I’ve often heard that traffic lights have sensors in them that detect emergency vehicles coming by catching the light from their sirens, and this makes the light turn green for that street. The practical upshot of this is supposed to be that you can turn the light green by flashing your brights at it at night. Is this true? It seems to be, but maybe I’m just commiting the ‘post hoc, ergo propter hoc’ fallacy, that if a light turns green after I’ve flashed my brights at it, that my brights must have caused it to turn green.
JB
I know of a couple of intersections where all the lights turn red to allow trucks from a fire station at those intersections to get out and to get back into their garages. But I’m pretty sure they have a control in the firehouse for those.
In those same areas, none of the lights do anything like you ask. It’d be too messy if any ol’ Joe could trigger light changes.
(We used to have a superstition that if you were driving through a yellow light that you should tap your sun visor. The ‘theory’ was that it would generate static electricity that would jam the light yellow. I know, total BS. But to this day I still do it. :rolleyes: )
“(We used to have a superstition that if you were driving through a yellow light that you should tap your sun visor. The ‘theory’ was that it would generate static electricity that would jam the light yellow. I know, total BS. But to this day I still do it. )”
Huh, I tap the visor going through yellows because it’s supposed to earn me 5 seconds of sex, each time. During a dry spell, that can start to add up.
Thanks, LoadedDog. That answers my Q! 
There is a device triggered by approaching emergency vehicles which turns the signal red all the way around: see
They don’t control it from the firehouse.
Don’t you find it interesting that the same subject seems to pop up in two or three threads at the same time?