traffic lights were on red and the 3 firetrucks had their lights flashing and after they all left the station and were on their way, the traffic lights went back to their normal function. I was just wondering what sort of system they use and where is it and does it ever happen that they forget to let the lights go back to normal?

Answer 1

I know here in Illinois our depts (which include police, fire and ambulance vehicles) use an "Opticom" system which sends out a signal to a device that's attached to the traffic lights. When it activates, it turns the light to green so the emergency vehicle will have the clearance to go. What sucks about that though is that if a cop is on a traffic stop near one of those lights, it will keep their light green (the signalling device unfortunately has no way of knowing that a vehicle is just sitting there for a traffic stop. If the lights are going, that light is going to stay green). I had that happen once- I couldn't make a left turn at an intersection because a cop was on a traffic stop right before it and I had to sit there on a red light until he cleared the stop and turned his lights off.

Answer 2

They use an infrared transmitter, which sends a signal to a sensor somewhere on the traffic signal support. Some people have sold the transmitters for non-fire-department use, but such sales (and private possession of the devices) is generally unlawful.

Answer 3

It's the frequency of the strobe light on their truck. There is a sensor on traffic lights that picks it up and changes all the lights to red except in their direction. Don't try to duplicate it. You can't.

Answer 4

Emergency vehicles now have strobe lights with a certain frequency. The traffic signals have a receiver and there you go

Answer 5

They might have some sort of signalling device or there could be traffic cameras that can see when a fire truck is coming.

Answer 6

I'm not sure how accurate this it but I was told that there is something in all emergency vehicle's light (like a radar) that switches the lights for them to go through.

Answer 7

The manual controls are probably inside the firehouse.

Answer 8

I don't know, but I'll bet you it's made from parts off the space shuttle.